Optical sensing of protein adsorption on titanium implants

Adsorption of the elongated human plasma fibrinogen (HPF) and globular human serum albumin (HSA) molecules on titanium-based surface is monitored by analyzing permittivity and optical roughness of protein-modified surfaces by using a diffractive optical element (DOE) based sensor and a variable angle spectro-ellipsometry (VASE). Both DOE and VASE confirmed that HSA forms a thicker and more packed surface adlayer compared to a more porous fibrinogen adlayer. A linear relation of the permittivity (ε´) and dielectric loss (ε") was found for some of the dry titanium doped hydrocarbon (TDHC) surfaces with excellent HPF adsorption ability. Aging process of TDHC´s influenced the fibrinogen adsorption.