Immune cell type, cell activation, and single cell heterogeneity revealed by label-free optical methods

Area of Science:

• Biophysics
• Cell Biology
• Spectroscopy

Background:

• Understanding complex cellular responses requires sensitive, high-throughput measurement techniques.
• Current methods often involve trade-offs between sensitivity, multiplexing, throughput, and invasiveness.
• There is a need for noninvasive approaches to analyze both morphological and molecular cellular phenotypes at the single-cell level.

Purpose of the Study:

• To develop and validate a noninvasive optical technique for quantitative analysis of single-cell phenotypes.
• To establish statistical tools for assessing experimental parameter influences on label-free biomarkers.
• To demonstrate the capability of the method in distinguishing cell sub-populations and activation states.

Main Methods:

• Utilized a combination of quantitative phase imaging and Raman spectroscopy for label-free biomarker retrieval.
• Developed generalized statistical tools to analyze biomarker responses to controlled and uncontrolled experimental variables.
• Applied the technique to analyze macrophage cell sub-populations and their activation states.

Main Results:

• Successfully retrieved quantitative biomarkers of morphological and molecular phenotypes from individual cells.
• Demonstrated the ability to detect different macrophage sub-populations and their activation states based on label-free indicators.
• Identified sensitivity to experimental variations, including differences between cells from different animals and outlier behaviors.

Conclusions:

• The presented noninvasive optical approach offers a sensitive method for analyzing single-cell phenotypes without labeling.
• The technique effectively differentiates cell states and responses to experimental conditions, including subtle variations.
• This approach provides a powerful tool for studying dynamic biological processes and improving experimental design in cell biology.