Computer Simulation Of The Interaction Between Hydrophilic Structural Surface - Modified Polyurethane Materials And GLA Domain Of Coagulation Factor

Nowadays, biomedical materials research develops so quickly. However, the experimental evaluation for material’s biocompatibility can only provide us with specific results, and it can’t explain the clotting mechanism on the molecular level. As the most direct method of theoretically investigating the behaviors of complex molecular systems, molecular modeling is very suitable for the simulation and explanation of the protein-surface interactions. So we use the molecular modeling software, Discovery Studio 2.1 for the following research. We choose the GLA domain of prothrombin(coagulation factor II) as research objects to simulate the system of protein and different hydrophilic surfaces:(1) Cationic hydrophilic structures methacrylatoethyl trimethyl ammonium chloride(DMC) and diallyl dimethyl ammonium chloride (DMDAAC) grafted polyurethane surface; (2) Anionic hydrophilic structures sodium p-styrenesulfonate(SSS) and methacrylic acid(MAA) grafted polyurethane surface; (3) Zwitterionic hydrophilic structure methacryloxyethyl sulfobetaine (DMAPS) grafted polyurethane surface; (4) Dual ionic hydrophilic structure grafted polyurethane surface interactions in the implicit solvent and explicit solvent model, respectively. In addition, the system of undisturbed protein is simulated to represent the natural behavior due to compared with other interaction systems. By comparing the relevant data (RMSD, the deformation of dihedral angle and interaction energy), the grafted polyurethane surface which most maintaining the natural behavior of protein as well as the relationship of surface properties and protein interaction can be obtained. It also can provide a theoretical basis for designing better anti-clotting biomaterials.The research provides the details of the protein-surface interactions on molecular level, and shows the change of the protein (segment) conformation caused by different surface. The results of the dynamics simulations show that the methacrylic acid(MAA) grafted polyurethane surface behaves the best to maintain the natural behavior of the protein and the optimum grafting degree of the MAA grafted polyurethane surface is around 40%. Molecular modeling provide us with a probe into protein-surface interaction, through gathering the information about the modeling systems in molecular level we can analyze the mechanism of biomaterials anti-clotting and it has important significance for the further research.