Bent-to-planar Si-rhodamines: a distinct rehybridization lights up NIR-II fluorescence for tracking nitric oxide in the Alzheimer's disease brain.

An ongoing revolution in fluorescence-based technologies has transformed the way we visualize and manipulate biological events. An enduring goal in this field is to explore high-performance fluorogenic scaffolds that show tunability and capability for analysis, especially for small-molecular near-infrared (NIR) fluorophores. We present a unique bent-to-planar rehybridization design strategy for NIR fluorogenic scaffolds, thus yielding a palette of switchable bent/planar Si-rhodamines that span from visible to NIR-II wavelengths.

Rational Design of Ratiometric Near-Infrared Aza-BODIPY-Based Fluorescent Probe for Imaging of Endogenous Hydrogen Peroxide.

Precise tracking of hydrogen peroxide is still challenging due to its dynamic complexity and intrinsic background interference. Herein, we describe a rational design strategy to construct asymmetric aza-boron-dipyrromethane derivative (BODIPY)-based ratiometric probes for tracking HO, which are composed of a near-infrared aza-BODIPY core, active targeting group, and HO-specific recognition unit. We take advantage of two terminal functionalized conjunctions in the bis-condensed aza-BODIPY by rationally introducing carbonyl group as an electron-deficiency linker for regulating intramolecular charge transfer-induced wavelength shift and by attaching hydrophilic polyethylene glycol-biotin segment as the active targeting moiety.