Highly Bioactive SDF-1α Delivery from Low-Melting-Point, Biodegradable Polymer Microspheres.

Aliphatic polyester biodegradable microspheres have been extensively studied for controlled and minimally invasive in situ protein delivery. However, they are commonly characterized by protein denaturation via acidic polyester degradation products, whereas their supraphysiologic modulus contributes to the inflammatory response upon implantation. To address these limitations, low-melting-point poly(ε-caprolactone--glycolide)--poly(ethylene glycol)--poly(ε-caprolactone--glycolide) (PEG-(PCG)) copolymers were prepared and characterized for their ability to release bioactive stromal-derived factor-1α (SDF-1α) as a representative therapeutic protein.