[Effects of material interfaces on orientation and function of fibrinogen]

Fibrinogen (Fg) in human plasma plays an important role in hemostasis, vascular repair and tissue integrity. The surface chemistry of extracellular matrix or biological materials affects the orientation and distribution of Fg, and changes the exposure of integrin binding sites, thereby affecting its adhesion function to platelets. Here, the quantity, morphology and side chain exposure of Fg adsorbed on hydrophilic, hydrophobic and avidin surfaces were measured by atomic force microscopy (AFM) and flow cytometry (FCM), then the rolling behavior of platelets on Fg was observed through a parallel plate flow chamber system. Our results show that the hydrophobic surface leads to a large amount of cross-linking and aggregation of Fg, while the hydrophilic surface reduces the adsorption and accumulation of Fg while causing the exposure and spreading of the α chain on Fg and further mediating the adhesion of platelets. Fg immobilized by avidin / biotin on hydrophilic surface can maintain the monomer state, avoid over exposure and stretching of α chain, and bind to the platelets activated by the A1 domain of von Willebrand factor instead of inactivated platelets. This study would be helpful for improving the blood compatibility of implant biomaterials and reasonable experimental design of coagulation in vitro.