Structured illumination multimodal 3D-resolved quantitative phase and fluorescence sub-diffraction microscopy.

Area of Science:

• Biophysics
• Optical Imaging
• Cell Biology

Background:

• Sub-diffraction resolution imaging is crucial for visualizing sub-cellular structures.
• Current far-field sub-diffraction techniques are limited to either fluorescence or coherent-diffraction regimes.
• A multimodal sub-diffraction technique bridging these regimes has been lacking.

Purpose of the Study:

• To demonstrate structured illumination (SI) for multimodal sub-diffraction imaging.
• To bridge the gap between fluorescent and coherent-diffraction sub-diffraction imaging techniques.
• To visualize biological samples with enhanced resolution in both quantitative-phase and fluorescence channels.

Main Methods:

• Demonstrated SI-enabled three-dimensional (3D) quantitative-phase (QP) sub-diffraction imaging using calibration microspheres.
• Developed an optical system utilizing SI for multimodal 3D sub-diffraction imaging.
• Visualized A549 biological cells fluorescently tagged for F-actin.

Main Results:

• SI achieved enhanced lateral and axial resolutions in 3D QP sub-diffraction imaging compared to diffraction-limited QP imaging.
• Established parallels between coherent SI and conventional optical diffraction tomography.
• Successfully performed 3D sub-diffraction multimodal QP/fluorescent visualization of biological cells.

Conclusions:

• Structured illumination (SI) enables multimodal sub-diffraction imaging, unifying coherent-diffraction and fluorescence regimes.
• SI offers enhanced resolution for visualizing sub-cellular structures.
• This technique has unique utility for studying biological phenomena with molecular, biophysical, and biochemical components.