Ken Suslick (BS '74), Chemist, Biotechnologist, and Research Leader in Ultrasound Techniques

Ken Suslick's research lab touches on almost all sub-disciplines of chemistry, which has left his graduate students and postdocs with a challenge as they look to forge their professional identities: "What kind of chemist am I?" As he relates in the discussion below, Suslick provides an easy answer: "A damn good one!" The humor belies a deeper truth that gets at the heart of Suslick's incredibly varied and impactful career: so much good science requires one to follow his or her interests wherever they lead. The result encourages the harnessing of intuition and collaborations with colleagues with unique areas of expertise and perspective, and invites a level of passion that can be both curiosity driven, or geared to translating basic science to societal benefit.

For Suslick, hardly a week goes by when he doesn't reflect on the foundational role his Caltech undergraduate education played in creating his wide-ranging research interests. After attending a very large high school, the smallness of Caltech attracted Suslick, and he availed himself of numerous opportunities to explore the wide world of chemistry from his professors. Following his graduate work in bioinorganic chemistry at Stanford, Suslick went straight into his faculty position at the University of Illinois at Urbana-Champaign, foregoing a postdoctoral opportunity in favor of a stable faculty offer. In retrospect, Suslick explains why this was a regrettable decision: as he now understands, being a postdoc affords a near-magical experience of being an established scholar fully engaged in research without any of the administrative or educational demands placed on professors. But in light of Suslick's research achievements, this missed opportunity has hardly posed a problem.

Over the past forty five years, the Suslick group has made pioneering contributions to the physics and chemistry of ultrasound technology, to the study of sonoluminescence - the phenomenon whereby sound waves in a bubble reach an intensity threshold and cause the bubble to burst and emit light - and to chemical sensing, a field inspired by the olfactory capabilities of biological noses which can be mimicked to create sensors with similar capacities. Suslick's ultrasound work was the basis point for the creation of the modern field of sonochemistry, and his sensing work and associated fabrication of sensors and electronic noses has launched companies with a broad range of applications in industry and medicine.

In recognition of his pathbreaking career, Suslick was named a recipient of Caltech's prestigious Distinguished Alumni Award in 2023. Suslick is no stranger to professional honors and awards, but this recognition is particularly special, given Suslick's love of Caltech and its unique approach to creating scientific leaders.

DAVID ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It is Friday, June 30th, 2023. I am delighted to be here with Professor Kenneth S. Suslick. Ken, it's great to be with you. Thank you so much for joining me today.

KENNETH SUSLICK: Thank you for having me, David. It's really a bit intimidating, frankly, but I'm looking forward to our discussion.

ZIERLER: Ken, first, the thing that brings us together, you were recently named to Caltech's 2023 class of Distinguished Alumni Awardees. First, congratulations on that.

SUSLICK: Thank you.

ZIERLER: I wonder if you can tell me what it was like for you when you got the call, and if you took it as an opportunity to reflect on what your Caltech education has meant for you.

SUSLICK: [laughs] Actually, I was a bit surprised. I had known that I had been nominated, by my son, who actually is also a Caltech alumni.

ZIERLER: Oh, wow.

SUSLICK: I hadn't thought it would actually go anywhere, so I was very pleasantly surprised. As to thinking about Caltech and its impact on me, well, I don't think a week goes by where I don't think about that. Caltech was really my intellectual development from start to finish. Nothing after that delivered as much to the way I think and the way I approach problems—not graduate school, not my career. That was a very special time for me.

ZIERLER: What is it? What is Caltech's secret sauce in that regard? What you're expressing, I've heard so often from alumni. What was it about your education that makes you feel that way?

SUSLICK: All the other Techers. Being on campus with a whole bunch of really smart people, the concentration of intelligence—that was incredibly special. It didn't hurt having some of the best faculty in the world as one's teachers, but the intellectual stimulation, the discussions with other students, the bull sessions, the interactions with people—and most Techers didn't get that kind of development in high school, and so having that available, the social milieu at Caltech, was such a special experience.

ZIERLER: We'll get to the full narrative as we approach the chronology, but I'm curious—your time at Caltech, 1970 to 1974, perfectly overlaps the first class of women undergraduates at Caltech.

SUSLICK: Yes, it did. [laughs]

ZIERLER: Did that register with you at the time? Did you realize that Caltech—

SUSLICK: [laughs]

ZIERLER: —went coed right when you joined?

SUSLICK: Oh, yeah, I think that was primary on everyone's mind. We were, after all, 17- and 18-year-olds, coming in. Yeah, that was quite noticeable! As was the big banner on the Winnett Student Center that said, "Welcome Co-Techs."

ZIERLER: "Co-Techs."

SUSLICK: Yes. [exhale] It was not a politically correct era.

ZIERLER: No, no it was not. On the question of politics, obviously Caltech is a very different place than something like a Berkeley or a Columbia. Did you feel the Vietnam era? Did you feel the late 1960s and early 1970s in Pasadena, on Caltech's campus?

SUSLICK: Bottom line, no. Caltech was a surprisingly apolitical environment. Was it good? Was it bad? I don't have an opinion very much on that. But we were not particularly concerned with political issues. The closest concerns we got was when the lottery for the draft was instigated. For most of us, as soon as we got the number and knew we were safe, there were other things of more immediate attention.

ZIERLER: For your own political sensibilities as an incoming 18-year-old, was that apolitical environment what you were looking for? Was that the best place for you at that time?

SUSLICK: Interesting question. Yes, I think so. I'm certainly more politically inclined now than I was as an undergrad. I had friends who were very active in politics in high school. Remember the police-induced riots in Chicago at the Democratic Convention; some of my friends were there. But I have to say, that wasn't a primary interest for me.

ZIERLER: On a more official note, please tell me your title and institutional affiliation.

SUSLICK: I am the Marvin T. Schmidt Professor, Emeritus, at the University of Illinois at Urbana-Champaign. I am also CEO of a new startup called Iridescent Sensors. That is located in the Research Park of the University of Illinois.

ZIERLER: When did you go emeritus?

SUSLICK: A year ago.

ZIERLER: Do you still have a lab? Do you still have ongoing affiliations with the University?

SUSLICK: I still have my office, and I still have my lab. We'll be moving the lab to the Research Park, because increasingly we're doing things that are commercial. That is to say, we hope to be selling something. That's the red line that one does not cross in academic labs at the University. You can do research that's applied, applicable, even tending towards commercialization. But the minute you start doing something that is for sale, that has to be in the incubator lab or in private lab or office space.

ZIERLER: Is part of the equation that you have had students who now are interested in pursuing these private industry enterprises with you?

SUSLICK: Yes, in part. The CTO of Iridescent Sensors is a former PhD student of mine.

ZIERLER: Who is or was Marvin T. Schmidt, and was there any connection between Schmidt and your research?

SUSLICK: That's a good question. There's actually surprisingly little known about him. He bequeathed money to the Department of Chemistry. He was an undergrad at the University of Illinois. We know little more about him than that!

Traversing Research Boundaries in Chemistry

ZIERLER: Some overall questions about your research career. Within chemistry, your research interests and achievements are quite broad. There's inorganic, there's organic, there's bioorganic, there's physical chemistry, surface analytical. I could go on. What is the home subdiscipline within chemistry from which all of your wide-ranging interests come?

SUSLICK: When my students used to go out on the job market, they would ask me, because of this problem, "Ken, how am I supposed to market myself? When somebody asks me what kind of a chemist I am, what should I tell them?" I said, "If somebody asks you what kind of a chemist you are, you should say ‘a damn good one' and shut up." I would say I learned to think like a physical organic chemist when I was at Caltech, and that's still the way I think. In the department structure, we have six areas of interest that faculty can be in, and they can be in multiple of them. I was always in inorganic and materials and sometimes physical and sometimes organic-y. But my organic colleagues told me I was a physical chemist. My physical colleagues told me I was an inorganic chemist. My inorganic colleagues told me I was an analytical chemist. So, I'm neither fish nor fowl nor good red meat.

ZIERLER: What about on the theory versus experiment side? Where do you lean more?

SUSLICK: Experiment. Chemistry, to me, is still an experimental science. Theory has been useful, and becomes increasingly useful, but there are enough variables, enough complexity, so that empirical science still dominates.

ZIERLER: What are some of the key technologies or instruments in your lab that have been fundamental for your work over the decades?

SUSLICK: Oh, we make use of every analytical technique that was applicable. One of the great things about the University of Illinois is we have had traditionally really, really good facilities, in many areas better than Caltech's. And accessible, because we have had state-supported PhDs who are not faculty running the facilities. At many universities, and especially private universities, having people in charge of facilities was expensive, and especially at the beginning of my career, uncommon. That meant that groups had limited access, often, to instruments that were departmental but were in some other professor's lab. That was never a problem, here at Illinois. In terms of unusual technologies, my group pioneered the interest in the chemical effects of ultrasound, and aspects of mechanochemistry, which has become very topical recently. So, we made heavy use of high-intensity ultrasonic transducers and apparatus for looking at the chemical and physical effects of ultrasound.

ZIERLER: What about computation? Has your work gotten more computational over the years as computer power has increased so much?

SUSLICK: Not really. I have collaborated with people who are much more calculational than experimental, but that has never been my bailiwick.

ZIERLER: I assume maybe the same would be true for AI?

SUSLICK: Well, now there's an interesting distinction. It depends on what you mean by AI. AI used to be called machine learning, and before machine learning, it used to be called chemometrics in the chemical community. Our chemical sensor work has been right at the cutting edge of chemometrics and machine learning technologies. We make use of support vector machine analysis, which is the starting point for all of the facial recognition software. But we make use of it for a very different application. Pattern recognition is still core to that.

ZIERLER: Because of your expertise in materials, material chemistry, the question about what a quantum computer will be good for, quantum information, you often see cited chemical applications, chemistry and materials science and things like that. Are you following those developments? Do you have a good sense of how quantum information might be put to use in this area?

SUSLICK: In a general sense, but that's well outside of my expertise. I understand why they cite chemistry, because that's where computation still is weakest. Our computational expertise for understanding black holes is a whole lot better than our computational expertise in explaining chemical phenomena.

ZIERLER: The national labs that are nearby—Argonne, Fermilab—has that been an asset to you over the course of your career?

SUSLICK: On occasion. We've collaborated and published maybe a dozen papers that involved Argonne.

The Origins of Ultrasound Chemistry

ZIERLER: Let's go in a little deeper now in the areas of expertise that have been closest to you. You mentioned it already but it bears some explanation—the chemical effects of ultrasound; what exactly does that mean?

SUSLICK: That's a good question. That was one of my original assistant professor research proposals. In fact, that proposal is the reason why Harvard didn't make me an offer. E.J. Corey, Nobel laureate, told me after I had had my offer from Illinois, which is in fact where he started, that I wasn't going to get an offer from Harvard because some of the faculty were concerned that that proposal indicated that I wasn't serious about my science.

ZIERLER: [laughs]

SUSLICK: The chemical effects of ultrasound do not come from a direct interaction of sound with molecules. Ultrasound sound has wavelengths that are meters down to millimeters. Molecules are nanometer in size and below, and so the scales are just very different. But what does happen is a phenomena known as cavitation. Imagine that you have high frequency sound, at tones above human hearing, anything greater than about 15 kHz, passing through a liquid. Well, sound consists of expansion and compression waves. That's all sound is. If the sound is loud enough, if the acoustic field is intense enough, you can pull the liquid apart during one of those expansion waves, and generate a bubble, a cavity. A compression wave comes along, takes this bubble and compresses it a little bit. An expansion wave comes along and re-expands it, so you have an oscillating bubble. This oscillating bubble tends to grow because the surface area on expansion is a little bit bigger than on compression so gas flow in is a little bigger on each oscillation than gas flow out. Eventually the bubble can go into resonance with the sound field, in which case it grows rapidly. Now it's overgrown, and the next compression wave, combined with the surface tension of the liquid, will compress this bubble very rapidly. When you compress a gas, you get heating. When you compress it this fast there's no time for the heat to flow out, so you get a localized hotspot.

This is a big part of what we demonstrated, and we were the first to measure the temperature generated inside that hotspot. It ranges from 5,000 to 20,000 Kelvin. At the low end, that's the surface temperature of the Sun. At the high end, that's a blue giant star. What happens inside the bubble is high-energy processes, because you've just hit every molecule that's inside the bubble with an enormous hammer, but you hit it for a very short period of time, because after the compression, the bubble re-expands, and cools. So, it's a very unusual way of introducing energy into matter. In fact, fundamentally that's what all chemistry is—the interaction of energy and matter. At zero degrees Kelvin, there ain't no chemistry, and the ways in which we can put energy into matter are relatively limited. Mostly we do it with heat, temperature. A number of scientists are interested in photochemistry, the interaction of light, the energy that you get from making excited states of molecules. There's a longstanding area of research called radiolysis where you're looking at high-energy particles bashing into molecules, usually in liquids, but also solids. And, plasma chemistry, where you generate, again, high-energy charge species in the gas phase, and you run them onto surfaces to modify properties of the surface or into liquids to generate ionization in the liquid. And then there's this phenomena of ultrasound and cavitation.

ZIERLER: The question from Harvard about you potentially not being serious about your science, to what extent is this simply they didn't know what you were talking about? And how much of it was this was a pretty far-out concept for a junior scholar to be talking about at that time?

SUSLICK: It was a pretty far-out concept. My own thesis advisor at Stanford—well, one of my two thesis advisors—thought I was crazy. About 25 years later, he admitted that he might have been wrong. But very begrudgingly.

ZIERLER: Should credit be given to the University of Illinois with a certain degree of adventurousness in hiring you?

SUSLICK: No, I just think they weren't paying attention.

ZIERLER: [laughs] Where did the idea come from?

SUSLICK: It came from a paper in the bioinorganic area, which was my thesis work, by a man named Fridovich who had discovered an enzyme called superoxide dismutase that's very important for controlling free radical production in vivo. He had discovered that using an ultrasonic horn, which biologists were already using for cell disruption, for breaking open cells, was causing changes to the oxidation state of his superoxide dismutase. His opening line was something like, "As is well known, ultrasound can cause a plethora of chemical reactions." He cited a Russian book, 1965, El'piner, The Physical, Chemical, and Biological Effects of Ultrasound. In Russian. Well, the first thing I did was look up the word "plethora," and having then understood the sentence, I thought to myself, "Now, this isn't right." So I went and talked to about 10 faculty at Stanford and said, "Do you know anything about the chemical effects of ultrasound?" Every one of them except one said, "No, there can't be any." John Brauman, my other thesis advisor, said, "Well, there used to be this guy at Caltech—Zechminer, Zechmeister, something like that"—it was Zechmeister—"who did some work in the fifties on this."

Now it turns out that Stanford actually had the country's largest collection of translated Russian works, because of the Hoover Institute, which was a big anti-communist center. Among the collection was El'piner's book, translated. So, I checked out El'piner's book. As far as I could tell, I was the first to have ever checked the book out. I read through it and there were competing theories, none of them proven or really well demonstrated, as to how ultrasound did this. But in the fifties, the Russians were making pretty heavy use of ultrasound, especially for materials processing. The Soviets had better titanium than we did, and that was important for jet engine turbine blades. The reason they had better titanium is, they were able to drive hydrogen, trace hydrogen, out of molten titanium metal using ultrasound to coalesce hydrogen bubbles and remove them from the melt. Hydrogen embrittlement was a big problem for titanium in those days. So, that was a niche area that the Soviets had developed using ultrasound to affect chemical and physical processes. It just hadn't taken off anywhere else. My goal as an assistant professor was to make use of ultrasound to drive catalytic reactions, organometallic reactions, in much the same way that the photochemistry was being done at that time.

ZIERLER: Because this relies on nanomaterials, were there advances generally in nanotechnology that you were waiting for that needed to catch up with your ideas?

SUSLICK: No, really the other way around. We developed some of the earliest techniques for making nanoparticles of transition metals. Gold nanoparticles and silver had been around for a much longer time, in fact really back to the Middle Ages. Some of the brilliant red stained glass turns out to be gold nanoparticles suspended in glass. Nobody knew that at the time, of course, but that's what they were. Making transition metal nanomaterials was a lot more difficult because the nanoparticles were a lot more reactive. One of our early successes was in the generation of amorphous iron. Because we were starting with volatile organometallic precursors like iron carbonyl. When those got compressed and heated in the cavitation event, the carbon monoxide is blown off. You're left with iron atoms, even iron atoms in excited states that you can see in the light emission.

In fact, that was one of the ways we measured the temperature inside the bubble, was by the effective temperature of the iron atoms emitting light, which is the same way that astronomers measure the temperature of distant stars, a spectroscopic measurement of temperature. When the expansion of the collapsed bubble occurs, you get cooling rates that are 10 million degrees per second. To give you a sense of that, if you take a poker of red hot iron and you plunge it into ice water, you'll get a cooling rate of a few thousand degrees per second. So, if you quench the iron atoms fast enough, they don't have time to crystallize. They form amorphous solids. There are some interesting magnetic properties that had been a matter of controversy, and I think we contributed to the understanding of the formation of amorphous iron and its magnetic properties.

ZIERLER: For our non-specialist audience, I wonder if you can translate the phrase "mechanochemistry of inorganic solids" and where this research topic has taken you.

SUSLICK: Mechanochemistry is simply the conversion of mechanical energy into chemical energy or vice versa. If you take a pencil and you break it, you actually break chemical bonds, and if you look in an instrument that can detect free radicals, you'll find macro radicals that are relatively stable that are the remnants of what used to be a carbon-carbon bond. It got broke, when you mechanically cleaved the material. There has been research in this area, if you will, going back to the ancient Greeks. 340 BC is the first report of generating mercury by grinding cinnabar, which is a mercury sulfide mineral. You grind it, and that's mechanical, and you get metallic mercury out of that: that's a chemical transformation, hence "mechanochemical". Michael Faraday's second paper, when he was—well, not a graduate student, but at the equivalent stage of his career—was the grinding of silver chloride and generating metallic silver. That actually became relevant to the developing field of photography at the time. The interaction of the mechanical world and the chemical world is one that goes way back, but one that we still really have an incomplete understanding of. There has been a renaissance of interest in mechanochemistry. Sonochemistry, the chemical effects of ultrasound, is in fact one of those fields of mechanochemistry. Because after all, ultrasound is a mechanical process, and cavitation is an example of that as well. Does that give it at a non-technical level?

Chemical Sensing and Translational Science

ZIERLER: Absolutely. When did you get involved in chemical sensing? And your use of that phrase—does everybody in the field know what you mean, or is there a distinct brand that you have, what you mean by chemical sensing?

SUSLICK: I think chemical sensing is probably a general term recognizable at this point. We got into it from my long-term interest in metalloporphyrins and bioinorganic chemistry. Chemical sensing is sometimes called "artificial olfaction" because the nose is Mother Nature's most important method of chemical sensing. Chemical sensing is the ability to tell one odor from another, and the first electronic nose has been around for almost 50 years now. Over the past twenty years, we developed a new type of sensor array called an optoelectronic nose. We got involved in that [laughs] because a prospective graduate student, during a recruiting dinner, asked me the question that no research advisor ever wants to be asked by an incoming prospective student, and that is, "Ken, if I come to Illinois and I join your group, what am I actually going to work on?" This graduate student, Neil Rakow, did in fact come to Illinois and work for me. But when he asked me that question, I turned over the paper placemat at this restaurant, and I started sketching out ideas that I had been mulling over but never really formally written down, that turned out to be a good part of his thesis.

What we developed was basically a digital multidimensional extension of litmus papers. There are lots of dyes whose color depends on their chemical environment. Litmus paper changes color depending on whether the solution is acidic or basic. There are many examples of that. Take black tea; you squeeze lemon in it, and the color changes. Same kind of phenomena. There are other dyes that change color depending on other chemical properties that they're interacting with. I can list them. They're all the interactions that occur between one molecule and another molecule. Lewis acid-base interactions, Brønsted acid-base interactions, redox interactions, hydrogen bonding, and so on, and so forth. If you have an array of whole bunch of these different dyes that change color depending on their environment, then the change in the pattern of their colors on exposure to an odorant turns out to be a molecular fingerprint. So, you can tell one odor from another based on a color pattern. I sometimes refer to this as smell-seeing, because you get a really nice way of visualizing the data just from digital imaging of the array before and after exposure. You can just do a difference map—red minus red, green minus green, blue minus blue—and that difference map is the molecular fingerprint. Turns out this is really useful for identifying reactive gases, like the kind bacteria produce or like the kind that occur in fires in warehouses or even in homes. So you have a way of telling what's in the gas phase in a toxic environment.

We continued to develop the concept and explore and expand its uses for many years in in my group, and eventually successfully commercialized it for rapid detection of bacteria and rapid antibiotic susceptibility testing. The third startup in the succession of this was Specific Diagnostics, which was located out in Mountain View in Silicon Valley, that I cofounded, and that company was bought by bioMérieux, the largest French biotech company, just about a year ago. With some of the proceeds from that, for my 70th birthday, I started Iridescent Sensors to look at non-biomedical applications, commercial applications, specifically for toxic gas sensors for first responders.

ZIERLER: The story you shared about sketching out on the back of a paper placemat at the restaurant what this graduate student might do, how can we read into your overall approach as a graduate mentor? Are you generally hands-on? Are you generally very involved in helping students formulate their thesis projects?

SUSLICK: It depends. It depends on the student; it depends on the project. Mentoring of graduate students or postdocs is not a one-size-fits-all. Different projects need more or less of my attention. Graduate students and postdocs for that matter needed more or less of my attention, depending on the circumstances, depending on the moment. The way I usually put it to incoming grad students was, first off, you're not working for me. I've already got my PhD. You're working for you. And you need to own the project. When you come into your thesis defense, you will know more about your thesis than anybody else in the room, up to and including me. Think of me more as a maître d' at a rather exclusive restaurant. I will bring you into the restaurant. I'll sit you down. I'll give you a menu. I'll point out the items the chef is doing that are particularly nice, or that the ingredients are especially fresh. But you have to order. It's your meal. I'll take your order, and I'll eventually bring out the food, and then I will leave you in peace to enjoy your meal. But I will be attentive. If I notice that your water glass needs filling, I will be there. If you indicate you need something, I will be there. But I will not be coming by every five minutes and asking you, "how's the chow?"! So, my goal as a research advisor has always been to create, to develop, an independent research scientist, and you cannot do that if you treat them like a technician and you hound them with things that they need to find out for themselves.

ZIERLER: Given all of the graduate students and postdocs that you've mentored, all of the different personalities, what are some of the common characteristics that they've displayed in your lab that might explain or help you understand who is going on to achieve great things?

SUSLICK: Two characteristics—curiosity and endurance, which sometimes is hard to tell the difference between stubbornness.

ZIERLER: [laughs]

SUSLICK: One of my jobs was to try and figure out, when a project wasn't working, why it might not be working. That's very difficult, because you don't actually have evidence or data on why something doesn't work. Once you get something to work, you can always optimize it, at least to some point. But if a project is not working, you don't know why it's not working. Sometimes, it's because in spite of the fact that you think it's a brilliant idea, and the graduate student at least says that they think it's a brilliant idea, mother nature disagrees, and she has veto power. So, at some point, it's sort of Mark Twain's statement—"If at first you don't succeed, try, try again. Then quit; there's no point in making a damn fool of yourself."

ZIERLER: Tell me about your work in the legal world, when you get called on to be an expert witness. What kinds of expertise they're looking for, from you, what kinds of court cases they are.

SUSLICK: Mm! Well, that varies. Usually they're calling me because I have a very specific expertise, like ultrasound. That gives me clout as an expert witness. Those are the most common cases that I've been involved in. They are most commonly patent infringement cases, where somebody has a patent and somebody else is developing a technology that may or may not infringe on that patent. There have been some interesting cases that I have been involved in, ranging from cataract surgery, which is done with a little needle that's ultrasonically vibrated to emulsify the lens inside the eyeball, and suck out the fluid. It makes you a little queasy if you think too much about it. Other cases have involved light absorbance by nanoparticles and a variety of sometimes very fundamental science that have import to the question of whether that patent applies to this process.

Masks and a Love of Art

ZIERLER: As I can see behind you, you have masks on display in your office. I know you have an abiding interest in art in general. Do you look for points of convergence between art and science? Or is art really a refuge, a separate world for you?

SUSLICK: A separate world. It's different. I don't really look for convergence generally between my science and my art. I have done bronze sculpting. I have actually about 20 pieces. I collect masks. I have about 400 ethnographic masks from all over the world. Art was very much part of my upbringing. My mother was an artist. I collected my first mask when I was about eight years old, and I still have it.

ZIERLER: Why masks, of all things? What is so captivating about masks, for you?

SUSLICK: Ah! That's an interesting question. It's not that I'm opposed to Dutch master oil paintings, but they're a little too pricey. Ethnographic art is really still quite inexpensive. We're born with facial recognition hard-wired into our brains, in fact probably into the wiring of our retina, and nothing has more emotional impact than faces. It's because we're social creatures, and the way in which we model what's going on inside the skull of any other person is their face. So, I think masks represent a fundamental aspect of art and its emotional impact.

ZIERLER: As you've alluded, you've been interested in applied science, in getting involved in startups and things like that. Just at the most basic level, is all of your interest in that world, does it all stem from fundamental research? Are all of the ideas coming from your lab, and you see something that might be translatable? Or are some of these endeavors born applied, so to speak?

SUSLICK: No, they all come from the fundamental. I would back away from this question of applied versus fundamental, or translational versus basic. Partly, that kind of classification, I just have never found useful, just as "What kind of a chemist are you?" questions aren't useful. I don't care whether it's applied or fundamental, basic or translational. Is it interesting or is it boring? That's much more important to me, in the science. Look, there's an awful lot of basic academic research that is tedious, boring, should never have been funded except for the fact that there's a community of people that want to fund that, because that's what they do. There's also applied research which may have an application that might save two cents on a ton of material but is also boring and not interesting. There's fundamental research that's exciting and interesting. There's applied research that's exciting and interesting. I'll take exciting and interesting any day of the week.

ZIERLER: If the starting point for all of your research is it has to be interesting, what then makes the leap into something that might become a product or might warrant a startup?

SUSLICK: That's where you have to let the project determine that. I have always told my students that you must let the project take you where it wants to go. You must not force it into those areas that you're most comfortable with. There's a tendency among scientists in general, humans in general, to want to do the same thing that they've always done. It's easier that way! It requires less effort. That's where habits come from, and we are all creatures of habit. But if you let the project take you where it wants to go, and you learn the techniques that you need to further the project, then it may or may not lead to something applied, or applicable, or commercializable. But if it does, go with it! The interest in chemical sensing came out of very fundamental, basic research on metalloporphyrins and heme proteins, and synthetic analogs of heme proteins, and it evolved far away from that.

ZIERLER: The University of Illinois, the Department of Chemistry in general, are they supportive when professors have ideas that might translate into a bubble opportunity?

SUSLICK: They are now. They weren't when I started.

ZIERLER: Aha! So you are part of that historical transition.

SUSLICK: Yes, very much so. I tried to patent some fundamental aspects of sonochemistry as an assistant professor, and my Department Head took me aside and said, "We are a state university. We diffuse knowledge by publication, not by patenting."

ZIERLER: [laughs]

SUSLICK: So there was no interest back in the early eighties in patenting. But that evolved and changed. The first web browser, Mosaic, came out of the University of Illinois. The University patented it and had a founder's share in Netscape, which eventually became the dominant browser for a while and then got bought out. The University sold its founder's shares before Netscape went public for what they thought was a tidy sum and which turned out to be a trivial amount by comparison. We have a very effective Office of Technology Management at the University now, and they've been actively involved with my startups, and I think in a very positive way.

ZIERLER: The fact that there's a Research Park that's part of the University, does that speak to this transformation over the years?

SUSLICK: Absolutely. The University provided the land and a very modest amount of money for one building, but all of the rest of the Research Park, which is quite large now, was developed by local real estate developers who built the buildings, leased the land. We have one of the more vibrant technology research parks at any university anywhere in the country.

From Chicago to Caltech

ZIERLER: Let's go back now and establish some personal history. Let's start with your parents. Tell me about them and where they're from.

SUSLICK: My father, Alvin, known as Al—I'll tell a story about that in a minute—was from Chicago, originally. My mother spent most of her childhood in Saint Louis but ended up in Chicago. In 1942, my father at the age of 17 enlisted in the Army. He had to memorize the eye chart to get in because his vision was about as bad as mine. So, different times. He ended up in the Battle of the Bulge, and the truck he was in went over a landmine. There were three guys in the front row. The driver walked away unscathed, my dad had a compound fracture in his right leg, and the guy to the right of him on the front seat died. Al came back to recuperate, back to a hospital in Chicago, and there he met my mom, who was a nurse dealing with returning soldiers. The GI Bill allowed my dad to go to college and on to medical school, and so he became an MD. My mother was a RN at Presbyterian St. Luke's, one of the big hospitals at the time in Chicago, and became the head nurse of the whole hospital. Then, I came along. My mother was 26 at that time, so she was considered an old maid. It's funny how times have changed. I was the eldest of four, and my dad had a successful practice in downtown Chicago. He was a psychoanalyst. I grew up mostly in Glencoe, one of the North Shore suburbs of Chicago.

ZIERLER: This is an upper middle class environment?

SUSLICK: Upper middle class, for sure. Yeah. I wasn't aware of it at the time, but I came from a privileged background. But my grandfather ran a hot dog stand in Chicago. He actually went on to get his CPA, but I can remember eating at the counter of this little restaurant that he ran on the north side of Chicago when I was a very young kid. It's one of my earlier memories.

ZIERLER: Were religious affiliations important for your family growing up?

SUSLICK: No. My father was a disbeliever. Our heritage was Jewish, but not in any way religiously so.

ZIERLER: No Bar Mitzvah for you? No synagogue attendance?

SUSLICK: No. My father wouldn't join the synagogue, and they would not allow children of a non-member to attend the shul, and so, no, no Bar Mitzvah.

ZIERLER: No Yom Kippur? No matzo on Passover? None of that?

SUSLICK: Well, we'd go over to my father's parents' house for the High Holidays. With some dread, because my grandmother was the worst cook in all of Cook County.

ZIERLER: [laughs]

SUSLICK: When my father joined the Army, he was the only guy in his brigade that thought the food was pretty good! He once told me that his mother, my grandmother, was known as the woman who could burn water.

ZIERLER: [laughs]

SUSLICK: So, yeah, going over for meals at my grandparents' was not the high point of my childhood.

ZIERLER: Probably the connection between your grandmother's cooking and the High Holidays was not good for religiosity in general, I would imagine.

SUSLICK: Yeah. I suppose. One of the ways to seduce children into religiosity is to feed them really well at religious holidays.

ZIERLER: Were you scientifically inclined as a boy? Did you have chemistry sets, that kind of thing?

SUSLICK: Yeah, I did, for sure. And strategically placed books. I only found out about this when I was in college, that my parents paid attention to what I would come from school talking about, and there would be an appropriate book from the library sitting where I did my homework to read. We didn't watch much television when I was a kid. We had one black and white television set. My father refused to get a color television set. It wasn't a matter of cost; it was just, "There's nothing on worth watching in color." When I went to Caltech, I was in Lloyd House and was there over the Thanksgiving weekend. It used to be a tradition that on one of the broadcast channels, The Wizard of Oz would be shown on Thanksgiving weekend. I wandered down to the lounge and was sitting there with a bunch of guys watching it, from the opening, and then suddenly, the scene when she winds up in Oz where the movie changes to color, I said, "Oh my god, it's in color!" Everybody looked at me like I was from Mars! But when we watched it in my house, it was always in black and white because that's all the television showed!

ZIERLER: [laughs] You went to public schools throughout?

SUSLICK: I did, although I went to New Trier Township High School, and New Trier is one of the very best public schools in the country. It is always ranked very highly. And so, I had a real advantage in high school. When I came to Caltech, I did not find my freshman year difficult, and I attribute that largely to the quality of my high school.

ZIERLER: How did Caltech get on your radar? Were you aware of its reputation? Did you know of names like Richard Feynman, Linus Pauling?

SUSLICK: I knew Pauling. Feynman, no. Caltech was on my radar. In fact, what I was looking for—New Trier was a very large high school. There were 800 kids in my graduating class. There were almost 4,000 in the high school.

ZIERLER: That's four times as big as Caltech.

SUSLICK: That's right. I went looking intentionally for a much, much smaller environment, and Caltech suited the bill. I applied to Caltech, early admission; Harvey Mudd, which was a brand new school at that point; and MIT. Caltech admitted me early, and I accepted immediately. I was accepted at the other two, and my mother's bragging rights to all of her friends was, "He's going to Caltech. He turned down MIT." In the community of educated people that we were friends with, I don't think Caltech was generally on the radar.

ZIERLER: This would have been at the very tail end—this would have been much more prevalent in the 1940s and the 1950s and the 1960s—but the concept of a Jewish quota at elite institutions, were you aware of this? Were you aware that this was a thing? Did you have any sense that Caltech was ever involved in those kinds of things?

SUSLICK: I wasn't, but I was aware of that kind of quota system. My father was turned down for medical school at Northwestern because of that. He was accepted at the University of Illinois Medical School, and that's where he did his MD.

ZIERLER: What were your impressions when you first arrived in Pasadena? What was it like?

SUSLICK: It was smoggy, but I didn't know that. You couldn't see the mountains. Impressions—hmm. I don't remember being overwhelmed by it. Oddly enough, I had not visited the campus. My parents had made a trip out to California, not just to look at colleges, but they took a vacation together and they did look at Caltech, and they also looked at Stanford. I don't know if they went to Harvey Mudd or not. So I relied on my parents' reports. Air travel back then was really expensive, and it was not at all common, I think, for students to look at schools that were far away from them in advance of going to them. So I showed up, and, "Oh, okay. This is the place."

Life in Lloyd House

ZIERLER: You mentioned it was Lloyd House that you joined?

SUSLICK: Yeah.

ZIERLER: Tell me about Lloyd House. What were some of its unique characteristics?

SUSLICK: Ah! Well. When I came in, Lloyd House was bifurcated. There was a group of jocks—hard to believe, but true—and there were a group of pot smokers. There was significant polarization in the House. Most of the freshmen were just sort of—"What do we do with this?" Some picked sides. Most of my class, I think, were pretty much just left out. The upperclassmen weren't particularly interested in us. They were a lot more fascinated by the girls in our class than they were by the boys. Lloyd House had a reputation—I think they had the lowest GPA among all the houses at that time. At least that was the rumor. Now, in my graduating class, Lloyd House had the highest GPA. So, times changed, significantly during my time.

ZIERLER: Was it chemistry from the beginning for you? Was that your game plan?

SUSLICK: I came in—I was either going to be a math major or a chemistry major. My roommate, Mike Yoder, was a math whiz. After about a week, it was very clear to me that I was not going to be a math major.

ZIERLER: [laughs]

SUSLICK: So, yeah, I settled on chemistry pretty quickly, I think.

ZIERLER: What were some of the really important early classes that helped focus your interest in chemistry?

SUSLICK: There was a course called Chem 2. It was for students who had had AP high school chemistry and placed out of a placement exam. Chem 1 was being taught by Harry Gray, and was a great course, but I had already had the material. Chem 2 was being taught by a couple of his postdocs, Dan Harris and Mike Bertolucci. It was a very advanced, really physical methods, instrumentation methods course. Taught group theory at a level that was equivalent to what I taught graduate students at Illinois. Dan and Mike eventually put out a textbook on group theory and symmetry in chemistry. It was a fantastic course. So, that was my introduction to Chemistry at Caltech. Combined with the fact that I joined Fred Anson's research group my second quarter at Caltech and spent the summer working with him, and learned a lot of analytical chemistry, electrochemistry, and inorganic synthesis.

ZIERLER: Tell me about Fred Anson and what he was working on, at that point.

SUSLICK: Fred was a Techer through and through! He was an undergrad at Caltech, he did his PhD at Caltech, and he was on the faculty at Caltech for 50 years. He's still kickin'! And couldn't be a better beginning advisor. He worked on electrochemistry. He really was one of the founders of modern electrochemistry in the United States. I enjoyed my time with him, but then I got interested in organic chemistry, and so I changed and worked for Bob Bergman, a physical organic chemist who left in the early eighties for Berkeley and has been at Berkeley ever since. Bob taught me to think like a physical organic chemist. A nice combination of kinetics and thermodynamics and basic chemical principles. And really that remains the foundation of my intellectual development in chemistry.

ZIERLER: I asked about art and science. Given how your cited your interest in organic chemistry, I've talked to many physicists who became physicists after they took an organic chemistry class and they realized that they had very little in the way of visualization skills. I wonder if, for you, the visualization aspect of organic chemistry came easier, if that was something that you were just naturally good at.

SUSLICK: I was decent at it. I wouldn't say I was great at it. I'm not really an organic chemist, any more than I'm really any kind of card-carrying chemist. The biggest problem with organic chemistry, and what actually I think mostly frightens people away from chemistry, is that organic chemistry is at least half foreign language. The terminology is very much like learning a foreign language. That's not one of the aspects of organic chemistry that I actually appreciate that much. I was willing to learn it, and I still have, for [laughs] no good reason, sitting on a shelf, a card deck of about a thousand cards, flash cards, that I created for myself from organic chemistry. I still have them. I tried to give them to my son; he wasn't the least bit interested in having them: they weren't electronic.

ZIERLER: What were some of the formative lab experiences for you at Caltech?

SUSLICK: The most formative one was an accident that I don't think Fred Anson ever heard about. I was making nitrosyl perchlorate, which is made from nitric oxide gas—a very, very, very toxic gas—and concentrated perchloric acid—a very, very strong acid that also has a tendency to react with organics and form explosives. I was bubbling the nitric oxide—in a fume hood—through the ice-cooled perchloric acid, and it slipped, and I spilled a cupful of the concentrated perchloric acid on my leather shoes. I immediately rushed over—I had gloves on, so there wasn't any problem—I rushed over to the shower and rinsed off my shoes, and put sodium bicarb on the acid spill and cleaned everything up, and everything was just fine. Then a week later, the creases in my shoes dissolved away, and suddenly there were holes in the top of the shoe. The perchloric acid had taken—even though it had been rinsed off, it had soaked in enough so that it eventually ate the leather away. That was probably the most dangerous chemical reaction I ever did in my life.

ZIERLER: [laughs] What about the summers? Did you stay on campus? Did you have SURF scholarships? Did you go home?

SUSLICK: SURF scholarships didn't exist back then, but I did stay on campus after my freshman and my sophomore years, and I did research, the first summer in Fred's labs and the second summer in Bob Bergman's labs. The third summer, I got an AEC— the Atomic Energy Commission, precursor to the Department of Energy—Fellowship to work at Berkeley, and so I worked at Berkeley. I got there right after the last student riots. I went to Berkeley intentionally because I wanted to see, "Well, what's the rest of the world like?" Pasadena being very quiet during all of that. I got there, and Telegraph Avenue was completely boarded up. All of the windows had been broken out of all the shops. It was a really interesting summer, in just a very different environment.

ZIERLER: As an undergraduate, was the plan or the intent graduate school from the beginning? Did you ever think about industry?

SUSLICK: Briefly. But it became very clear that to get anywhere in the chemical industry, you still would need a PhD. I think sometime late in my freshman year, it just became obvious that I was going to go to graduate school.

ZIERLER: What was your game plan? Did you rely on the advice of professors? Did you look at particular professors to work with? How did you chose Stanford?

SUSLICK: I had applied to MIT, Stanford, UCLA, and Berkeley.

ZIERLER: Notably not Caltech. You didn't want to stay there?

SUSLICK: You couldn't.

ZIERLER: You couldn't.

SUSLICK: No. In the sciences at that time—and it's still pretty much true—you just didn't do your PhD at the same place you did your bachelor's degree. That was considered incest. It was considered much better for you to get a broader view of the world by going somewhere else. Now, that was maybe a little less true for master's degree and engineering, but in the sciences, for a PhD, you pretty much had to go elsewhere. And so, I had picked out faculty that looked interesting in their research to me at each of those places, and then I went and visited them. In fact, UCLA was initially my first choice, but I visited there and rapidly was disillusioned. I went to MIT, and [laughs] found that the graduate students were amazingly disgruntled. I went in the first day, talked to the faculty, and there was one faculty member in particular that shall remain nameless but we both know him, and that was the guy I wanted to work for. That was clear. Then the second day, I was on my own; I went into the labs and talked to students. I went into his labs and was talking with the graduate students. One of the senior graduate students came up, sort of listened, and then he pulled up a chair and he sat down and said, "Now, let me get this straight. You've got offers from Berkeley and Stanford and UCLA, and you're thinking of coming here?!"

ZIERLER: [laughs]

SUSLICK: Yeah, the graduate students at MIT at that time were not happy. And so, I ended up going to Stanford. That had the advantage of staying on the West Coast. I had no intention of coming back to the Midwest—that was how that decision got made.

Bioinorganic Chemistry at Stanford

ZIERLER: In the way that Caltech helped form your boundlessness in chemistry—no easy way to define yourself—of course a graduate degree mandates that to some respect; you have to get specific for a dissertation. How did you navigate that at Stanford?

SUSLICK: That's a good question. Formally I was a physical chemist. My degree was in physical chemistry. I worked for two people on a joint project—John Brauman and Jim Collman. Jim Collman was an organic chemist turned organometallic. He did his PhD at Illinois, actually. John Brauman as an organic chemist turned physical. I was a physical chemist working on a bioinorganic project. So, the answer to your question is, I didn't resolve it. I was in a very interdisciplinary field working for very interdisciplinary guys.

ZIERLER: Bioinorganic—if you could explain, how is that not an oxymoron?

SUSLICK: Well, it turns out that a third of all of our enzymes use metal ions in them, the most obvious of which is hemoglobin and myoglobin, the red color of blood and meat. In fact, I was working on small molecules that were synthetic analogs of the active sites of myoglobin and hemoglobin, looking at what you needed from the protein to make them work but without all of the extra shrubbery that comes from the 20,000 amu molecular weight protein.

ZIERLER: What were some of the big research questions that drove your work at Stanford?

SUSLICK: [laughs] First, can you make a stable oxygen complex involving iron? Second, does it bind oxygen the same as in the protein or is the protein doing something special? Third, carbon monoxide binds to the same site. Does carbon monoxide bind the same way that oxygen does? Those were some of the fundamental questions. How does cooperativity happen in hemoglobin? Hemoglobin is the oxygen transport molecule. It takes oxygen from the lungs to the tissues. It does so in a very clever fashion. It binds—it's fully saturated, binds all the oxygen it can in the lungs, but it's really good at unloading it, like a dump truck, in the tissues. That's what we call cooperativity in the way it binds oxygen. It gets a little oxygen that makes it want more oxygen. It loses oxygen and then it wants to lose more oxygen. That's a really unusual phenomena and it was not well understood at the time. We found that we could even do that in solid state porphyrin complexes, that the crystal structure would force cooperativity onto the binding because of the size change of the complex during oxygen binding.

ZIERLER: How much reading in biology did this research require? How well prepared from Caltech were you in that regard?

SUSLICK: Fairly well. I had taken a biochem course. There was more specialized reading for understanding the heme proteins, but it wasn't difficult.

ZIERLER: The arrangement—you were co-advised through the PhD?

SUSLICK: Yeah.

ZIERLER: What were the main results or conclusions of your thesis research?

SUSLICK: That oxygen binding was pretty much the same in our synthetic analog as it was in myoglobin. That carbon monoxide was bound much more strongly, and that's because oxygen is bound in a bent fashion and carbon monoxide is bound linearly. In the protein, there's an amino acid residue that gets in the way of the carbon monoxide but doesn't get in the way of the bound oxygen. That's important because we produce carbon monoxide inside our own bodies, and amusingly, we produce it from the metabolism of old heme. And so, carbon monoxide poisoning of heme proteins is a real problem that Mother Nature had to overcome, because we produce a poison from the old hemoglobin that would poison the same binding site where the heme is. That was, I think, an important discovery. Then discovering cooperativity in the solid state of metalloporphyrins, that was pretty exciting at the time.

ZIERLER: In light of your later interest in health science applications, did this research plant a seed, at Stanford?

SUSLICK: Not really specifically. Any interest that I had in life sciences or biomedical applications really came later, I think, and were because the project went that way.

Learning the Value of a Postdoc Appointment

ZIERLER: In 1978, you joined the faculty at Illinois directly. There's no postdoc in between.

SUSLICK: No.

ZIERLER: How common or not was that, at that point?

SUSLICK: It was getting to be very uncommon. Shortly thereafter, I don't think anybody went on to academia directly without a postdoc. It was the stupidest thing I did in my entire career.

ZIERLER: Not doing the postdoc?

SUSLICK: Not doing a postdoc. I had a NATO postdoc fellowship lined up with Jean-Marie Lehn, in Strasbourg.

ZIERLER: What is a NATO postdoc?

SUSLICK: Oh—money—NATO sponsored American-European exchange programs for postdocs.

ZIERLER: This is the North Atlantic Treaty Organization, NATO?

SUSLICK: Yeah. If you ask the question, "Why do governments spend money on science?" it's because they need technically trained personnel, for many applications, military not being the least of them. And so, NATO sponsored postdoctoral education among the NATO allies. It was one of the few postdoctoral sources of money, actually, if you wanted to go to Europe. My original plan was to spend a year or two in France and work for this guy who a few years later was going to get the Nobel Prize. Now, some of that was because the academic market was terrible in the mid 1970s, late 1970s. Nobody was hiring assistant professors.

ZIERLER: You had a job and grabbed it, essentially?

SUSLICK: As it turned out, in September of my fourth year in graduate school, Collman came down and said, "There are a bunch of places looking this year for assistant professors. This hasn't happened for quite a few years. You might as well apply to a few places, and maybe they'll let you take your postdoc, or maybe they'll just make you a job offer. Maybe they won't do anything, but you might as well take the chance." So, I applied to Illinois and Harvard and Berkeley and UCLA, and I got interviews at all four places. Harvard, I've already told you about. Berkeley wasn't really looking for an assistant professor; they had just hired somebody from Stanford the year before, but all they had to do was pay for my gas for me to drive over and give a seminar. UCLA hired at the senior level. Illinois made me an offer by Christmas, and that, pretty much, was that.

ZIERLER: The road not taken—what would you have done in France, and why would that have been so good for you?

SUSLICK: Yeah, the road not taken—you never get to run these experiments the second time, you know.

ZIERLER: But calling it the stupidest thing you've ever done, I'm sure you've wondered.

SUSLICK: When I showed up at Illinois, I was so green you couldn't tell me from the lawn on the Quad. Yeah, I really needed a year or two of seasoning, in my opinion. I survived, but only barely. What would have happened? I would have learned a whole different area of chemistry that would have influenced my research a lot. Maybe not for the best. Certainly I would have given up on the sonochemistry. I would have learned how to speak French, which I had tried to do in high school without any notable success. I would have made a lot more political connections that would have proved useful in my career.

ZIERLER: Philosophically, what is a postdoc good for, then?

SUSLICK: A postdoc is good for multiple things. It's good for learning a new area of chemistry. It's good for having time to think about your own research and what you really want to do. It's good for just letting your frontal lobe develop a little further. It's good for political connections, and that's probably frankly the most important aspect of it. It's good for recovering from the rush of getting your thesis completed. I finished my thesis, we went off on a vacation for 10 days, came back, packed up the apartment, cleaned up the apartment, drove cross country in three days, arrived on a Saturday evening, couldn't get into the apartment because—hadn't thought about how do you get into an apartment on a Saturday evening—Sunday, began to unpack, and on Monday, I was lecturing 50 graduate students in Physical Methods in Inorganic Chemistry. That's not an experience I'd want to go through again.

ZIERLER: [laughs] Trial by fire.

SUSLICK: Yeah. Oh, very much.

ZIERLER: Tell me about setting up your lab as a junior faculty member. What was most important to you at that point?

SUSLICK: Getting space. Illinois had hired two assistant professors in roughly inorganic chemistry. The space that they had shown me, he was there already as a teaching postdoc. They gave him that space. So, I showed up and there wasn't any space for me. They were remodeling a lab, and eventually that became available, but it took about six months.

ZIERLER: What were you doing in those six months?

SUSLICK: Teaching, recruiting graduate students, writing research proposals.

ZIERLER: Once you had the space—I'm thinking instruments—what was important to you?

SUSLICK: We started doing synthetic chemistry, so traditional glassware. My startup package consisted of a gas chromatograph. Nowadays, startup packages for assistant professors are well above a million dollars. Back then, it was maybe $15,000, $20,000 dollars. And, yeah, there has been inflation, but not that much inflation. We bought an ultrasonic horn. That was pretty much a standard chemistry startup.

ZIERLER: Did you want the lab to be eclectic from the beginning? Was that baked into your research vision?

SUSLICK: I had four assistant professor research proposals. The sonochemistry was one of them. There was some metalloporphyrin chemistry that was another one. There was a third project that was much more biological involving leghemoglobin; that comes from legumes, not legs. There was a fourth project on isotope separation. So, yeah, it was pretty damned eclectic. We ended up really only working on the first three of those, and the leghemoglobin didn't go anywhere, so we ended up abandoning that relatively soon. There were two different branches of my research group.

ZIERLER: In recruiting graduate students, was the understanding that they would funnel into one of those areas, or was there an expectation that they should be utility players in the lab?

SUSLICK: It was an option, but mostly they were going to work on one project, at least initially. I did have graduate students that ended up doing a little bit of both areas, and sometimes a third one, but most of the graduate students stayed in one area.

Forging Sonochemistry Into a Research Community

ZIERLER: As you were building up the research in sonochemistry, was there a research community? Are there journals? Are there conferences? Are you all out on your own at this point?

SUSLICK: All out on my own at that point. There were no conferences. There were conferences of engineers involved with ultrasound, and some of those had pieces dealing with medical ultrasound, or cavitation, but no, there were no—it was clear blue sky.

ZIERLER: How did you manage that? That's not generally how scientists work. There's an infrastructure there to lean on.

SUSLICK: Yeah, there is, and there's a penalty for not being part of a community. I organized symposia at American Chemical Society meetings. I edited a book from one of those symposia on high-energy processes in organometallic chemistry. I was pulling together a community.

ZIERLER: When do you feel like—I don't know, maybe it's still under process now—when did the sonochemistry community really start to coalesce?

SUSLICK: Late eighties. There was enough interest in Europe as well, and there was a meeting organized by one of those researchers at a Royal Society of Chemistry meeting in Bath. The Europeans are much bigger on small groups of researchers in specialized areas, so in the late eighties, there was a European Sonochemical Society created. I would go to those meetings pretty much every year.

ZIERLER: What was the culture of tenure at Illinois Chemistry? Was the assumption that they were there to support junior faculty—

SUSLICK: [laughs]

ZIERLER: —and help you achieve tenure? Or was it more like the Harvard model of eating up the young?

SUSLICK: Somewhere in between. Illinois was not Harvard and did not devour its young [laughs], but on the other hand, Illinois didn't put a lot of resources into their assistant professors, and therefore didn't have that much to lose if they didn't make it. My entering year—we're talking about 1978—there were four assistant professors who were hired. Eventually, two of those got tenure, and two didn't. That was about right, at that time, at Illinois; about half of the assistant professors would get tenure.

ZIERLER: Do you think you were unique in the regard that—I would say most; correct me if I'm wrong—but most junior professors, they're hyper-specific, they want to make a big name for themselves in one field. It sounds like just structurally the way your lab was set up, that wouldn't have been possible. Or, did you have ambitions to make a big name for yourself in four or five fields?

SUSLICK: Well, at least two. I had ambitions! Game plan—you talk as if all of this was rationally planned out—

ZIERLER: [laughs]

SUSLICK: —and an awful lot of it just happened. So, yeah, my plan was to make enough of an impact in the metalloporphyrin community that I would be known. That was building on my thesis work, and I knew that was going to work. Then there was this very high-risk area that could have a lot of visibility but wasn't at all clear that it was going to go anywhere, and that was the sonochemistry. So, yeah, I intentionally worked on two different areas rather than focusing narrowly on one. It turned out they both worked out okay.

ZIERLER: When it was time to come up for tenure, is there a tenure talk? Is there an opportunity to review what you've accomplished so far?

SUSLICK: Yep.

ZIERLER: What did you emphasize in those opportunities?

SUSLICK: It was about half and half. I talked about both of them. The dividing slide—when I got to the end of the porphyrin chemistry, I had a—this is back in 35-millimeter slides, okay?—I had a giant foot descend, and a Monty Python—"And now for something completely different"—showed up on I think two or three slides in quick succession as if it were animated.

ZIERLER: [laughs] When you got tenure, did that free you up at all? Did you feel less constrained about the kinds of things that you could work on?

SUSLICK: No, I never had felt any constraints. I felt a lot of relief, that I was going to be able to continue doing what I was doing and wouldn't have to look for a new job. But I never felt constrained on what I wanted to do.

ZIERLER: What about your interest in popularizing the science in writing, in encyclopedias or magazines for a more generalized audience? Was that something that post-tenure you had more bandwidth to do?

SUSLICK: No, I think the projects just developed for that. I would have done that as an assistant professor if it had been ready. I published an article in Scientific American pretty early on in my career on the sonochemistry. The sonochemistry became—was new enough and became interesting enough that encyclopedias, which were still a thing back then, sought me out, asked me to write articles, because it was a new topic and they didn't have any article. That's where that kind of popularization came from—yeah, I felt it was worth popularizing things to an extent, not only to the chemical community—because remember, nobody was familiar with sonochemistry, so popularizing it to the chemistry community was just as valid as writing it for the general scientifically interested public. Both communities had about the same understanding of it, so it wasn't [laughs] difficult. I didn't have to dumb it down for Scientific American any more than I did for other chemists.

ZIERLER: Essentially the creation of this new subfield, sonochemistry, as you said it coalesced—it took about 10 years, the late 1980s. Who joined? Was it a mix of both senior people who wanted to jump in, and graduate students who saw this as a new, exciting area? Where did the community come from?

SUSLICK: First, it was never that large a community. We're talking about—the European Sonochemical Society meetings had 20, 30 people at that time. There were research scientists who began to get interested, partly out of my publications, partly out of some publications from France, some from England. There were three or four main players. Then other smaller research groups thought of things to try and would try them, and would publish. It was never a huge community back then.

ZIERLER: We talked about it—now we'll talk about it in the narrative context—the basis for metalloporphyrins leading to chemical sensing, what were some of the experimental works or advances that allowed you to make that transition?

SUSLICK: That one we took pretty much from scratch. There was really not very much work going on in the metalloporphyrin community in terms of chemical sensing. All of the work that had been going on in electronic noses had involved either metal oxide sensors—those are the kind of sensors, for example, that are used in carbon monoxide sensing devices in the home now—and, there was work being done by Nate Lewis at Caltech, using conductive polymers. There was a lot of interest in electronic noses, but the electronic nose technology then really wasn't delivering the goods. The reason was quite fundamental, and that was that the interaction of analytes, of odorants, with either metal oxide sensors or with conducting polymers, was essentially all physical adsorption and not very chemically specific, and so it was really hard to tell the difference between one odorant and something close to it. You could tell the difference between very different chemicals. Fine. But if you wanted to tell the difference between one single malted scotch and another one, or the difference between mouth odor before and after brushing, the technology didn't work very well. Part of the reason for that was because the sensors had to be robust. They were built into the electronics. If the sensors are robust, they can't interact very strongly with any of the odorants, because if they do, the odorants will poison them. It won't be reversible. Our approach from the beginning was, forget about reversibility; let's make the sensors separate from the electronics, and disposable. That's where we had a real breakthrough, because once you do that, you can have strong interactions of a whole bunch of different kinds, and you can now begin to tell the difference between one scotch and another, or the difference between one bacterium and another. The price you pay for that is you have to throw the sensor away after each use. Okay; that's a reasonable tradeoff.

Taking an Idea from Lab to Market

ZIERLER: This narrative arc, as you were explaining, where at the beginning of your career there was not a lot of support or enthusiasm for having startup ideas, to where obviously Illinois is now, what would be an early example of something where, as you've already explained, it's interesting—that's your starting point—but where you did see that marketability potential, but you were discouraged initially? What would be an example of that kind of exchange?

SUSLICK: Oh, the sonochemistry, I'd say.

ZIERLER: What was the product? What could you have done if there was an infrastructure to do it?

SUSLICK: A very specific example is, one of the very first so-called nanomedicines, Abraxane, is the go-to delivery system of Taxol for resistant breast cancer. It's also being used pretty heavily now for pancreatic cancer. Abraxane came out of research based on discoveries in my lab that were patented by VivoRx Pharmaceuticals which became Abraxis Pharmaceuticals. I was heavily involved in those startups as founding consultant, and eventually Abraxane became FDA approved and has been in widespread use for almost two decades now.

ZIERLER: At a very general level, can you explain the basis of sonochemistry being so valuable for cancer therapy?

SUSLICK: Ah! What we discovered was that if you took an albumin solution and we—this is a really stupid experiment, okay? This is something that no biochemist in their right mind would do. You take a solution of a protein, and the cheapest protein around is serum albumin—It's 60% of all blood plasma proteins—and you layer it with an organic solvent. Now, first off, biochemists don't do that. You don't put any protein solution near an organic solvent, because the protein will denature. We took an ultrasonic horn and we put it at the interface, and we turned it on, and it turns into a milkshake. Any self-respecting biochemist would see that and say, "I told you so," and pour it down the drain. Actually, they'd put it in waste disposal these days, because it had an organic solvent. What we discovered was that you formed micron-sized capsules where the core was the organic liquid and the outside shell was the protein, and it was chemically cross-linked, which gave it some permanence. This then turned out to be a way to deliver hydrophobic drugs, like Taxol, that is not water soluble, in a very easily injected suspension. Using human serum albumin meant that it wasn't the least bit immunogenic. That was the basis for Abraxane, which was Taxol suspended in an organic medium and coated with serum albumin. We used ultrasound to make these, at least initially, and that was the connection between sonochemistry and a drug delivery system.

ZIERLER: A question about knowledge transfer—do you see the relevance yourself? Do you have a sense and you need to bring in clinicians? Is there a hospital that Illinois works with where you can talk to people? How do you make those connections?

SUSLICK: These connections were made in the other direction. There was an MD at UCLA, Patrick Soon-Shiong, who now owns the L.A. Times and the Lakers, or at least part of the Lakers, I think. He contacted me and brought me in as a consultant to VivaRx Pharmaceuticals, because he wanted our microencapsulation technique. Now, we had published on it, but we had not patented anything because the University wasn't interested in patenting. So, I have 12 patents with Patrick that his company paid for. This came up out of some previous research that we had been involved in using air-filled protein microspheres. That was research that was accidentally discovered at the University of Chicago by Steven Feinstein. Steve had me up, said, "Explain what's going on here," and I said, "I don't know, but I'll go look at it." That led to our understanding of what these microspheres were, in that case air-filled, and those became used as the first echocardiogram contrast imaging agent. That was Feinstein's discovery but our refinement and consulting with MBI, the company that commercialized these protein microspheres. So, it's push and pull.

ZIERLER: Were you involved in the regulatory mechanisms, working with the FDA to get these things approved?

SUSLICK: No. You need someone who has got specialized knowledge about filling out the forms for the regulatory aspects.

ZIERLER: What did it feel like when these things were approved and they were actually making an impact? They were saving lives.

SUSLICK: That was good. That wasn't what actually motivated me, truth be known. I was driven by my curiosity. The fact that they ended up being useful biomedical products that saved lives? Yeah, I like that. I'm proud of that. But I would have done it anyway, even if it wasn't going to lead to that, because it was interesting!

ZIERLER: Sure, and it's part of a proud history of curiosity-driven science leading in directions that no one saw coming.

SUSLICK: Exactly.

ZIERLER: Was that your entrée into the world of consulting, this experience? All the consulting that you've done, was that the first?

SUSLICK: No. That's an interesting question, what was my first consulting gig? Give me a second. I can look that up. Actually, most of my early consulting were one-night stands at industrial research centers. They read about the sonochemistry, they want to hear if there's something that could be useful to them, so they bring me in for a day. That happened a lot in the eighties and early nineties. My first chemical consulting specifically on sonochemistry would have been Exxon—no, Eli Lilly in 1986. M&T Chemicals in 1986. Yeah, that's an old list. Was it consulting? Sure. Did they pay me? Sure. But it was just a seminar. They were exploring this new area. Maybe it was useful to them; maybe it wasn't. "We'll have in this young guy from Illinois and listen to him talk." That's a common interaction between academia and industry.

One Beckman and Two Institutes

ZIERLER: Your affiliation with the Beckman Institute for Advanced Science and Technology—first, it's good for Caltech people to know that there are two Beckman institutes out there.

SUSLICK: Not only that, but your Beckman Institute would practically fit in the lobby of our Beckman Institute.

ZIERLER: [laughs] Was that a substantive appointment for you? Did that allow you to do things that might not have otherwise been possible?

SUSLICK: It brought together an interdisciplinary team at the Beckman dealing with chemical recognition. In some ways, that might have been the start of our interest in sensors. It was a mixture of scientists and engineers in all kinds of different fields, brought into this one very large building. It was, at the time, the largest building on campus. I think that was Arnold's request at both institutions, actually.

ZIERLER: [laughs]

SUSLICK: It was useful in terms of developing interactions.

ZIERLER: This was a place for interdisciplinarity.

SUSLICK: Yes. The original mission was the understanding of intelligence both artificial and biological. The two legs of that were biological and computational. Because both of those communities didn't really interact very well or speak the same language, the first director was Ted Brown, Professor of Chemistry, and in many ways Ted was my mentor as an assistant professor. That's how I got involved in it.

ZIERLER: You located your increasing interest in sensors within the interactions you had at the Beckman Institute. Who would you have talked to there, or what kinds of ideas might you have been exposed to there, that helped in this new interest?

SUSLICK: I don't have a specific interaction there that led to it, but it changed a lot of my way of thinking about programs, because it was a pretty heavy influence of engineering, and meeting engineers that otherwise I wouldn't have come across. Scientists used to poo-poo engineering as doing things by rules of thumb. That hasn't been the case for a long time now, primarily because of advances in computation, but engineers and scientists have actually grown much closer together over my career, and now it's very hard to tell the difference between a chemical engineer, a chemist, and a materials scientist or engineer.

ZIERLER: Were there technological or engineering advances around this time, late eighties and early nineties, that made the sensor research more feasible?

SUSLICK: Yeah! Digital imaging. Digital cameras. We used some of the very first digital cameras in our initial efforts. The first paper, which was published in Nature, got published not so much I think because of the research itself but because we used an ordinary flatbed scanner as a scientific instrument. That was of great novelty back then. Flatbed scanners, I don't know when they first came out, but they became readily available and inexpensive in the late eighties. Yeah, I would say digital imaging was the big advance.

ZIERLER: Were you thinking about—again, it's an interesting problem—are there sensors to develop that specifically have a market? Or are these tools to use in the laboratory first and you see where it goes?

SUSLICK: No, they specifically have a market. Specific Diagnostics, which I co-founded, developed an array of colorimetric arrays for rapid diagnosis of sepsis from blood poisoning, from microwell culturing of blood samples and from that, antibiotic susceptibility testing. If you have an array of 96 well plates and you pre-dope them with a growth media that has different antibiotics at different doses, and you use a layer of sensor arrays on top of those wells, then the change in the arrays' colors depend on the gases that the bacteria give off. Then you can very rapidly, in a matter of a few hours, tell what antibiotic and at what dose is going to kill that bacterium. That's really important, because sepsis is a huge killer. Often, that's not what shows up on the death certificate, but it's sepsis that causes massive organ failure that kills the patient—and that was often true during the COVID pandemic.

Another specific market, and this is the one we're working on now—first responders to chemical spills or fires in chemical or industrial warehouses, they have no way of knowing what the gases are that are coming off. There's no way of personally detecting most of the toxic gases that are being released. We've seen this in railcar spills recently. Let me give you an anecdote that I learned from a retired Chicago fire chief. I posed this question to him: "What do you do when you hear about a fire in a chemical warehouse, and you don't know what toxic materials are in there?" He says, "Well, Ken, when we get a call like that, we rush to our lockers as quick as we can, and we get into our gear, as quick as we can, and we rush to our trucks, as quick as we can, and we drive to the site of the fire, as quick as we can, and when we see dead cops on the sidewalk, we back up, as quick as we can."

ZIERLER: [laughs] Wow.

SUSLICK: Now, that's the level of technology that they have; They're using policemen as canaries in the coalmine.

ZIERLER: As you were explaining just a minute ago the blurring of chemistry and chemical engineering and materials science—in 1993, you take on an additional title, Professor of Materials Science and Engineering. Was that simply indicative of where your research was at that point, or do you feel like officially you had joined those clubs?

SUSLICK: No, I've never—[laughs] I wouldn't join a club that would have me as a member! No, it was an indication of my research at that point. I ended up getting a few graduate students out of the materials science and engineering pool, and served on some committees. It was a courtesy appointment. It didn't change where my labs were or where my teaching was.

ZIERLER: In the 1990s, with the technology boom, all the things that were happening in Silicon Valley, was that relevant for you? Did that pull you in new directions?

SUSLICK: That's where digital imaging came out of it, in part, so, yes. The startup of Specific Diagnostics, and it's precursor, iSense—which predated the iPhone, by the way (our "i" was for Illinois)—was with Paul Rhodes, a PhD entrepreneur in Palo Alto. He was actually interested in neural networks and mimicking neurological processing and wanted a multidimensional data feed so that he could use software to do things like what the olfactory bulb was doing in the olfactory system. He approached me for our sensor arrays, and that's where we started a business.

ZIERLER: This was ChemSensing?

SUSLICK: This succeeded ChemSensing. There's a long, sad story about ChemSensing involving an incompetent CEO and then an outright embezzling CEO. That was the precursor, that failed, to iSense.

ZIERLER: Is this your first full-fledged startup from the ground up—ChemSensing?

SUSLICK: Yes, I'd say so. As being a consultant and brought in early, no. But where I'm a principal from the beginning, yes.

ZIERLER: You lived to tell the tale, and lots of lessons learned, I imagine.

SUSLICK: Yeah. There is a strong correlation between CEOs of startup companies and sociopathy. I think we're fully aware of that as a society, but [exhale]—yeah.

ZIERLER: Because you're not new to patents and intellectual property and being a consultant, why does it take until the turn of the century, 2001, for you to be inspired to really build your own company from the ground up, and not, for example, sell this idea to an extant company?

SUSLICK: I think that in part reflects my evolution and the evolution of my research. Also, my son was born in 1992, and so, there's an eight-year period of time where, as the primary caregiver, I was kind of booked up. Partly it also reflects just the development of research that had a clear market. When we started the sensor work, it wasn't to build a company. That came after we found that it was actually going to be useful and proved useful.

ZIERLER: Looking back, what were some of the fatal flaws of ChemSensing? The choice of the CEO from the beginning?

SUSLICK: Yep.

ZIERLER: Is that to say a good CEO and the company may have succeeded?

SUSLICK: Oh, I'm sure of it, yeah. And it could have succeeded 10 or 20 years earlier.

ZIERLER: It's financial mismanagement, mostly? It's a lack of vision?

SUSLICK: Lack of vision in the first CEO. In the second CEO, it was financial mismanagement, for sure.

ZIERLER: At this point—again, to go back to the narrative of when Illinois becomes supportive of these kinds of endeavors—circa 2001, had that transition been completed?

SUSLICK: Yeah, pretty much, although they were still learning, and we were still learning. There could have been a lot better vesting of the CEOs. Some of that is at my door. But it's also—one of the disadvantages of being in downstate Illinois is in the past, we haven't had a lot of entrepreneurial expertise in the community, so when you go looking for a CEO, it's not like there's a lot of choice out there.

ZIERLER: The obvious question with iSense Systems, starting in 2008, how much of it was simply ChemSensing 2.0 done right, lessons learned, and what were the advances in your research that might have made it a different company?

SUSLICK: I think a lot of it was 2.0. But the focus on biomedical applications was a wise decision, although often a frustrating one. It was a wise decision in the sense that that's where the money is. "So, why do you rob banks? Because that's where the money is." The downside, though, is it takes a long time, even for medical devices, much less anything that is not a device, to gain regulatory approval. That's a much, much harder game, I think, than the market we're pursuing with Iridescent.

ZIERLER: Did you consider being CEO of iSense, given your experiences? Would that have even been feasible?

SUSLICK: No, because I was a professor. It would not have been feasible, unless I was willing to give up my professorship and tenure and that was not enticing.

ZIERLER: You mentioned the lack of a talent pool in downstate Illinois at that point. Is that part of your decision to have iSense Systems located in Northern California?

SUSLICK: No, that was because that was where Paul Rhodes lived. iSense started in the UI Research Park, and the chief science officer was one of my postdocs. It started here. After about a year and a half, it got moved out to Mountain View.

ZIERLER: Thinking of all not being lost from ChemSensing, was it good in terms of building contacts in the business community? Did you have something to build on, in that regard?

SUSLICK: No, not really. There's very little good to be said about how ChemSensing went.

ZIERLER: Total write-off, basically?

SUSLICK: Not a total write-off in terms of knowledge, but yeah, if we were to re-run that, it would be very different.

ZIERLER: Are there competitors in this space? Are you operating all out on your own, or are there other sensor companies that have your kind of expertise?

SUSLICK: We own it. We still have the patents on it, and so the colorimetric sensor arrays is pretty much still ours. There is a lot of research, but no other competing companies so far.

ZIERLER: The additional wrinkle—2008, that's a hell of a time to start a company. The financial crisis hits. How did you navigate that?

SUSLICK: Mostly that was Paul Rhodes's problem. So, yeah, SBIRs, DARPA funding. He had pretty deep pockets because he had made a fortune in Florida real estate after having gotten his PhD in neuroscience. He's an interesting character.

ZIERLER: When did iSense feel successful to you, having the opposite experience? When did it feel like it was a stable company?

SUSLICK: Oh, when it was sold to bioMérieux. It had been touch and go every couple of years from the get-go, and so, even prior to the sale, it was—if you had asked me two years ago, "Do you think iSense is going to go anywhere?"—or Specific Diagnostics—I would have said, "I don't know." But, when the ink was dry on the sale, yeah, now it's successful.

ZIERLER: When did that happen? When was the sale?

SUSLICK: June 2022.

ZIERLER: Oh! That's the one, the recent one.

SUSLICK: Yeah.

ZIERLER: That's really a long incubation period.

SUSLICK: It was, yes.

ZIERLER: What were some of the lessons you learned from ChemSensing that kept iSense afloat for all these years?

SUSLICK: Well, I was not actually running iSense or Specific Diagnostics. I founded and provided scientific and technical expertise, but I wasn't running the company. So I haven't really got something to add to that.

ZIERLER: The graduate students that were starting to work with you around this time, would they have been more likely to have interests in industry rather than academia? Did that shift at all, given your work in this space?

SUSLICK: No. During that time period, some of my very best students actually went into academia, rather than industry. Illinois has always generated graduate students more oriented towards industry than academia. Not outrageous, not twenty to one, but maybe maybe three or four to one. So, at Illinois, we've never had a really strong bias towards academic positions. Our graduate students are not told, "If you don't go into academia, you're a failure." Which is definitely the feeling that you get at some graduate programs. We've been a pretty diverse provider of personnel both to industry and to academia, and to national labs, and even to regulatory agencies.

ZIERLER: As you emphasized, you remained a professor. It was not attractive for you to leave that. Given your experience in industry, did that change your research? Let's say if we can bookend the first 10 or 15 years of your career at Illinois with the last 10 or 15 years, what are some of the connecting points? What are some of the things that really changed?

SUSLICK: Hmm. You know the paradox of the Argos?

ZIERLER: I don't know that one.

SUSLICK: I'll tell the simpler version. The Smithsonian purportedly has the original axe that George Washington may or may not have chopped down a cherry tree with. But it was part of a working plantation, and they were able to document that the head had been changed three times, and the shaft four times. Nonetheless, the axe that they collected, in 1810, is George Washington's axe. Asking me to compare the first 10 years and the last 10 years—

ZIERLER: [laughs]

SUSLICK: —is a lot like George Washington's axe. It's still me.

ZIERLER: Like sonochemistry; it was there at the beginning, and it's there today.

SUSLICK: Yeah, yeah, and it's still an active field. I just got back from a meeting on cavitation in Crete. It's still an active field of research. It has had high points and low points over 40 years.

ZIERLER: I want to switch now to some thematic questions, now that we're getting closer to the present. The scientific societies that are most important to you. Acoustical Society of America. For sonochemistry in particular, has that been a society that has really helped the field grow? Again, I know it's small in relative terms.

SUSLICK: Yes. There are three societies that are probably most important to me over the years—the American Chemical Society, the Acoustical Society of America, and the Royal Society of Chemistry. And then, to a lesser extent, the Materials Research Society, which was important once in my career and isn't any longer.

ZIERLER: Where have you been most active from a service perspective in these societies?

SUSLICK: Probably the Acoustic Society. But I'm not that big a service provider.

ZIERLER: [laughs]

SUSLICK: I sometimes feel a little guilty about that. Just as I've never been department head. Not because I wasn't offered the position, but because I didn't want the position.

ZIERLER: In all the fellowships that you've had internationally, do you feel like you've ever made up for that lost time in France? Have you ever filled that hole, the best you could?

SUSLICK: No. No. No, never got it back. We could talk more about that offline, but—

ZIERLER: Culturally and scientifically, what have been some of the most meaningful fellowships you've had internationally?

SUSLICK: Oh, without a doubt the Eastman Professorship at Oxford.

ZIERLER: Why so? It's Oxford?

SUSLICK: It's Oxford. I've never been treated so well in my life than the year at Oxford, and I never enjoyed academia as much as at Oxford. Caltech has had a few Eastman Professors over the years, Harry Gray among them. I know he feels pretty much the same way.

ZIERLER: [laughs] If you'll indulge me, we already talked about the Distinguished Alumnus Award. You've been richly honored in various societies throughout your career. Are there any besides just them feeling good that have been professionally useful to you, that have established connections, allowed you to meet people, that actually was beneficial for the science?

SUSLICK: Hmm, there's an interesting question. My knee-jerk response is, no, they're just awards. Do they open doors to meetings or interactions with other people, because they gave me credibility? Yeah, probably, but how would I know?

ZIERLER: I'm thinking, for example, like the Centenary Prize from the Royal Society of Chemistry; would that be an example of symbolizing that sonochemistry is for real? I'm thinking along those lines.

SUSLICK: [laughs] Yeah. Maybe. Awards give you credibility. But you don't want to take them too seriously. You know the story of the Russian general? Okay, good. A Soviet general is invited to give the commencement talk to a bunch of graduating cadets at the military academy. He comes dressed in the regalia that only a Soviet general could have, medals up and down his whole chest. He gives his lecture, and then afterwards, there's a party with a fair bit of drinking, good Russian tradition. One of the cadets, who is already slightly inebriated, comes up and says, "Comrade General, please, could I ask you a personal question?" The general looks at him, and the general has had a couple too, so he's beaming. He says, "My son, it's your graduation day. Yes, of course you may ask me any question you want." The cadet looks at his chest full of medals and says, "Comrade General, please, tell me, whatever is it that you did to earn all those medals?" The general smiles at him, and he points to the oldest, smallest, littlest medal, and he says, "This medal, this medal I won for bravery in the face of the enemy!" The cadet is wide-eyed—"Yes, yes!" The general then says, "And all these other medals, all these other medals, I won for having won that medal."

ZIERLER: [laughs] Yeah, there you go. If you look at the chronology, there's a cascading effect for your awards, that they really take off in the past 10 or 15 years. There's an allegory there, there's a similarity there, that at a more senior stage of your career, to get all of these awards.

SUSLICK: It's the anointment process. And that's what I lost by not postdoc'ing. There's definitely an anointment that occurs in the scientific community, and it's very hard to rewin that anointment if you've lost it, and very hard to gain if you didn't have it from an early age.

ZIERLER: Moving our conversation closer to the present, when COVID hit, did you see an opportunity to contribute to COVID research? Or was there an opportunity just to look for COVID relevant research so you could keep your lab open?

SUSLICK: Not for me. I was already pretty much shut down immediately prior to COVID.

ZIERLER: Because you were already in the process of winding down your lab?

SUSLICK: Yeah. I had begun winding things down partly so that I could go to Oxford. I spent a year in Oxford, I came back, and COVID happened three months, four months later. So, I did not run a research group pretty much during COVID.

ZIERLER: Oh, wow. So you cycled out your last graduate students before.

SUSLICK: Yeah.

ZIERLER: Oh, wow. That's pretty good timing.

SUSLICK: Not so much intentional as part of becoming the Eastman Professor made it convenient to do that.

Current Focus on Business and Societal Applications

ZIERLER: To bring the story right up to today, tell me about the status of the company. What are you involved in? What's on your plate?

SUSLICK: It's a small startup. Depending if you count the consultants, we've got six employees. We're moving into research space in the Research Park. We are building the next generation of our optoelectronic nose. The target market is specifically first responders, but there are other markets available as well. It actually is a pretty good tool for art conservationists to check the effects of VOCs in sealed artwork cases and frames, for example. We had a collaboration a few years ago with the Getty Museum and the Disney Animation Research Library. The first original Disney works that went to Beijing had our sensors on them to monitor their exposure to air pollution. It's not a great financial market, but it was really a pretty cool experience. But, think about it: every fire truck and every highway patrol car in the United States should have a general purpose chemical sensor so that they can know what's being emitted from spills, from fires.

ZIERLER: Circa 2023, it's still that same allegory about the dead policeman on the sidewalk? That's still what we're working off of?

SUSLICK: Yeah.

ZIERLER: Wow. Ken, in your status as emeritus, are you now involved in a way that simply wouldn't be possible before? Are you CEO?

SUSLICK: Yeah, I'm CEO of the company. Also it's angel funder, so I'm not looking at the moment for any venture funding. I'll be my own venture funder. That gives me control so that I don't have to deal with sociopathic CEOs.

ZIERLER: [laughs]

SUSLICK: The direction we're going with this is I think really quite straightforward. It's a question of scaling up. Learning how to print a million sensor arrays a year, it is an interesting challenge. We printed many thousands of them in my labs over the years, but not a million a year.

ZIERLER: Some self-assessment at this stage in your career—how are your business chops? What has been the steepest of learning curves for you?

SUSLICK: One of the things I have discovered is you can buy other people's expertise. If you're not soliciting other people's money, a big part of what a CEO is supposed to do isn't needed. Handling personnel—well, that was my job as a professor, so that part doesn't change much. Marketing—you'd be surprised how much marketing a professor has to do, so that doesn't come as something new. Writing grant proposals, that's not something that I enjoy doing anymore, but it's certainly something I have competence in.

Reflecting on the Meaning of Scientific Impact

ZIERLER: Now that we've worked right up to the present, what you're doing on a daily basis now, for the last part of our talk, if I may I'd like to ask a few retrospective questions about your career, and then we'll end looking to the future. How do you measure impact? I know you want to erase these distinctions between applied and fundamental, translational, basic science, all of these things. When you look at the body of work all together, how do you measure impact, and is that even something that is important for you to measure?

SUSLICK: [laughs] You know the movie Caddyshack?

ZIERLER: Oh yeah!

SUSLICK: Chevy Chase doesn't keep score in his golf game. The president of the golf association—"So how do you rank yourself compared to other golfers?" Chevy Chase says, "By height."

ZIERLER: [laughs]

SUSLICK: Impact. [exhale] Impact to whom? Impact implies someone receiving the impact. In terms of the scientific community, I actually am a pretty firm believer in bibliometrics. Are your papers being cited, compared to other people in your community? Because there are different microcultures in the scientific community and it's hard to compare a mechanical engineer to an inorganic chemist. But there is so much subjective evaluation that goes on in the scientific community, and all of that is frankly just bullshit. It has no basis in reality other than who's the cool kid in high school, and it's just as silly and meaningless as it was back then.

Impact on the general society? Well, okay, lives saved is not a bad one, if you can link your research to that. But for many, many—in fact, most scientists—no matter how excellent they are, their research isn't likely to have had any significant impact on saving lives. That wasn't why they were doing it. It may happen inadvertently. That's pretty much the way I see it in my career. Look, think about impact as a multidimensional space. You have different dimensions for different communities that you have impact on. A chemist can have impact on mechanical engineering or the physics community sometimes, even though the primary dimension is chemistry. Society—well, what part of society? Healthcare, scientific policy, all kinds of different aspects of society. When you have a multidimensional space and you ask for a ranking, you've collapsed that space into one dimension, and that inherently involves so much loss of information that it's not a meaningful exercise.

ZIERLER: Having spent your entire professional career at one institution, from junior faculty to emeritus, do you see yourself as a rare bird in that regard? Or even in the way that it wasn't even an option to stay at Caltech for graduate school? Is it considered advisable, in certain circumstances, to switch professorships?

SUSLICK: It certainly often is advisable, if for no other reason than simply financially, both in personal salary and in lab equipment. Many faculty will go out on the market and move, or not move if they're retained, simply because they don't have any other way of getting a big chunk of money to revamp their labs—replace old equipment, or buying new equipment for a field they want to move into. So there are strong financial incentives to move positions. Illinois has had a lot of stability. We traditionally have kept faculty for their whole career much more than many universities. Champaign-Urbana is a really pleasant community to live in. It's a micro-urban environment, has almost all the advantages of a big city with none of the disadvantages. Friday at 5:00 p.m. we have what we refer to as "rush minute" when the undergrads go back to Chicago to have their parents do their laundry. But I live 12 minutes from campus, and when I tell people where I live, I get, "Oh, you're really out in the boonies." I live on a lake, in a house with 5,000 square feet, and I couldn't touch that as an academician in California or New York, Boston. So, life is compromise.

ZIERLER: You've been happy at Illinois?

SUSLICK: No, let's not go that far.

ZIERLER: [laughs]

SUSLICK: I occasionally think about writing an autobiography that reads, "Now I can die less unhappy."

ZIERLER: [laughs]

SUSLICK: Life is compromise, and you don't get to run it again, and there are pluses and minuses to every situation.

ZIERLER: Thinking about impact, one area you didn't touch on was all of the great things that your students—your graduate students, your postdocs—have gone on to do. Just as a composite, without necessarily naming names, what's the kind of thing that your students have gone on to do that makes you most proud?

SUSLICK: I have had students be successful both in academia and in industry. Some have been leaders in nanomaterials. Some have been leaders in very high temporal resolution studies, electronic phenomena. Some of have been in biomedical applications and have founded their own companies, and been successful. The students that have gone on to lead research groups in industry, I'm equally proud of. It's true that the most important product that most faculty ever develop is their students. We had a group reunion a few years ago where we had a significant fraction of all of my students came back to campus for, and I've got to tell you, that was by far the best reward and the best conference I ever went to. And it wasn't about me; they came back in large part to see each other. And, yeah, also me, but it was such a pleasure to see them reunite with other friends.

ZIERLER: Looking to the future, are all of your energies now devoted to this new initiative? Is that how you want to spend however long you want to be active for? Or are there still scientific endeavors that you are a part of or want to be a part of?

SUSLICK: I'd say this is probably the primary scientific endeavor that I'll be involved in. I'd like to get back to sculpture, and I have some ideas about that. Bronze is a hard medium to work in because it requires an awful lot of infrastructure, but there are some interesting polymeric alternatives.

ZIERLER: Is sculpture the kind of thing that will have to wait until you can sell the company?

SUSLICK: No, no, not at all. It's a question of time and dividing interests. I think that's something that is for personal gratification. I'm not interested in selling artwork, but I do enjoy making it.

ZIERLER: On that note, this has been such a fun conversation for me. I hope you enjoyed it, too. A gem for Caltech. I want to thank you so much for doing this.

SUSLICK: I appreciate that, David.

[END]