As for ENT—I fell in love with the anatomy. Everything that makes us human is concentrated in the head and neck: how we speak, swallow, smile, hear, and see one another. Serving that anatomy felt like serving the essence of people. The challenge—and privilege— of caring for patients as a surgeon while safeguarding these delicate functions has always inspired me.
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January 2026Dr. Rapoport: You chose to pursue an MD/PhD. What inspired you to take this dual-degree path rather than a more traditional MD track?
Dr. Nguyen: I wanted to make an impact on a bigger scale. While I treasure the one-on-one interactions with my patients—one of my favorite surgeries is stapedectomy because of the tangible, immediate restoration of hearing it facilitates—I also felt a pull towards making a broader contribution. I had the curiosity and the patience for lab work, to see something new that no one had ever seen before. I wanted to discover something that could help many. I was fortunate to be accepted into the MD/ PhD program at Washington University in St. Louis, which had the experience and capability to nurture a physician– scientist with my goals. My time there was a defining period for me professionally.
Dr. Rapoport: Your early PhD work involved creating the first transgenic mice expressing fluorescent protein in neurons. What was that discovery like?
Dr. Nguyen: Magical. I was cutting facial nerves in tiny mice, then performing time-lapse imaging as they degenerated and regenerated. I was often alone in the dark, sometimes in the middle of the night, watching these glowing nerve branches search and grow. I remember thinking, “This is the first time anyone has ever seen this.”
Those “aha” moments live inside you forever.
They also planted the seed: If we could see nerves in mice, why couldn’t we illuminate them in humans?
Dr. Rapoport: Your work on fluorescent nerve imaging is fascinating. Can you tell us about your journey to that innovation?
Dr. Nguyen: It really began during my PhD in the 1990s. We were the first to create transgenic animals with green fluorescent protein (GFP) under a neuron-specific promoter. I was working on the facial nerve in mice, watching degeneration and regeneration in living animals through time-lapse videography.
When I came to UC San Diego, I had the opportunity to work with the late Dr. Roger Tsien, who would later win the Nobel Prize for his work on GFP. We developed a fluorescent peptide that, when injected, is cleaved by nerve-specific enzymes, causing it to fluoresce and essentially “paint” the nerves so they light up. This has incredible implications for surgery, where the visual field is often a narrow dynamic range from tan to red. Fluorescence in surgery adds a whole new dimension to operating, helping surgeons improve their ability to identify and preserve critical nerves.
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