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Bovine serum albumin conformational changes upon adsorption on titania and on hydroxyapatite and their relation with biomineralization
Author(s) -
Serro A. P.,
Bastos M.,
Pessoa J. Costa,
Saramago B.
Publication year - 2004
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.30096
Subject(s) - adsorption , bovine serum albumin , isothermal microcalorimetry , protein adsorption , materials science , biomineralization , chemical engineering , biocompatibility , mineralization (soil science) , simulated body fluid , molecule , biophysics , chemistry , chromatography , organic chemistry , scanning electron microscope , composite material , enthalpy , physics , metallurgy , quantum mechanics , biology , nitrogen , engineering
The biocompatibility of implant materials used for substitution of bone tissue depends on its ability to induce the deposition of a hydroxyapatite layer when in contact with body fluids. In previous work, some of the authors found that bovine serum albumin (BSA) promotes calcium phosphate deposition if preadsorbed on hydroxyapatite and retards precipitation if preadsorbed on titania. In the present study, we investigated the adsorption of BSA upon particles of titania and hydroxyapatite in order to understand the different role played by the protein on the mineralization of both biomaterials. The adsorption isotherms were determined and the structural changes induced by adsorption at different surface coverages were investigated by circular dichroism spectroscopy and differential scanning microcalorimetry. At low surface coverages, the adsorbed BSA molecules lost part of their α‐helix content. However, at high surface coverages, corresponding to the plateau values of the adsorption isotherms, the BSA molecules did not undergo structural rearrangements upon adsorption. In the latter circumstances, the availability of BSA calcium binding sites, which should be responsible for inducing mineralization, depends on the electrostatic interactions between BSA and the sorbent surface. A possible explanation for the different mineralization behavior of hydroxyapatite and titania is advanced. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 420–427, 2004