Multi-modal chip-based fluorescence and quantitative phase microscopy for studying inflammation in macrophages.

Area of Science:

• Biophysics
• Cell Biology
• Microscopy

Background:

• Total internal reflection fluorescence (TIRF) microscopy offers high-sensitivity, low-background imaging of cell membranes.
• However, TIRF microscopy lacks quantitative morphological analysis capabilities.
• Quantitative phase imaging (QPI) provides label-free quantification of cellular morphology.

Purpose of the Study:

• To develop an integrated waveguide chip-based microscopy system combining TIRF and QPI.
• To enable simultaneous high-contrast imaging and quantitative analysis of cellular structures.
• To investigate the effects of lipopolysaccharide (LPS)-induced inflammation on rat macrophages.

Main Methods:

• An evanescent field from a waveguide excites fluorescence for TIRF imaging.
• An upright microscope, converted into a Linnik-type interferometer, acquires both TIRF and QPI data.
• The system utilizes a multi-modal approach for comprehensive cellular analysis.

Main Results:

• TIRF imaging revealed that LPS disrupts the macrophage cell membrane, leading to significant cell expansion.
• QPI quantified alterations in sub-cellular content, indicated by a decrease in maximum phase values in LPS-challenged cells.
• The integrated system demonstrated effective multi-modal imaging of cellular responses to inflammation.

Conclusions:

• The proposed waveguide chip-based TIRF and QPI system provides a powerful tool for label-free, quantitative analysis of cellular dynamics.
• This multi-modal microscopy advances the study of cellular inflammation and membrane-related processes.
• The technology offers advantages in imaging sensitivity, quantitative accuracy, and system integration.