3D localization at the nanometer scale and thermal sensing of living cells

Abstract

Despite the fact that the theory and application of particle 3D localization have been studied extensively, it is still difficult to apply this technique to 3D measurements of temperature field distribution of cells at the micro-nano scale. In this study, an optical system exhibiting double helix point spread function was developed based on the properties of vortex beams, which is suitable for examining particle 3D localization at nanometer scale. Then calibration was performed along the axial and transverse dimensions. The measurement range was 133 × 133 × 1.36 µm3, and the spatial resolution was about 140 nm. Combining with QD fluorescence thermometry, a 3D positioning and temperature measurement method for living cells is proposed. The system was applied into temperature field measurement for living cells. We realized 3D positioning and temperature measurement of quantum dot probes at nanoscale and reconstructed the temperature field of cells. The experimental results of cells show that the measurement system fulfilled 3D localization requirements and could be used to measure the temperature of QDs. Based on the experiment, we draw a schematic diagram of the temperature field distribution of tumor cells. The method proposed in this paper offers an effective tool for studying the dynamics of nanoparticles in complex environments and for studying thermal field variations caused by cytopathic diseases.