Stabilization of zirconia nanoparticles by collagen protein and calcium carbonate extracted from eggshell and its biodegradation, radical scavenging and mineralization activity

Abstract

In this current study, collagen protein extracted from eggshell membrane and calcium carbonate (a main component of eggshell) are used as additive to enhance the stability and hardness of the zirconia crystals. Five different samples are prepared by adding membrane containing eggshell content as, 1 g, 2 g, 3 g, 4 g and 5 g in aqueous zirconium oxychloride sol. Phase purity is confirmed by XRD and FTIR. Phase pure and dense particles divulges the high hardness (∼1389 HV) and fracture toughness (12.89 MPa m1/2). FESEM analysis illustrates the formation of dense, well separated, non-agglomerated and spherical nanoparticles at 5 g of eggshell content. Eggshell works as a surfactant and stabilizer for formation of phase pure tetragonal spherical nanoparticles. Biodegradation study of optimized tetragonal zirconia (t-ZrO2 )in phosphate buffered saline (PBS) presents that minor change in weight and hardness after 72 h of immersion. Antioxidant study shows the 96% of radical scavenging activity (RSA). In vitro bio-mineralization study shows the formation of new bone after 5 weeks. After 5 weeks all pores were filled and minerals were deposited on the surface of the scaffolds. SEM images confirms that eggshell-zirconia composite form new bone. So eggshell addition results in formation of phase pure t-ZrO2 nanoparticles with well-defined boundaries which exhibit higher hardness, fracture toughness, stability and enhanced antioxidant properties.

Keywords

• Eggshell
• ZrO2
• Tetragonal
• Biodegradation
• Antioxidant
• Bone implantation