In the same way that written English is built around an alphabet of just 26 letters, all life on Earth is built around a standard set of just 20 amino acids, which are the building blocks of all proteins. And just as we’ve invented special characters like emoji to go beyond our standard letters, it turns out that biologists can expand their repertoire of powers using non-standard amino acids—those that either occur rarely in nature, or that can only be made in the lab. GRO Biosciences, a spinout from the laboratory of the renowned synthetic biology pioneer George Church at Harvard Medical School, is one of the companies working to explore the exciting applications of non-standard amino acids (NSAAs), and Harry’s guest this week is GRObio’s Co-founder and CEO, Dan Mandell. He says NSAAs could help overcome some of the limitations that keep today’s gene and protein therapies from being used more widely, while also expanding the kinds of jobs that protein-based therapies can do.