Modified zinc oxide nanoparticles against multiresistant Enterobacteriaceae: stability, growth studies, and antibacterial activity

The development of new strategies to combat bacterial growth is a focus of many studies. Zinc oxide nanoparticles (ZnO NP) have been shown to possess great antibacterial activity. ZnO NP antibacterial activity is highly dependent on particle size, with smaller sized NP achieving higher performance. Based on this property, in the current study, we have demonstrated the formation and growth of small ZnO NP with 5 nm synthesized by a sol–gel method and characterized by small-angle X-ray scattering (SAXS). The radius of the ZnO NP increased throughout the synthesis, being more pronounced in the beginning of the synthesis (10–20 min) and continuing to grow more slowly until 180 min. The surface of the ZnO NP was modified by (3-glycidyloxypropyl) trimethoxysilane (GPTMS) dispersed in water without significant changes to the ZnO NP size. GPTMS-ZnO NP stability studies realized by zeta potential, SAXS, and UV–vis spectroscopy demonstrated that GPTMS-ZnO NP dispersed in water were stable for 62 days when stored at 5 °C and for 35 days when stored at room temperature, with no size increase detected. ZnO NP dissolve in acidic pH, are stable at alkaline pH, and form fractal aggregates at pH 7. The GPTMS-ZnO NP antibacterial activity against ESBL-producing Escherichia coli and carbapenemase (KPC)-producing Klebsiella pneumoniae was assessed. The GPTMS-ZnO NP had excellent antibacterial activity. To date, there are no studies on GPTMS-ZnO NP antibacterial activity against multiresistant Enterobacteriaceae. Thus, this study indicates that GPTMS-ZnO NP have great potential to combat multiresistant enterobacteria.