Bridging microbiology and therapeutics, this postdoctoral researcher builds responsive microbial medicines.
Rajkamal Srivastava is a postdoctoral researcher in Cammie Lesser’s group at Tufts Medical Center. In this Postdoc Portrait, he shares his work on engineering commensal microbes for therapeutic drug delivery to combat infectious diseases in the gut and cancer.
Q | What’s your research background?
Throughout my academic journey, I became particularly drawn to synthetic biology because it bridges basic science with real-world applications. The ability to design and program microbes for specific purposes felt like both a challenge and an opportunity to make a tangible impact. This perspective has shaped my current research in the Lesser Lab, where I work on engineering commensal microbes for therapeutic drug delivery. For me, science is not only about answering fundamental questions but also about creating innovative tools that improve health and combat diseases such as infections and cancer.
Q | How did you first get interested in science?
I first became interested in science through my curiosity about how things work at the most fundamental level. As a child, I often opened up simple machines such as wall clocks and bicycles, trying to fix them (sometimes successfully, sometimes not), and I found great joy in the process. As a student, I was fascinated by the idea that living systems could be “programmed” much like computers to perform human-desired tasks. During graduate school, I built bacterial biocomputers capable of solving logic problems in a predictable manner. The realization that commensal microbes—organisms we often take for granted—could be engineered to influence health and disease further captured my imagination.
Q | Tell us about your favorite research project you’re working on.
Currently, I am working on engineering commensal microbes for therapeutic drug delivery in the gut. I find it fascinating because it combines fundamental microbiology with the potential for real-world impact on human health. The idea that bacteria we live with every day can be reprogrammed to fight infections or even deliver treatments for cancer is both exciting and motivating.
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In this project, I work on designing genetic circuits that enable microbes to sense their environment and respond in a controlled way—for example, producing a therapeutic molecule only when it’s needed. What excites me most is the elegance of the approach: instead of relying solely on traditional drugs, we are creating living systems that can adapt and persist in the body.
Q | What has been the most exciting part of your scientific journey so far?
The most exciting part of my scientific journey so far has been the moment when abstract ideas turned into living, functioning systems. During graduate school, I built bacterial “biocomputers” that could solve logic problems. Seeing colonies of bacteria actually process information—like tiny living circuits—was both surreal and deeply motivating. It was the first time I felt the true creative power of synthetic biology: the ability to design life in ways that go beyond what nature provides.
More recently, in the Lesser Lab, the excitement has come from translating these concepts toward real-world applications. Engineering commensal microbes that can deliver therapies in the gut or combat cancer feels incredibly meaningful because the work moves from theoretical designs to solutions that could impact human health. For me, those moments when science leaps off the page—when an experiment works and a new possibility emerges—are the most thrilling, and they continue to fuel my passion for discovery.
Q | If you could be a laboratory instrument, which one would you be and why?
I would be an incubator. An incubator creates the right environment—warmth, stability, and space—for many different cultures to grow. I also love that an incubator is patient. It works quietly in the background, but what happens inside can lead to big discoveries. To me, being an incubator means supporting growth, fostering creativity, and giving potential the conditions it needs to become something meaningful. Plus, everyone loves the incubator because it always has space for all.
Responses have been edited for length and clarity.
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