Haibo Yu, Guli Li, Jieqiong Wang, Youtao Song

School of Environment, Liaoning University

Bei Zhang

College of Chemistry, Liaoning University

Xinfu Zhang, Yi Xiao 

Dalian University of Technology

Abstract

A neutral pH fluorescent probe (Rh-Met) based on rhodamine spirolactam is firstly developed according to the modulation strategy of hydrogen bonds on pKa values. The pKa value of Rh-Met was 6.81(+0.06) and higher than that of other rhodamine spirolactams known. Rh-Met showed a 240-fold enhancement of fluorescence intensity at 585 nm with attenuation of pH values from 9.7 to 3.5. In addition, Rh-Met displayed an excellent selectivity and reversible  response to hydrogen ion. And it was successfully employed for imaging endocellular hydrogen  ion in mitochondria and lipid droplets. These results suggested that Rh-Met could be a potential  tool to assess pH fluctuation in mitochondria and lipid droplets, and would promote many new  opportunities for studying the biological effect of pH in living cells.

Read the article here:   5-A neutral pH probe of rhodamine derivatives inspired by effect of hydrogen bond on pKa and its organelle-targetable fluorescent imaging.pdf