Surface Zwitterionization of Expanded Poly(tetrafluoroethylene) via Dopamine-Assisted Consecutive Immersion Coating
Résumé
Expanded polytetrafluoroethylene (ePTFE) is one of thematerials widely used in the biomedicalfield, yet its application is being limitedby adverse reactions such as thrombosis when it comes in contact with blood.Thus, a simple and robust way to modify ePTFE to be biologically inert issought after. Modification of ePTFE without high-energy pretreatment, such asimmersion coating, has been of interest to researchers for its straightforwardprocess and ease in scaling up. In this study, we utilized a two-step immersioncoating to zwitterionize ePTFE membranes. Thefirst coating consists of the co-deposition of polyethylenimine (PEI) and polydopamine (PDA) to produceamine groups in the surface of the ePTFE for further functionalization. Theseamine groups from PEI will be coupled with the epoxide group of thezwitterionic copolymer, poly(GMA-co-SBMA) (PGS), via a ring-openingreaction in the second coating. The coated ePTFE membranes were physicallyand chemically characterized to ensure that each step of the coating is successful. The membranes were also tested for theirthrombogenicity via quantification of the blood cells attached to it during contact with biological solutions. The coated membranesexhibited around 90% reduction in attachment with respect to the uncoated ePTFE for both Gram-positive and Gram-negativestrains of bacteria (Staphylococcus aureusandEscherichia coli). The coating was also able to resist blood cell attachment from humanwhole blood by 81.57% and resist red blood cell attachment from red blood cell concentrate by 93.4%. These ePTFE membranes,which are coated by a simple immersion coating, show significant enhancement of the biocompatibility of the membranes, whichshows promise for future use in biological devices.
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