Patel Khushbu, Singh Nimisha, Yadav Jyoti, Nayak Jyotsna M, Sahoo Suban K, Lata Jeevan, Chand Duni, Kumar Shashank, Kumar Rajender
Department of Applied Chemistry, S.V. National Institute of Technology, Surat-395007, Gujarat, India.
Phys Chem Chem Phys. 2018 Feb 21;20(8):5744-5755. doi: 10.1039/c7cp08406d.
The morphology and physicochemical properties of polydopamine are not totally inherent and undergo changes with differing reaction conditions like the choice of solvent used for polymerization. The polymerisation of dopamine to polydopamine carried out in different solvents like sodium hydroxide, sodium bicarbonate, PBS and Tris leads to polydopamine with exceptionally different morphological and physicochemical features with each solvent. Additionally, the different physicochemical characteristics and morphologies bestow the polymer films with different extents of antimicrobial activity. Moreover, the findings supported by chemical evidence from X-ray photoelectron spectroscopy reveal that higher antibacterial activities were obtained against E. coli and S. aureus with polydopamine films prepared by Tris and NaOH solvent induced polymerization. The antibacterial activity observed in saline was found to be higher than that in PBS medium for both E. coli and S. aureus. The higher antibacterial activity of polydopamine films prepared in Tris and NaOH solvents was attributed to the covalent incorporation of -OH groups on the surface provided by nucleophilic Tris and NaOH solvents during the polymerisation process. The distinct physicochemical and morphological changes were supported by the results from contact angle measurements, FE-SEM, EDAX, AFM, and XPS analysis. The present finding provides insight into the different chemistry, morphologies and properties of the designed polydopamine films with controlled antibacterial/antifouling properties. Additionally, new insights into the mechanism of formation, physicochemical changes in morphology and properties of polydopamine coatings were revealed.
聚多巴胺的形态和物理化学性质并非完全固有，会随着不同的反应条件而发生变化，如用于聚合的溶剂选择。在氢氧化钠、碳酸氢钠、磷酸盐缓冲液（PBS）和三羟甲基氨基甲烷（Tris）等不同溶剂中进行多巴胺向聚多巴胺的聚合反应，会得到具有截然不同形态和物理化学特征的聚多巴胺。此外，不同的物理化学特性和形态赋予聚合物薄膜不同程度的抗菌活性。而且，X射线光电子能谱的化学证据支持的研究结果表明，通过Tris和氢氧化钠溶剂诱导聚合制备的聚多巴胺薄膜对大肠杆菌和金黄色葡萄球菌具有更高的抗菌活性。对于大肠杆菌和金黄色葡萄球菌，在盐溶液中观察到的抗菌活性高于在PBS培养基中的抗菌活性。在Tris和氢氧化钠溶剂中制备的聚多巴胺薄膜具有更高的抗菌活性，这归因于在聚合过程中亲核性的Tris和氢氧化钠溶剂在表面提供的-OH基团的共价结合。接触角测量、场发射扫描电子显微镜（FE-SEM）、能谱分析（EDAX）、原子力显微镜（AFM）和X射线光电子能谱（XPS）分析的结果支持了明显的物理化学和形态变化。本研究结果为具有可控抗菌/防污性能的设计聚多巴胺薄膜的不同化学、形态和性质提供了见解。此外，还揭示了聚多巴胺涂层形成机制、形态和性质的物理化学变化的新见解。
