Novel alginate-hydroxyapatite composite cryogel for bone regeneration

Bone tissue engineering requires biomaterials that not only support cell growth and differentiation but also mimic the mechanical and structural properties of native bones. In this study, we developed a novel alginate-hydroxyapatite (HA) composite cryogel using a one-step cryogelation process, where alginate chains were covalently crosslinked via carbodiimide (EDC) chemistry, with HA incorporated to enhance osteoconductivity. The resulting cryogels were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Solid-State Nuclear Magnetic Resonance (¹³C NMR), water uptake analysis, mechanical testing, scanning electron microscopy (SEM), and Micro-Computed Tomography (µ-CT). In vitro studies with MC3T3-E1 pre-osteoblasts were conducted to evaluate biocompatibility and osteogenic potential. The cryogels exhibited a highly interconnected porous architecture, maintaining mechanical integrity and excellent swelling properties. Structural and chemical analyses confirmed successful crosslinking and uniform distribution of HA. In vitro cytocompatibility studies demonstrated enhanced cell viability and alkaline phosphatase (ALP) activity, indicating the material’s ability to support osteogenic differentiation. These results suggest that the developed composite cryogels hold great potential as a platform for bone regeneration applications.