The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.
STATEMENT AS TO FEDERALLY-SPONSORED RESEARCH
 This invention was made with government support under grant number GM48142 awarded by the National Institutes of Health, grant number DE-AC05-000R22725 awarded by the Department of Energy, and DAAK60-97K-9502 awarded by the U.S. Army. The U.S. government has certain rights in the invention.