Localization microscopy: mapping cellular dynamics with single molecules.

Area of Science:

• Biophysics
• Optical Microscopy
• Molecular Imaging

Background:

• Optical microscopes are limited by diffraction to ~200-250 nm resolution for visible light.
• Localization microscopy measures object positions with high precision, surpassing diffraction limits.
• Superresolution fluorescence localization microscopy (SRFLM) combines imaging and localization of fluorescent molecules.

Purpose of the Study:

• To review the concept, process, and recent advances in SRFLM.
• To highlight SRFLM's ability to overcome diffraction limits for molecular-level imaging.
• To discuss SRFLM's applications in understanding cell biology and dynamic processes.

Main Methods:

• Controlling fluorophore visibility to sparsely activate and spatially separate fluorescent tags.
• Acquiring time-lapse images (movies) of fluorescing molecules using a camera.
• Computer analysis to independently measure and record the positions of single molecules.

Main Results:

• SRFLM achieves spatial resolutions better than 20 nm, an order of magnitude improvement over diffraction-limited resolution.
• Specialized optics allow splitting signals into multiple channels for color, orientation, and 3D position information.
• SRFLM is compatible with living samples, enabling visualization of dynamic biological processes.

Conclusions:

• SRFLM has revolutionized molecular imaging since its 2006 inception.
• The technique's versatility allows investigation of biological questions below the diffraction limit.
• SRFLM significantly enhances the understanding of cell biology at the molecular scale.