Hyperbranched Supramolecular Polymer of Tris(permethyl-β- cyclodextrin)s with Porphyrins: Characterization and Magnetic Resonance Imaging

A hyperbranched supramolecular polymer(HSP)is constructed based on the intermolecular inclusion complexation of bridged tris(permethyl-β-cyclodextrin)with Mn^(Ⅲ)-porphyrin bearing poly(ethylene glycol)(PEG)side chains(Mn^(Ⅲ)-TPP),and characterized by UV/vis absorption spectroscopy,isothermal titration calorimetry(ITC),NMR,dynamic light scattering(DLS),atomic force microscopy(AFM)and transmission electron microscopy(TEM),respectively.The presence of permethyl-β-cyclodextrin can stabilize the low-valent Mn^(II)-TPP.In vitro cell experiment indicates that this HSP has no remarkable cellular toxicity against NIH 3T3 cells.In vitro MR imaging experiment indicates a slightly increased T_(1) relaxivity for this HSP compared to that for the linear supramolecular polymer.