Pan Cheng,Ke Liu,Yucai Wan,Wei Hu,Cancan Ji,Peng Huang,Qihao Guo,Jia Xu,Qin Cheng,Dong Wang
Engineering 3D nanofibrous monolithic materials with a controllable porous channel structure and chemical activity is promising for the rapid and efficient separation of environmentally sensitive biomacromolecules such as RNA. Herein, freeze-drying method via regulating the viscosity of nanofiber dispersions is developed to fabricate nanofibrous sponges (NFSs) with 3D structures of microsphere, lamella, and honeycomb by combining poly(vinyl alcohol- co -ethylene) (PVA- co -PE) nanofibers with chitosan (CS) and polyethyleneimine (PEI) in dispersions. Among sponges, a honeycomb nanofibrous sponge (HNFS) possesses highly oriented open-cells and optimal performance, including water permeability of 7.431 × 10 3 L h m −2 at 1 psi, static saturated capacity of 887.6 mg g −1 , dynamic capacity of 763.2 mg g −1 at a flow rate of 1 mm min −1 , and mechanical robustness, superior to reported state-of-the-art ion-exchange chromatography materials. Furthermore, HNFS-packed chromatographic, funnel, and centrifugal columns present exceptional performance and broad applicability in rapid-separation of RNA from model solution and diverse organisms without degradation. They are attributed to the highly oriented open-cell structure and high-density adsorption ligands on the surface of nanofibrous cell walls. This work provides a facile approach to design advanced NFSs with versatile physicochemical structure and outstanding performance.
Pan Cheng,Cancan Ji,Wei Hu,Peng Huang,Qihao Guo,Ming Xia,Qin Cheng,Jia Xu,Ke Liu,Dong Wang
Construction of ion-exchange chromatography membrane with appropriate pore size and high-density ligands is essential to improve its working efficiency and service life for the separation and purification of biomacromolecules such as RNA . Herein, surface aminated ethylene vinyl alcohol copolymer (EVOH) ion-exchange chromatography nanofibrous membrane (PEI-NFM) with 0.7 µm pore size was fabricated by sea-island spinning and in situ crosslinking (EVOH nanofibers reacted with glutaraldehyde (GA) and polyethyleneimine (PEI) in dispersion). Morphological and chemical characterization of PEI-NFM indicated that GA and PEI crosslinked on the surface of nanofibers uniformly. Benefiting from the 3D network scaffold structure stacked by nanofibers and high-density amine groups, PEI-NFM exhibits high saturated capacity toward RNA (191.16 mg/g), and still possesses more than 93% of its initial adsorption capacity after ten times cyclic adsorption-elution. Moreover, PEI-NFM packed syringe-driven filter shows high water flux of 10.38 L/h at 0.1 MPa and a high dynamic adsorption performance toward RNA (144.07 mg/g at 1 mm/min). Besides, PEI-NFM exhibits high-recognition binding property toward RNA mixed with other biomacromolecules by adjusting pH of mixed solution to make other biomacromolecules positively charged. This work provides a facile strategy for the preparation of high performance and long service life ion-exchange chromatography membrane.
Yuxi Wang,Pan Cheng,Tiange Chen,Mingyue Li,Qihao Guo,Qin Cheng,Dong Wang,Ke Liu
Developing monolithic materials for chromatography columns with a novel interconnected porous structure is vital for the enhancement of the separation efficiency of RNA purification processes. Herein, a porous nanofibrous sponge (PNFS) is constructed by freeze molding and freeze-drying a nanofiber dispersion with ethylene vinyl alcohol copolymer nanofibers as the skeleton, chitosan (CS) and polyethylenimine (PEI) as the binders, and glutaraldehyde (GA) as the crosslinking agent. The results show that when the CS content of the dispersion is 1.5 wt %, PNFS demonstrates a high static adsorption capacity of 406.5 mg/g (30.7 mg/m2) and a dynamic adsorption capacity of 382.6 mg/g (28.9 mg/m2) at a flow rate of 1 mm/min. Moreover, PNFS shows a high specific adsorption performance toward RNA in the presence of bovine serum albumin, lecithin, or DNA by adjusting the solution pH value and the method of gradient elution. Besides, PNFS presents exceptional performance in the rapid separation of RNA from HT22 cells without degradation. This result can be attributed to optimized morphology, pore structure, and comprehensive performance of PNFS, benefiting from the synergistic effect of the highly oriented porous structure and CS–PEI interaction derived from the high-density adsorption ligands on the channel walls of PNFS. This work provided an efficient strategy to handle the permeability/adsorptivity trade-off for ion-exchange chromatographic materials.
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