Tumor microenvironment as a bioreactor for Au&Fe3O4-DNA complex synthesis and targeted cancer therapy

The comprehensive diagnosis and treatment, integrating multiple diagnosis and treatment modalities into one system, is beneficial for disease prognosis and efficacy monitoring. Herein, in this contribution, we have constructed a unique cancer microenvironment responsive bioreactor to induce bio-self-assembly DNA with metal precursors (i.e., Au(III) and Fe(II)) to form the fluorescent and magnetic nanocomposites of the Au&Fe3O4-DNA complexes in situ. DNA acts as relevant metal ion carriers, and the photothermal effect will increase with the presence of DNA complexes with Au(III) and Fe(II), which helps to achieve accurate tumor lesions localization and precise tracing / imaging of cancer cells and tissues. Our observations demonstrate that the as-prepared Au&Fe3O4-DNA complexes could efficiently inhibit tumor growth by effectively consuming intracellular glutathione (GSH) in cancer cells, which usually induces oxidative stress injury and activates apoptosis. In addition, it allows enhanced photothermal therapy (PTT) under near-infrared (NIR) light irradiation. Therefore, these results illustrate that specific tumor micro-environment-responsive self-assembly formation of Au&Fe3O4-DNA complex can dual regulation of intracellular reactive oxygen species (ROS) and GSH levels in cancer cells; Meanwhile, this in situ bio-self-assembly DNA functional probes have the advantages of precise tumor localization and targeted thermal imaging as well as multi-modal therapy, and thus provide a promising approach for cancer early diagnosis and efficient treatment.