This video produced by WGBH profiles Karmella Haynes, a post-doctoral researcher working in the emerging field of synthetic biology. Karmella explains how she uses biotechnology to build living machines, or devices, from genes. She then puts these devices into the cells of living things and studies the results. Haynes hopes that one day the devices she's working on will carry out complicated functions in human bodies, such as curing a disease. The video demonstrates how Karmella is using synthetic biology to detect cancer cells before they spread.