Molecular dynamics study on adsorption and desorption of lysozyme above polymer antifouling membranes

Due to the lack of molecular understanding of the adsorption mechanism of protein on the surface of antifouling materials’ surface, the rational design and optimization of antifouling coatings are limited. In this work, a series of molecular dynamics simulations were conducted to study the adsorption and desorption of lysozyme above three kinds of antifouling polymer membranes, i.e. poly(sulfobetaine methacrylate) (T4-SB), poly(3-(methacryloyloxy)propane-1-sulfonate) (T4-SP), and poly(2-(dimethylamino)ethyl methacrylate) (T4-DM) grafted on polysiloxane membranes. The adsorption configuration, adsorption process, binding sites and energy, stability after adsorption and desorption ability were analyzed to reveal the adsorption and desorption mechanisms. The following conclusions were derived. The adsorption of lysozyme above T4-SB was the hardest, which is consistent with our previous work that the strongest hydration layer above T4-SB served as a physical and energy barrier to protein adsorption. The interaction between lysozyme and antifouling membranes after adsorption follows the ranking of T4-SP > T4-SB > T4-DM. The structure of lysozyme was not changed during adsorption onto all antifouling surfaces, except that the binding areas were slightly affected. The desorption ability of lysozyme above T4-DM was the worst as it adsorbed with the largest radius parallel to the surface.