Enhancing using glucose encapsulation, the efficacy of CdO NPs against multi-drug resistant Escherichia coli

In this study, monodispersed, highly biocompatible and substantially stable glucose encapsulated CdO nanoparticles (G-CdO NPs) of uniform sizes were synthesized using a sol-gel route. In addition, naked CdO (n-CdO) NPs without any capping or surface functionalization were synthesized using the same method. These NPs were uniformly dispersed in an aqueous solution. The synthesis of G-CdO and n-CdO NP was confirmed by UV-Vis spectroscopy, transmission electron microscopy (TEM), zeta potential, and dynamic light scattering analyses. The average size of G-CdO and n-CdO NP was found to be 17±1and 27 ± 1 nm, under TEM, respectively. X-ray diffraction analysis of G-CdO and n-CdO NPs confirmed their sizes to be 18.83 and 28.41 nm, respectively, and revealed their cubic crystal structures with no impurity. The surface functionalization of G-CdO NPs with glucose was confirmed by Nuclear Magnetic Resonance and Fourier-transform infrared spectroscopy analyses. As per our knowledge, this is the first report to investigate the potencies of G-CdO and n-CdO NPs against gram-negative and gram-positive multi-drug resistant (MDR) bacteria. The minimum inhibitory concentrations of G-CdO and n-CdO NPs were6.42 and 16.29 μg/ml, respectively, against Escherichia coli (NCIM 2571-MDR), whereas 7.5 μg/ml & 11.6 μg/ml, respectively against S. aureus (NCIM- 2079) as determined by the double dilution method. The minimum bactericidal concentration was determined at the concentration for which no growth was observed. TEM analysis of E. coli cells treated with G-CdO NPs revealed cell shrinkage and degraded cell membranes, while the cell surfaces of untreated viable cells were smooth.