Kalugin Denis, Bahig Jumanah, Shoker Ahmed, Abdelrasoul Amira
Department of Chemical and Biological Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada.
Division of Biomedical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada.
Membranes (Basel). 2023 Aug 3;13(8):718. doi: 10.3390/membranes13080718.
The goal of the current study is to enhance the hemocompatibility of polyethersulfone (PES) membranes using heparin immobilization. Heparin was immobilized covalently and via electrostatic interaction with the positively charged PES surface (pseudo-zwitterionic (pZW) complex) to investigate the influence of each method on the membrane hemocompatibility. In situ synchrotron radiation micro-computed tomography (SR-µCT) imaging, available at the Canadian Light Source (CLS), was used to critically assess the fibrinogen adsorption to the newly synthesized membranes qualitatively and quantitatively using an innovative synchrotron-based X-ray tomography technique. The surface roughness of the synthesized membranes was tested using atomic force microscopy (AFM) analysis. The membrane hemocompatibility was examined through the ex vivo clinical interaction of the membranes with patients' blood to investigate the released inflammatory biomarkers (C5a, IL-1α, IL-1β, IL-6, vWF, and C5b-9). The presence and quantitative analysis of a stable hydration layer were assessed with DSC analysis. Surface modification resulted in reduced surface roughness of the heparin-PES membrane. Both types of heparin immobilization on the PES membrane surface resulted in a decrease in the absolute membrane surface charge from -60 mV (unmodified PES) to -13 mV for the pZW complex and -9.16 mV for the covalently attached heparin, respectively. The loss of human serum fibrinogen (FB) was investigated using UV analysis. The PES membrane modified with the heparin pseudo-ZW complex showed increased FB retention (90.5%), while the unmodified PES membrane and the heparin covalently attached PES membrane exhibited approximately the same level of FB retention (81.3% and 79.8%, respectively). A DSC analysis revealed an improvement in the content of the hydration layer (32% of non-freezable water) for the heparin-coated membranes compared to the unmodified PES membrane (2.84%). An SR-µCT analysis showed that the method of heparin immobilization significantly affects FB adsorption distribution across the membrane thickness. A quantitative analysis using SR-µCT showed that when heparin is attached covalently, FB tends to be deposited inside the membrane pores at the top (layer index 0-40) membrane regions, although its content peak distribution shifted to the membrane surface, whereas the unmodified PES membrane holds 90% of FB in the middle (layer index 40-60) of the membrane. The ex vivo hemocompatibility study indicates an improvement in reducing the von Willebrand factor (vWF) for the heparin pseudo-ZW PES membrane compared to the covalently attached heparin and the untreated PES.
本研究的目的是通过肝素固定来提高聚醚砜（PES）膜的血液相容性。肝素通过共价结合以及与带正电荷的PES表面（假两性离子（pZW）复合物）的静电相互作用进行固定，以研究每种方法对膜血液相容性的影响。利用加拿大光源（CLS）提供的原位同步辐射微计算机断层扫描（SR-µCT）成像，采用基于同步辐射的创新X射线断层扫描技术，对新合成膜上纤维蛋白原的吸附进行定性和定量的严格评估。使用原子力显微镜（AFM）分析测试合成膜的表面粗糙度。通过膜与患者血液的离体临床相互作用来检查膜的血液相容性，以研究释放的炎症生物标志物（C5a、IL-1α、IL-1β、IL-6、vWF和C5b-9）。用差示扫描量热法（DSC）分析评估稳定水合层的存在和定量分析。表面改性导致肝素-PES膜的表面粗糙度降低。两种在PES膜表面固定肝素的方法均使膜表面绝对电荷从-60 mV（未改性PES）分别降至pZW复合物的-13 mV和共价连接肝素的-9.16 mV。使用紫外分析研究人血清纤维蛋白原（FB）的损失。用肝素假-ZW复合物改性的PES膜显示出FB保留率增加（90.5%），而未改性的PES膜和共价连接肝素的PES膜表现出大致相同水平的FB保留率（分别为81.3%和79.8%）。DSC分析表明，与未改性的PES膜（2.84%）相比，肝素涂层膜的水合层含量有所提高（不可冻结水的32%）。SR-µCT分析表明，肝素固定方法显著影响FB在膜厚度上的吸附分布。使用SR-µCT进行的定量分析表明，当肝素共价连接时，FB倾向于沉积在膜顶部（层指数0-40）膜区域的膜孔内，尽管其含量峰值分布转移到了膜表面，而未改性的PES膜在膜的中间（层指数40-60）保留了90%的FB。离体血液相容性研究表明，与共价连接肝素的膜和未处理的PES膜相比，表示肝素假-ZW PES膜在降低血管性血友病因子（vWF）方面有所改善。
