In the present study, the microemulsion-assisted co-precipitation method was utilized for the synthesis of the size-controlled silver nanoparticles and PEGylated silver nanoparticles at different pH (10–12). The nanoparticles were characterized by X-ray diffraction, Fourier-transform infra-red spectroscopy, transmission electron microscopy and energy-dispersive X-ray spectroscopy. These particles were employed for bactericidal activity against Staphylococcus aureus and compared with levofloxacin as a standard bactericidal drug. The results showed that smaller silver nanoparticles (SNPs) possessed higher antibacterial activity. The activity was further enhanced using polyethylene glycol as surface functionalization agent. The pronounced bactericidal effect can be associated to the increase in hydroxyl ions on the surface of silver nanoparticles. The sample P₅₀₀₀SNPs (PEG of M. wt. 5000) exhibited outstanding bactericidal activity against S. aureus and displayed the zone of inhibition (ZOI) 29 mm at pH 10. Furthermore, PEGylation of silver (smaller size of silver ions) with higher molecular weight has shown pronounced bactericidal effect. Therefore, PEGylated SNPs with higher molecular weight are recommended as excellent disinfectants.

在本研究中，微乳液辅助共沉淀法用于在不同pH值（10–12）下合成尺寸可控的银纳米颗粒和PEG化的银纳米颗粒。通过X射线衍射，傅里叶变换红外光谱，透射电子显微镜和能量色散X射线光谱对纳米颗粒进行表征。这些颗粒被用于针对金黄色葡萄球菌的杀菌活性。并与左氧氟沙星作为标准杀菌药物进行比较。结果表明，较小的银纳米颗粒（SNPs）具有较高的抗菌活性。使用聚乙二醇作为表面官能化剂可以进一步提高活性。明显的杀菌作用可能与银纳米颗粒表面上羟基离子的增加有关。样品P ₅₀₀₀ SNP（分子量为_5,000的PEG）对金黄色葡萄球菌具有出色的杀菌活性，在pH 10时显示29 mm的抑制区（ZOI）。此外，银的PEG化（银离子的尺寸更小）与较高的分子量显示出明显的杀菌作用。因此，推荐使用具有较高分子量的PEG化SNP作为优良的消毒剂。