Enantioselective Antiport in Asymmetric Nanochannels

Abstract

Enantioselective sensing and separation are major challenges. Nanochannel technologies are energy-saving and efficient for membrane separation. Herein, inspired by biological antiporter proteins, artificial nanochannels with antiporter behavior were fabricated for chiral sensing and separation. Tyrosine enantiomers were incorporated into hourglass-shaped nanochannels via stepwise modifications to fabricating multiligand-modified asymmetric channels. Chiral distinction of naproxen enantiomers was amplified in the l-Tyr/d-Tyr channels, with an enantioselectivity coefficient of 524, which was over 100-fold that of one-ligand-modified nanochannels. Furthermore, transport experiments evidenced the spontaneous antiport of naproxen enantiomers in the l-Tyr/d-Tyr channels. The racemic naproxen sample was separated via the chiral antiport process, with an enantiomeric excess of 71.2%. Further analysis using electro-osmotic flow experiments and finite-element simulations confirmed that the asymmetric modified multiligand was key to achieving separation of the naproxen enantiomers. We expect these multiligand-modified asymmetric nanochannels to provide insight into mimicking biological antiporter systems and offer an approach to energy-efficient and robust enantiomer separation.

Chiral Covalent Organic Framework Packed Nanochannel Membrane for Enantioseparation

“…Facing the increasing demand for chiral drugs, enantioseparation methods with high selectivity and flux are required. Compared with chromatography, [4–9] the nanochannel membrane‐based separation methods have the advantage of large processing capacity, continuous operation, and high efficiency, demonstrating a great prospect for chiral drug separation [10–14] . Currently, most nanochannel membranes are fabricated by modifying the surface of nanochannel with a monolayer of chiral receptors, such as amino acids [11, 12] and cyclodextrins [13, 14] .…”

“…The COF was in situ synthesized in nanochannels of polyethylene terephthalate (PET) membrane by interfacial hydrothermal method [28–32] . Then the COF packed nanochannels were modified by L‐tyrosine, which was proved as a receptor of S‐naproxen [12, 33] . The pore size of chiral COF was 2.0 nm, matching with the molecular size of S‐NPX.…”

“…To improve enantioselectivity, the structure of functionalized nanochannels is improved. One efficient strategy is localized introduction of multiple receptors in the nanochannel [12] . Another strategy was size‐matching, by reducing the diameter of transmission channel to 0.1–10 nm [19, 37] .…”

“…Compared with chromatography, [4][5][6][7][8][9] the nanochannel membrane-based separation methods have the advantage of large processing capacity, continuous operation, and high efficiency, demonstrating a great prospect for chiral drug separation. [10][11][12][13][14] Currently, most nanochannel membranes are fabricated by modifying the surface of nanochannel with a monolayer of chiral receptors, such as amino acids [11,12] and cyclodextrins. [13,14] The strategy of chiral receptor functionalization realizes the recognition of enantiomers, but is not secure for controlled transport and enantioseparation.…”

Controlled release of drug molecules by pillararene-modified nanosystems

“…Various stimuli-responsive host–guest systems have been applied in different fields, such as fluorescent sensors, 11 drug delivery systems, 12 and smart functional materials. 13,14…”