Synthetic Monosaccharide Channels: Size‐Selective Transmembrane Transport of Glucose and Fructose Mediated by Porphyrin Boxes

Here we report synthetic monosaccharide channels built with shape‐persistent organic cages, porphyrin boxes (PBs), that allow facile transmembrane transport of glucose and fructose through their windows. PBs show a much higher transport rate for glucose and fructose over disaccharides such as sucrose, as evidenced by intravesicular enzyme assays and molecular dynamics simulations. The transport rate can be modulated by changing the length of the alkyl chains decorating the cage windows. Insertion of a linear pillar ligand into the cavity of PBs blocks the monosaccharide transport. In vitro cell experiment shows that PBs transport glucose across the living‐cell membrane and enhance cell viability when the natural glucose transporter GLUT1 is blocked. Time‐dependent live‐cell imaging and MTT assays confirm the cyto‐compatibility of PBs. The monosaccharide‐selective transport ability of PBs is reminiscent of natural glucose transporters (GLUTs), which are crucial for numerous biological functions. Shape‐persistent organic cages, porphyrin boxes (PBs), have been used to construct synthetic monosaccharide channels. These cages facilitate the transmembrane transport of glucose and fructose through their windows, while impeding the transport of larger sized sugars because of the limited size of the cage windows, thus facilitating size‐selective transport. Live cells treated with the PBs show glucose uptake and enhanced cell viability.