Fluorescent nanoprobes for the sensing of gasotransmitters hydrogen sulfide (H2S), nitric oxide (NO) and carbon monoxide (CO).

Fluorescent nanomaterials as sensing probes have experienced immense growth in recent years due to the intrinsic optical and physicochemical properties, high sensitivity, specificity, targeting ability, and suitability for medicinal applications. The fluorescent detection of gaseous signaling molecules, such as Hydrogen sulfide (H2S), nitric oxide (NO) and carbon monoxide (CO) are very important due to their potential therapeutic application. This review intends to provide the recent progress in the detection of H2S, CO and NO via fluorescent based nano probes. These probes work based on different mechanisms such as fluorescence enhancement and quenching, also defined as "turn-on" and "turn-off" responses respectively. It could be achieved through PET, FRET or ratiometric methods. In this article, we have discussed about a variety of fluorescent nanoprobes of QDS, CDs, AuNPs and UCNPS, working on the fluorescent sensing mechanisms and applicable for the detection of H2S, CO and NO in biological and environmental samples. Methods used for the detection, structural features of nanomaterials, type of fluorescence response observed, fluorescence sensing mechanism and their sensitivity are highlighted.