Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (2): 565-572.doi: 10.3866/PKU.WHXB201511301

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FTIR-ATR Spectrometry of BSA Adsorption on Hydroxyapatite

Qing YE2,Ren HU1,Jian-Zhang ZHOU1,Yi-Wen YE1,Zhao-Xi XU3,Chang-Jian LIN1,Zhong-Yu LIN1,*()   

  1. 1 State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian Province, P. R. China
    2 Chuyang Honors College, Zhejiang Normal University, Jinhua 321004, Zhejiang Province, P. R. China
    3 Xiamen AERTE System Engineering CO., LTD, Xiamen 361005, Fujian Province, P. R. China
  • Received:2015-07-02 Published:2016-01-30
  • Contact: Zhong-Yu LIN E-mail:stzylin@xmu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(51571169)

Abstract:

The microcosmic process of bovine serum albumin (BSA) adsorbing onto hydroxyapatite (HA) for different time intervals was investigated by Fourier transform infrared attenuated total internal reflectance (FTIRATR) spectrometry. The initial dissolution and re-precipitation of PO43-, Ca2+, and OH- ions from the HA coating led to the occurrence of the coating including adsorbed BSA on the HA from surface-to subsurface-molecular layers and to in-depth interaction between BSA and HA. The subtraction results gained in the adsorption regions of HA and BSA reveal that the binding of P=O, from the phosphate (PO43-), to the hydrogen of amide II, methyl and methene of the BSA appears to be considerably more rapid and stronger than that of the P―O group. In addition, it is very likely that Ca2+ plays an important role in the interaction of BSA with HA. It appears that the binding of Ca2+ to the carbonyl-oxygen of the peptide bond in BSAcaused a significant, molecular, conformational rearrangement of polypeptide backbones from β-pleated sheet to helical circles of α-helix and β-turn. This change appears to have been followed by much hydrogen of polypeptides being driven to bind PO43- and OHeffectively and much ―C=O and H―N―groups of the peptide bond being freed from inter-chain hydrogenbonding to act on Ca2+ and combine strongly with the HA surface. This might reasonably be expected to promote hard tissue regeneration. BSA seems to be activated by the inductive effect of Ca2+ via the molecular rearrangement of polypeptide backbones from pleated sheet to helical circles and in turn reacts strongly on the HA, resulting in profound effects on the course of biomineralization.

Key words: Biomaterial, Protein adsorption, Polypeptide, IR spectroscopy, FTIR-ATR, Biomineralization