Three kinds of poly(lactide-co-glycolide)/chitosan microspheres(abbreviated as PLGA/chitosan microspheres) were prepared with multiple emulsion technique.PLGA microspheres were prepared with the double emulsion method(W/O/W) based on PLGA as the matrix and bovine serum albumin(BSA) as the model protein.The PLGA microspheres were re-emulsified with chitosan solution containing BSA followed by cross-linking with sodium tripolyphosphate(TPP).Three kinds of PLGA were used as the raw material of PLGA microsphere...