Cell detection and counting through cell lysate impedance spectroscopy in microfluidic devices.

Area of Science:

• Biomedical Engineering
• Microfluidics
• Biosensing

Background:

• Cell-based microfluidic devices are valuable for various applications.
• Existing optical methods for cell detection have limitations.
• Sensitive, non-optical methods for quantifying surface-attached cells in microdevices are needed.

Purpose of the Study:

• To develop and validate a novel electrical method for non-optical cell counting in microfluidic devices.
• To demonstrate the sensitivity and efficiency of the proposed method for cell enumeration.
• To explore the potential of this technology for point-of-care applications.

Main Methods:

• An electrical method based on measuring conductivity changes caused by ions released from lysed cells.
• Surface-immobilized cells are lysed using hypotonic media.
• Impedance spectroscopy with surface-patterned electrodes is used for detection and quantification.

Main Results:

• Bulk solution conductance increases linearly with the number of cells.
• The cell lysate impedance spectroscopy method is sensitive down to 20 cells/µL.
• The approach provides a simple and efficient way to enumerate cells in microfluidic devices.

Conclusions:

• This non-optical method offers high sensitivity for enumerating immobilized cells in microfluidic devices.
• The technology has potential for applications like CD4 cell counts in resource-limited settings.
• The microfluidic device can serve as a disposable cartridge for handheld instruments, enabling affordable point-of-care cell counting.