In vivo single-cell labeling by confined primed conversion

Area of Science:

• Biophysics
• Neuroscience
• Microscopy

Background:

• Optical selection of single cells in vivo is challenging with standard photoconversion techniques.
• High-power pulsed lasers are typically used for photoconversion, but this is often inefficient and lacks spatial confinement.

Purpose of the Study:

• To develop a method for spatially confined green-to-red photoconversion of fluorescent proteins in vivo.
• To enable optical selection and detailed anatomical visualization of individual neurons within complex living tissues.

Main Methods:

• Implementation of a 'primed conversion' technique using low-power, dual-wavelength, continuous-wave illumination.
• Modification of a conventional confocal microscope with a straightforward addition for primed conversion.
• Application of the technique in living zebrafish models.

Main Results:

• Achieved pronounced and spatially confined photoconversion under low-power illumination conditions.
• Demonstrated the ability to optically select and visualize individual neurons in densely packed neural tissue.
• Successfully revealed the complex anatomy of individual neurons in living zebrafish.

Conclusions:

• Primed conversion offers a superior alternative to high-power pulsed laser illumination for in vivo cellular photoconversion.
• This method significantly enhances the capability for optical selection and detailed anatomical study of single cells in living organisms.
• The technique provides unprecedented insights into neural circuit architecture in vivo.