Study On The Antibacterial Properties Of Expanded Polytetrafluoroethylene Promoted By Double ZnO

Backgrounds and Objective:Expanded polytetrafluoroethylene(ePTFE)has been widely used as an implant porous material in biomedical fields.The microporous structure of e PTFE is conducive to the in-growth of tissue,making e PTFE more tightly connected to the surrounding tissue and less prone to displacement.Unfortunately,this microporous structure is also safe habitats for microbes to escape from immune elimination,eventually leading to infection during the perioperative period.Therefore,it is urgent to develop a reliable and convenient method to modify e PTFE to improve its antibacterial performance.Methods:We developed a double ZnO modification method to resolve the e PTFE-induced implantable infection in clinical application.Soluble Zn O(SZ)was pre-embedded into the microporous structure of e PTFE with the aid of pressure(Alternate positive and negative pressure),followed by the partial surface coating on e PTFE with a layer of porous Zn O(PZ)-loaded calcium alginate hydrogel(CA-PZ).After the entire system was constructed,the plate count method was used to verify its antibacterial performance in vitro and in vivo.The biocompatibility of the modified e PTFE was judged by cytotoxicity and hemolysis experiments,both of which were used the extract method.Finally,SD rats were used to verify a series of performances of the modified e PTFE in vivo.Results:1.After the modified e PTFE was implanted into the desired site,the exposed SZ in the micropores of e PTFE would immediately dissolve and release when contacting with the tissue liquid to achieve rapid defense against microbial invasion.Meanwhile,PZ would be released at a steady speed with the gradual degradation of CA gel on e PTFE surface for long-term antibacterial effect.2.Antibacterial experiment in vitro:When e PTFE was co-cultured with S.aureus alone,the antibacterial rate was a negative value,while the group of the modified e PTFE showed antibacterial performance comparable to that of the antibiotic cefazolin.3.Antibacterial experiment in vivo:Compared with the antibiotic cefazolin group,the modified e PTFE showed more durable antibacterial properties.4.Both cytotoxicity and hemolysis experiments showed that the modified e PTFE has mild antibacterial properties and no obvious damage to normal cells.5.It is noteworthy that the addition of PZ enhanced the photothermal response performance to near infrared light(NIR,808 nm),endowing e PTFE with physical-chemical dual antibacterial effect on S.aureus.Conclusion:The concept of ZnO sequence release proposed in this work can not only take into account the effective and long-term antibacterial properties of e PTFE,but provide a new design inspiration for the internal and external modification strategy of porous materials.