Self-Propelled Asymmetrical Nanomotor for Self-Reported Gas Therapy.

Gas therapy has emerged as a new therapeutic strategy in combating cancer owing to its high therapeutic efficacy and biosafety. However, the clinical translation of gas therapy remains challenging due to the rapid diffusion and limited tissue penetration of therapeutic gases. Herein, a self-propelled, asymmetrical Au@MnO2 nanomotor for efficient delivery of therapeutic gas to deep-seated cancer tissue for enhanced efficacy of gas therapy, is reported. The Au@MnO2 nanoparticles (NPs) catalyze endogenous H2 O2 into O2 that propels NPs into deep solid tumors, where SO2 prodrug is released from the hollow NPs owing to the degradation of MnO2 shells. Fluorescein isothiocyanate (FITC) is conjugated onto the surface of Au via caspase-3 responsive peptide (DEVD) and the therapeutic process of gas therapy can be optically self-reported by the fluorescence of FITC that is turned on in the presence of overexpressed caspase-3 as an apoptosis indicator. Au@MnO2 nanomotors show self-reported therapeutic efficacy and high biocompatibility both in vitro and in vivo, offering important new insights to the design and development of novel nanomotors for efficient payload delivery into deep tumor tissue and in situ monitoring of the therapeutic process.