Viscosity-responsive styryl benzoxazole probes for lipid droplet visualization

Area of Science:

• Organic chemistry
• Materials science
• Biophysical chemistry

Background:

• Styryl benzoxazole dyes are valuable fluorophores.
• Developing efficient and environmentally friendly synthesis methods is crucial.
• Understanding structure-property relationships is key for designing advanced probes.

Purpose of the Study:

• To synthesize novel styryl benzoxazole fluorophores using a rapid, solvent-minimized solid-state method.
• To investigate their photophysical properties, including absorption, emission, and solvatochromism.
• To evaluate their potential as viscosity-responsive probes for live-cell lipid droplet imaging.

Main Methods:

• Solid-state synthesis under ambient conditions.
• Spectroscopic characterization (absorption, fluorescence).
• Photophysical studies including solvatochromism and viscosity dependence.
• Live-cell imaging experiments in COS-7 cells.

Main Results:

• Rapid synthesis (40-180 seconds) without chromatography.
• Dyes exhibit strong visible absorption and efficient fluorescence with intramolecular charge transfer (ICT).
• Significant solvatochromic emission shifts and large Stokes shifts observed.
• Viscosity-dependent fluorescence enhancement noted, linked to molecular structure.
• Selective accumulation in lipid droplets with negligible cytotoxicity.
• Probes successfully report oleic acid-induced lipid droplet biogenesis.

Conclusions:

• Established clear structure-property-function relationships for styryl benzoxazole dyes.
• Demonstrated the potential of these dyes as efficient, viscosity-responsive probes for lipid droplet imaging.
• Highlighted the utility of these probes in live-cell studies and biological process monitoring.