Facile fabrication of biomimetic silicified gelatin scaffolds for angiogenesis and bone regeneration by a bioinspired polymer-induced liquid precursor

Abstract

Bioinspired materials with dual capabilities of pro-osteogenesis and pro-angiogenesis have attracted increasing scientific interest in the field of orthopedics. Herein, inspired by the mineralization process of natural bone, a biomimetic strategy is presented to fabricate highly bioactive hybrid nanocomposite scaffolds via impregnation of Si-containing polymer-induced liquid precursor (PILP) into biocompatible porous gelatin scaffolds followed by in situ free radial polymerization. The well-designed biohybrid scaffold exhibited not only a micro/nano fiber-like porous architecture (pore size: 100–200 μm; porosity: 80–90 %), high specific surface area (≈20 m2/g), vastly improved mechanical performance, tunable swelling and degradation behaviors but also a sustained release profile of bioactive Si ions up to 21 days. In vitro experiments revealed the excellent biological performance of the resulting biohybrid scaffold, including good biomineralization capacity and biocompatibility, establishing a favorable microenvironment for facilitating cell adhesion, proliferation, migration, osteogenic differentiation, and vascularization. In rat calvarial critical-size defect models, the newly developed biohybrid scaffold could potentially trigger a chain of biological events: stimulating the polarization of M2 macrophages, recruiting endogenous stem cells and endothelial cells at the injury site to enable a suitable regenerative microenvironment for accelerating coupled osteogenesis and angiogenesis, and eventually promoting vascularized bone regeneration.