A further insight into the adsorption mechanism of protein on hydroxyapatite by FTIR-ATR spectrometry

Abstract

The adsorption mechanism of bovine serum albumin (BSA) on hydroxyapatite (HA) for different time intervals has been studied by Fourier transform infrared (FTIR)-attenuated total internal reflectance (ATR) spectrometry in this paper. The difference spectra obtained in HA and BSA frequency regions demonstrate that the binding of PO, from the phosphate (PO43−) of HA, to the hydrogen of methyl (−CH3), methene (−CH2) and amideII (−CNH) in the protein appears to be much faster and stronger than that of the PO group. In addition, Ca2+ must serve as a key role in the interaction of BSA with HA. The binding of Ca2+ to the oxygen of the peptide bond seems to induce a significant reconformation of polypeptide backbones from β-pleated sheet to α-helix and β-turn of helical circles. This alteration seems to have been accompanied by much hydrogen of polypeptides driven to bind PO43− and OH– of the HA actively and much –C=O and HN groups of the peptide bond freed from inter-chain hydrogen bonding to react on Ca2+ and combine strongly with the HA surface. This might be well expected to promote the HA biomineralization.