Label free optical transmission tomography for biosystems: intracellular structures and dynamics

Area of Science:

• Biophotonics
• Cellular imaging
• Optical physics

Background:

• Need for label-free methods to visualize intracellular structures and dynamics.
• Limitations of existing techniques in revealing real-time cellular processes.

Purpose of the Study:

• Develop and validate a novel optical tomography method for label-free cellular imaging.
• Demonstrate the capability of FF-OTT to visualize intracellular dynamics and metabolic activity.

Main Methods:

• Implementation of full-field optical transmission tomography (FF-OTT), a common-path interferometer.
• Utilizing the Gouy phase shift for optical sectioning by modulating the focus position.
• Measuring forward scattering signals and demodulating phase-shifted images to reject background.

Main Results:

• FF-OTT successfully imaged single-cell diatoms and ex vivo biological samples.
• Intracellular motions in fresh samples were visualized as intensity fluctuations.
• Demonstrated FF-OTT's ability to reveal time-dependent metabolic signals and dynamic contrast.

Conclusions:

• FF-OTT is an efficient, label-free technique for imaging cellular dynamics.
• The method is readily implementable due to its robust, speckle-free interferometer design.
• FF-OTT offers a promising approach for label-free visualization of live biological samples.