High-density volumetric super-resolution microscopy.

Area of Science:

• Biophysics
• Optical Microscopy
• Super-resolution Imaging

Background:

• Volumetric super-resolution microscopy uses point spread function (PSF) engineering to encode 3D single-molecule fluorescence into 2D images.
• Complex PSFs lead to large spatial footprints, limiting imaging speed and requiring low labeling densities to prevent signal overlap.

Purpose of the Study:

• To quantitatively compare the density dependence of single-molecule light field microscopy (SMLFM) with other 3D PSF methods.
• To evaluate SMLFM's performance in high-density, whole-cell, and live-cell imaging scenarios.

Main Methods:

• Comparative analysis of SMLFM against astigmatism, double-helix, and tetrapod PSFs.
• Experimental validation using high-accuracy and high-sensitivity localization.
• Application to scan-free, whole-cell imaging and tracking of membrane proteins in primary B cells.
• Demonstration of high-density volumetric imaging in dense cytosolic tubulin datasets.

Main Results:

• SMLFM achieves an order-of-magnitude speed improvement over the double-helix PSF by resolving overlapping emitters via parallax.
• Demonstrated high localization accuracy (>99.2% ± 0.1% at 0.1 locs μm⁻²) and sensitivity (>86.6% ± 0.9% at 0.1 locs μm⁻²).
• Successful whole-cell imaging and tracking of single membrane proteins in live primary B cells.
• Exemplified high-density volumetric imaging (0.15 locs μm⁻²) in dense cytosolic tubulin.

Conclusions:

• SMLFM offers a significant advantage in speed and emitter-capacity for 3D super-resolution microscopy.
• The technique is robust and accurate, enabling efficient imaging of biological structures at high densities.
• SMLFM expands the applicability of super-resolution microscopy for studying dynamic processes in live cells and complex biological systems.