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 P O, from the phosphate (PO 4 3 − ) of HA, to the hydrogen of methyl (− CH 3 ), methene (− CH 2 ) and amideII (− CNH) in the protein appears to be much faster and stronger than that of the P O group. In addition, Ca 2 + must serve as a key role in the interaction of BSA with HA. The binding of Ca 2 + 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 PO 4 3 − and OH – of the HA actively and much –C = O and H N groups of the peptide bond freed from inter-chain hydrogen bonding to react on Ca 2 + and combine strongly with the HA surface. This might be well expected to promote the HA biomineralization.