Enhanced antibacterial activity of Cr doped ZnO nanorods synthesized using microwave processing

Abstract

In this work we concentrate on enhancing the antibacterial activity of ZnO nanoparticles by Cr doping, synthesized using a microwave assisted method. The obtained nanoparticles were systematically characterized by X-ray diffraction, Fourier transformation infrared spectroscopy, UV-Vis spectroscopy and field emission scanning microscopy, and the results were correlated. Powder diffraction patterns reveal that Cr is incorporated into the ZnO crystal lattice without disturbing the original wurtzite crystal structure. The vibrational spectra show significant shifts in the peaks with Cr addition, indicating the successful incorporation of Cr ions into ZnO. Optical absorption measurements reveal that the band gap of ZnO decreased from 3.19 to 3.09 eV, which confirmed the existence of a ZnO-Cr catalyst influence interaction. The surface morphology of ZnO changed from hexagonal rod to spherical-hexagonal nanorod structures after Cr doping. Energy dispersive spectral analysis confirms the phase-purity of the synthesized powders. Here, we show that in addition to altering the structure, composition, morphology and optical absorption characteristics of ZnO, the introduction of Cr dopant can also lead to dramatic changes in the antibacterial activity of Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. The investigated Cr doped ZnO nanocomposite material showed excellent antimicrobial activity compared to ZnO. The bacterial activity was found to be higher for Gram positive bacteria possessing thicker cell walls than that for Gram negative bacteria. ; Tel: +91 9994647287 † Electronic supplementary information (ESI) available. See

Mixed structure Zn(S,O) nanoparticles: synthesis and characterization

“…Moreover, the existence of zinc, sulfur and oxygen peaks also supports the formation of mixed structure of Zn(S,O) nanoparticles. Similar type of elemental analysis for oxygen rich Cr doped ZnO nanorods having an atomic percentage of 70 % for oxygen, ∼23 % for zinc and ∼5 % for Cr has also been reported by researchers [40]. The high oxygen content (at.%) in the synthesized nanoparticles may be attributed to the presence of moisture content as a result of traces of acetone and water which are used in the washing of nanoparticles.…”

Investigations on the ZnO- and Cr-doped ZnO powders

“…In particular, transition metal Cr is quite interesting, because it modifies the surface properties of metal oxide nanoparticles and therefore increases its disposable and saturation kinetics with living cells. An earlier study has shown the importance of Cr doping in metal oxide nanoparticles in the antibacterial activity [39]. In the present study, though Cr-doped ZnO showed the synergetic effect on the antibacterial activity, however, the reports on chromium oxide alone showed independent antibacterial action in different bacterial strains [40,41].…”

Antibacterial potential of Ni-doped zinc oxide nanostructure: comparatively more effective against Gram-negative bacteria including multi-drug resistant strains

“…25 Several reports are available regarding the doping of ZnO with metal ions of Ni, Co, Fe, Mn, Cr, Al, and Ag to change its properties for photocatalysis, sensors, and antibacterial activity. [26][27][28][29][30][31][32] Among the above dopants, Ni 2+ is favorable to incorporate into the ZnO lattice due to its same valence state (+2) and similar ionic radii (Ni 2+ , 0.69 A; Zn 2+ , 0.74 A). Moreover, various reports regarding the antibacterial activity of metal ion-doped ZnO, Ag, 27,28 Co, 29,30 and Cr 31,32 have been reported.…”