On-chip refractive index cytometry for whole-cell deformability discrimination

Area of Science:

• Biophotonics
• Cellular analysis
• High-throughput screening

Background:

• Label-free biomarkers like cell deformability and refractive index are crucial for single-cell phenotyping.
• Existing methods may lack the throughput or simultaneous measurement capabilities for comprehensive cell characterization.

Purpose of the Study:

• To develop an on-chip refractive index cytometry (RIC) system for high-throughput analysis of whole-cell deformability.
• To enhance cellular discrimination by simultaneously measuring refractive index and deformability.
• To investigate the potential of RIC for distinguishing complex cell populations, such as myeloid cells.

Main Methods:

• Development of an integrated on-chip system for refractive index cytometry.
• Simultaneous measurement of cellular refractive index, effective volume, and whole-cell deformability.
• Utilizing numerical simulations and a modified HL-60 cell model to validate findings.
• High-throughput analysis with a measurement rate of up to 5000 cells per second.

Main Results:

• The on-chip RIC system successfully probed cellular refractive index, effective volume, and whole-cell deformability simultaneously.
• A high measurement rate of up to 5000 cells/second was achieved.
• The asymmetry of the measured curve was found to reflect the relative position of the nucleus within the cell, confirmed by simulations.
• The device effectively discriminated between HL-60 derived myeloid cells (neutrophils, basophils, promyelocytes), which are typically indistinguishable by flow cytometry.

Conclusions:

• This work presents the first integrated device capable of simultaneously characterizing cellular refractive index and whole-cell deformability.
• The developed RIC technology offers enhanced discrimination capabilities for large myeloid cell populations.
• On-chip RIC provides a powerful, label-free tool for high-throughput single-cell phenotyping.