In this study, copper nanoparticles (CuNPs) were synthesized using the extract of Opuntia ficus - Indica and Geranium as a reducing agent. By transmission electron microscopy, the morphology of the nanoparticles was determined to be mostly spherical, with a particle size about 3–10 nm. The UV–Vis spectra displayed absorption bands between 525 and 550 nm, associated with the surface plasmon resonance in the CuNPs. The various particle sizes obtained were tested as SERS substrate with the pyridine molecule. Antibacterial activity of copper nanoparticles against Escherichia coli gram-negative bacteria was studied. Bacteriological inhibition tests were performed on nutrient agar plates supplemented with different concentrations of copper nanoparticles. The copper nanoparticles with a concentration of 150 μg/mL and a size distribution around 6 nm showed the largest bactericidal effectiveness against E. coli.

中文翻译：

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绿色化学获得的铜纳米粒子的表面增强拉曼散射和抗菌性能

在这项研究中，使用仙人掌 - 籼和天竺葵的提取物作为还原剂合成了铜纳米粒子 (CuNPs)。通过透射电子显微镜，确定纳米颗粒的形态主要是球形，粒径约为 3-10 nm。UV-Vis 光谱显示出 525 到 550 nm 之间的吸收带，这与 CuNP 中的表面等离子体共振有关。将获得的各种粒径作为具有吡啶分子的 SERS 底物进行测试。研究了铜纳米颗粒对大肠杆菌革兰氏阴性菌的抗菌活性。在补充有不同浓度铜纳米颗粒的营养琼脂平板上进行细菌学抑制试验。