Mechanochemically synthesized phase stable and biocompatible β-tricalcium phosphate from avian eggshell for the development of tissue ingrowth system

Bioceramics obtained from naturally derived materials are gaining much interest as implants for bone and dental defects. The present study aims to synthesize phase stable β-tricalcium phosphate (β-TCP) from avian eggshell assisted with ball milling process followed by a wet chemical precipitation method (Group CPM). The effect of mechanical stimulation on phase conversion of CaO was also studied. The study was carried alongside the powders synthesized from chemical precursors (Group CPS) as well as eggshell derived powders without ball milling process (Group CPN). The phase behaviour and surface morphology were studied by XRD, FT-IR, and SEM analysis. Scaffolds were fabricated using sponge replication method to simulate a potential bone graft analogue. The cytocompatibility study was performed by human adipose-derived stem cells (ADSCs) over a period of 21 days by live-dead assay and Alamar blue dye reduction assay. The process of mechanically stimulating CaO precursor through extensive milling plays a major role on phase stabilization of β-TCP, as compared to the mixed phases of Hydroxyapatite (HAp) and β-TCP formed from unmilled CaO. Group CPN scaffolds were found to be biologically equivalent to group CPS scaffolds. This novel route, aided with ball-milling process for the synthesis of β-TCP from naturally occurring eggshell waste seems promising enough to replace commercially available β-TCP produced from harmful nitrate precursors and has the capability to develop implantable biomaterial for tissue regeneration.