Construction of a Supramolecular Polymer by Bridged\nBis(permethyl-β-cyclodextrin)s with Porphyrins and Its Highly\nEfficient Magnetic Resonance Imaging

Abstract

A supramolecular\npolymer is first constructed through the intermolecular inclusion\ncomplexation of bridged bis­(permethyl-β-cyclodextrin) (<b>1</b>) with Mn^III-porphyrin bearing poly­(ethylene glycol)\n(PEG) side chains (Mn^III-TPP) and characterized by UV/vis\nabsorption spectroscopy, NMR, dynamic light scattering (DLS), atomic\nforce microscopy (AFM), and transmission electron microscopy (TEM).\nMn^III-TPP in the supramolecular polymer <b>1</b>·Mn^III-TPP would be reduced effectively to a higher electronic\nspins Mn^II-TPP by sodium ascorbate, but free Mn^III-TPP cannot be reduced in the same condition. The toxicity of the\nsupramolecular polymer <i>in vitro</i> and the magnetic\nresonance imaging effectiveness both <i>in vitro</i> and <i>in vivo</i> are estimated, and the results obtained not only\ndemonstrate the supramolecular polymer to have no cellular toxicity\nbut also show the MR signal enhancement.