High-numerical-aperture cryogenic light microscopy for increased precision of superresolution reconstructions

Area of Science:

• Biophysics
• Cell Biology
• Microscopy

Background:

• Superresolution microscopy offers high-resolution imaging of subcellular structures.
• Dense, single-molecule-sized elements pose challenges for current superresolution techniques.
• Cryogenic fluorescent imaging may reduce photobleaching and enhance imaging precision.

Purpose of the Study:

• To develop and validate a cryogenic photoactivated localization microscopy (cPALM) approach.
• To enable imaging of frozen samples using room-temperature objectives.
• To enhance the resolution and accessibility of superresolution imaging for complex biological targets.

Main Methods:

• Implementation of a cryogenic setup compatible with room-temperature high-numerical-aperture objectives.
• Utilizing photoactivatable/switchable fluorophores for localization microscopy.
• Imaging of two distinct labeled structures within the same frozen sample.

Main Results:

• The cPALM approach successfully imaged frozen samples in their native state.
• Cryogenic conditions increased photon yields compared to conventional methods.
• Effective resolution was enhanced for dual-labeled structures, enabling higher precision reconstructions.

Conclusions:

• The developed cPALM technique improves superresolution imaging precision.
• This method increases photon yields and reduces photobleaching.
• The two-color cPALM extension broadens the applicability of high-resolution cryo-imaging.