Dth. Wassell et G. Embery, ADSORPTION OF CHONDROITIN-4-SULFATE AND HEPARIN ONTO TITANIUM - EFFECT OF BOVINE SERUM-ALBUMIN, Biomaterials, 18(16), 1997, pp. 1121-1126
The adsorption of chondroitin-4-sulphate (C4S) and heparin onto titani
um has been studied in the absence and presence of bovine serum albumi
n (BSA). Isotherm data (0.02 M calcium acetate, pH 6.8) have shown tha
t BSA in solution and BSA-coated titanium result in decreased adsorpti
on for both C4S and heparin. For the BSA in solution data, C4S/heparin
and BSA may compete for the same sites on the titanium surface via ca
lcium ions, or alternatively in the case of heparin, complexes of hepa
rin and BSA form in solution, leading to less binding due to steric ef
fects. Evidence of an interaction between heparin and BSA in solution
has been shown in this study, there being negligible interaction betwe
en C4S and BSA. BSA adsorption from solution investigated in the prese
nce of C4S/heparin decreases with increasing C4S/heparin solution conc
entration. This may be due to a glycosaminoglycan (GAG) induced confor
mational change of BSA from a compact to an extended structure. The de
creased adsorption onto BSA-coated titanium may be due to masking of t
he GAG binding sites, this effect being greater for C4S. Desorption of
BSA from the pre-coated titanium in the presence of C4S and heparin i
s <10% and <30% respectively, indicating that BSA is strongly bound to
the titanium surface. (C) 1997 Elsevier Science Limited. All rights r
eserved.