Tiny Fluorescent Temperature Sensors with Super-Reliability

Assistant Professor Liu Xiaogang’s group (SUTD/SMT) has developed a new design strategy to build highly reliable fluorescent temperature sensors, in collaboration with Assistant Professor Michinao Hashimoto (SUTD/EPD) and Professor Xu Zhaochao’s group from Chinese Academy of Sciences.

Fluorescent temperature sensors accurately measure temperature changes in microenvironments with high speeds. However, their accuracy is often compromised as fluorescent dyes degrade (or become photo-bleached) under repetitive laser irradiations.

Professor Liu’s team solves the reliability problem by selecting semi-rigid fluorescent dyes that behave like a “transformer”. These “transformers” possess multiple molecular conformations that emit different colors of fluorescence. Relative populations of these molecular conformations are governed by temperature changes. Consequently, the ratio of their emission intensities accurately quantifies temperature changes. Moreover, this ratio is not affected by dye degradation, since the degradation proportionally reduces the quantities of various conformations in these molecular “transformers”.

Their research work has been published in Materials Chemistry Frontier as an Invited Article. Dr. Chi Weijie, a postdoctoral research associated from SUTD, is the first author of this paper. (Image: fluorescence images of a SUTD-shaped microfluidic channel. The intensity ratio of the blue and green channels of this color image affords accurate temperature information)