Controlled release of BSA by microsphere-incorporated PLGA scaffolds under cyclic loading

Localized delivery of bioactive molecules from porous biodegradable scaffolds is very important in advanced tissue engineering strategies, and it is necessary to study the delivery under dynamic loading which mimics the in vivo biomechanical environments. In this study, bovine serum albumin (BSA), a model of bioactive proteins, was incorporated into porous poly(l-lactide-co-glycolide) (PLGA) scaffolds by seeding BSA-loaded microspheres onto the scaffold pore wall, where the microspheres of poly(ethylene glycol)-b-poly(l-lactide) (PELA) were prepared by double emulsion technique. The in vitro release behavior of BSA from the scaffold under dynamic cyclic loading was studied in comparison with that under a static condition as well as from PELA microspheres. It was observed that the microsphere-incorporated scaffold prolonged BSA release with respect to the microspheres. The cyclic loading accelerated the release of BSA from the scaffold and the cumulative release on day 10 reached 85% of the totally encapsulated BSA. The delivery under a dynamic condition would be an initial study of in vivo localized delivery of growth factors.