Preparation And Zwitterionic Modification Of Poly(Hydroxyethyl Methacrylate-co-glycidyl Methacrylate)membrane

Polyhydroxyethyl methacrylate?p HEMA?is a synthetic polymer membrane with good biocompatibility,excellent physical properties and low toxicity.It is commonly used in the preparation of contact lenses.Deposition of protein and lipidin the tears on the p HEMA hydrogelsurface may cause complications,such as bacterial infection.Itis extremely important to improvethe hydrophilicity and anti-cell adhesionproperties of p HEMA membrane surface to expand itsapplication in ophthalmology.Poly?hydroxyethyl methacrylate-co-glycidyl methacrylate?copolymer membrane?p?HEMA-co-GMA??were prepared by blue light induced-fragment chain transfer radical polymerization.Then the membranes were modifiedwithzwitterionicstructural molecules?Glycerylphosphorylcholine?GPC?,sulfobetaine?NS?and amino acid?to improve the anti-fouling ability ofmaterials.The main results are described asfollows:1.p?HEMA-co-GMA?membranes were prepared by blue light-induced electron transfer-reversible addition fragmentation radical polymerization?PET-RAFT?with?4-cyanovaleric acid?-4-dithiobenzoic acid?CPADB?as chain transfer agent and Red Y?EY?as a photocatalyst.The analysis of moisture content,contact angle and mechanical properties showed that the GMA weight content had a great influence on the properties of membranes.So the membranes with GMA mass percentage of 3%,6%,9%,12% and 15% were selected for surface modification,the illumination time was 30 h and the concentration of CPADB was 7.05 mmol/L.2.With the p?HEMA-co-GMA?membranes as a substrate,GPC was grafted onto the surface via ring opening reactionbetween hydroxyl group of GPC and epoxy groups of GMA to improve the anti-protein adsorption and anticell adhesion properties of p?HEMA-co-GMA?membrane.The hydrophilicity of the grafted p?HEMA-co-GMA?membranes were improved,the water content was above 60%,and the contact angle was reduced from 71.7° to 28.38°.After grafted zwitterions,the anti-protein adsorption capacity of p?HEMA-co-GMA?membrane was significantly increased and the lowest adsorption amount was down to 0.06129 ?g·mm^-2,which is reduced about 44.60% in comparison to the blank membrane.The membranes were considered as non-toxic and had good anti-cell adhesion properties after grafted the zwitterionic.3.Sulfobetaine?NS?was synthesized by 3-dimethylaminopropylamine and 1,3-propane sultone with a molar ratio of 1:1.1?v/v: 1.3:1?in absolute ethanol.The structure of NS was characterized by IR and 1H NMR,subsequently.A sulfobetaine zwitterion was grafted on the surface of the membrane to improve the antifouling property of the p?HEMA-co-GMA?membrane under alkaline conditions by the reaction of an epoxy ring with a primary amino group.After grafting zwitterions,the water content of p?HEMA-co-GMA?film was above 62% and the contact angle was reduced from 71.7° to 27.9° compared to the blank membrane,the thermal properties after grafting decreased slightly,and the decomposition temperature was advanced to 220 °C.The anti-protein adsorption capacityof p?HEMA-co-GMA?membranes was significantly increased and the lowest adsorption amount was down to 0.06551 ?g·mm^-2 compared with the blank membrane,the protein adsorption amount was reduced about 40.78%.The cytotoxicity test showed that theinitial and grafted membranes were basically considered to be non-toxic,and the surface of the membrane had good anti-cell adhesion properties after grafting the zwitterions.4.Zwitterionic amino acid?glycine,serine,aspartic acid and glutamic acid?were immobilized on the surface of p?HEMA-co-GMA?membranes via ring opening reaction between amino group in amino acid and epoxy groups of polymer chains.After grafting zwitterions,the water content of p?HEMA-co-GMA?membrane was above 61% and the contact angle decreased from 71.7°to 31.1°,29.9°,31.4°and 32.8° respectively.The thermal properties after grafting decreased slightly,and the decomposition temperature was advanced to about 310?.After grafted zwitterions,the anti-protein adsorption capacity of p?HEMA-co-GMA?membranes was significantly increased and the lowest adsorption amount was down to 0.0609 ?g·mm^-2,0.05991 ?g·mm^-2,0.06148 ?g·mm^-2,and 0.06379 ?g·mm^-2,which reduced the protein adsorption amount by 44.94%,45.84%,44.43% and 42.34% compared with the blank membrane.Furthermore,cytotoxicity in vitro analysis demonstrated that both initial and grafted membranes were nontoxic and biocompatible.The surface of the membrane had good anti-cell adhesion properties after grafting zwitterions.