Study On The Improvement Of Biocompatibility By Grafting Betaine Derivatives Onto Hollow Fiber Membrane Of ECMO Oxygenator

Objective:Isocyanate sulfopropyl betaine was modified on hollow fiber membrane of extracorporeal membrane oxygenation by plasma surface treatment and verify its biocompatibility.Methods:1)Preparation and validation of NCO-SB.NCO-SB was synthesized by the addition reaction of-NH₂ of 3-dimethylaminopropylamine with-NCO of isophorone diisocyanate,and the obtained product was quaternized with 1,3-propanesulfonate.The group composition was detected by Fourier transform infrared spectroscopy and the molecular structure was determined by ¹H nuclear magnetic resonance.2)Graft NCO-SB,verify and group.Polymethylpentene（PMP）HFM was treated by oxygen plasma and reduced by sodium borohydride to obtain monohydroxy functionalized PMP-HFM.NCO-SB was grafted onto PMP-HFM by nitrogen plasma surface treatment.Fourier transform infrared Spectroscopy（XPS）and X-ray Photoelectron Spectroscopy（XPS）were used to analyze the composition of elements and groups of PMP-HFM,mono-hydroxyl functionalized PMP-HFM and PMP-HFM grafted with NCO-SB.PMP-HFM group（labeled PMP）was set as the control group,PMP-HFM group（labeled PMP-OH）and PMP-HFM group（labeled PMP-NCO-SB）were set as the experimental group.3)Biocompatibility verification.Protein adsorption experiment:Through the co-incubation of Bovine Serum Albumin（BSA）and Bovine Fibrinogen（Fg）solution with the membrane sample,verify the adsorption of protein on the membrane;Hemolysis test:the membrane sample was co-placed with fresh healthy adult red blood cell suspension,and the hemolysis percentage was calculated by absorbance to verify the hemolysis situation.Complement activation experiment:membrane samples were co-placed with human plasma,and C3a and C5a kits were used to detect the effect on complement activation.Platelet activation experiment:the membrane samples were co-placed with human plasma,and the Platelet Factor 4（PF4）andβ-thromboglobulin（βTG）kits were used to detect the effects on Platelet activation.Plasma recalcification test:the membrane samples were co-placed with human Platelet Poor Plasma（PPP）,and the time of Plasma recalcification was calculated after the addition of calcium to detect the effect on coagulation.All experimental data were expressed as X±SD,and statistical analysis was performed using Graph Pad Prism 8.0.All experimental data were analyzed using anova to determine differences between groups.With P<0.05 was considered statistically significant.Results:1)Characterization of synthetic compounds.The characteristic absorption peak of the synthesized NCO-SB was analyzed by Fourier transform infrared spectrosco py and the structure of the synthesized NCO-SB was verified successfully.2)Characterization of coating.Fourier transform infrared spectroscopy and char acteristic wave peak of XPS showed that the preparation of PMP-OH and PMP-N CO-SB groups was successful.3)Biocompatibility results.Protein adsorption experiment:Compared with the s urface of PMP-HFM,the surface of HFM in PMP-NCO-SB and PMP-OH groups showed less BSA and Fg adsorption（P<0.0001）;Hemolysis test:In vitro experim ent proved that the hemolysis rate of 1.185%in PMP group was significantly high er than that of 0.2377%in PMP-NCO-SB group（P<0.05）;Complement activation experiment:Compared with PMP-HFM surface,PMP-NCO-SB group and PMP-O H group inhibited the activation of complement system by decreasing the expressio n of C3a and C5a.Platelet activation test:compared with p MP-HFM group,the ex pression levels of PF4 andβTG were lower（P<0.05）,proving that PMP-NCO-SB group has a smaller activation of platelets.Plasma recalcification test:the plasma recalcification time of PMP,PMP-OH and PMP-NCO-SB were 230±6.380s,261±7.517s and 352±9.220s,respectively.Compared with PMP-HFM group,PMP-NCO-SB group and PMP-OH group significantly prolonged the plasma re-calcification time.Conclusion:NCO-SB can be grafted onto PMP-HFM by plasma surface treatment.PMP-H FM grafted with NCO-SB by plasma surface treatment has better biocompatibility than PMP-HFM alone.