Continuous analysis of dye-loaded, single cells on a microfluidic chip.

Area of Science:

• Biotechnology
• Analytical Chemistry
• Microfluidics

Background:

• Single-cell analysis is crucial for understanding cellular heterogeneity.
• Existing methods often face challenges with throughput and sample preparation.
• Microfluidic devices offer potential for integrated and automated cellular analysis.

Purpose of the Study:

• To develop and characterize a microfluidic chip for continuous, laser-based lysis of single mammalian cells.
• To integrate laser lysis with on-chip electrophoretic separation for intracellular analyte analysis.
• To optimize device parameters for efficient cell lysis and high-performance separation.

Main Methods:

• Utilized hydrodynamic flow for cell transport to a laser-induced cavitation bubble lysis junction.
• Employed electrophoretic separation to analyze intracellular dyes post-lysis.
• Incorporated phosphatidylcholine (PC)-supported bilayer membrane coatings (SBMs) to prevent cell fouling.
• Investigated the impact of channel dimensions and electric field strength on separation performance.

Main Results:

• Achieved continuous single-cell analysis with a maximum throughput of 30 cells min(-1).
• Demonstrated device stability over a 2-hour period, analyzing 600 single cells.
• Identified optimal channel width ratios (2:1 focusing:flow, 3:1 flow:separation) and electric field strength (up to 333 V cm(-1)).
• Showcased reproducible migration times (<10% RSD) for cell-derived dyes, with peak variability reduced to 30% RSD using automated lysis.

Conclusions:

• The developed microfluidic platform enables efficient and continuous single-cell lysis and analysis.
• The integration of laser lysis and electrophoresis on-chip is effective for intracellular dye analysis.
• The device demonstrates robustness and potential for high-throughput single-cell diagnostics and research.