Revisiting intracellular thermal dynamics with mid-infrared photothermal microscopy

In the field of cellular thermal biology, there has been a controversial debate known as the 10^5 gap issue, a significant discrepancy between experimental results from intracellular temperature measurements using fluorescent nanothermometers and theoretical heat conduction calculations. We tackled this issue by utilizing our label-free mid-infrared photothermal (MIP) microscopy. By comparing temperature measurements obtained through fluorescent nanothermometry with those from our label-free MIP thermometry, we discovered a peculiar effect in fluorescent nanothermometry that cannot be explained by thermal conduction. In this talk, we will discuss this intriguing cellular phenomenon revealed by the MIP microscopy measurements.