A biocompatible ratiometric fluorescent nanoprobe for intracellular hydrogen sulfide accurate detection based on rare earth nanoparticle.

Hydrogen sulfide (HS) is an important signal molecule involved in intracellular activities. To understand the role of HS in cellular physiological and pathological process, the development of sensitive and selective methods, especially biocompatible assays, for efficient monitoring the level of HS is necessary. Herein, we modified novel rare earth element europium (EU) based fluorescent nanospheres with azide (-N) based sensor to construct an ingenious ratiometric fluorescent nanoprobe EU-N3. This nanoprobe showed excellent water solubility and high biocompatibility for intracellular HS accurate detection. Nanoprobe EU-N3 had two obvious emission peaks, the green fluorescence peak at 540 nm increased according to the increasing of HS concentration and the red fluorescence peak at 616 nm was stable as ratiometric reference. The fluorescence intensity ratio (I/I) displayed good linear response (R = 0.99136) in HS range of 0.5 ∼ 30 μM. The analytes response assay demonstrated that the nanoprobe EU-N3 possessed a better specificity for HS, compared with other 9 anions and 3 cations. The cell viability assay indicated the nanoprobe EU-N3 had an excellent biocompatibility. The cell imaging showed that the proposed nanoprobe could be applied for detecting the intracellular HS changes accurately in live cells. Such nanoprobe provided a safe and accurate strategy for intracellular HS detection, which is helpful for the real-time HS visualization in the live cell activities.