Stepwise Assembly of Fibrin Bilayers on Self-Assembled Monolayers of Alkanethiolates: Influence of Surface Chemistry

Abstract

Fibrin bilayers are formed in a stepwise manner on four model surfaces: hydrophobic, neutral hydrophilic, positively charged, and negatively charged. These surfaces are self-assembled monolayers (SAMs) of alkanethiolates on gold with different terminal groups. A surface plasmon resonance (SPR) sensor is used to monitor the formation of fibrin bilayers in real time. The structures of the fibrin bilayers formed on SAMs of different surface chemistries are proposed, based on the amount of fibrinogen in each layer. The efficiency of the physically adsorbed fibrinogen to promote fibrin formation is assessed by the ratio of the amount of fibrinogen in the second layer to that in the first layer. It is shown for the first time that the orientation/conformation of an adsorbed fibrinogen layer determined by underlying surface chemistry affects its reactivity with soluble fibrinogen, resulting in fibrin bilayers with different molecular arrangements. Bovine aortic endothelial cells cultured on fibrin bilayers formed on CH3− and OH− SAMs exhibited different morphologies and growth characteristics. Results show that fibrin bilayers with different molecular arrangements and thus different mechanochemical properties lead to different cellular responses.