Behavior of molybdenum lowly doped SiO2–CaO–P2O5 composite interfacing a simulated biologic medium with serum albumin

Abstract

This study is focussed on the biocompatibility evaluation by probing the affinity of bovine serum albumin (BSA) towards the surface of a silica based material containing CaMoO4 and hydroxyapatite nanocrystals. The adsorption occurring upon BSA interaction with the sample surface was investigated by Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) Spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The elemental composition and evaluation of protein surface coverage based on information from the outermost few nanometres surface layer was achieved by XPS analysis. The ratio between carbon and nitrogen on the material surface after incubation in BSA solution was found to be reasonable close to the value obtained from the measurement of pure BSA, that proves the protein adsorption. The comparative analysis of FTIR spectra recorded from lyophilized protein and from biomaterial surface after protein adsorption was considered in order to obtain information about the secondary structure of the proteins. The protein surface coverage was also confirmed by SEM morphological characterization. The results obtained by in vitro test indicate that the nanostructured SiO2–CaO–P2O5−MoO3 system has a great potential for bone tissue engineering with respect to the ability to bind to serum protein.