Design, Preparation And Properties Of Zwitterionic Polymers For Constructing Biomimetic Anti-bioadhesive Surfaces

It is of great significance to decrease or eliminate the bioadhesion on surfaces in thefields of marine antifouling, separation membrane materials, biomedical materials and so on.The studies have indicated that the excellent anticoagulation and anti-bioadhesion of the cellouter membrane are resulted from the phosphorylcholine (PC), a head group ofphospholipids consisting in the cell outer membrane. This finding provides us with a perfectbiomimetic template for constructing anti-bioadhesive surfaces. Inspired by it, a researchthought of constructing biomimetic anti-bioadhesive surfaces is put forward using thechemical composition and molecular structure of the cell outer membrane as a chemicallybiomimetic template. Based on the understanding of the structure and charateristic of PC,the biomimetic surfaces bearing zwitterionic groups can be constructed by modifying asubstrate surface with zwitterionic compouds similar to the chemical structure of PC, thusendowing the modified surfaces with excellent performance of anti-bioadhesion. However,the zwitterionic compouds or polymers currently used as an interfacial material have only alimited application due to their poor mechanical properties and low adhesive strength to thesubstrate surface to be modified.To solve this problem, the betaine zwitterionic monomers containing a double bond orhydroxyl groups were designed and synthesized, and then a series of the reactivezwitterionic copolymers and the zwitterionic polyurethane with different zwitterion contentswere synthesized by the radical polymerization of zwitterionic monomers containing adouble bond and glycidyl methacrylate and the reaction between the zwitterionic monomercontaining hydroxyl groups and isocyanate, respectively. On the basis of this, the stablebiomimetic anti-bioadhesive surfaces with zwitterions were prepared using a glass slide as asubstrate via the graft modification of surface or the method of surface coating. Thehydrophilicity and the morphology of the prepared biomimetic surfaces were characterizedby measuring water contact angle and AFM images, and their antibacterial adhesionperformance is evaluated through an antibacterial adhesion test. The results show that on thesurfaces modified with sulfobetanie or carboxybetaine zwitterionic polymers whosezwitterion content ranges between50and90mol%, the water contact angle will change within the range of30qa37q and22qa29q, respectively. The water contact angle on thebiomimetic surface coated with zwitterionic polyurethane is smaller than that on the controlsurface modified with polyurethane without zwitterion (86.5q). On the surfaces modifiedwith sulfobetanie or carboxybetaine zwitterionic polyurethane with22.91wt%or19.15wt%zwitterion content, the water contact angle is58.3and55.1, respectively. As thezwitterion content increases, the contact angle on the biomimetic surfaces bearingzwitterion will decrease and the hydrophilicity will be enhanced. The AFM images showthat the microphase separation structure can be observered on the surface modified withzwitterionic polyurethane, and the degree of microphase separation will become moreobvious with an increase in the zwitterion content. Compared to the unmodified glass slidesas a control sample, the number of bacterial adhesion on the biomimetic surfaces modifiedwith the reactive zwitterionic copolymer or the zwitterionic polyurethane can decreaseobviously, thereby exhibiting excellent performance of antibacterial adhesion.