Tandem Coordination, Ring-Opening, Hyperbranched Polymerization for the Synthesis of Water-Soluble Core–Shell Unimolecular Transporters

A water-soluble molecular transporter with a dendritic core–shell nanostructure has been prepared by a tandem coordination, ring-opening, hyperbranched polymerization process. Consisting of hydrophilic hyperbranched polyglycerol shell grafted from hydrophobic dendritic polyethylene core, the transporter has a molecular weight of 951 kg/mol and a hydrodynamic diameter of 17.5 ± 0.9 nm, as determined by static and dynamic light scattering, respectively. Based on evidence from fluorescence spectroscopy, light scattering, and electron microscopy, the core–shell copolymer transports the hydrophobic guests pyrene and Nile red by a unimolecular transport mechanism. Furthermore, it was shown that the core–shell copolymer effectively transports the hydrophobic dye Nile red into living cells under extremely high and biologically relevant dilution conditions, which is in sharp contrast to a small molecule amphiphile. These results suggest potential applicability of such core–shell molecular transporters in the administration of poorly water-soluble drugs.