Methods for preparing uniformly sized micropanicles, with an optional polymeric coating generally include: 1) providing nanoparticles, preferably having a size of between 1 nm and 100 nm； 2) adding a hydrophobic surface layer to the nanoparticles； 3) making a suspension of the hydrophobic nanoparticles and a polymerization initiator in an hydrophobic solvent； 4) dissolving a monomer in the hydrophobic solvent； 5) making an emulsion by dispersing droplets of the hydrophobic solvent in a continuous aqueous phase with an emulsifier； 6) sizing the first emulsion to provide a second emulsion of the same components in which the droplets are substantially uniform and between 2 and 20 um in size； 7) evaporating at least a substantial portion of the dispersed hydrophobic droplets to assemble nanoparticles to form micropanicles suspended now in the aqueous phase； 8) replacing the first surfactant with a second surfactant, which is preferably a polymerizable surfactant； 9) adding a polymerizable monomer to the aqueous phase and allowing it to adsorb into the microparticle； 10) polymerizing the monomer(s) to provide a polymer layer on the micropanicles； and 11) functionalizing the polymer surface layer erf the micropanicles with one or more polymer, nanoparticle or biological macromolecular layers.
