Study On The Biological Safety Of Chitosan Composite Nano-silver Latex Ureteral Stent

Background:Ureteral stent has become an indispensable implant in urology,but it is easy to cause ureteral stent associated infection because of long-term indwelling,so it has become the main focus of current research.A chitosan composite nano silver latex ureteral stent with good antibacterial properties has been made in the early st age of the research group.Objective:we made ureteral stent tubes by blending chitosan,nano-silver and natural latex.The biological safety of chitosan silver natural latex ureteral stent need to be evaluated.。Methods:1.In vitro toxicity test:Cultured with polyurethane ureteral stent tube extract,chitosan composite nano-silver latex ureteral stent tube extract,and ordinary cell culture fluid for 2,5,and 7days.The absorbance value of each group of cells was measured by CCK8 experiment,and calculated The relative cell proliferation rate(RCR),it is used to evaluate the toxicity of the experimental materials.2.Hemolysis testTake 10 ml of the compound ureteral stent tube extract of the experimental group and place the negative control(0.9% normal saline)and the positive control(PBS)in a centrifuge tube.Each group has 6 centrifuge tubes,and they are placed in a 37 ° C constant temperature water bath.30 min.Add 0.2ml of freshly diluted rat heart blood into the centrifuge tubes of the experimental group,the negative control group and the experimental control group,and shake and shake them well.Then it was placed in a constant temperature water bath at 37°C for 1 hour,and the centrifuge tube was placed in a centrifuge for centrifugation for 5 minutes at a speed of 5000 r/min.After centrifugation,the color of the supernatant in each centrifuge tube and whether there is hemolysis can be observed.Take 1000μL of the supernatant in each centrifuge tube and measure the absorbance(OD value)at 545 nm with a spectrophotometer.Results:1.Chitosan composite nano-silver latex ureteral stent tube and ordinary ureteral stent tube are slightly toxic.There was no significant difference in the relative cell proliferation rate between the two groups(P> 0.05).The results show that the chitosan composite nano-silver ureteral stent tube has little effect on cell growth and low toxicity,which meets the requirements of biological evaluation standards for medical devices.2.The hemolysis test results show that the hemolysis rate of the chitosan composite nano-silver latex ureteral stent tube extract is 0.94%,which is in line with the medical device hemolysis test(<5%)and has good biological safety.Conclusion:The results show that the chitosan composite nano-silver latex ureteral stent tube has excellent biological safety performance.