The multi-faceted mechano-bactericidal mechanism of nanostructured surfaces
The multi-faceted mechano-bactericidal mechanism of nanostructured surfaces
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DOI：
10.1073/pnas.1916680117
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发表时间：
2020-06-09
影响因子：
11.1
通讯作者：
Crawford, Russell J.
中科院分区：
文献类型：
--
作者：
Ivanova, Elena P.;Linklater, Denver P.;Crawford, Russell J.
纳米结构表面的机械杀菌活性已成为开发新一代抗菌表面的深入研究的焦点，特别是在当前抗生素耐药性不断出现的时代。这项工作证明了纳米柱高度的增量增加对纳米结构诱导的细菌细胞死亡的影响。我们提出，细菌细胞的机械裂解可能受到高度有序的硅纳米柱阵列的弹性程度和聚集程度的影响。在此，使用深紫外浸没式光刻技术制造了直径为 35 nm、周期为 90 nm、高度增加为 220、360 和 420 nm 的硅纳米柱阵列。 360 nm 高度的纳米阵列对革兰氏染色阴性铜绿假单胞菌和革兰氏染色阳性金黄色葡萄球菌细菌表现出最高程度的杀菌活性，分别诱导 95 +/- 5% 和 83 +/- 12% 的细胞死亡。在 360 nm 的高度，增加的纳米柱弹性有助于响应细菌粘附到表面而发生柱变形。柱弹性的理论分析证实，对于具有更柔性柱的基底，挠度、变形力和机械能更为重要。机械能的储存和释放的增加可以解释这些纳米柱阵列对接触表面的细菌细胞的增强的杀菌作用；然而，随着纳米柱高度（420 nm）的进一步增加，力（和张力）可以通过不可逆的柱间粘附来部分补偿，从而降低其杀菌效果。这些发现可用于为抗菌表面技术的具有可调杀菌特性的下一代机械响应表面的设计提供信息。
The mechano-bactericidal activity of nanostructured surfaces has become the focus of intensive research toward the development of a new generation of antibacterial surfaces, particularly in the current era of emerging antibiotic resistance. This work demonstrates the effects of an incremental increase of nanopillar height on nanostructure-induced bacterial cell death. We propose that the mechanical lysis of bacterial cells can be influenced by the degree of elasticity and clustering of highly ordered silicon nanopillar arrays. Herein, silicon nanopillar arrays with diameter 35 nm, periodicity 90 nm and increasing heights of 220, 360, and 420 nm were fabricated using deep UV immersion lithography. Nanoarrays of 360-nm-height pillars exhibited the highest degree of bactericidal activity toward both Gram stain-negative Pseudomonas aeruginosa and Gram stain-positive Staphylococcus aureus bacteria, inducing 95 +/- 5% and 83 +/- 12% cell death, respectively. At heights of 360 nm, increased nanopillar elasticity contributes to the onset of pillar deformation in response to bacterial adhesion to the surface. Theoretical analyses of pillar elasticity confirm that deflection, deformation force, and mechanical energies are more significant for the substrata possessing more flexible pillars. Increased storage and release of mechanical energy may explain the enhanced bactericidal action of these nanopillar arrays toward bacterial cells contacting the surface; however, with further increase of nanopillar height (420 nm), the forces (and tensions) can be partially compensated by irreversible interpillar adhesion that reduces their bactericidal effect. These findings can be used to inform the design of next-generation mechano-responsive surfaces with tuneable bactericidal characteristics for antimicrobial surface technologies.