Institute for Frontier Materials , Deakin University , Waurn Ponds , Victoria 3216 , Australia.
Department of Chemical Science and Engineering , Kobe University , 1-1 Rokkodai-cho , Nada, Kobe , Hyogo 657-8501 , Japan.
ACS Appl Mater Interfaces. 2018 Aug 15;10(32):27477-27487. doi: 10.1021/acsami.8b07945. Epub 2018 Aug 6.
A new biocatalytic nanofibrous composite ultrafiltration membrane was developed to reduce protein fouling interactions and self-clean the membrane surface. The dual-layer poly(vinylidenefluoride)/nylon-6,6/chitosan composite membrane contains a hydrophobic poly(vinylidenefluoride) cast support layer and a hydrophilic functional nylon-6,6/chitosan nanofibrous surface layer where enzymes were chemically attached. The intrinsic surface chemistry and high surface area of the nanofibers allowed optimal and stable immobilization of trypsin (TR) and α-chymotrypsin enzymes via direct covalent binding. The enzyme immobilization was confirmed by X-ray photoelectron spectroscopy and visualized by confocal microscopy analysis. The prepared biocatalytic composite membranes were nanoporous with superior permeability offering stable protein antiadhesion and self-cleaning properties owing to the repulsive mechanism and digestion of proteins into peptides and amino acids, which was quantified by the gel electrophoresis technique. The TR-immobilized composite membranes exhibited 2.7-fold higher permeance and lower surface protein contamination with 3-fold greater permeance recovery, when compared to the pristine membrane after two ultrafiltration cycles with the model feed solution containing bovine serum albumin/NaCl/CaCl. The biocatalytic membranes retained about 50% of the enzyme activity after six reuse cycles but were regenerated to 100% activity after enzyme reloading, leading to a simple and cost-effective water remediation operation. Such surface- and pore-engineered membranes with self-cleaning properties offer a viable solution for severe surface protein contamination in food and water applications.
一种新型的生物催化纳米纤维复合超滤膜被开发出来，以减少蛋白质的污染相互作用并自清洁膜表面。双层聚（偏二氟乙烯）/尼龙-6,6/壳聚糖复合膜包含一个疏水性聚（偏二氟乙烯）铸膜支撑层和一个亲水性功能尼龙-6,6/壳聚糖纳米纤维表面层，其中酶通过化学附着固定在膜表面。纳米纤维的固有表面化学性质和高表面积允许通过直接共价键合优化和稳定地固定胰蛋白酶（TR）和α-糜蛋白酶。通过 X 射线光电子能谱和共焦显微镜分析证实了酶的固定。制备的生物催化复合膜具有纳米多孔结构，具有优异的渗透性，由于排斥机制和蛋白质被消化成肽和氨基酸，提供了稳定的蛋白质抗黏附和自清洁性能，这通过凝胶电泳技术进行了量化。与原始膜相比，TR 固定化复合膜在经过两次含有牛血清白蛋白/NaCl/CaCl 的模型进料溶液的超滤循环后，具有 2.7 倍的高通量和 3 倍的更高通量恢复率，同时表面蛋白质污染更低。生物催化膜在六个再循环周期后保留了约 50%的酶活性，但在酶再加载后可恢复到 100%的活性，从而实现了简单且具有成本效益的水修复操作。这种具有自清洁性能的表面和孔工程化膜为食品和水应用中的严重表面蛋白质污染提供了可行的解决方案。
