Artificial Transmembrane Channels for Selective Ascorbic Acid Transport and Bioorthogonal Signal Transduction.

Ascorbic acid (AA), an essential bioactive molecule, plays a pivotal part in maintaining physiological functions in cells and organisms, and its intracellular homeostasis is regulated by specific natural transporter proteins. Here we report a class of artificial transmembrane channels constructed from discrete covalent organic nanotubes that mediate the selective transmembrane transport of AA. X-ray structural analysis and vesicle-based fluorescence assays confirmed that these molecules adopt a rigid tubular architecture with a near-nanometer pore size, enabling their insertion into lipid bilayers to form stable transmembrane channels that mediate efficient AA transport. Importantly, AA transport mediated by these molecules can initiate bioorthogonal reactions, thereby converting an external chemical stimulus into a fluorescent signal within a biomimetic system.