Anion-exchange membrane adsorbers with silane-modulated biomimetic amination surface for efficient DNA separation

Abstract

Ion exchange membrane adsorbers, an alternative to overcome the bottleneck of present deoxyribonucleic acid (DNA) solid-phase extraction material, still suffer from scarce binding capacity and uncontrollable recovery efficiency. Herein, inspired by mussel adhesion combined with in-situ coupling technique, a silane-modulated biomimetic amination strategy is proposed to construct an anion-exchange membrane adsorber for efficient DNA separation. The coupling of polyethyleneimine to the biomimetic interlayer formed by the co-coating of pyrogallol and 3-glycidoxypropyltrimethoxysilane onto polyethersulfone membranes provides high coverage of DNA-binding ligands for the resulting membrane adsorber. Furthermore, its surface charge properties are tailored by the tunable content of epoxy groups in the biomimetic interlayer, resulting in the pH-responsive reversible DNA binding capacity. Consequently, the resulting membrane adsorber exhibits unprecedented DNA adsorption capacity (396.2 mg g⁻¹), which is renewable and requires no external binding agent. More importantly, this membrane adsorber in the form of spin columns achieves outstanding DNA recovery efficiency up to 88 %, which is 32 % improvement over commercial silica matrices. This research provides a new perspective on the design of novel ion exchange membrane adsorbers and holds promise for the low-loss, high-efficiency downstream separation and purification processes of biomacromolecules.