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2019 Cohort

Kadina Johnston 

Advisor: Frances Arnold

Option: Bioengineering


Lab website:

Current ResearchDirected evolution was pioneered nearly three decades ago on the basis of iterative rounds of mutation and screening for a desired activity, and it has been an extremely successful tool that has solved protein engineering problems from expression to stability to enzymatic catalysis of non-natural reactions. However, there are still many limitations in screening throughput and library construction that can make some properties of interest very difficult to evolve for. Additionally, the greedy single step walk of traditional directed evolution can fall prey to becoming stuck in a local maximum. Therefore, Kadina is interested in designing machine learning methods for the next generation of protein engineering. She plans to develop methods for more efficient screening and effective evolution as well as improve the protein engineer’s ability to reach the global fitness optimum of their protein.

Why Kadina chose Caltech:  "I chose Caltech because of the excitement for science that surrounds the campus. Being surrounded by so many innovators is inspirational, and it makes me even more excited about my own science. Having a culture where science is encouraged within the entire student body and collaborations are encouraged (and much easier than at larger or public institutions) has also allowed me to learn from fellow students about many things other than those directly pertinent to my own research."

In Kadina's words: "I am excited about the simultaneous growth of big tech and the biotech industry. The number of resources companies like Google and Amazon are devoting to applying their computational tools to biological problems is a testament to the promise of such technologies. Computational tools being developed for completely different purposes can be fused with our biological knowledge to help design enzymes or cellular systems capable of chemical transformations that are vital for medicinal chemistry. This field is ready for a complete overhaul in scientific approach, and I am excited to be part of it."

Michael Porter

Advisor: Rustem Ismagilov

Option: Chemical Engineering


Lab website:

Current ResearchThe gut is home to over trillions of bacteria that interact amongst themselves and with the host, and the structure of these bacterial communities have been shown to affect the function of these microbes and the health of the host organism. Also, the gut abounds in polymers including those from host secretions, dietary fibers, and administered therapeutics. Though the interplay of bacteria and polymers has been well studied in theoretical and idealized in vitro contexts, it’s effect on bacterial aggregation and community structure has been understudied in the gut. My goal is to establish a mechanistic link between gut polymers and the bacterial behavior that arises from their aggregation and control this behavior through the dietary fibers that we consume.

Why Michael chose Caltech: "Caltech’s small size and rigorous scientific culture enable interdisciplinary work perfect for meeting new people and for discovering techniques and collaborations outside of my field. The expertise and resources available to me have empowered me to pursue ideas that I would otherwise be unable to develop. Caltech’s flexibility allows me to expand my project into unique avenues that would not be available otherwise, and these opportunities will help me grow as both an individual and a researcher."

In Michael's words: "My undergraduate research focused on medical applications and patient outlook. Coming to Caltech, I wanted to pursue more fundamental research I could use as my own foundation for performing impactful work. With BLP, I am looking forward to being on the forefront of innovation beyond the lab through the program’s networking and internship opportunities as I build my career as a scientist."

Sam Davidson

Advisor: Lulu Qian

Option: Bioengineering


Lab website:

Current Research: Sam joined the Qian Lab immediately after his rotation in Spring 2019. The Qian Lab’s DNA robots and circuitry could eventually power smart diagnostics and therapeutics, but must first overcome long reaction times and undesired strand interactions. These limitations could be resolved by tethering DNA circuits to the surface of a DNA origami structure. Much as spatial organization promotes efficient molecular interactions in cells, DNA strand displacement reactions would proceed rapidly on surfaces. Furthermore, only neighboring strands can interact. So far, the few experimental demonstrations of spatially-organized DNA circuits all lack traits that general-purpose tasks require—for example, signal amplification. 

Sam is developing a mechanism for signal amplification in spatially organized DNA circuits. If successful, Sam will advance DNA circuitry one step closer to general-purpose applications. Subsequent efforts would demonstrate the merits of the new system, and would entail constructing robust, rapid DNA circuits with record-setting properties

Why Sam chose Caltech: "The professors in Caltech’s Bioengineering department have a tradition of collaboration with each other, and within their own labs. They envision futuristic technologies that sound like science fiction, and have developed plans to make these concepts practical. In many cases, they have already succeeded. I was inspired by the professors’ fearlessness and imagination; other institutions seemed timid or short-sighted in comparison. Ultimately, that is why I chose Caltech over anywhere else."

In Sam's words: "To me, the most exciting part of engineering is finding a workaround for scientific principles of the universe that historically limited the advance of technology. Of all the applied scientists, bioengineers most regularly defy the established laws of nature. We transfer genes between organisms with relative ease. We have invented the gene drive, which spreads a trait through a population without any selective pressure. In the Qian lab, we are using DNA in ways found nowhere in the natural world. Already bioengineers are starting to tinker with human genomes in cases where the benefits greatly outweigh the risks. Organic chemists can’t form many molecules without costly, toxic catalysts, extreme conditions, and inefficient processes. If only we could directedly evolve an enzyme for that…  The best part is that the field is advancing exponentially, as its own technologies expedite and accommodate other research."