As a professor at UCSD, Steinmetz became the founding director of the Center for Nano-ImmunoEngineering and co-director of the Center for Engineering in Cancer. She also co-founded a biotechnology startup, called Mosaic ImmunoEngineering Inc, with Steven Fiering. During the COVID–19 pandemic, the pair began developing fridge-free COVID-19 vaccines for easier distribution. They also created and licensed the cowpea mosaic virus nanotechnology as a cancer immunotherapy. As a result of her research, Steinmetz was elected a Fellow of the National Academy of Inventors and Biomedical Engineering Society in 2022.
