Sustainable Development of a Bioactive Material from Recycled Rice Husk and Eggshell for Bone Regeneration Application

Developing an efficient, economical, green, and sustainable approach for the synthesis of a bioactive material (BM) for bone tissue engineering is a need of the moment because BM possesses appealing characteristics (excellent binding efficiency, bioactivity, osteogenesis, angiogenesis, antimicrobial activity, and controlled degradation rate). The present work demonstrates the synthesis of 70S30C calcium silicate (CS) using recycled rice husk (silica source) and eggshell (calcium source) via a simple precipitation method. The BET analysis confirmed its mesoporous nature (surface area of 74.65 m²/g). Furthermore, the bioactivity study using simulated body fluids revealed the growth of hydroxyapatite (HAp) on the synthesized material (XRD, FTIR, and SEM-EDS analysis), which plays a crucial role during bone regeneration. The 70S30C CS exhibited excellent mechanical properties, biocompatibility (in vitro study using MG-63 cells), antibacterial activity (in vitro and in vivo against E. coli and Staphylococcus aureus), and angiogenesis (CAM model). The Cirrhinus mrigala fish used for the in vivo study revealed its nontoxicity and showed matrix proteoglycans, vascularization, collagen I protein, and bone healing at the fracture site. The current study broadens the biomedical application of rice husk and eggshell-derived BM prepared completely from recycled waste (eco-friendly approach), offering bioactivity, bacterial inhibition, angiogenesis, and bone healing capability.