Rational design of aggregation-induced emission-active bisboron complexes (BOQHYs) for high-fidelity lipid droplet imaging

Abstract

Lipid droplets (LDs) are dynamic intracellular organelles that participate in a wide range of physiological and pathological processes. Consequently, the development of high-selectivity and high-resolution tools for LD detection and tracking is of paramount importance. In this study, we describe the straightforward synthesis of a series of novel BODIPY analogs, BOQHYs 3a–3e, through the condensation of 2,3-dihydrazinylquinoline with acetone or benzophenone, followed by complexation with BF₃·OEt₂. Spectroscopic properties indicate that these dyes exhibited significantly larger Stokes shifts (>100 nm) than the commercial LD-Tracker BODIPY 493/503 (≈10 nm). Additionally, the incorporation of phenyl “rotors” endows BOQHYs 3b–3e with heightened aggregation-induced emission activity, viscosity responsiveness, and exceptional lipophilicity, enabling their selective staining of LDs in a rapid and wash-free manner, with outstanding signal-to-noise ratios. Time-resolved confocal fluorescence imaging of 3d further validates these dyes’ capability to effectively capture LD fusion and fission events, highlighting their potential applications in LD-related cell biology and disease diagnostics.