Effect of Zinc Oxide Nanocrystals in Media Containing E. coli and C. xerosis Bacteria
- PDF / 66,520 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 108 Downloads / 189 Views
0900-O03-08.1
Effect of Zinc Oxide Nanocrystals in Media Containing E. coli and C. xerosis Bacteria.
Triana Merced, Stephanie Santos, Omayra Rivera, NicoleVillalba, Yahira Baez, José Gaudier, Javier Avalos, Oscar Perales *, M. S. Tomar*, A. Parra-Palomino*, Amarilis Ruiz-Mendoza*. Department of Science and Technology, Universidad Metropolitana, San Juan, PR 00928-1150. * Department of General Engineering-Materials Science and Engineering, University of Puerto Rico, Mayaguez, P.R, Puerto Rico.
ABSTRACT The present investigation is centered on the study of the growth curves of E. coli and C. xerosis bacteria in the presence of nanosize particles of Zinc Oxide. Previous works1, 2 demonstrated the sensitivity of the bacteria, when these were reproduced in mediums that contain nanoparticles of luminescent silicon and Cobalt Ferrite. Doped ZnO nanocrystals were synthesized by conventional precipitation in ethanol solutions as reported by Spanhel and Anderson for bare ZnO. In our case, the syntheses were carried out under room-temperature conditions. The experimental results of E. coli bacteria in contact with a stable suspension of nanoparticles of Zinc Oxide, showed a growth curve without adaptation period. Moreover a short and slowly logarithmic stage have been observed, reaching the stationary stage after approximately four hours compared with one in absence of the nanoparticles (standard curve). During the observations, a change in the lifetime of the bacteria (metabolism) with particulate was noticed, as well as the beginning of the mortality stage. However different results were recorded for silicon and ferrite. For the case of the bacteria C. xerosis , the curve with particles is above its standard curve for all times with none of the oscillations which occurred in the nanometer silicon. For these bacteria the beginning of the mortality stage is observed when they have particles. For both bacteria with Zinc Oxide nanoparticles this occurs approximately after nine hours.
INTRODUCTION Some properties of the Zinc Oxide are its insolubility in water but solubility in acids or alkalines. Its structure looks like white hexagonal crystals or a white powder known as zinc white. It has an enormous refractive index and comes right under the refractive capabilities of diamonds. Zinc Oxide blocks ultraviolet radiation in sunlight from reaching the skin, which why it is used in ointments, creams, and lotions to protect against sunburn. The aim of this research is to study the behavior of the growth curves of the E.coli and C. xerosis bacteria in media containing diamagnetic nanocrystals of Zinc Oxide. Previous publications 1,2 demonstrated the sensitivity of the bacteria, when these were reproduced in media that contained nanoparticles of luminescent Silicon and Cobalt Ferrite.
0900-O03-08.2
The antibacterial effect of the ZnO will be measured by means of its growth curves. It Is possible that the blocking of the UV radiation may be a factor that permits bacteria colony growth under the ointment used to block the radiati
Data Loading...
