Single-visible-light-modulated photoswitches with aggregation-induced emission for super-resolution imaging

Super-resolution fluorescence imaging (SRI) overcomes the traditional optical diffraction limit, enabling the visualization of microstructures at the nanoscale. Central to this technique is the precise photo-modulation of molecular fluorescence emission, yet it remains a formidable challenge to develop visible-light-responsive photoswitching systems with aggregation-induced emission (AIE) that are biocompatible and suitable for solid-state applications. Herein, we construct a series of unique fluorescent photoswitches with single-visible-light modulation by incorporating sulfone units into a sterically hindered diarylethene. By introducing sulfone units and adjusting the substituent effect, the fluorescent photoswitches exhibit band-tail absorption, demonstrating superior single-visible-light-stimulation ability (488 or 561 nm light) and efficiently preventing damage from short-wavelength light. Notably, the weak π-π stacking and the activated restriction of intramolecular vibration (RIV) process, caused by the large, bulky ethylene bridge, also endow the fluorescent photoswitch with unique aggregation-induced emission properties. Thus, such fluorescent photoswitches exhibit fluorescence emission with a high fluorescent quantum yield and on-off ratio (>100) in the aggregated state, which successfully enables a single long-wavelength 561 nm laser, a privileged source, to perform Stochastic Optical Reconstruction Microscopy (STORM) imaging of nano-micelles with high resolution. This work offers a robust photonics-based approach to the development of remote and non-invasive fluorescence modulation platforms, fundamentally advancing the frontiers of SRI techniques.