#6572 FLUORINATED GRAPHENE REDUCES PLATELET ACTIVATION AND ADHESION ON HEMODIALYSIS CATHETER

Abstract

Abstract Background and Aims Catheter thrombosis remains one of the major complications of hemodialysis. Superhydrophobic surfaces are suggested to be capable of creating an energy barrier that prevents cells and proteins from contacting with the catheter surface directly, making catheter less thrombotic. Fluorinated graphene (FG) is a superhydrophobic material. It has been applied to create self-cleaning surfaces. It also shows good biocompatibility. Based on these features of FG, we prepared an FG coating on hemodialysis catheter attempting to reduce clinical thrombotic events. Method FG suspension was made in a solution of 95 wt.% ethanol, 5 wt.% deionized water and 3 wt.% 1H,1H,2H,2H-Perfluorooctyltriethoxysilane (POTS, C14H15F17O3Si). Immediately following the plasma activation, catheter segments of 1 cm²(Gamcath, GDHK1325) were spray coated with FG suspension both inside and outside the catheter lumen. Samples were air-dried for later use. We tested the hemolysis rate, platelet activation and adhesion performances, and the partial thromboplastin time (PTT) of the FG-coated samples. Test for hemolysis was performed with FG-coated catheter and the isotonic extract of the FG coating in direct contact with fresh rabbit blood respectively. Platelet activation and adhesion was performed according to the ASTM F2888-19 standard and also assessed by scanning electron microscope. PTT assay was performed according to the ASTM F2382-18 standard. Results FG-coated catheter is hydrophobic and shows a water contact angle of 150° (Figure 1a). It reduced 83.5% of platelet adhesion per 100 μm² catheter surface area and avoided 35.86% of platelet loss from the blood when compared to uncoated catheter (Figure 1b, 1c). It has a hemolysis rate of less than 2% in both direct blood contact test and the extract test (Figure 1d). The PTT of FG-coated sample was 88.92±1.31s versus 83.03±9.49s of the uncoated catheter yet with no statistical significance (P>0.05) (Figure 1e). Conclusion FG coating has great hemocompatibility. Though no significant improvement was observed in the PTT assay, FG coating still significantly reduced the adherent and activated platelet on catheter, which seems promising to reduce thrombotic events. Yet, more tests needed to be performed, and the antithrombotic ability of FG coating in the fluid state needs to be further confirmed in the following study.