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Single-Molecule Tracking Microscopy - A Tool for Determining the Diffusive States of Cytosolic Molecules
Published on: September 5, 2019
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Dry mass photometry of single bacteria using quantitative wavefront microscopy.
Maëlle Bénéfice1, Aurore Gorlas2, Baptiste Marthy1
1Institut Fresnel, CNRS, Aix Marseille University, Centrale Marseille, Marseille, France.
Biophysical Journal
|July 2, 2023
Summary
Quantitative phase microscopy (QPM) accurately measures the dry mass (DM) of single bacteria and archaea. This high-resolution technique also introduces optical polarizability (OP) for potential species identification.
Area of Science:
- Microscopy
- Cell Biology
- Biophysics
Background:
- Quantitative phase microscopy (QPM) offers noninvasive cell observation and dry mass (DM) measurement.
- QPM is widely used for mammalian cells but less for bacteria due to size-related resolution and sensitivity demands.
Purpose of the Study:
- To demonstrate high-resolution QPM for accurate DM measurement in single bacteria and archaea.
- To introduce novel metrics like normalized optical volume and optical polarizability (OP) for enhanced microbial analysis.
Main Methods:
- Utilized cross-grating wavefront microscopy, a high-sensitivity QPM technique.
- Developed strategies to overcome light diffraction and sample focusing challenges.
- Applied algorithms for measuring DM, optical volume, and OP.
Main Results:
- Successfully performed accurate DM measurements on single microorganisms.
- Demonstrated monitoring of DM changes in a microcolony with varying temperature.
- Showcased OP as a potential species-specific signature for bacteria and archaea.
Conclusions:
- Cross-grating wavefront microscopy enables precise QPM analysis of small microorganisms.
- Normalized optical volume and OP provide valuable insights beyond DM, aiding in microbial identification and characterization.
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