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.

Automated summary

This study presents synthetic monosaccharide channels based on shape-persistent organic cages, porphyrin boxes (PBs), for facile transmembrane transport of glucose and fructose. PBs have a higher transport rate for glucose and fructose compared to disaccharides, demonstrated by enzyme assays and molecular dynamics simulations. The transport rate can be controlled by changing the length of the alkyl chains on the cage windows. When the natural glucose transporter GLUT1 is blocked, PBs are able to transport glucose across living-cell membranes and enhance cell viability. Time-dependent live-cell imaging and MTT assays confirm the cyto-compatibility of PBs. The monosaccharide-selective transport ability of PBs resembles that of natural glucose transporters (GLUTs), which play critical roles in biological functions.