Hydrogel microparticle formation in aqueous solvent for biomedical applications

A process for forming a coating on a surface, wherein the surface comprises microparticles of a cross-linked water-soluble polymer, the process comprising:

• combining macromers comprising at least one water-soluble polymer and at least one cross-linking agent in an aqueous solvent, wherein at least one of the macromers comprises a functionality of greater than 2, wherein at least one of the water-soluble polymers comprises a lower critical solution temperature (LCST), wherein functional groups of the cross-linking agent and the macromers react to form covalent bonds, wherein the covalent bonds form the cross-linked water-soluble polymer;
• coacervation polymerizing the macromers to form a solution, wherein the coacervation polymerization comprises cross-linking the macromers at a temperature that is above the lower critical solution temperature (LCST) of at least one of the macromers, wherein the coacervation polymerization is done in the absence of mixing or agitation, wherein polymer-rich phases of the cross-linked water-soluble polymers gel before the solution coarsens to form droplets less than about 1 mm in diameter;
• and
• forming the coating by contacting a solution of the microparticle with the surface, wherein the surface is derivatized with functional groups that react with microparticle functional groups, wherein the macromers comprises at least one water-soluble polymer selected from the group consisting of polyacrylate, polyacrylamide, poly(acrylamide sulphonic acid), polyacrylonitrile, polyamines, poly(ethylene glycol), poly(ethylene imine), poly(ethylene oxide), poly(ethyloxazoline), polyhydroxyethylacrylate, polymethacrylate, polymethacrylamide, poly(oxyalkylene oxide), poly(propylene oxide), polyurethane, poly(vinyl alcohol), and poly(vinyl pyrrolidone).