Photoactivation of BODIPY Fluorescence with Green Light

Area of Science:

• Chemical Biology
• Microscopy
• Biophotonics

Background:

• Existing photoactivatable fluorescent dyes require UV or violet light, causing significant phototoxicity in biological samples.
• There is a critical need for dyes that can be activated by longer wavelengths (>500 nm) with low power densities for live-cell imaging.

Purpose of the Study:

• To develop a novel photoactivatable synthetic dye strategy for live-cell super-resolution imaging.
• To enable fluorescence photoactivation using visible light, specifically in the green spectrum, to reduce phototoxicity.

Main Methods:

• Design and synthesis of a novel borondipyrromethene (BODIPY)-based dye conjugated with an oxazine heterocycle.
• Photoactivation experiments using a 561 nm laser and subsequent imaging with 581 nm excitation.
• Localization of single fluorescent molecules and reconstruction of subdiffraction images of cellular structures (lysosomes) in live cells.

Main Results:

• Demonstrated that green light illumination (561 nm) cleaves the oxazine ring, generating a red-emitting fluorescent product.
• Achieved precise single-molecule localization and super-resolution imaging of cellular structures in live cells.
• Confirmed negligible phototoxicity under the employed visible light irradiation conditions.

Conclusions:

• The developed BODIPY-oxazine system provides a viable photochemical strategy for creating photoactivatable dyes.
• This approach enables super-resolution microscopy in live cells under significantly reduced phototoxicity conditions.
• The findings pave the way for advanced live-cell imaging techniques with improved biocompatibility.