Iridium oxide nanoparticles-based theranostic probe for in vivo tumor imaging and synergistic chem/photothermal treatments of cancer cells

A novel iridium oxide nanoparticles-based probe was developed for in vivo fluorescence imaging of microRNA and synergistic chem/photothermal treatments of tumor. The theranostic nanoprobe was constructed by functionizing iridium oxide nanoparticles with split DNAzyme precursor and chemotherapeutic agent doxorubicin. The split DNAzyme precursor was used for specifically recognizing the target microRNA in cancer cells and then releasing the preloaded fluorescence for detection through DNAzyme cleavage reaction. Because the fluorescence was enhanced by cycle amplification process, the nanoprobe exhibited high sensitivity in the cell-free test. Both in vitro and in vivo fluorescence imaging studies proved the specificity and feasibility of the nanoprobe in tumor imaging. In order to enhance the effectiveness of cancer cell therapy, synergistic chem/photothermal treatments were designed on the nanoprobe. Based on the photothermally controlled drug release and chemotherapeutic treatment of doxorubicin, and the photothermal effect of iridium oxide nanoparticles, the nanoprobe exhibited excellent synergy effect on cancer cell treatment under near-infrared irradiation. In particular, in vivo therapeutic studies proved a great inhibition of the tumor growth. Therefore, this work provided a promising theranostic nanoprobe for both tumor imaging and synergistic treatment of cancer cells.