Abstract：
Planktonic bacterial presence in many industrial and environmental applications and personal health-care products is generally countered using antimicrobials. However, antimicrobial chemicals present an environmental threat, while emerging resistance reduces their efficacy. Suspended bacteria have no defense against mechanical attack. Therefore, we synthesized silica hexapods on an α-Fe2O3 core that can be magnetically-rotated to inflict lethal cell-wall-damage to planktonic Gram-negative and Gram-positive bacteria. Hexapods possessed 600 nm long nano-spikes, composed of SiO2, as shown by FTIR and XPS. Fluorescence staining revealed cell wall damage caused by rotating hexapods. This damage was accompanied by DNA/protein release and bacterial death that increased with increasing rotational frequency up to 500 rpm. Lethal puncturing was more extensive on Gram-negative bacteria than on Gram-positive bacteria, which have a thicker peptidoglycan layer with a higher Young\'s modulus. Simulations confirmed that cell-wall-puncturing occurs at lower nano-spike penetration levels in the cell walls of Gram-negative bacteria. This approach offers a new way to kill bacteria in suspension, not based on antimicrobial chemicals.
摘要：
在许多工业和环境应用和个人健康护理产品中存在的浮游细菌通常使用抗微生物剂来对抗。然而,抗菌化学品对环境造成威胁,而出现的抗性降低了它们的功效。悬浮细菌对机械攻击没有防御作用。因此,我们在α-Fe2O3核心上合成了二氧化硅六足动物，该核心可以磁性旋转以对浮游革兰氏阴性和革兰氏阳性细菌造成致命的细胞壁损伤。六足动物具有600纳米长的纳米尖峰，由SiO2组成，如FTIR和XPS所示。荧光染色显示旋转六足动物引起的细胞壁损伤。这种损伤伴随着DNA/蛋白质释放和细菌死亡，随着旋转频率增加到500rpm而增加。革兰氏阴性细菌的致死性穿刺比革兰氏阳性细菌更广泛，其具有较厚的肽聚糖层，具有较高的杨氏模量。模拟证实,在革兰氏阴性细菌的细胞壁中,细胞壁穿刺发生在较低的纳米尖峰穿透水平。这种方法提供了一种杀死悬浮液中细菌的新方法，不是基于抗菌化学品。
