Tissue engineering and nanomaterials science have been merged to improve material−cell interactions [1]. Nanobioactive glass (NBG) with a high specific surface area promotes cellular uptake, allowing intracellular and localized release of therapeutic ions [2]. NBG was synthesized via the sol–gel process. Its chemical composition is 55 mol% SiO₂, 40 mol% CaO, and 5 mol% P₂O₅ (n55S5). Chitosan was incorporated into the glass matrix to form CH-n55S5 composite. It was selected for its favorable biocompatibility and its range of biological activities involved in bone remodeling [3]. It was used as drug delivery system for osteoporosis treatment. The Osteoporosis conditions was induced following ovariectomy in the experimental rats. This work investigated the physicochemical and biological properties of n55S5 and CH-n55S5. The n55S5 nanoparticles exhibited an average size of 98.6 nm and a specific surface area of 69.4 m²/g, enhancing ion release. In vitro assays were conducted after immersion of biomaterials in the Simulated Body Fluid (SBF). In vivo experiments were carried out on the femoral condyles of Wistar rats at different delays of implantations. 

Several physicochemical and biologicals evaluations were employed. Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) analysis confirmed the structural and textural characteristics of n55S5 and CH-n55S5. Differential Scanning Calorimetry (DSC) revealed chitosan decomposition at 275°C within the CH-n55S5 composite. X-ray Diffraction (XRD) disclosed the amorphous nature of n55S5 and hydroxyapatite formation on both n55S5 and CH-n55S5 when immersed in simulated body fluid (SBF). Ion exchanges followed by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), suggested the apatite formation. Histological analyses carried out confirmed bone regeneration and trabecular bone formation under osteoporotic conditions induced by ovariectomy. Implant sites exhibited favorable tissue tolerance, with histological analysis showcasing implant degradation and blood vessel formation. Biochemical analyses highlighted stable calcium and phosphorus levels indicators of active bone remodelling. 

In conclusion, n55S5 and CH-n55S5 exhibit considerable potential for bone filling and osteoporosis treatment, rendering them promising candidates for further exploration in bone tissue engineering.