EFFECTS OF SILVER NANOPARTICLES ON PATHOGENIC E.COLI & SOME HEMATOLOGICAL PARAMETERS

Background:-Silver nanoparticles (AgNPs) have become one of the commercialized nanoparticles because of its properties. It is used in biomedical applications as antimicrobial agent, drug delivery systems and targeting agent. Objective:-to study the antibacterial effects of silver nanoparticles on E.coli isolated from blood and the effect of these particles on hematological parameters: total WBCs count, hemoglobin concentration and the morphology of WBCs and RBCs. Methods:- Silver nanoparticles of 20 nm size and 99.9 % purity were used. The effect of different concentrations of silver nanoparticles on Escherichia coli (E.coli) isolated from blood was studied. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of these AgNPs against pathogenic strainsof E. coli were determined by micro dilution technique and measured by spectrophotometer. The impact of silver nanoparticles on white blood cells count and hemoglobin was investigated using different concentrations of silver nanoparticles and different incubation times. The effects on WBC and RBC morphology were studied by incubating equal volumes of silver nanoparticles and blood. Results:- The MIC and MBC values of silver nanoparticles on E.coli were 10μg/mL and 50 μg/mL respectively. The total white blood cells (WBCs) counts decreased depending on the concentrations and incubation time. The lowest WBC count was observed at concentration of 100 μg/mL of silver nanoparticles and after 4 hours of incubation. Hemolysis was observed at all concentrations of silver used in the study. WBCs morphology was not affected and they showed no evidence of phagocytosis. Conclusions:- 1. Silver nanoparticles inhibit E.coli at the concentration 10 μg/mL while 50 μg/mL kills this bacteria. 2. Silver nanoparticles when mixed with blood lead to the decrease in the total WBCs count, the decease ratio depend on the concentration of the silver nanoparticles and on the time of the incubation. 3. Silver nanoparticles cause complete hemolysis of the RBCs. 4. There is no evidence of silver particles phagocytosis by WBCs while there are moderate and severe degree of RBC damage according to the concentration of silver nanoparticles in blood film.