A turn-on fluorescent nanosensor for HS detection and imaging in inflammatory cells and mice.

Hydrogen sulfide (HS) is an endogenously generated gaseous signaling molecule and is known to be involved in the occurrence and development of inflammation. To better understand its physiological and pathological process of inflammation, reliable tools for HS detection in living inflammatory models are desired. Although a number of fluorescent sensors have been reported for HS detection and imaging, water-soluble and biocompatibility nanosensors are more useful for imaging in vivo. Herein, we developed a novel biological imaging nanosensor, XNP1, for inflammation-targeted imaging of HS. XNP1 was obtained by self-assembly of amphiphilic XNP1, which was constructed by the condensation reaction of the hydrophobic, HS response and deep red-emitting fluorophore with hydrophilic biopolymer glycol chitosan (GC). Without HS, XNP1 showed very low background fluorescence, while a significant enhancement in the fluorescence intensity of XNP1 was observed in the presence of HS, resulting in a high sensitivity toward HS in aqueous solution with a practical detection limit as low as 32.3 nM, which could be meet the detection of HS in vivo. XNP1 also has a good linear response concentration range (0-1 μM) toward HS with high selectivity over other competing species. These characteristics facilitate direct HS detection of the complex living inflammatory cells and drug-induced inflammatory mice, demonstrating its practical application in biosystems.