The adsorption of bovine serum albumin (BSA) on to titanium powder has
been studied as a function of protein concentration and pH, and in th
e presence of calcium and phosphate ions. Isotherm data have shown tha
t the adsorption process does not follow the Langmuir model (inflectio
n points). The maximum adsorption (Ad(max)) at pH 5.8 is 1.13 +/- 0.21
mg m(-2). For the pH dependence of adsorption the amount adsorbed inc
reases with decreasing pH (at pH 5.15 Ad(max) = 1.31 +/- 0.2 mg m(-2))
, indicating that hydration effects are important. Adsorption increase
s and decreases in the presence of calcium (at pH 6.8 for 0.002 M Ad(m
ax) = 1.73 +/- 0.23 mg m(-2)) and phosphate (at pH 6.8 for 0.002 M Ad(
max) = 0.64 +/- 0.14 mgm-2) ions, respectively, indicating that electr
ostatic effects are important. The time dependence, isotherm and desor
ption data provide indirect evidence of possible conformational change
s in the BSA molecule.