Fibrinogen and lysozyme adsorption on amorphous carbon film surface detected by multilayer device from the back side of the film

To develop hydrogenated amorphous carbon (a-C:H) as a biocompatible coating, a-C:H was studied in terms of its protein adsorption during the initial process of cell adsorption. A multilayer surface plasmon resonance (SPR) device consisting of an a-C:H layer on Au was built in the Kretschmann configuration to detect protein adsorption on an a-C:H film surface. From the dependence of reflectivity on the laser incident angle, SPR angle was determined to the incident angle in which the light intensity was reduced drastically. The proteins considered were lysozyme (Lyz) and fibrinogen (Fib). The SPR angle increased from 58.09 to 58.69° upon the adsorption of Lyz when the nonadsorbed Lyz was removed after introduction of 20 μM Lyz-containing solution. Upon the adsorption of Fib, the SPR angle increased from 60.95 to 61.76° when the nonadsorbed Fib were removed after the introduction of 0.4 μM Fib-containing solution. The shift in the SPR angle was small for both cases. Obtained results suggested that the number of adsorbed Lyz was higher than that of adsorbed Fib.

Research Highlights► A multilayer surface plasmon resonance (SPR) device consisting of an a-C:H layer on Au was applied to detect lysozyme and fibrinogen adsorption on an a-C:H film surface. ► The SPR angle increased from 58.09 to 58.69 degrees upon the adsorption of Lyz on 20 mM Lyz-containing solution. ► The SPR angle increased from 60.95 to 61.76 degrees upon the adsorption of Fib on 0.4 mM Fib-containing solution. ► Obtained results suggested that the number of adsorbed Lyz was higher than that of adsorbed Fib.