Ratiometric fluorescent nanoparticles for sensing temperature

A ratiometric type of fluorescent nanoparticle was prepared via an encapsulation–reprecipitation method. By introducing an alkoxysilanized dye as a reference, the nanoparticles (NPs) give both a green and a red fluorescence under one single-wavelength excitation. The resulted ratiometric fluorescence is found to be highly temperature-dependent in the physiological range (25–45 °C), with an intensity temperature sensitivity of ?4.0%/°C. Given the small size (20–30 nm in diameter) and biocompatible nature (silica out layer), such kind of NPs were very promising as temperature nanosensors for cellular sensing and imaging.