Protein encapsulation and release from degradable sugar based hydrogels

Acid labile sugar based hydrogels have been synthesized using a commercially available acid sensitive cross-linker, 3,9-divinyl-2,4,8,10-tetraoxaspiro-5,5]-undecane. The monomers used for polymerization are N-isopropylacrylamide (NIPAM) and d-gluconamidoethyl methacrylate (GAMA), which when polymerized in the presence of the acid labile cross-linker yield hydrogels that can swell and degrade under acidic conditions, making them ideal for drug delivery. The hydrogels are synthesized using either a photo-initiator, Irgacure-2959 or a conventional initiator, potassium persulfate. The hydrogels obtained by photo-polymerization exhibit defined and unique microstructures, when analyzed by scanning electron microscopy (SEM). The swelling capacity and protein release from the hydrogels as a function of pH is studied. The protein release from the hydrogels is found to be dependent upon the degree of cross-linking and the pH of the environment.