Department of Polymer Science and Engineering, University of Massachusetts , 120 Governors Drive, Amherst, Massachusetts 01003, United States.
Langmuir. 2017 Nov 28;33(47):13708-13717. doi: 10.1021/acs.langmuir.7b03391. Epub 2017 Nov 14.
Poly(2-methacryloyloxyethyl phosphorylcholine) (pMPC), when end-tethered to surfaces by the adsorption of copolymeric cationic segments, forms adsorbed layers that substantially reduce protein adsorption. This study examined variations in the molecular architecture of copolymers containing cationic poly(trimethylammonium ethyl methacrylate (pTMAEMA) anchor blocks that adsorbed strongly to negative surfaces. With appropriate copolymer design, the pTMAEMA blocks were shielded, by pMPC tethers, from solution-phase proteins. The most protein-resistant copolymer layers, eliminating fibrinogen and lysozyme adsorption within detectible limits of 0.01 mg/m, had metrics (the amount of pMPC at the surface and the reduced tether footprint) consistent with the formation of an interfacial polymer brush. The p(TMAEMA-b-MPC) copolymer layers substantially outperformed the protein resistance of surface-polymerized pMPC layers when compared on a per-polyzwitterion-mass basis or on the basis of the scaled tether area. Additionally, p(TMAEMA-b-MPC) copolymer layers offered advantages over the much-studied cationically anchored poly(ethylene glycol) (PEG) graft copolymer system, which forms PEG brushes by the adsorption of a poly l-lysine (PLL) backbone. Although the optimized p(TMAEMA-b-MPC) and PLL-PEG copolymers were similarly fibrinogen-resistant, the cationic protein lysozyme was repelled by pMPC but adhered to the PEG brush via PEG-lysozyme attractions. Additionally, the adsorbed p(TMAEMA-b-MPC) copolymers were not displaced by poly l-lysine homopolymers, which completely displaced the PLL-PEG copolymer to expose a protein-adhesive surface. Thus, the p(TMAEMA-b-MPC) copolymer system comprises a scalable means to produce protein-repellent surfaces, free of the complexities of surface-initiated polymerization and with the advantages of polyzwitterions.
聚（2-甲基丙烯酰氧乙基磷酰胆碱）（pMPC）通过吸附共聚阳离子段末端连接到表面，形成吸附层，可显著减少蛋白质吸附。本研究考察了含有阳离子聚（三甲基铵乙基甲基丙烯酸酯（pTMAEMA）锚定块的共聚物的分子结构变化，这些锚定块强烈吸附在负表面上。通过适当的共聚物设计，pTMAEMA 块被 pMPC 键合屏蔽，免受溶液相蛋白的影响。具有最抗蛋白性的共聚物层，在可检测的 0.01mg/m 范围内消除了纤维蛋白原和溶菌酶的吸附，其参数（表面上的 pMPC 量和减少的键合足迹）与界面聚合物刷的形成一致。与表面聚合的 pMPC 层相比，p(TMAEMA-b-MPC)共聚物层在每聚电解质质量基础上或按比例键合面积基础上都表现出更好的抗蛋白性能。此外，p(TMAEMA-b-MPC)共聚物层优于研究较多的阳离子锚定聚乙二醇（PEG）接枝共聚物体系，后者通过吸附聚 L-赖氨酸（PLL）主链形成 PEG 刷。尽管优化的 p(TMAEMA-b-MPC)和 PLL-PEG 共聚物具有相似的抗纤维蛋白原性，但带正电荷的蛋白质溶菌酶被 pMPC 排斥，但通过 PEG-溶菌酶相互作用粘附到 PEG 刷上。此外，吸附的 p(TMAEMA-b-MPC)共聚物不会被聚 L-赖氨酸均聚物取代，而聚 L-赖氨酸均聚物完全取代 PLL-PEG 共聚物，暴露出蛋白质粘附表面。因此，p(TMAEMA-b-MPC)共聚物系统提供了一种可扩展的方法来制备抗蛋白表面，无需涉及表面引发聚合的复杂性，并具有聚两性离子的优点。
