The antibacterial effect of zinc oxide nanoparticles were synthesized by co-precipitation and wet chemical methods on Escherichia coli bacteria

The antibacterial effect of zinc oxide nanoparticles were synthesized by co-precipitation and wet chemical methods on Escherichia coli bacteria
Faezeh SamieiPour,^1,* horiyeh rezaee,²
1. Biotechnology Group, Islamic Azad University Falavarjan Branch, Isfahan, Iran
2. Biotechnology Group, Islamic Azad University Falavarjan Branch , Isfahan, Iran
Introduction: Nanoparticles are particles with dimensions less than 100nm that due to their very small size and surface to volume ratio, have high properties and performance, including antibacterial properties. So far, the antibacterial properties of nanoparticles have been investigated on a variety of bacteria. Nanoparticles are produced in different ways such as co-precipitation, chemical wet with inhibitor, microwave, and ... In this paper, the antibacterial power of ZnO nanoparticles that has been investigated by both sediment and chemical methods wet with inhibitor.
Methods: Materials required for the co-precipitation method: ZnCl 1.36 gr, NaOH 1.6 gr, and distilled water. Production of ZnO nanoparticles by co-precipitation method At first, combine 1.36 g of ZnCl and 1.6 g of NaOH in separate beakers in distilled water and bring each to a volume of 100 cc. Next, place two beakers on a heater and a magnet and by placing a few magnets in beakers, we turn on the devices and wait until the material reaches the boiling point. Then, we add the contents of two beakers to each other. As soon as the contents of the beakers are mixed, the white substance ZnO is produced. The nanoparticles are washed several times and then sterilized by using UV light. Afterwards, we determine the concentration of nanoparticles. To determine the concentration, we put 5cc of the produced material in a plate and weigh it. By placing the plate in the oven, drying it completely and weigh it again. In this case, we have the amount of grams in 5cc and it is possible to calculate the concentration in grams per liter with simple calculations. Using the UV spectrophotometer, we read the maximum wavelength of its UV absorption and measure the optical size of the produced nanoparticles by performing mathematical calculations. The size of nanoparticles produced by this method was reported to be 5-6nm. After producing nanoparticles, we create 6 wells in the culture medium of Ecoli bacteria and in the wells, nanoparticles added with the concentrations of 14gr / lit, 7gr / lit, 3.5gr / lit, 1.75gr / lit, 0.87gr / lit and additional control, respectively. Place the plates in the incubator for 24 hours and check for inhibition zone conditions. Production of nanoparticles by wet chemical method with inhibitor Weigh the ingredients as before and dissolve them in distilled water to a volume of 100cc. Pour ZnCl into a balloon and place it on th heater and magnetic stirrer. Attach the soxhlet to the balloon and pour mercaptoethanol inhibitor into it. Add a drop of mercaptoethanol every 3 seconds. When the mercaptoethanol is finished, fill the inside of the soxhlet with NaOH and allow it to be added to the material at the same rate. Gradually, white ZnO nanoparticles are produced in the balloon. Sterilize the resulting material as a co-precipitation method and determine the concentration and finally calculate its optical size. The size of nanoparticles is 4-5nm. By creating 6 wells in the plate, ZnO nanoparticles which produced by chemically wet with inhibitor with concentrations of 2gr / lit, 1gr / lit, 0.5gr / lit, 0.25gr / lit, 0.125gr / lit, and 2gr / sample are poured without washing, respectively and after 24 hours of incubation, check the plates for diameter in a state of non-growth halo.
Results: In this study, zinc oxide nanoparticles were produced by co-precipitation and wet chemical methods with optical sizes of 5 and 4 nm, respectively. Then, to investigate its antibacterial properties, it was done by plate drilling and grass culture with concentrations of 10, 2.5, 1.25, and 0.62 for co-sedimentation method and concentrations of 2, 1, 0.5, 0.25, and 0.125 g / l for wet chemicals. In addition, in the wet chemical method, because it was synthesized with mercaptoethanol inhibitor, it was used in a well without washing nanoparticles with a concentration of 2 g / l. The results showed that zinc oxide nanoparticles synthesized by wet chemical method have inhibitory properties on bacterial growth. Also, the diameter of the growth inhibition halo decreases with decreasing concentration, and the maximum halo is related to the concentration of 2 g / l with a size of 13 mm and unwashed nanoparticles of 16 mm. The reason for the difference is the inhibitory effect.
Conclusion: According to the observed results, ZnO nanoparticles produced by co-precipitation method with an optical size of 5-6nm in none of the concentrations have not shown in non-growth halo in Ecoli bacterial culture medium. And it seems that the nanoparticles produced in this way have not been able to develop antibacterial properties against Ecoli bacteria. However, in the use of ZnO produced by wet chemical method with inhibitor with optical size of 4-5nm, despite the use of much lower concentration, at a concentration of 2gr / lit, a state with a diameter of 13 mm has been observed. And if the nanoparticles are not washed with the same concentration, a non-growth halo with a diameter of 16 mm is created. It can be concluded that the use of different methods of nanoparticle production due to the creation of different optical sizes and other properties in nanoparticles also create different properties. For example, nanoparticles produced by wet chemical method have more antibacterial properties than co-precipitation method.
Keywords: Nanoparticles Zinc oxide Wet chemical Co-precipitation E coli