Fibrinogen adsorption onto microwave plasma chemical vapor deposited diamond films

This study investigates the haemocompatibility of diamond films and attempts to correlate the results to structural characteristics and surface termination. The samples evaluated consisted of polycrystalline and nanocrystalline diamond films, single crystal diamond, titanium and silicon. Raman spectroscopy detailed the sp³ and sp² bonding configurations while surface morphology was imaged using atomic force microscopy. Initial contact angles of deionized water were obtained using the sessile drop method. Samples exposed to a hydrogen plasma, and thus hydrogen terminated, became more hydrophobic while samples oxidized by a nitric acid etch became more hydrophilic. The adsorption process of the human protein fibrinogen was then studied on each of the samples. The water contact angle for the MPCVD and single crystal diamond samples did not change, indicating little protein adsorption. Titanium and silicon samples became more hydrophilic as a result of adhered fibrinogen protein.