A red mitochondria-targeted AIEgen for visualizing H2S in living cells and tumours.

Hydrogen sulfide (H2S) exists in the cytosol and mitochondria of mammalian cells as a signaling molecule. Scientists have explored many important physiological functions of H2S, such as regulating vasodilator relaxation, protecting living cells and avoiding damage. The measurement of H2S is therefore necessary for exploring the biological function of cells and tissues. Herein, we report the design and synthesis of a new aggregation-induced emission luminogen (AIEgen) with greater conjugation and more positive charges, based on previous research on mitochondrial-targeted luminogens. The Indo-TPE-Indo can enter cells rapidly, as compared with an AIEgen with only one indolium (TPE-indo), and can selectively recognize HS- in mitochondria with the nucleophilic reaction of indolium and HS-. The linear range (1-100 μM) of HS- sensing can satisfy the requirement for HS- concentration in living cells and tumors.