In this study, starch-based films incorporating metal oxide (MO2 ) nanoparticles (NPs) of TiO2 and SiO2 (at a concentration of 1 to 4 wt. %) were produced by solution casting method. In order to exhibit antimicrobial properties, MO2 NPs were modified by synthesizing silver (Ag) ions over the NPs using cationic adsorption method. Ag ions were then reduced to metallic Ag by sodium borohydride solution. Scanning electron microscopy showed a smooth surface for the pure starch film. Incorporating MO2 @Ag NPs in the films increased surface roughness with agglomerated NPs within starch matrix. Energy dispersive X-ray analysis exhibited a uniform dispersion of Ag-loaded MO2 NPs, which increases surface contact between these NPs and the biopolymer matrix leading to improved physical and mechanical properties of the resulting films. With increasing in the NPs concentrations, the tensile strength and elongation at break % of the films increased and decreased, respectively. Incorporating MO2 @Ag NPs into starch matrix decreased solubility in water and water vapor permeability of the obtained films, and significantly inhibited the growth of Escherichia coli and Staphylococcus aureus. The most antibacterial effect was obtained for the films containing higher weight concentrations of Ag-loaded SiO2 -NPs.

中文翻译：

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负载有Ag修饰的SiO 2 和TiO 2 纳米颗粒的生物纳米复合薄膜的物理、机械和抗菌特性

在这项研究中，通过溶液浇铸法生产了包含 TiO2 和 SiO2（浓度为 1 至 4 重量％）的金属氧化物 (MO2) 纳米颗粒 (NPs) 的淀粉基薄膜。为了表现出抗菌性能，MO2 NPs 通过使用阳离子吸附法在 NPs 上合成银 (Ag) 离子进行了修饰。然后通过硼氢化钠溶液将银离子还原为金属银。扫描电子显微镜显示纯淀粉膜表面光滑。在薄膜中加入 MO2 @Ag NPs 会增加表面粗糙度，并在淀粉基质中聚集 NPs。能量色散 X 射线分析显示出负载 Ag 的 MO2 NPs 的均匀分散，这增加了这些 NPs 与生物聚合物基质之间的表面接触，从而改善了所得薄膜的物理和机械性能。随着NPs浓度的增加，薄膜的拉伸强度和断裂伸长率分别增加和减少。将MO2@Ag NPs掺入淀粉基质中降低了所得薄膜的水溶性和水蒸气渗透性，并显着抑制了大肠杆菌和金黄色葡萄球菌的生长。含有更高重量浓度的载银 SiO2 -NPs 的薄膜获得了最大的抗菌效果。