A University of Illinois scientist studying how membranes wrinkle has discovered a novel system for on-demand drug delivery. Sahraoui Chaieb, a professor of mechanical and industrial engineering, has created temperature-sensitive capsules that can release drugs on demand. The capsules, which can range in size from 10 to 100 microns, can be tuned to deliver drugs at different rates. Chaieb reports his findings in the Feb. 17 issue of the journal Physical Review Letters.