Zinc oxide nanoparticles (ZnO NPs) are known as a multifunctional material because of its unique physical and chemical properties. The result of zinc oxide nano powder was characterized using various analytical techniques, such as UV-Vis spectroscopy, Fourier Transform Infra-Red (FTIR), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) patterns. Synthesized zinc oxide nano powder was stored in dried form in the room temperature for further study. Sharp and stable plasmon peak were monitored at 390nm. The size of ZnO NPs obtained in the range of 20-24nm as reported by TEM. The shape and size again confirmed by using SEM. The synthesis ZnO NPs in the form of crystalline nature and particle size again in the range of 20-24nm were observed in XRD pattern and clearly indicate that the zinc nitrate acted both as reducing and capping agents in the formation of ZnO NPs. Successfully synthesized of ZnO NP binds with an antibiotic ciprofloxacin. ZnO NP was then amine functionalized by using a saline coupling agent aminopropyltriethoxysilane under refluxing condition using dimethyl sulphoxide as the solvent. Ciprofloxacin was then conjugated with ZnO NP using EDC/NHS chemistry to produce ciprofloxacin conjugated zinc oxide nanoparticle (ZnO-CIPNPs). Conjugation was confirmed by UV-Vis spectroscopy and exhibited significant antibacterial activity 5.2 cm in Klebsiella spp. followed by 3.2 cm in E. coli, 2.9 in B. subtilis and 2.8 in Streptococcus spp. against pathogenic bacteria of gram negative and positive respectively. It showed that, when antibiotic ciprofloxacin was conjugated with ZnO NPs, the conjugated system was successfully able to produce an overwhelming response against pathogenic bacteria. ZnO NPs linchpin of the bacterial cell membrane and damaged the it through reactive oxygen species (ROS) generation with free electrons and holes in presence of light, which assisted antibiotic ciprofloxacin to enter into the cell and, thereby, inhibit bacterial growth. Keywords: Antibiotic ciprofloxacin, FTIR, reactive oxygen species, SEM, TEM, XRD pattern, zinc oxide nanoparticles
