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

Proposed sensing mechanism of NCR with H2O2. [Display omitted] •NCR exhibits long emission wavelength (670 nm) avoids the interference of biological autofluorescence.•Its colorimetric characteristic provides a clear naked eye recognition (colourless turned to green under UV light and light purple turned to colorless under visible light).•NCR shows high sensitivity to viscosity with or without the addition of H2O2 and has a suitable water-octanol partition coefficient (logP, 0.521 ± 0.003).•Exogenous and endogenous H2O2 was detected successfully by NCR in living Hela cells. Considering to the importance of hydrogen peroxide (H2O2) in a number of pathological processes and fluorescence sensor as a powerful tool for imaging and therapy of H2O2-related diseases, herein, a near-infrared fluorescent sensor for colorimetric and ratiometric detecting H2O2 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 H2O2, 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 H2O2. It was also found alkaline environment contribute to enhance fluorescence response to H2O2. 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 H2O2 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 H2O2 level in biological process.