Design And Characterization Of Biliary Stent Film To Prevent Bacterial Adhesion And Cholestasis

Biliary obstruction is a disease of biliary obstruction caused by benign or malignant biliary strictures.Stent implantation is an effective way to treat biliary strictures.Compared with plastic stents,metal stents have obvious advantages in prolonging the patency time of stents.However,related complications such as biliary tract infection,pancreatitis,biliary obstruction and restenosis of the stent caused by the implantation of the stent will still cause pain and even cause the operation failed.The use of antibacterial stents is an effective way to solve postoperative infections,but active antibacterial stents will cover the antibacterial active sites after the bacteria die,and the inhibition of biofilm formation is not obvious.Passive antibacterial stents such as hydrophilic and hydrophobic types are due to Unstable surfaces can also cause bacteria adhesion.Based on the above background,this project introduces the super-smooth surface of imitated Nepenthes on the inner wall of the biliary stent,and prepares the PTFE porous nanofiber membrane as the solid substrate of the super-smooth surface by electrostatic spinning.Super smooth surface with good sliding performance and anti-adhesion performance.The sliding stability of the ultra-smooth surface and the adhesion performance and biocompatibility of inhibiting proteins,bacteria,biliary sludge and other organisms were characterized.The main research contents and related conclusions are as follows:(1)Preparation and sintering process of PTFE/PEO composite nanofiber membrane.Ultra-high molecular weight polyethylene oxide(PEO)is used as a spinning aid for PTFE electrospinning.When the mass ratio of PEO is 3% and above,continuous PEO/PTFE composite nanofibers can be obtained,and the higher the PEO content,the larger the fiber diameter.The sintering temperature range of the composite nanofiber membrane was determined by DSC and TGA.The apparent morphology and mechanical test results of the sintered PTFE fiber membrane show that when the sintering temperature is 400℃ and the sintering time is 10 minutes,the PTFE nanofiber membrane exhibits a good microscopic morphology and excellent mechanical properties.The test results of DSC,TGA and EDS before and after sintering all show that the PEO component in the fiber membrane is completely removed.(2)Research on the preparation of super smooth surface and the influencing factors of slip performance.The ultra-smooth surface prepared by impregnating the surface of the PTFE porous solid substrate with silicone oil has a very low(<5°)rolling angle and excellent slip rate.It can still maintain excellent slip performance after being soaked in simulated bile for 7 days.Compared with e PTFE membranes,solid substrates prepared by electrospinning have higher porosity,and have obvious advantages in improving the slippage stability of ultra-smooth surfaces.The ultra-smooth surface prepared by low-viscosity silicone oil has a lower rolling angle(0.77°)and a higher slip rate(12.61mm/s),but the ultra-smooth surface filled with high-viscosity silicone oil has stronger sliding stability.(3)Research on anti-bioadhesion performance and biocompatibility of super smooth surface.Compared with PTFE nanofiber membranes,the ultra-smooth surface prepared by infusing silicone oil can significantly inhibit the adhesion of protein,Escherichia coli,Staphylococcus aureus and Pseudomonas aeruginosa,and can also significantly reduce bile sludge adhesion in a simulated bile environment.Cytotoxicity experiments show that human foreskin fibroblasts have a good growth trend on the super-smooth surface.Compared with the control group,the cell absorbance of the super-smooth surface after 3 days of culture has no significant difference,indicating that the super-smooth surface has good biocompatibility.In summary,this project has obtained a super smooth surface with excellent sliding properties and good stability by pouring silicone oil on the surface of the high-porosity PTFE nanofiber membrane,which can effectively prevent the adhesion of protein,bacteria and biliary sludge and has good biocompatibility.This result has reference value for the research and development of biliary stent products that prevent bacterial adhesion and cholestasis.