A Nd–Yb ratiometric luminescent nanothermometer for assessing thermal resistance discrepancies between A549 and BEAS-2B cells to achieve selective hyperthermia†

Temperature is a crucial physical parameter in living organisms, directly associated with cellular activities. Elevated temperatures induce cell death, thereby establishing hyperthermia as a viable modality for cancer therapy. The demand for determining appropriate cancer types for hyperthermia lies in identifying cancer cells that exhibit poorer heat tolerance compared to normal cells. Herein, we have designed NaNdF₄:4%Yb@NaYF₄ with bright luminescence in the near-infrared region for the purpose of achieving in situ cellular temperature detection. The Nd–Yb nanothermometer provides temperature feedback based on a ratiometric luminescence intensity signal. By employing a universal cytobiology method to assess the heat resistance differences between cancer cells and normal cells across various organs, it has been observed that lung epithelial cells exhibit superior heat resistance compared to lung cancer cells. Once the Nd–Yb nanothermometer incubates within lung cells, the temperature differences between live and dead cells can be detected. The absolute temperature differences between live and dead lung cancer cells (0.1 °C) and lung epithelial cells (1.4 °C) under identical thermal stimulation (50 °C) are detected by the Nd–Yb co-doped nanothermometer, confirming that the heat resistance of normal lung cells is significantly superior to that of lung cancer cells. The differential heat resistance of lung cells enables selective hyperthermia for killing A549 cells while maximally protecting BEAS-2B cells. This research may establish rare earth nanothermometry as a valuable protocol for assessing cellular heat resistance, thereby guiding selective hyperthermia for precise lung cancer treatment.