Dr. Hari Shroff: Sure! I entered the University of Washington at an early age through this special program that they still have today, actually—where they take fifteen or sixteen kids every year, and you do kind of intensive study in a “transition school.” If you complete that, then you’re accepted as a full-time student at the University of Washington. So that’s how I got in early. Now I think a huge part of my continuing in scientific research was that I was lucky enough to work as an undergraduate researcher in a lab in the Chemistry Department at the University of Washington. That was really transformational because I was able to see that real research isn’t done just by taking classes. It’s kind of messy, and one has to get into the lab, and the answers are not always straightforward. I realized that I really enjoyed the feeling of knowing that, if I wasn’t invested in this research into the unknown, then maybe this wouldn’t get done. We were trying to do things that weren’t written in the textbooks. That’s how I got the “research bug,” I guess you could say.
After that things kind of progressed: I went to graduate school at UC Berkeley in biophysics—because I couldn’t really make up my mind about what I wanted to do after my undergrad. I liked the interdisciplinary research that I was doing as an undergrad which was partially chemistry, partially physics, partially biology. I figured if I did a graduate degree in biophysics I could continue that. So that’s when I got into single molecule microscopy. I worked for a guy—Jan Liphardt— who had been studying single molecules of RNA. He had just finished his postdoc and had just started his lab. I was his first graduate student. He’d just gotten his position at Berkeley, and initially my goal was to do some real science. But I found that, despite my intentions, I ended up in tool development and in tool building. I worked on constructing a microscope that let us both pull on molecules of DNA and observe the single molecule fluorescence. So that was kind of my entry into microscopy. Actually I built a TIRF microscope before you could buy them.
Prashant: Oh really?
Dr. Hari Shroff: Yes, and this would have been the early 2000s; they were just starting to come on the market. In order to isolate the fluorescent emissions from a single molecule without background—TIRF was the sensible choice. So I built a magnetic microscope with tweezers in place of the brightfield pillar of your microscope. Then below the stage there was a high numerical aperture objective so we could do objective side TIRF. Actually it was the first time I realized the value of getting good optical filters, although that predated Semrock, I think.
Prashant: Semrock was founded in September 2000.
Dr. Hari Shroff: I was, at the time, trying to find the best filters I could from Omega Optical, which used filter technology that has now been replaced by your technology. That’s when I realized the value of very good filters for isolating single molecules against a huge background. So the TIRF was part of it, and the filters were the other part. I built this microscope, and then I designed and calibrated these probes. The idea was to build single-molecule force sensors. It’s funny because that idea was a little ahead of its time. I wanted to put these things inside cells, but I didn’t understand anything about cell biology. I only got as far as making these sensors and putting them in vitro DNA loops to measure stresses and strains. That original paper has been cited a bunch because now force-sensing is a hot topic, along with protein polymer sensors and with FRET dyes.
But I left that behind because, as I was finishing my PhD and starting to think about what to do next, Eric Betzig rolled through Berkeley. He was actually talking not about PALM and STORM, although he had hinted that he had this great super-resolution idea, he was instead talking about this idea he had for doing lattice microscopy. I was very taken with his talk.