Synthesis and Evaluation of Mesoporous Silica-Biopolymer-Based Bone Substitutes for Tissue Engineering

Bone substitutes for tissue regeneration should provide an appropriate environment for cell attachment, differentiation, proliferation, and migration. 3D structure, degradability, swelling, porosity, and cytotoxicity have been highlighted as key points in their design. For this research, mesoporous silica-biopolymer composites were synthesized from mesoporous silica (Mes-Si) particles combined with either collagen (C/Mes-Si) or chitosan (CS/Mes-Si). The composites were evaluated for tissue engineering purposes, as bone substitutes intended to imitate features of the natural bone matrix, thereby providing an appropriate biochemical environment for bone repair. Physicochemical-biological evaluation was performed to identify the features that would be useful for bone tissue engineering. For the Mes-Si particles, the specific surface area was 750.95 m²/g and the average pore size was 3.47 nm. SEM images showed that Mes-Si particles were distributed within the chitosan (CS) or collagen (C) matrix. Both composites swelled rapidly and had low cytotoxicity. Histologically, no acute inflammatory infiltrate or giant multinucleated cell was observed 14 days after implantation. In C/Mes-Si, newly woven bone tissue and areas of osseointegration at the C/Mes-Si-tissue interface were observed. In CS/Mes-Si, only reparative granulation tissue was observed. The physicochemical properties and biocompatibility of both composites were adequate for a bone scaffold. Moreover, Mes-Si particles have a tunable surface area for chemical modifications and anchoring bioactive materials, which may enhance composite bioactivity or the delivery of bioactive materials.