Adsorption characteristics of bovine serum albumin on the surface of 316L stainless steel coated with diethoxydimethylsilane/chitosan composite films

In this study, diethoxydimethylsilane (DEDMS) was blended with chitosan (CS) to fabricate DEDMS/CS composite films, which were deposited on the surface of 316L stainless steel to assess their anticoagulant properties. A neat CS film exhibits a high concentration of bovine serum albumin (BSA) protein adhesion of 458.3 ± 6.2 μg/L in a bicinchoninic acid protein assay because the carbonyl and amide functional groups on the CS surface easily form hydrogen bonds with the carboxylic acid functional groups of the BSA protein. The DEDMS/CS composite films exhibited lower BSA adhesion concentration than neat CS films because some of the carbonyl and amide functional groups on the surface of CS were replaced by the –Si-O-Si and –Si-(CH3)2 functional groups. Increasing the DEDMS content in the DEDMS/CS composite films led to a higher concentration of –Si-O-Si and –Si-(CH3)2 functional groups on the surface and lower BSA adhesion concentration. Blending excess amounts of DEDMS caused an undesirable rougher surface morphology because of the hydrolysis and self-condensation reactions of DEDMS; this deteriorated the anticoagulant properties of the composite films. The study confirmed that a DEDMS/CS composite film with an appropriate DEDMS/CS content ratio of 8/92 mL/mL possesses hydrophobic characteristics and the lowest BSA protein adhesion of 155.5 ± 1.0 μg/L and has potential for biomedical coating applications.