Department of Chemical Engineering, National Chung Hsing University, Taichung, 40227 Taiwan, ROC.
ACS Appl Mater Interfaces. 2012 Jan;4(1):338-50. doi: 10.1021/am2014103. Epub 2011 Dec 16.
A novel method to exfoliate the montmorillonite clay was developed previously to generate random nanosilicate platelets (NSP), one kind of delaminated clay. To improve their dispersion in a polymer, we modified NSPs by three types of surfactants (cationic Qa, nonionic Qb, and anionic Qc) in this study and used them to prepare nanocomposites with polyurethane (PU). The zeta potential, antimicrobial ability, and biocompatibility of these surfactant-modified NSPs (abbreviated "NSQ") were characterized. It was found that the zeta potential of Qa-modified NSP (NSQa) was positive, whereas those of NSP and the other two NSQs (NSQb and NSQc) were negative. All NSQ presented less cytotoxicity than NSP. NSQa and NSQc showed excellent antimicrobial activities against S. aureus (Gram-positive strain) and E. coli (Gram-negative strain). The nanocomposites of NSQ with PU were then characterized for surface and mechanical properties, cell attachment and proliferation, antimicrobial activity in vitro, and biocompatibility in vivo. A higher surfactant to NSP ratio was found to improve the dispersion of NSQ in PU matrix. The mechanical properties of all PU/NSQ nanocomposites were significantly enhanced. Among various NSQ, only NSQa were observed to migrate to the composite surface. The attachment and proliferation of endothelial cells and fibroblasts in vitro as well as biocompatibility in vivo were significantly better for PU/NSQa containing 1% of NSQa than other materials. The microbiostasis ratios of PU/NSQ nanocomposites containing 1% NSQa or NSQc were >90%. These results proposed the safety and potential antimicrobial applications of surfactant-modified delaminated clays and their nanocomposites with PU polymer.
先前开发了一种将蒙脱石粘土剥离的新方法，以生成随机纳米硅酸盐片（NSP），这是一种层状粘土。为了改善它们在聚合物中的分散性，我们在这项研究中使用三种类型的表面活性剂（阳离子 Qa、非离子 Qb 和阴离子 Qc）对 NSP 进行改性，并使用它们与聚氨酯（PU）制备纳米复合材料。对这些表面活性剂改性的 NSP（缩写为“NSQ”）的 ζ 电位、抗菌能力和生物相容性进行了表征。结果发现，Qa 改性 NSP（NSQa）的 ζ 电位为正，而 NSP 和另外两种 NSQ（NSQb 和 NSQc）的 ζ 电位为负。所有 NSQ 的细胞毒性均低于 NSP。NSQa 和 NSQc 对金黄色葡萄球菌（革兰氏阳性菌）和大肠杆菌（革兰氏阴性菌）表现出优异的抗菌活性。然后对 NSQ 与 PU 的纳米复合材料进行了表面和机械性能、细胞附着和增殖、体外抗菌活性以及体内生物相容性的表征。发现表面活性剂与 NSP 的比例越高，NSQ 在 PU 基质中的分散性越好。所有 PU/NSQ 纳米复合材料的机械性能均显著提高。在各种 NSQ 中，只有 NSQa 被观察到迁移到复合材料表面。体外内皮细胞和成纤维细胞的附着和增殖以及体内生物相容性，对于含有 1% NSQa 的 PU/NSQa 均优于其他材料。含有 1% NSQa 或 NSQc 的 PU/NSQ 纳米复合材料的抑菌率均>90%。这些结果表明，经表面活性剂改性的层状粘土及其与 PU 聚合物的纳米复合材料具有安全性和潜在的抗菌应用。
