In Vivo Contactless Brain Nanothermometry

Despite attracting increased attention from clinicians, brain temperature distribution, fluctuations, and changes in response to external stimuli are still largely unknown and refractory to conventional temperature‐probing approaches. Fluorescence nanothermometry in the second near‐infrared window (NIR‐II, 1000–1700 nm), as shown here, can provide contactless brain thermal sensing through the scalp and skull in real time with a subdegree resolution. As a proof of concept, Ag2S nanothermometers have been used to monitor brain thermoregulation in a cooling/heating process and temperature changes associated to a barbiturate coma.