César de la Fuente is on a mission to combat antimicrobial resistance by looking at nature's own solutions. César de la Fuente is an associate professor at the University of Pennsylvania, where he leads the Machine Biology Group. When he was just a teenager trying to decide what to do with his life, César de la Fuente compiled a list of the world's biggest problems. He ranked them inversely by how much money governments were spending to solve them. Antimicrobial resistance topped the list. Twenty years on, the problem has not gone away.