Chemical cytometry on a picoliter-scale integrated microfluidic chip.

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Cell Biology

Background:

• Single-cell analysis is crucial for understanding cellular heterogeneity.
• Existing methods often require large sample volumes and complex procedures.
• Microfluidic technologies offer potential for miniaturized and automated cellular analysis.

Purpose of the Study:

• To develop an integrated microfluidic device for comprehensive chemical cytometry of single cells.
• To demonstrate the device's capability for cell handling, reagent delivery, lysis, derivatization, and detection.
• To validate the device's performance using Jurkat T cells and amino acid analysis.

Main Methods:

• Fabrication of an integrated microfluidic device using multilayer soft lithography.
• Incorporation of novel three-state valves and a picopipette for precise fluid control.
• Development of a workflow for single-cell lysis, chemical derivatization, and capillary electrophoresis separation.
• Detection of derivatized compounds using laser-induced fluorescence.

Main Results:

• The microfluidic device successfully integrated four key functions for chemical cytometry.
• A reaction volume of approximately 70 picoliters was achieved for single Jurkat T cell lysis and derivatization.
• Electropherograms of amino acids from individual Jurkat T cells were successfully recorded.
• Results from single-cell analysis were comparable to those from multiple-cell homogenates.

Conclusions:

• The developed integrated microfluidic device enables efficient and precise chemical analysis of single cells.
• The novel valve and picopipette designs are critical for minimizing reaction volumes and optimizing analysis.
• This technology advances the field of chemical cytometry, offering a powerful tool for single-cell research.