Chitosan derived from chitin is one of the most abundant naturally occurring biocompatible polymers obtained from fungi and arthropods. In this work, we report the enhancement in the bactericidal efficacy of CHI in the presence of a sharp nanotopography. High-aspect ratio nanostructured surface (NSS) was fabricated using a single-step deep reactive ion etching technique (DRIE). Post fabrication, CHI coating was carried out using a layer-by-layer (LBL) dip coating process on the flat and nanostructured surfaces. Antibacterial efficacy of the flat silicon surface coated with CHI (Si_CHI) and NSS coated with CHI (NSS_CHI) was tested against both Gram-negative (G-ve) bacteria E. coli and Gram-positive (G+ve) bacteria S. aureus. NSS_CHI exhibited superior antibacterial property against G-ve and G+ve microbes as compared with Si_CHI and NSS substrates. Scanning electron microscopy (SEM) and fluorescence microscopy were used to study the morphology and viability of the bacteria on all the surfaces. Also, biofilm quantification was carried out on all the engineered surfaces for both E. coli and S. aureus using crystal violet (CV) staining. NSS_CHI was found to have the minimum biofilm formation on its surface exhibiting its superior antibacterial property. This study shows that the antibacterial and antibiofilm efficiency of CHI can be augmented by combining it with a sharp nanotopography.

中文翻译：

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受生物启发的纳米形貌对壳聚糖的抗菌和抗生物膜功效的影响

衍生自甲壳质的壳聚糖是从真菌和节肢动物中获得的最丰富的天然生物相容性聚合物之一。在这项工作中，我们报告了在存在锐利的纳米形貌的情况下CHI的杀菌功效的增强。使用一步深反应离子刻蚀技术（DRIE）制作了高纵横比的纳米结构表面（NSS）。在制造后，在平坦和纳米结构的表面上使用逐层（LBL）浸涂工艺进行CHI涂层。测试了涂有CHI（Si_CHI）和NSS涂有CHI（NSS_CHI）的扁平硅表面对革兰氏阴性（G-ve）细菌大肠杆菌和革兰氏阳性（G + ve）细菌金黄色葡萄球菌的抗菌功效。。与Si_CHI和NSS底物相比，NSS_CHI对G-ve和G + ve微生物表现出优异的抗菌性能。扫描电子显微镜（SEM）和荧光显微镜用于研究细菌在所有表面的形态和生存能力。同样，使用结晶紫（CV）染色在大肠杆菌和金黄色葡萄球菌的所有工程化表面上进行生物膜定量。发现NSS_CHI在其表面上具有最小的生物膜形成，表现出其卓越的抗菌性能。这项研究表明，通过与锐利的纳米形貌相结合，可以提高CHI的抗菌和生物膜效率。