Near-infrared voltage-sensitive dyes based on chromene donor

Area of Science:

• Biophysics
• Neuroscience
• Optical Imaging

Background:

• Voltage-sensitive dyes (VSDs) are crucial for high-speed optical imaging of cellular electrical activity.
• Existing VSDs often use push-pull chromophores, limiting spectral range and potentially interfering with optogenetic tools.
• Red-shifted dyes are needed for deeper tissue penetration and reduced phototoxicity.

Purpose of the Study:

• To develop novel voltage-sensitive dyes with red-shifted spectra.
• To evaluate the performance of these new dyes in imaging cardiac electrical activity.
• To assess the compatibility of these dyes with optogenetic manipulation.

Main Methods:

• Synthesis of chromene-based chromophores as VSDs.
• Spectroscopic characterization of absorption and emission properties.
• In vitro and ex vivo testing on murine hearts, including simultaneous optical imaging and optogenetic stimulation.

Main Results:

• Chromene substitution resulted in a 60-80 nm red-shift in spectra compared to naphthalene-based dyes.
• Achieved 12% ΔF/F per action potential in ex vivo murine hearts using 730 nm excitation.
• Demonstrated artifact-free, all-optical monitoring of action potential propagation in channelrhodopsin-expressing hearts.

Conclusions:

• Chromene-based VSDs provide superior spectral properties for voltage imaging.
• These dyes enable high-resolution, real-time imaging of cardiac action potentials.
• The developed VSDs are compatible with optogenetics and hold promise for broader applications in neuroscience and biophysics.