Freeze-Dried Chitosan/Magnesium-Doped Hydroxyapatite Nanocomposite Scaffold Functionalized with Lithium Chloride for Enhanced Osteogenesis and Bone Regeneration

Bone defects arising from trauma, tumor resection, or degenerative disease pose persistent clinical challenges. This study aimed to develop and evaluate a multifunctional, growth factor-free chitosan/Mg-HAp/LiCl nanocomposite scaffold for bone tissue engineering, with a focus on enhancing osteogenic activity, antibacterial properties, mechanical strength, and bone regeneration in critical-sized defects. Scaffolds were fabricated via freeze-drying and characterized using FTIR, XRD, and SEM. Porosity, biodegradation, and mechanical properties were evaluated. Cytocompatibility and osteoblast proliferation were assessed in Saos-۲ cells by MTT assay. Antibacterial activity against Staphylococcus aureus and Escherichia coli was tested by agar well diffusion. Drug release was monitored under physiological conditions (PBS, pH ۷.۴, ۳۷ °C). In vivo bone regeneration was examined in a critical-sized rat calvarial defect model at ۸ and ۱۲ weeks. The scaffold demonstrated high porosity (۸۶.۱۱±۴.۳%), controlled biodegradation (۴۸±۲.۱۶% mass loss at ۱۴ days), and adequate mechanical strength (Young's modulus: ۷.۲۵ ± ۰.۰۸ MPa; tensile strength: ۱.۷۲ ± ۰.۲۲ MPa). SEM revealed an interconnected porous network with ۱۵۰–۲۰۰ µm pore sizes. MTT assay confirmed cytocompatibility and progressive osteoblast proliferation over ۷ days. Inhibition zones reached ۱۶ mm (Staphylococcus aureus) and ۱۱ mm (Escherichia coli) at ۲۵ mg/mL. Cumulative drug release reached ۵۲.۵۴% at ۴۸ hours. Histological analysis showed significantly enhanced bone formation at both timepoints versus untreated controls. The chitosan/Mg-HAp/LiCl scaffold exhibits promising mechanical, antibacterial, and osteogenic properties, representing a viable growth factor-free platform for critical-sized bone defect repair.

کلیدواژه ها:

Bone tissue engineering ، Chitosan Scaffold ، Magnesium-doped hydroxyapatite ، Lithium Chloride ، Wnt/&szlig ، -catenin signaling ، Nanocomposite biomaterials