Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Akron, Ohio 44325, United States.
Department of Polymer Engineering, The University of Akron, Akron, Ohio 44325, United States.
Langmuir. 2020 Mar 24;36(11):2757-2766. doi: 10.1021/acs.langmuir.0c00165. Epub 2020 Mar 11.
Antifouling materials and coatings have broad fundamental and practical applications. Strong hydration at polymer surfaces has been proven to be responsible for their antifouling property, but molecular details of interfacial water behaviors and their functional roles in protein resistance remain elusive. Here, we computationally studied the packing structure, surface hydration, and protein resistance of four poly(-hydroxyalkyl acrylamide) (PAMs) brushes with different carbon spacer lengths (CSLs) using a combination of molecular mechanics (MM), Monte Carlo (MC), and molecular dynamics (MD) simulations. The packing structure of different PAM brushes were first determined and served as a structural basis for further exploring the CSL-dependent dynamics and structure of water molecules on PAM brushes and their surface resistance ability to lysozyme protein. Upon determining an optimal packing structure of PAMs by MM and optimal protein orientation on PAMs by MC, MD simulations further revealed that poly(-hydroxymethyl acrylamide) (pHMAA), poly(-(2-hydroxyethyl)acrylamide) (pHEAA), and poly(-(3-hydroxypropyl)acrylamide) (pHPAA) brushes with shorter CSLs = 1-3 possessed a much stronger binding ability to more water molecules than a poly(-(5-hydroxypentyl)acrylamide) (pHPenAA) brush with CSL = 5. Consequently, CSL-induced strong surface hydration on pHMAA, pHEAA, and pHPAA brushes led to high surface resistance to lysozyme adsorption, in sharp contrast to lysozyme adsorption on the pHPenAA brush. Computational studies confirmed the experimental results of surface wettability and protein adsorption from surface plasmon resonance, contact angle, and sum frequency generation vibrational spectroscopy, highlighting that small structural variation of CSLs can greatly impact surface hydration and antifouling characteristics of antifouling surfaces, which may provide structural-based design guidelines for new and effective antifouling materials and surfaces.
具有抗污性能的材料和涂料具有广泛的基础和实际应用。聚合物表面的强水合作用已被证明是其抗污性能的原因，但界面水分子行为的分子细节及其在蛋白质抗阻中的功能作用仍不清楚。在这里，我们使用分子力学 (MM)、蒙特卡罗 (MC) 和分子动力学 (MD) 模拟相结合，计算研究了具有不同碳间隔长度 (CSL) 的四种聚(-羟烷基丙烯酰胺) (PAMs) 刷的堆积结构、表面水合作用和蛋白质抗阻性。首先确定了不同 PAM 刷的堆积结构，为进一步研究水分子在 PAM 刷上的 CSL 依赖性动力学和结构及其表面抵抗溶菌酶蛋白的能力提供了结构基础。通过 MM 确定 PAMs 的最佳堆积结构和 MC 确定 PAMs 上的最佳蛋白质取向后，MD 模拟进一步表明，具有较短 CSL = 1-3 的聚(-羟甲基丙烯酰胺) (pHMAA)、聚(-(2-羟乙基)丙烯酰胺) (pHEAA) 和聚(-(3-羟丙基)丙烯酰胺) (pHPAA) 刷比具有 CSL = 5 的聚(-(5-羟戊基)丙烯酰胺) (pHPenAA) 刷具有更强的结合更多水分子的能力。因此，CSL 诱导的 pHMAA、pHEAA 和 pHPAA 刷上的强表面水合作用导致对溶菌酶吸附的高表面阻力，与溶菌酶在 pHPenAA 刷上的吸附形成鲜明对比。计算研究证实了表面润湿性和蛋白质吸附的实验结果来自表面等离子体共振、接触角和和频产生振动光谱，突出了 CSL 的微小结构变化可以极大地影响抗污表面的表面水合作用和抗污特性，这可能为新型有效抗污材料和表面提供基于结构的设计指导。
