ABSTRACT

Ciprofloxacin (CIP) antibiotic was loaded on silver nanoparticles (AgNPs), which were prepared by three different methods to enhance their antibacterial activity against Gram-negative (Escherichia coli) bacteria and Gram-positive (Staphylococcus aureus) bacteria. AgNPs were prepared by using sodium borohydride (NaBH4), lactose and sodium citrate followed by one-year aging, in order to produce a uniform prism shape. Finally, the synthesized AgNPs were functionalized with CIP to form composite of AgNPs-CIP. Various analytical techniques were used to characterize the prepared nanocomposites such as ultraviolet-visible (UV-Vis) absorption spectra, Fourier-transform infrared spectroscopy (FTIR) and transmission electron microscope (TEM). TEM images showed some differences in average particle size of AgNPs and their distribution according to the preparation methods. Disc diffusion method was used to investigate the antibacterial activity of AgNPs-CIP composites. Results showed a significant improvement in antibacterial activity against both classes of bacteria especially for the prism AgNPs-CIP. Owing to nanoprisms vertexes and edges which facilities the penetration of Ag ions into the cell wall. AgNPs-CIP composites exhibited higher antibacterial activity against Gram-positive than Gram-negative bacteria due to the differences in bacteria cell walls compositions between the two types.

摘要

将环丙沙星（CIP）抗生素装载在银纳米颗粒（AgNPs）上，这些银纳米颗粒通过三种不同的方法制备，以增强其对革兰氏阴性（Escherichia coli）和革兰氏阳性（Staphylococcus aureus）细菌的抗菌活性。通过使用硼氢化钠（NaBH4），乳糖和柠檬酸钠，然后老化一年，制备AgNP，以产生均匀的棱柱形状。最后，将合成的AgNPs用CIP功能化以形成AgNPs-CIP的复合物。各种分析技术被用来表征制备的纳米复合材料，例如紫外-可见（UV-Vis）吸收光谱，傅里叶变换红外光谱（FTIR）和透射电子显微镜（TEM）。TEM图像表明，根据制备方法，AgNPs的平均粒径及其分布存在一些差异。采用圆盘扩散法研究AgNPs-CIP复合材料的抗菌活性。结果表明，对两类细菌的抗菌活性都有显着提高，尤其是对棱镜AgNPs-CIP。由于纳米棱镜的顶点和边缘，使Ag离子渗透进入细胞壁。由于两种类型之间细菌细胞壁组成的差异，AgNPs-CIP复合材料对革兰氏阳性菌的抑制作用要高于革兰氏阴性菌。结果表明，对两类细菌的抗菌活性都有显着提高，尤其是对于棱镜AgNPs-CIP。由于纳米棱镜的顶点和边缘，使Ag离子渗透进入细胞壁。由于两种类型之间细菌细胞壁组成的差异，AgNPs-CIP复合材料对革兰氏阳性菌的抑制作用要比革兰氏阴性菌高。结果表明，对两类细菌的抗菌活性都有显着提高，尤其是对棱镜AgNPs-CIP。由于纳米棱镜的顶点和边缘，使Ag离子渗透进入细胞壁。由于两种类型之间细菌细胞壁组成的差异，AgNPs-CIP复合材料对革兰氏阳性菌的抑制作用要比革兰氏阴性菌高。