Chad A. Mirkin is a pioneering American chemist at Northwestern University, where he holds the George B. Rathmann Professorship in Chemistry and serves as Director of the International Institute for Nanotechnology. His research focuses on manipulating molecules and materials on the 1–100 nanometre scale, and he is renowned for inventing technologies such as dip-pen nanolithography and spherical nucleic acids (SNAs)—innovations that have spawned new diagnostic tools, therapeutic approaches and manufacturing techniques for materials.