A near-infrared, colorimetric and ratiometric fluorescent sensor with high sensitivity to hydrogen peroxide and viscosity for solutions detection and imaging living cells.

Considering to the importance of hydrogen peroxide (HO) in a number of pathological processes and fluorescence sensor as a powerful tool for imaging and therapy of HO-related diseases, herein, a near-infrared fluorescent sensor for colorimetric and ratiometric detecting HO and viscosity, named NCR, was constructed and reported. Its long emission wavelength (670 nm) avoids the interference of biological autofluorescence. When NCR interacted with 10 equiv. of HO, colorimetric characteristic provides a clear naked eye recognition (colourless turned to green under UV light and light purple turned to colorless under visible light). In addition, NCR shows high sensitivity to viscosity with or without the addition of HO. It was also found alkaline environment contribute to enhance fluorescence response to HO. A suitable water-octanol partition coefficient (logP, 0.521 ± 0.003) and low cytotoxicity displayed that NCR is very favorable to image living cells. Furthermore, exogenous and endogenous HO was detected successfully by NCR in living Hela cells. These studies indicate that NCR has great potential to develop as a practical tool for monitoring HO level in biological process.