Dual Noncovalent Binding Modes Enabled via Single Thiourea Motif: An Emerging Arsenal for Supramolecular Polymeric Nanomedicine

Abstract

AbstractThe structural rigidity of thiourea (TU) motifs has made them useful in supramolecular (bio)materials. However, the role of the TU motif in a single system endowing dual noncovalent interactions, i.e., Hydrogen‐bonding (H‐bonding) association and metal‐coordination interaction, to afford nanomedicine is still unexplored. Herein a smart supramolecular polymeric nanomedicine constructed via TU motifs privileged dual noncovalent interactions, toward synergistic chemo/chemodynamic (CT/CDT) cancer therapy is reported. The study first synthesized a six‐arm star‐shaped amphiphilic polymer vehicle containing pendant TU motifs, poly(acylthiourea‐co‐oligo(ethylene glycol) ethyl acrylate)6 (P(TU‐co‐OEGEA)6), followed by addressing both H‐bonding association and metal‐coordination to fabricate supramolecular nanomedicine (e.g., Dox/Cu@P(TU‐co‐OEGEA)6). Structural privilege and functional diversity of TU motifs constitute an outstanding scaffold, not only offering an H‐bonding site to associate doxorubicin (Dox) but also acting as a ligand to coordinate copper (Cu). Thereby, one TU motif can enable dual noncovalent binding modes, triggering multiple curative outcomes. TU/Dox and TU/Cu noncovalent interactions can induce intermolecular configuration, yielding prompted cargo loading and in vivo stability. Moreover, benefiting from pH‐responsive Dox release and Fenton‐like copper redox chemistry, accompanied by Dox‐induced intratumoral H2O2 elevation and prompted •OH generation, synergistic CT/CDT with extraordinary anti‐tumor efficacy is indeed accomplished. This work provides a new paradigm using TU motifs regulated dual supramolecular forces to meet therapeutic goals.