The Interaction of Blood with Amorphous Carbon

The initial stages of adsorption of plasma derived proteins on artificial surfaces in a controlled flow environment

Surfaces of amorphous carbon, polystyrene, and polycarbonate were exposed to solutions of fibrinogen, a modified fibrinogen which lacked the alpha chain protuberance, and serum albumin. The results were studied by electron microscopy. The exposures occurred in a well characterized flow environment at a shear rate of 135/s. All three protein species formed a film when adsorbed to carbon films. When the proteins were adsorbed to polystyrene surfaces, formation of a network was observed. Polycarbonate surfaces adsorbed the proteins both as a network and as a continuous film. It was observed that the nature of the adsorption process depended upon the specific combination of molecule and material. For example, on carbon, individual fibrinogen molecules retain their trinodular structure and adsorb randomly until a monolayer forms. On polystyrene, the individual fibrinogen molecules appear as globules and a network forms before complete coverage occurs.