لخّصلي

This study is based on two parts, the first one is based on using a physical method to prepare AgNPs-CNTs by arc discharge method, and the second part is Using nanoparticles as an antibacterial by injecting them into a bacterial culture and studying the effect of these molecules on bacteria.
These tools were used to prepare the nanoparticles using the electric arc technique: an inverter DC welding machine (CT33102 CROWN) manual metal arc (MMA) with a power supply for vaporizing silver metal, a cooling system to maintain a temperature of -10 C during the preparation, and a high purity 99.99 percent silver electrode. an anode with a cylinder-shaped form.a high-purity carbon cathode in the form of a cylinder that is submerged in ethanol and inside of which the electric arc discharge process takes place, The anode electrode gradually moved towards the cathode electrode by utilizing a DC power supply with a low voltage of 80V and a high current of 20A. Pure carbon served as the cathode and pure silver served as the anode of the arc discharge, which caused the silver and carbon electrode poles to melt or evaporate when they came into contact. These electrodes were spaced about 1 mm apart, vertically orientated at an angle of roughly 60 degrees, and submerged in ethanol for a total of 10 cm. During arc discharge, the two electrode holders were free to move forward and backward, enabling ideal electrode gap adjustment. The procedure didn't include the use of chemical agents. Pure solutions were used as the medium (ethanol). The creation of silver metal nanoparticles goes via three stages: nucleation, cluster development, and condensation in ethanol. The bulk particles were created by transferring the ethanol to another container while keeping the bulk particles in the first container and allowing it to sit at room temperature to allow the ethanol to volatilize, resulting in the concentration of the silver carbon under the container and the carbon silver tubes suspended in the ethanol. To make it easier to obtain the suspended nanoparticles, they are left in ethanol for 30 minutes until they become concentrated at the bottom of the container. Then, they are removed, transferred to another container, and left in the air until the ethanol volatilizes and the nanoparticles are left behind. The TEM, EDX, XRD, and UV rays were used to analyze the crystals of AgNPs-CNT nanostructures that were created. The TEM images show morphologies, nanoscale dimensions, and homogeneity. The Silver Nanoparticles in arc discharge-produced AgNPs-CNTs are typically uniform and spherical, as shown by TEM micrographs. the growth of CNTs along the examined sample's AgNP-adorned border. The average size of Silver Nanoparticles, according to the Silver Nanoparticles sizes distribution, is about 15 nm. The range of CNT diameters is between 10 nm and 16 nm with an average size of 13 nm, and the average size of the synthesized Silver Nanoparticle was confirmed to be between 15 and 19 nm. The XRD spectrum, which spans a temperature range of 5 to 80 degrees, represents the phase analysis in the 2ϴ range of the AgNPs-CNTs samples. The major AgNPs-CNT peaks were identified using the spectra at 2ϴ. The generated peaks agreed well with the diffraction peaks from the hexagonal phase zinc oxide. The chemical makeup of the produced AgNPs-CNTs was verified using EDX spectroscopy. Nearly 87.5% of the yield's weight was made up of silver components, 7% was carbon, and 5.5% was made up of impurities, according to the area beneath the EDX curves' peaks. On the other hand, research on the antibacterial efficiency of AgNPs-CNTs against gram-negative bacteria (P. aeruginosa) was conducted both qualitatively and quantitatively. The bacteriostatic and bactericidal characteristics of AgNPs-CNTs were investigated, and the MIC and MBC values were determined. P. aeruginosa samples were subjected to AgNPs-CNT concentrations ranging from 45 g/ml to 0.0879 g/ml. After overnight incubation, a MIC level was calculated when there was no discernible bacterial growth in broth cultures, and an MBC level was selected when three or fewer colonies were visible (>99.9% killed) in inoculated agar plates. The results after 24 hours of incubation revealed that the MIC and MBC values of P. aeruginosa treated with AgNPs-CNTs were, respectively, (>5.625 g/ml) and (>11.25 g/ml), By monitoring the growth pattern every hour for 24 hours while the bacteria were incubated after being exposed to AgNPs-CNTs at concentrations lower than the MIC limit (0.1, 0.4, 0.8, 1.0, and 1.2 g/ml), the bacterial growth kinetics were examined. The growth kinetics are a reflection of how AgNPs-CNTs affect bacterial viability and possibly visible delays. The kinetics were calculated every hour by using broth turbidity as an optical biomarker in terms of OD600nm. The gathered OD600nm values were graphed vs. incubation period and the growth curves that were produced. The observed growth patterns of the assigned P. aeruginosa samples are consistent with the typical growth phases, which started with a lag phase, progressed to rapid growth as a log phase, and finally ended with a stationary phase. Contrarily, a significantly delayed shift that started at 6 h of incubation as opposed to 6 h for other samples was seen in the log phase samples treated with AgNPs-CNTs (0.8, 1.0, and 1.2 g/ml). Additionally, the unique growth curves demonstrated flattening and suppression of the stationary phase as the concentration of AgNPs-CNTs increased, the number of bacteria was counted and a percentage of cell viability in comparison to control counts was calculated. It is clear that the vitality of the cells depends on the concentration of AgNPs-CNTs, and that greater inhibition occurred as the concentration rose. The viability vs. concentration trend line equation was found to be y = -11.139x + 115.07, where y represents cell viability and x represents the supplement concentration of AgNPs-CNTs. Taking into account the preceding findings, it is reasonable to suppose that AgNPs-CNTs delay cellular metabolic activity while simultaneously limiting bacterial growth counts. P. aeruginosa also measured the concentration of the important biomarker LDH at doses of (0.4, 1.2, 2.8, and 3.2 g/ml) to look for any potential cellular damage. The number of inter-constituents that lyse from the bacterial cells as a result of losing their outer cellular packing integrity could be counted using changes in LDH levels. Others claim that the ability of Silver Nanoparticles and decorated CNTs to link directly to the bacterial outer cell membrane may result in the rupture of that membrane. Effectively, Silver Nanoparticles change porin protein channels or regulate the permeability of P. aeruginosa's outer membrane, and they specifically target specific cell wall site receptors. Furthermore, the synthesized AgNPs-CNTs enhance Silver Nanoparticles' capacity to attach the cell membrane in several locations and produce significant cellular damage. The collected results showed that the largest relative change in protein leakage occurred at 3.2 g/ml AgNPs-CNTs, which was four times higher than 0.4 g/ml AgNPs-CNTs. Higher AgNPs-CNT concentrations increased the amount of Silver Nanoparticles that penetrated bacterial cells, damaged their outer membranes, and caused cell death, according to the data.