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.