Collagen Fibril-Assembled Skin-Simulated Membrane for Continuous Molecular Separation

A skin-simulated thin-film-composite membrane was fabricated using a vacuum-assisted interfacial polymerization method. A negatively charged surface-selective layer on a polyacrylonitrile (PAN) substrate was cross-linked using trimesoyl chloride to form polyamide and polyester with a three-layer structure that was similar to skin. The loading of collagen fibrils assembled on the membrane surface was varied, and a selective layer was obtained, of which the thickness, morphology, and hydrophilicity can be manipulated. The optimal membrane decorated with 0.5 mg of collagen fibril had a selective layer thickness of around 130 nm with pure water permeability up to 84.7 LMH bar^-1. Furthermore, the membrane exhibited impressive rejections toward dyes (Congo red with a molecular weight of 696.68 Da: 99.6%, reactive blue 19 with a molecular weight of 626.54 Da: 99.8%, and Coomassie blueG-250 with a molecular weight of 854.02 Da: 98.6%) while high permeations of Na₂SO₄ and NaCl were achieved. This facile strategy provides a useful guideline for constructing bionic membranes through biomaterials.