Mimicking the Architecture and Dissolution Chemistry of Cancellous Bone Tissue to Optimize the Biocompatibility of Bioactive Scaffolds

Abstract

Synthesis of mechanically stable porous scaffolds with an architecture analogous to cancellous bone tissue poses significant challenges to bioactive glass (BG) based scaffolds. This is primarily due to densification and crystallization of the BG's during heat treatment. This study presents a modified BG series (42SiO₂—xTiO₂—24Na₂O—21CaO—13P₂O₅, where x = 8 and 16 TiO₂). TiO₂ replaced the SiO₂ concentration in the glass and was incorporated due to its biocompatibility and influence on glass structure. Material characterization determined that TiO₂ did not induce crystallization within the glass but did increase the glass transition temperature (T_g) from 520°C to 600°C thereby indicating a more stable network connectivity. Scaffolds were synthesized using the foam replication method, resulting in scaffolds with a pore size of approximately 500 μm with the BG-4 composition (30SiO₂—12TiO₂—24Na₂O—21CaO—13P₂O₅) retaining its amorphous character post-heat treatment. Scaffold ion release was monitored over 5–60 days in simulated body fluid (SBF). Si⁴⁺ release was found to decrease, while Ca²⁺ levels increased in SBF as TiO₂ replaced SiO₂ within the glass series. Cytocompatibility studies revealed that MC3T3 Osteoblast cells proliferated on the BG-4 scaffold surface and at its interface within culture media, and cell numbers were not significantly reduced.