Lipid droplet-targeted AIEgen with dual-responsiveness for sulfur dioxide and viscosity monitoring in live-cell imaging and food analysis.

Sulfur dioxide (SO2) and viscosity play pivotal roles in regulating the physiological function within organisms. The abnormal levels of SO2 and viscosity can lead to various diseases, emphasizing the need for reliable detection methods in biological and real food samples. Herein, we introduce a lipid droplet-targeted novel triphenylamine-based fluorescent probe, TPA-CN, which exhibits aggregation-induced emission (AIE) properties for dual response to SO2 and viscosity. The TPA-CN could ratiometrically recognize SO2 with several advantages, such as excellent selectivity and anti-interference, rapid response rate, good sensitivity, and wide pH adaptability. The TPA-CN was also applied to monitor the changes in viscosity through the twisted intramolecular charge transfer (TICT) mechanism. In addition, bioimaging results demonstrated that TPA-CN can effectively monitor endogenous and exogenous SO₂ as well as viscosity in real time, with specific targeting of lipid droplets. Moreover, TPA-CN facilitates determining SO2 levels in water and food samples, demonstrating robust recovery performance.