Aptamer-Modified Ti3C2Tx MXene Fluorescent Nanoprobe for Monitoring ATP and GTP during a Mild-Photothermal-Activated Nucleolar Stress Process in Living Cells

Understanding the molecular energy metabolism of single cells in the nucleolus stress response induced by mild-photothermal therapy (mPTT) is of great importance for investigating the photothermal lethal mechanism. Herein, we successfully fabricated a "turn-on"-type fluorescent nanoprobe based on the fluorescently labeled aptamers (FAM-ATP-apt and Cy3-GTP-apt) and Ti3C2TX MXene. When the adapters on the nanoprobes bonded to intracellular ATP and GTP, the fluorescence of the nanoprobes was restored. We used the nanoprobes to monitor the variation of ATP and GTP contents in individual tumor cells and normal cells during the mPTT. Interestingly, we found that NPM1 translocated from the nucleolus to the nucleoplasm in MCF-7 cancer cells within 12 min of mPTT laser irradiation, which did not occur in normal MCF-10A cells. However, the content changes of ATP and GTP in tumor cells during the mPTT treatment were significantly higher than that of normal cells. The developed Ti3C2Tx-ATP/GTP nanoprobe enables simultaneous imaging of ATP and GTP in single living cells for bioimaging and molecular detection applications.