Enhanced Aggregability of AIE-Based Probe through H2S-Selective Triggered Dimerization and Its Applications to Biological Systems

We developed a disulfide-conjugated aggregation-induced emission luminogens (AIEgen) (1) that can dramatically enhance the aggregability through a H2S-selective disulfide cleavage and its dimerization. Probe 1 was composed of tetraphenylethene (TPE) as an AIEgen and disulfide bond as a reaction site for H2S. Under physiological conditions, probe 1 can provide strong fluorescence at 480 nm in response to H2S through the formation of TPE dimer (2). This fluorogenic reaction was highly selective for H2S over other potential interferants, such as biologically abundant thiols (e.g., glutathione, homocysteine, cysteine), reactive oxygen species, metal ions, and anions. In addition, probe 1 showed fluorescence change in the presence of H2S in the pH range of 5–8. The limit of detection for H2S was estimated to be 84 nM, which was a significant value at physiological H2S level. Moreover, probe 1 fluorescently imaged even the endogenous H2S, confirmed by the inhibition of H2S-related enzymes (cystathionine β-synth...