Cytotoxicity Evaluation Of Nano-Ag-SiO₂Urethral Catheter For External Urethral Mucosa Cells

Objective:Comparing the active influence of nano-Ag-SiO2urethral catheter and ordinary urethral catheter extracts on vitro cells of human prostatic urethra epithelial cells in different periods to evaluate the biosecurity of nano-Ag-SiO2urethral catheter.METHODS:Mechanical separation and enzymatic digestion were used to isolate and culture urothelial mucosa of BPH patient to make cell suspension after proliferation in vitro. The medium was replaced by immersion nano-Ag-SiO2and general catheter tube medium. MTT assay was performed to quantify the vitro cytotoxicity of two extracts on human urethra epithelial cells which were cultured for2,5and7days. Absorbance values of nano-Ag-SiO2and general urinary catheter groups were measured by enzyme-linked immunosorbent assay to calculate the relative growth rate, and compare and perform toxicity evaluation.Results:According to the absorbance value (OD) drawing cell growth curve:took the time as the horizontal axis and took the OD value as the vertical axis, drawn cell growth curve, absorbance values were significantly different among the three groups (F=3.737, P=0.026), further multiple comparison, there were significant differences between the nano group and control group,there were also significant differences between the normal group and the control group, but there no significant differences between normal group and nano group, with the prolonged incubation time, each group showed a rising trend in the OD value,each group of cells grew well, control group cells had stronger cell viability than the other two groups.Cell morphological observation:After cultured respectively by nano Ag-SiO2 catheter extracts and common catheter extracts, compared with the control group there was no significant difference between the urethral epithelial cells. When cultured2days, cell neurite outgrowth, polygonal; When cultured5days, cell proliferation was good; When cultured7days, Was "fried egg" shape, after covered was cobblestone-like, uniform size.Cytotoxicity evaluation results:Nano Ag-SiO2urethral catheter extract cytotoxicity was grade1,2days,5days,7days relative growth rates were:75.4%-76.4%,76.9%-92.1%81.8%-85.8%; the common medical catheter extracts cytotoxicity was0,1,2days,5days,7days relative growth rates were:75.3%-77.0%,80.2%-96.5%,79.3%-100.4%, it conformed to the standard requirements of biological evaluation of medical devices. By factorial design and variance analysis,it shown that relative growth rate group effect was no significant difference (F=0.544, P=0.475);the interaction between time and groups was no significant difference (F=0.130, P=0.879).Conclusion:The nano Ag-SiO2urethral catheter had effect on growth and reproduction at different culture interval of human prostatic urethral epithelial cell but the effects were minor,it conformed to biological evaluation standards of medical devices.