Strontium-doped mesoporous bioactive glass reinforced silk fibroin/decellularized extracellular matrix nanocomposite scaffolds for potential bone tissue engineering

Effective bone tissue engineering requires scaffolds to have both bioactive and mechanical properties to aid in the regeneration of the biochemical and mineral components of bone. In this paper, ternary nanocomposite scaffolds are introduced for the first time, which consist of a silk fibroin (SF) matrix reinforced with placenta-derived decellularized extracellular matrix (DCECM) and strontium-containing mesoporous bioactive glass nanospheres (SrMBNs). This composite design aims to overcome the limitations of each individual component and their binary combinations in bone tissue regeneration. For this purpose, the effects of varying the SF:DCECM:SrMBN ratio on the structure, mechanical, degradation, swelling, apatite-forming, cytocompatibility, and pro-osteogenic ¬potential of the scaffolds are systematically investigated. According to results, introducing 30 wt% DCECM transformed the lamellar structure of pure SF into a highly porous architecture of 90% porosity, with enhancements in compressive strength by 170%, swelling ratio by 70%, and in-vitro degradation rate by 185%. The incorporation of 15 wt% SrMBNs showed the most satisfactory results in terms of apatite formation, while the degradation and swelling rates of the SF-DCECM scaffolds were minimally affected. The scaffolds with 30% DCECM and 15% SrMBNs exhibited significantly improved attachment, viability, and proliferation of rat bone marrow mesenchymal stem cells (rBMSCs) compared to the pure SF scaffolds. Alizarin Red S staining confirmed that with the SrMBNs, there was greater calcium deposition, indicative of more osteogenic potential in comparison to the SF/DCECM scaffolds. Collectively, the SF/DCECM/SrMBNs scaffolds exhibited superior physicochemical, mechanical, and biological performances, with strong potential as bone-mimetic platforms for bone regeneration applications.