A Novel Fluoro-Pyrazine-Bridged Donor-Accepter-Donor Fluorescent Probe for Lipid Droplet-Specific Imaging in Diverse Cells and Superoxide Anion Generation.

Abstract

Purpose Lipid droplets (LDs) are dynamic organelles which associated with many metabolic processes. Reliable long-term imaging of LD is of great importance in LD-based therapy and research. Conventional fluorescent probes suffer from poor photostability and difficulty of preparation, which compromise their LD imaging ability. In this study, we aim to provide a novel and universal fluorescent probe for LD-specific imaging in both eukaryotic and prokaryotic cells. The versatile and potential applications of the probe were also evaluated. Methods We used one-step Suzuki coupling reaction to synthesize a fluoro-pyrazine-bridged donor-acceptor-donor fluorescent probe (T-FP-T). The fluorescent properties and stability of T-FP-T were detected. Then, LD-specific imaging and dynamic movement tracking capabilities of T-FP-T were studied in fungus, bacteria, plant and animal tissues. The biosafety and photodynamic toxicity of the probe under different light irradiation were characterized. Results T-FP-T showed large Stokes shift, superior brightness, excellent photostability, low toxicity. T-FP-T exhibited significant overlaps with adipophilin antibody or the commercial LD probe (LipidSpot™) in the cytoplasm, but not with Mitotracker red, Lysotracker red and Peroxisome Labeling dye. Moreover, T-FP-T also showed efficient superoxide anion generation capability under white LED light irradiation. The viability of Hela cells co-treated with T-FP-T and 1-h white LED light irradiation decreased to 62%. Conclusions All these outstanding capabilities make T-FP-T a new efficient LD-specific imaging probe. The generated superoxide anion from T-FP-T under white LED light irradiation could cause obvious cell death, which will inspire broad study in LD-targeted photodynamic therapy.

Code and data availability

This paper is a chemistry/bioimaging study of a fluorescent lipid-droplet probe (T-FP-T), not a plant-phenotyping study. The supplied blocks contain no public phenotype/trait datasets, plant image or sensor inputs, author analysis code, trained models, or supplements with explicit public deposit URLs. The supplementary

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