| The purpose of this research is to prepare silver nanoparticles with high antibacterial activity and appropriate size in 1 nm～100 nm. The product was observed by Ultraviolet spectrophotometer(UV-Vis)and Transmission Electron Microscope (TEM). Security experiment, stability experiment, pharmacodynamics experiment and animal clinical experiment of silver nanoparticles were carried out in order to be used in veterinary clinic.Test 1: The preparation of silver nanoparticles The method was adopted to get silver nanoparticles after carried out different technics contrast and analysis and chosen the best one by controlling dosage of reactant and superficial protector. The best technic was that 20 mL Silver nitrate solution(AgNO3)was confected which concentration was 0.1mol/L. Even 28% high concentration Ammonia wate(rNH3·H2O)was dropped, then mixed aroud them to limpidity, churned up them continuously and heated them little. 0.35g Polyvinylpyrrolidone K30 was joined into solution and dissolved, dropped 20ml 30% Hydrogen peroxide solution(H2O2)into Silver ammonia solution(Ag(NH3)2+), whisked them tempestuously until didn't produce gas under glacial state, then silver nanoparticles suspension was got. After being centrifuged and lyophilized, silver nanoparticles was got. The observation of Transmission Electron Microscope (TEM) showed that the average diameter of silver nanoparticles was under 50 nm and didn,t congregate.Test 2: Stability experiments of silver nanoparticles Silver nanoparticles were dispersed very well and didn't appear conglomeration under normal temperature and normal atmospheric pressure in 30 days, 60 days, and 90 days, and the diameter of silver nanoparticles was still at 20 nm～30 nm.Further more, the colour of silver nanoparticles didn't change and silver nanoparticles didn't appear conglomeration at -4℃in 12 months.Test 3: Security experiments of silver nanoparticles Acute toxicity experiment to chicken of silver nanoparticles was carried out with Sequential Method. The result showed that the LD50 was preponderated over 5000mg/kg. Totally 20 chicken were randomly arranged into three experimental groups and one comparison group(5 chicken each group). Chicken in experiment groups were administrated orally silver nanoparticles suspension at dose of 30 g/kg for 24 hours, equal to 30 times of clinical dosage. The results showed that chicken were healthy, feather was lustrous, eating and drinking were normal, and no died in 7 days. Experimental groups were killed, and the heart, liver, spleen, stomach, intestine, kidney and brain were observed, the results showed that no exceptional was appeared. There were no engorgement, dropsy, photophobia, and lachrymation in mucous membrane of eyes stimulating experiment.Test 4: The pharmacodynamics of silver nanoparticles The pharmacodynamics of silver nanoparticles were carried out, taken silver nanoparticles as experiment group and hydrochloric acid terramycin, Ciprofloxacin, Thiamphenicol as positive Comparison groups in vitro, through mensurating MIC and MBC of each group to determine the antibacterial effect of silver nanoparticles to E.coli, Staphylococcus, Streptococcus, antibacterial activity. The results showed that the MIC and MBC of silver nanoparticles to E.coli, Staphylococcus, Streptococcus were equivalent to Ciprofloxacin, the MIC and MBC of silver nanoparticles to Streptococcus respectively were 0.50 mg/mL and 1mg/mL. The pharmacodynamics indicated antibacterial effect of silver nanoparticles was superior to Ciprofloxacin, Thiamphenicol, but was inferior to hydrochloric acid terramycin. The results indicated that silver nanoparticles had strong antibacterial effect to E.coli, Staphylococcus, Streptococcus. Test 5: Clinical experiment on cow endometritis of silver nanoparticles The clinical experiment on cow endometritis of silver nanoparticles were carried out, taken silver nanoparticles as experiment group and hydrochloric acid terramycin, Ciprofloxacin, Thiamphenicol as positive Comparison groups. All cows suffering endometritis were diagnosed and cured, and the cure rate and the effective rate were calculated. The cure rate of silver nanoparticles experiment group was 91.67﹪.The effective rate of silver nanoparticles experiment group was 100﹪. There was remarkable difference between silver nanoparticles group and control groups. The results indicated that silver nanoparticles is effective to cure cows suffering endometritis.In sum, silver nanoparticles can be prepared by chemical deoxidization method, and the product was stable and dispersed very well and safe to animal. Silver nanoparticles had strong antibacterial effect to E.coli, Staphylococcus, Streptococcus. Clinical experiment showed that silver nanoparticles was effective to cows suffering endometritis. |
