ANNINE-6plus, a voltage-sensitive dye with good solubility, strong membrane binding and high sensitivity

Area of Science:

• Neuroscience
• Biophysics
• Organic Chemistry

Background:

• Voltage-sensitive dyes are crucial for optical recording of neuronal activity.
• Existing dyes often require organic solvents or surfactants for application, limiting their use in sensitive biological samples.
• There is a need for water-soluble, membrane-binding voltage-sensitive dyes.

Purpose of the Study:

• To synthesize and characterize a novel voltage-sensitive hemicyanine dye, ANNINE-6plus.
• To evaluate the voltage-sensitivity and applicability of ANNINE-6plus in neuronal membranes.
• To demonstrate the utility of ANNINE-6plus for optical recording in aqueous solutions without organic solvents.

Main Methods:

• Synthesis of ANNINE-6plus from ANNINE-6.
• Characterization of ANNINE-6plus solubility and membrane binding properties.
• Measurement of voltage-sensitivity in neuronal membranes using the molecular Stark effect.
• Optical recording of neuronal excitation with ANNINE-6plus.

Main Results:

• ANNINE-6plus is a water-soluble (1 mM) salt derived from ANNINE-6.
• It exhibits strong binding to lipid membranes and can stain cells from aqueous solution without surfactants or organic solvents.
• ANNINE-6plus displays a high voltage-sensitivity in neuronal membranes via the molecular Stark effect.
• Optimal illumination and detection are in the red spectrum.

Conclusions:

• ANNINE-6plus is a novel, water-soluble voltage-sensitive dye with high neuronal sensitivity.
• Its properties make it suitable for optical recording of neuronal excitation, especially in applications avoiding organic solvents, such as brain tissue staining.
• ANNINE-6plus offers a valuable tool for neuroscience research.