Innovative valorization of crab shells for hydroxyapatite‐based composite hydrogels in bone engineering applications

Abstract BACKGROUND Current osteoarthritis treatments, including physiotherapy, chondroplasty, and cartilage transplantation, often fail due to pain, infection, and immune complications, hindering bone healing. Bone tissue engineering relies on biomaterials with optimal mechanical strength, biocompatibility, and bioactivity. While chitosan (CS), hyaluronic acid (HA), and hydroxyapatite (HAp)‐based hydrogels show promise for bone regeneration, balancing mechanical performance and biological functionality remains a challenge. RESULTS The synthesized CS/HA/HAp hydrogel with a composition of 50/15/35 (wt%) demonstrated superior compressive strength (250 kPa) and elasticity (260 kPa), meeting the mechanical requirements for bone regeneration. The incorporation of crab shell‐derived HAp significantly improved bioactivity, as evidenced by phosphate ion integration in simulated body fluid. The hydrogels exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli, further supporting their suitability for biomedical applications. X‐ray diffraction confirmed HAp integration with preserved crystallinity, while scanning electron microscopy showed a uniform distribution, reducing aggregation and enhancing porosity for cell infiltration. Thermogravimetric analysis demonstrated thermal stability and controlled three‐stage biodegradation. CONCLUSION This study demonstrates that incorporating crab shell‐derived HAp into CS/HA hydrogels enhances their mechanical, biological, and antibacterial properties. The optimized hydrogel formulation holds promise for clinical applications in bone tissue engineering, offering a sustainable and effective alternative for regenerative medicine. © 2025 Society of Chemical Industry (SCI).