# Practical NIR Assay Derived from Cyanine to Evaluate Intracellular H2S in Living Cell Imaging

## TL;DR

This paper introduces a new fluorescent probe for detecting hydrogen sulfide in living cells using near-infrared imaging.

## Contribution

A novel NIR-sensitive fluorescent probe (FS-HS-1) was developed for real-time H2S detection in living cells.

## Key findings

- FS-HS-1 showed a 111-fold fluorescence enhancement at 715 nm for H2S detection.
- The probe detected H2S with a detection limit of 4.47 ± 0.11 nmol/L.
- The probe successfully monitored H2S changes in living cells using confocal and 2P imaging.

## Abstract

To monitor the biological function of H2S in real time, this investigation demonstrated the design and synthesis of a novel fluorescent probe integrated with cyanine and 2,4-dinitrophenol for the qualitative and quantitative detection of H2S. An NIR sensitive sensor (FS-HS-1) was provided with a straightforward process. Spectroscopy experiments elucidated that FS-HS-1 could selectively detect H2S in a PBS solution (containing 40% acetonitrile) with a 111-fold fluorescence enhancement at 715 nm (ex. 605 nm). The response towards NaHS occurred in less than 2 min, and the detection limit was confirmed to be as low as 4.47 ± 0.11 nmol/L. Furthermore, the probe is capable of monitoring changes in exogenous H2S concentrations within living cells with confocal and 2P imaging.