Morphology-directed synthesis of ZnO nanostructures and their antibacterial activity.
Zinc oxide (ZnO) nanostructures of various morphologies were produced in an aqueous system, with pyridine as a shape-directing agent. X-ray diffraction (XRD) and selected-area electron diffraction (SAED) revealed hexagonal wurtzite crystal structure. Variation in surface morphology was analyzed using transmission electron microscopy (TEM). Changes in surface morphology were attributed to the absence of steric stabilization in pyridine during synthesis process. Pyridine concentration affected morphology and optical properties. Fourier transform infrared spectroscopy (FTIR) confirmed the presence/absence of pyridine on the surface of ZnO nanostructures (ZnO-NSs). Optical measurements carried out using UV-visible spectrophotometer (UV-vis) and photoluminescence (PL) indicated the presence of defects. All the samples exhibited two PL peaks, at 350-370 nm and 560-624 nm. Variation in the intensities of PL peaks corresponded to the changes in the surface morphology from nanoparticles to rods and origin of deep-level defect luminescence is attributed to surface recombination. The toxicity of the nanostructures was tested on model Gram-negative and Gram-positive pathogens. Smaller nanorods were most toxic among the nanostructures tested.
Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur, Chennai 603203, Kancheepuram District, Tamil Nadu, India.
Meghana
M
Ramani
S
S
Ponnusamy
Chellamuthu
C
Muthamizhchelvan
Joseph
J
Cullen
Satheesh
S
Krishnamurthy
Enrico
E
Marsili
D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D049449:Luminescence; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction; D015034:Zinc Oxide / Q000138:chemical synthesis* / Q000494:pharmacology*
D011725:Pyridines; D017382:Reactive Oxygen Species; D015034:Zinc Oxide