Advances and challenges for fluorescence nanothermometry

Fluorescent nanothermometers can probe the change of local temperature in living cells and in vivo. This field attracts major international efforts in developing both temperature-responsive materials and detection procedures to achieve sub-degree temperature resolutions in biosystems. The newly demonstrated nanothermometers have shown superior sensing performance and multifunctionality, which enables state-of-the-art functional imaging techniques towards improved spatial, temporal, and temperature resolutions for monitoring metabolism of intracellular organelles and internal organs.  While the technology becomes mature, along with some debatable records, recent studies have also shown that these nanoscopic thermometers could come across possible biased sensing during the fluorescence-based detection. In this review, we introduce the design principle and advances of fluorescence nanothermometry, discuss the scenarios that may lead to biased sensing, analyze the challenges ahead from both fundamental levels and their practical implementations, and propose new directions to improve the mutual understandings of this interdisciplinary research field.