A phasor-based approach to improve optical sectioning in any confocal microscope with a tunable pinhole

Area of Science:

• Microscopy
• Biophysics
• Optical Imaging

Background:

• Confocal fluorescence microscopy generates optical sections using a pinhole aperture.
• Smaller pinhole sizes improve optical sectioning but reduce signal-to-noise ratio (SNR).
• Current limitations hinder the use of very small pinholes in confocal imaging.

Purpose of the Study:

• To introduce a novel method for enhancing optical sectioning in confocal microscopy.
• To overcome the SNR reduction typically associated with smaller pinhole sizes.
• To improve the resolution and clarity of confocal images without compromising signal quality.

Main Methods:

• Sequential acquisition of confocal images at varying pinhole sizes.
• Application of phasor analysis, inspired by Separation of Photons by Lifetime Tuning (SPLIT).
• Development of the SPLIT-pinhole (SPLIT-PIN) method for virtual pinhole size reduction.

Main Results:

• SPLIT-PIN enables virtual confocal imaging at smaller pinhole sizes (e.g., 0.2 Airy Units).
• Achieved improved optical sectioning with significantly better SNR compared to closed pinhole imaging.
• Demonstrated enhanced imaging of the apical membrane in intestinal epithelium models.

Conclusions:

• The SPLIT-PIN method effectively boosts the optical sectioning capability of confocal microscopes.
• Phasor analysis and SPLIT algorithms are innovatively applied to spatial pinhole information.
• This technique offers a valuable tool for high-resolution biological imaging with preserved signal integrity.