“A yeast lab?” I ask as I look at Alyssa Levy, whose neon pink workout tank reflects the late afternoon sun that streams from the trees in the Knight Physics Courtyard.
We both laugh as she says “Yes, I’m in a yeast lab, that’s what it’s called—technically it’s a microbio lab, which is the nicer word for it. It actually started with the HHMI PRISM labs freshman year.”
“Yeah! I’ll go from the beginning, so everything makes sense. There were two parts to the HHMI lab. In the first part of the lab we dealt with yeast—Saccharomyces cerevisiae was the species—and we learned how to transform it, how to manipulate it, and how to observe its growth—basic stuff. In the second part of the lab, we had to somehow apply the use of microfluidic devices with yeast.”
“What exactly are microfluidic devices, and what is the point in using them?”
“Microfluidic devices are devices that contain channels where fluids can flow or be confined. Our experiment consisted of making paper channels where we can grow our yeast—think of a bunch of bowling alleys printed onto paper. These channels allow you to place multiple environments in one channel—which usually takes robots to do at the micro-level—or compete different strains within the same channel. It’s all about forcing the yeast to grow however you want. Since these are literally channels on paper, you can print whatever design you want. We are showing that you can use paper as opposed to plates to grow yeast. We aren’t necessarily trying to find out anything new about yeast itself; we are trying to prove that this method of using paper channels to grow yeast actually works.”
“Okay, so what is so revolutionary about this method?”
“It’s all about high throughput. High throughput means you can test a lot of strains at the same time in an efficient way. When I was doing traditional assays to compare their efficiency with the paper channels, I had to use 30 plates and a spectrophotometer to analyze the yeast. But with the paper channel method, I tape the paper channels into used pipet boxes, grow my yeast, and re-use the boxes for the next test. So in comparison to the traditional method, my method is cost efficient, its high throughput—I only need four boxes for the equivalent of 30 plates—and instead of using the very expensive spectrophotometer for analysis, I use my phone to take pictures of the samples and analyze the pictures on Photoshop. It’s a faster, more economic, and more environmentally friendly method of growing yeast that works just as well as the traditional method.”
“In saying all this, you’ve already found that this method works, right?
“Yeah so we’re finishing up the project as we speak; I’m actually writing up the paper right now. The whole point of the paper is to explain how we optimized these channels for the experiment and how other researchers could optimize their own designs for their specific experimental purposes.”
“Does this method only work on yeast?”
“No; part of our paper is to show that you can use different species. We used two different strains of immobile yeast and we also used motile E. coli. By using two different species that grow in two different ways, we showed that there are a lot of possibilities for microbe growth using the paper channel method.”
“So walk me through the process of how you actually make these paper channels.”
“First, we print the channels with the wax printer, which is just a regular printer. That’s another thing—since this is just a regular printer, you could buy it for any lab to use whenever you need it. We then melt these channels onto the paper using any hot plate or oven so that the ink bleeds through and covers the whole span of the paper and is uniform on both sides. After that, we use clear nail polish to paint in-between each channel on one side of the paper. Since the agar—our growth medium—is hydrophilic and the paper absorbs water, the hydrophobic nail polish and melted wax outlines create boundaries for our agar-based environments. We then sterilize this entire system by taping the paper channels into the pipet boxes and placing the boxes into the autoclave. Our setup allows for eight different channels in one box, which is another way this method is more efficient. In the traditional plate method, one plate only contains one trial.”
Being the visual person that I am, I had to ask: “You don’t happen to have a picture, do you?”
“I do; I think I actually have more pictures of yeast on my phone than people.”
“That’s a great pickup line”, I joke as Alyssa scrolls through her phone. When she finally lands on a picture, she tilts her head and admires it, saying: “This is a pretty picture, wow”. She immediately looks at me with her large hazel eyes and we both laugh on cue at the sheer hilarity of her statement. Secretly though, I am admiring her obvious dedication to the project and her tangible ingenuity—Alyssa Levy is going places.
“So, do you think other people can use this method?”
“Yeah, that’s what I love about this project; there’s so much applicability. What I think is most interesting about this is the creation of different environments in each channel. When you pour an agar plate, it’s hard to make half the plate one environment and half the plate another, but with these channels you could theoretically have multiple different environments and see them all. Even though this isn’t necessarily revolutionizing anything, it is more efficient to use than a typical agar plate assay.”
“Earlier you had mentioned to me that at first you wanted to go to law school but then you decided on medical school for the same exact reason—to be around and help people. How do you think—or rather, do you think working in this lab has helped you with your future goals?”
“Well I realized a lot about myself and a lot about research—it’s a mental marathon. I came in with this mentality that I would start this project and I would be in and out in six months and everything would be okay…”
We both burst into laughter, recognizing the naivete of her freshman self.
“A year later…”
“Yeah”, she says, still chuckling. “A year later, we’re finishing. I also learned that people need a humbling experience. This was one of the most humbling experiences of my life. You know, you come in as a freshman and you think you’re all that; you think you know everything. On my first day with this lab I remember sitting there, working for four hours, only for a grad student to come to me and basically say “What the hell are you doing, you did this all wrong”. I wanted to get out of the lab at that point and just start crying; it was so humiliating. But as I look back, I’m thankful that happened. I go into every class and every lab now with the mentality that there are more things I don’t know than I do know. I don’t know all the answers and I’m happy to admit that I don’t know it—I think it’s liberating to be able to say that. Pretty deep stuff from yeast.”