“My dad is an engineer and my mom is in health care,” Mukasa says, “So I kind of ended up in this middle field of biomedical engineering. I wanted to do engineering because I think with a very technical mind, but I wanted it to help people. Working on biomedical problems–where I could, say, diagnose a disease early on–felt really exciting.”

While completing his undergraduate studies at Oberlin College, Mukasa set his sights on Caltech. “I wanted to come back home, come back to the sun, and do amazing physics while also trying to help people’s lives,” he says. “And I landed in the perfect spot for that.” Specifically, he landed in the innovative lab of Wei Gao, assistant professor of medical engineering, who has been developing wearable sensors that monitor biomarkers in sweat to allow for the detection and management of various diseases and health conditions.

Thanks to the diffusion of molecules from the bloodstream to the sweat duct, explains Mukasa, “almost everything that you find in a blood profile you’ll also find in your sweat profile.” But unlike blood tests, whose results are a snapshot in time, sweat monitoring is non-invasive and offers continuous, real-time data. Each sensor is designed to detect a specific metabolite or nutrient, including amino acids, vitamins, hormones, and proteins.

For example, Mukasa has worked on one device, worn on the forearm, that tracks the amino acid phenylalanine for a rare but serious disease called phenylketonuria. Another monitors glucose levels, which can correlate to diabetes. There are also applications to monitor women’s reproductive cycles. “There’s a company, Oura, that [currently] makes a ring which tells a woman roughly where she is in her cycle, primarily from changes in body temperature—but this isn’t nearly as accurate as what you could get from a device that’s actually tracking the estrogen coming out of you.”

Mukasa says that some people in the lab find a niche, concentrating their efforts on a certain disease. “I’m really interested in all diseases,” says Mukasa, “so I’ve been focused on how to make the chemical sensor as accurate as possible for any biomarker—so that once we know something correlates to a disease, we can just make a device and ship it out immediately.”