IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA.
ACS Nano. 2012 Oct 23;6(10):9191-9. doi: 10.1021/nn3035217. Epub 2012 Oct 1.
With the increased prevalence of antibiotic-resistant infections, there is an urgent need for innovative antimicrobial treatments. One such area being actively explored is the use of self-assembling cationic polymers. This relatively new class of materials was inspired by biologically pervasive cationic host defense peptides. The antimicrobial action of both the synthetic polymers and naturally occurring peptides is believed to be complemented by their three-dimensional structure. In an effort to evaluate shape effects on antimicrobial materials, triblock polymers were polymerized from an assembly directing terephthalamide-bisurea core. Simple changes to this core, such as the addition of a methylene spacer, served to direct self-assembly into distinct morphologies-spheres and rods. Computational modeling also demonstrated how subtle core changes could directly alter urea stacking motifs manifesting in unique multidirectional hydrogen-bond networks despite the vast majority of material consisting of poly(lactide) (interior block) and cationic polycarbonates (exterior block). Upon testing the spherical and rod-like morphologies for antimicrobial properties, it was found that both possessed broad-spectrum activity (Gram-negative and Gram-positive bacteria as well as fungi) with minimal hemolysis, although only the rod-like assemblies were effective against Candida albicans.
随着抗生素耐药感染的增加，迫切需要创新的抗菌治疗方法。正在积极探索的一个领域是使用自组装阳离子聚合物。这类相对较新的材料受到生物广泛存在的阳离子宿主防御肽的启发。人们认为，合成聚合物和天然存在的肽的抗菌作用与其三维结构相辅相成。为了评估形状对抗菌材料的影响，从组装导向对苯二甲酰胺-双脲核聚合了三嵌段聚合物。对该核进行简单的改变，例如添加亚甲基间隔物，可将自组装引导成不同的形态 - 球体和棒体。计算建模还表明，即使材料的绝大部分由聚（乳酸）（内部嵌段）和阳离子聚碳酸酯（外部嵌段）组成，核心的微小变化如何直接改变脲堆积模式，从而表现出独特的多向氢键网络。在测试球形和棒状形态的抗菌特性时，发现两者都具有广谱活性（革兰氏阴性和革兰氏阳性细菌以及真菌），并且溶血作用最小，尽管只有棒状组装对白色念珠菌有效。
