Calcium phosphate–gold nanoparticles nanocomposite for protein adsorption and mediator-free H2O2 biosensor construction

This work reports a new method for the preparation and application of a kind of biocompatible calcium phosphate–gold nanoparticles (Ca3(PO4)2–AuNPs) nanocomposite. UV–vis spectroscopy and transmittance electron microscopy (TEM) have been used to monitor the formation process of the nanocomposite and to examine the interaction between calcium phosphate and gold nanoparticles (AuNPs). The nanocomposite has multiple sites and improved conductivity which make it suitable for the binding of proteins to construct electrochemical sensors. Myoglobin (Mb) adsorbed on the nanocomposite retained its native structure which was proved by Fourier transform infrared spectroscopy (FTIR). Direct electron transfer between the adsorbed Mb and the electrode was observed. Further results demonstrated that the adsorbed Mb has good electrocatalytic activity towards the reduction of H2O2 in the absence of any mediator.