Endogenous nitric oxide (NO) is an important messenger molecule, which can directly activate K+ transmission and cause relaxation of vascular smooth muscle. Here, inspired by the K+ channel of smooth muscle cells, we report, a novel NO-regulated artificial nanochannel based on a spiro ring opening−closing reaction strategy. This nanofluidic diode system shows an outstanding NO selective response owing to the specific reaction between o-phenylenediamine (OPD) and NO on the channel surface with high ion rectification ratio (~6.7) and ion gating ratio (~4). Moreover, this NO gating system exhibits excellent reversibility and stability as well as high selectivity response. This system not only helps us understand the process of NO directly regulating biological ion channels, but also has potential application value in the field of biosensors.

The fabrication of a membrane with the capability of chiral selective transport is a big challenge in the membrane separation of chiral drugs. To solve the problem of chiral selectivity in membrane separation, drug/metabolite transport (DMT) in the cell membrane inspires a bionic strategy based on the nanochannel membrane. Herein, the DMT-inspired nanochannel membrane is fabricated by the self-assembly of cyclodextrin (CD) in nanochannels and used for the chiral transport and separation of model chiral drugs such as naproxen (NAP). As a result, the β-CD-self-assembled nanochannel membrane shows chiral transport of (S)-naproxen (S-NAP) and achieves the chiral separation of racemic drugs. Moreover, a mechanism of chiral separation is proposed that the chiral selective interaction increases the surface charge density, causing chiral enrichment and transport. Given these promising results, the study of the β-CD-self-assembled nanochannel membrane suggests a bionic strategy for the separation of chiral drugs.

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.

Stimuli-responsive nanosystems have attracted the interest of researchers due to their intelligent function of controlled release regulated by a variety of external stimuli and been applied in biomedical fields. Pillar[n]arenes...

Chiral discrimination has gained much focus in supramolecular chemistry, since it is one of the fundamental processes in biological systems, enantiomeric separation and biochemical sensors. Though most of the biochemical...