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.