Molecular Dynamics Simulations of Surface Hydration Layers Near Non-fouling Polymer Membranes

作者：Zhang Heng^*; Wang Hua; Lin Cunguo; Wang Li; Yuan Shiling

来源：Acta Chimica Sinica, 2013, 71(4): 649-656.

DOI：10.6023/A13010068

• poly-dimethylsiloxane
• poly-sulfobetaine methacrylate
• bio-fouling
• non-fouling material
• molecular dynamics

The prevention of nonspecific protein adsorption was a big challenge in biomedical and marine fields. Recent studies of the mechanisms of non-fouling materials have identified a strong correlation between material surface hydration and resistance to nonspecific protein adsorption. To investigate the molecular mechanism of two typical non-fouling materials PDMS and pSBMA on molecular level, a series of molecular dynamics simulations were conducted. This work concentrated on the structure properties and dynamic behaviors of water molecules that belong to the non-fouling membranes' surface hydration layers. Water's behavior near the membrane were analyzed in energetic, dynamics and structure aspects: PMFs (potential of mean force) between hydration layer water and polymer surfaces indicated pSBMA has more advantages on binding water molecules energetically; the analyzing of diffusion coefficients, residence time, and dipole residence time of hydration layer water showed pSBMA has slower dynamics properties which demonstrate water molecules were tightly bonded by pSBMA; the illustration of atoms density profile, hydrogen bond and their number distribution showed a rich hydrogen bond network structure around pSBMA. Based on above, following conclusions were then speculated: 1) the hydration layer near non-fouling membrane has a strong relationship with the nonspecific protein adsorption which forms a physical and energy barrier during particles in solution (including proteins) come into contact with non-fouling membranes. 2) Comparing with PDMS, pSBMA as a zwitterionic polymer can bind water molecules more strongly via both electrostatic and hydrogen bonding. And the caging effects of water network formed around pSBMA can also reduce water molecules' mobility. All these lead to a stable hydration layer that prevents non-specific protein adsorption. Simply, pSBMA generated a more energetic advantaged, tightly bounded and structured water layer by electrostatic, hydrogen bonding and caging effect. This hydration layer prevents protein from approaching the surface, resulting in a better non-fouling surface than PDMS.

• 出版日期2013-4-15
• 单位山东大学; 中国船舶重工集团公司第七二五研究所