A particle (and a composition that includes a plurality of the particles) that includes at least one polypeptide molecule and at least one polymer covalently bound to the polypeptide molecule so as to form a polymer shell substantially encompassing the polypeptide molecule, wherein the particle does not define a dimension greater than about 1 .mu.m. One example for making the particle includes modifying the polypeptide molecule to provide .alpha., .beta.-ethylenically unsaturated terminal functional groups, mixing the modified polypeptide molecule with a silicon-containing polymerizable compound, and subjecting the resulting mixture to conditions sufficient for polymerizing the polymerizable compound to form the particle.