Development of nanosilica bonded monetite cement from egg shells

This work represents further effort from our group in developing monetite based calcium phosphate cements (CPC). These cements start with a calcium phosphate powder (MW-CPC) that is manufactured using microwave irradiation. Due to the robustness of the cement production process, we report that the starting materials can be derived from egg shells, a waste product from the poultry industry. The CPC were prepared with MW-CPC and aqueous setting solution. Results showed that the CPC hardened after mixing powdered cement with water for about 12.5 +/- 1 min. The compressive strength after 24 h of incubation was approximately 8.45 +/- 129 MPa. In addition, adding colloidal nanosilica to CPC can accelerate the cement hardening (10 +/- 1 min) process by about 2.5 min and improve compressive strength (20.16 +/- 4.39 MPa), which is more than double the original strength. The interaction between nanosilica and CPC was monitored using an environmental scanning electron microscope (ESEM). While hardening, nanosilica can bond to the CPC crystal network for stabilization. The physical and biological studies performed on both cements suggest that they can potentially be used in orthopedics. (C) 2015 Elsevier B.V. All rights reserved.