Membrane adsorber for endotoxin removal

ABSTRACT The surface of flat-sheet nylon membranes was modified using bisoxirane as the spacer and polyvinyl alcohol as the coating polymer. The amino acid histidine was explored as a ligand for endotoxins, aiming at its application for endotoxin removal from aqueous solutions. Characterization of the membrane adsorber, analysis of the depyrogenation procedures and the evaluation of endotoxin removal efficiency in static mode are discussed. Ligand density of the membranes was around 7 mg/g dry membrane, allowing removal of up to 65% of the endotoxins. The performance of the membrane adsorber prepared using nylon coated with polyvinyl alcohol and containing histidine as the ligand proved superior to other membrane adsorbers reported in the literature. The lack of endotoxin adsorption on nylon membranes without histidine confirmed that endotoxin removal was due to the presence of the ligand at the membrane surface. Modified membranes were highly stable, exhibiting a lifespan of approximately thirty months.

摘要 本研究以双环氧烷（bisoxirane）作为间隔臂、聚乙烯醇（polyvinyl alcohol）作为涂层聚合物，对平板尼龙膜的表面开展改性处理。选取氨基酸组氨酸（histidine）作为内毒素（endotoxins）的配体，旨在将该材料用于水溶液的内毒素去除。本文对该膜吸附剂的表征、脱热源工艺分析及静态模式下的内毒素去除效率评价进行了探讨。该膜的配体密度约为7 mg/g干膜（dry membrane），可实现最高65%的内毒素去除率。相较于文献报道的其他膜吸附剂，本研究制备的聚乙烯醇涂层尼龙膜（以组氨酸为配体）的吸附性能更优。未修饰组氨酸的尼龙膜无内毒素吸附能力，这一结果证实内毒素的去除源于膜表面配体的存在。经改性的膜稳定性极佳，使用寿命可达约30个月。