Abstract
The intracellular delivery of enzymes is an essential methodology to extend their therapeutic application. Herein, we have developed dissociable supermolecule-enzyme polyelectrolyte complexes based on reduction-cleavable cationic polyrotaxanes (PRXs) for the reactivation of delivered enzymes. These PRXs are characterized by their supramolecular frameworks of a polymeric chain threading into cyclic molecules, which can form polyelectrolyte complexes with anionic enzymes while retaining their three dimensional structure, although their enzymatic activity is reduced. Upon the addition of a reductant, the PRXs dissociate into their constituent molecules and release the enzymes, resulting in a complete recovery of enzymatic activity. Under the intracellular environment, the PRX-based enzyme complexes showed the highest intracellular enzymatic activity and efficient activation of anticancer prodrugs to induce cytotoxic effects in comparison with the non-dissociable complexes and the commercial cell-penetrating peptide-based reagents. Thus, the intracellularly dissociable supermolecules are an attractive system for delivering therapeutic enzymes into living cells.