Intracellular temperature mapping with fluorescence-assisted photoacoustic thermometry

Measuring intracellular temperature is critical to understanding many cellular functions but still remains challenging. Here we present a technique – fluorescence-assisted photoacoustic thermometry (FAPT) – for intracellular temperature mapping applications. To demonstrate FAPT, we monitored the intracellular temperature distribution of HeLa cells with sub-degree (0.7 °C) temperature resolution and sub-micron (0.23 μm) spatial resolution at a sampling rate of 1 kHz. Compared to traditional fluorescence-based methods, FAPT features the unique capability of transforming a regular fluorescence probe into a concentration- and excitation-independent temperature sensor, bringing a large collection of commercially available generic fluorescent probes into the realm of intracellular temperature sensing.