Stimulated Raman scattering flow cytometry for label-free single-particle analysis

Area of Science:

• Biophotonics
• Analytical Chemistry
• Cell Biology

Background:

• Flow cytometry is crucial for high-throughput single-cell analysis, primarily using fluorescent labeling.
• Fluorescent tags can perturb biological function, especially for small molecules, limiting their applicability.
• Spontaneous Raman scattering flow cytometry offers non-invasive chemical detection but is limited by slow data acquisition.

Purpose of the Study:

• To develop a label-free, high-throughput method for single-particle analysis using Raman scattering.
• To overcome the speed limitations of spontaneous Raman scattering flow cytometry.
• To enable rapid chemical content analysis of individual cells and particles.

Main Methods:

• Development of a 32-channel multiplex stimulated Raman scattering flow cytometry (SRS-FC) technique.
• Measurement of chemical contents of single particles at a speed of 5 μs per Raman spectrum.
• Demonstration using mixed polymer beads for particle discrimination.

Main Results:

• Achieved a throughput of up to 11,000 particles per second, a four-orders-of-magnitude improvement over spontaneous Raman methods.
• Successfully demonstrated discrimination of different polymer beads based on their chemical composition.
• Showcased differentiation of 3T3-L1 cells in different states via label-free chemical content analysis.

Conclusions:

• The SRS-FC technique provides a significant advancement in high-throughput, label-free single-particle analysis.
• This method enables rapid and non-invasive chemical analysis of cellular and particle populations.
• SRS-FC opens new avenues for high-content chemical analysis of live cells.