Metal Phenolic Nanodressing of Porous Polymer Scaffolds for Enhanced Bone Regeneration via Interfacial Gating Growth Factor Release and Stem Cell Differentiation

Porous polymer scaffolds are essential materials for tissue engineering because they can be easily processed to deliver stem cells or bioactive factors. However, scaffolds made of synthetic polymers normally lack a bioactive cell-material interface and undergo a burst release of growth factors, which may hinder their further application in tissue engineering. In this paper, a metal-phenolic network (MPN) was interfacially constructed on the pore surface of a porous poly(dl-lactide) (PPLA) scaffold. Based on the molecular gating property of the MPN supramolecular structure, the PPLA@MPN scaffold achieved the sustained release of the loaded molecules. In addition, the MPN coating provided a bioactive interface, thus encouraging the migration and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). The PPLA@MPN scaffolds exhibited enhanced bone regeneration in a rat femoral defect model in vivo compared to PPLA, which is ascribed to the combined effect of sustained bone morphogenetic protein-2 (BMP-2) release and the osteogenic ability of MPN. This nanodressing technique provides a viable and straightforward strategy for enhancing the performance of porous polymer scaffolds in bone tissue engineering.