Entrapment of protein using electrosprayed poly(d,l -lactide-co-glycolide) microspheres with a porous structure for sustained release

Abstract

The entrapment of a protein in porous poly(d,l-lactide-co-glycolide) (PLGA) microspheres is demonstrated through the closure of their outer surface pores for sustained delivery of the protein. The porous PLGA microspheres with less than 10 μm in size are prepared by electrospraying. Aqueous solutions containing fluorescein isothiocyanate-dextran or bovine serum albumin (BSA) are penetrated into the inner pores as a result of vacuum treatment, and the outer surface pores of the porous PLGA microspheres are then closed using a solvent (dimethyl sulfoxide) to ensure entrapment of the macromolecules. Confocal microscopy images confirm the presence of a large amount of the macromolecules inside the porous structure. Circular dichroism spectroscopy and release analysis reveal that BSA is entrapped without denaturation and released in a sustained manner for a period of over 2 months, respectively. Porous biodegradable microspheres containing protein are fabricated through the electrospraying of a polymer solution, the entrapment of the protein into the inner pores of the microspheres, and the closure of their outer surface using an aqueous mixture of solvent (dimethyl sulfoxide). These porous microspheres can be used as carriers for the sustained release of proteins. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.