A microchip integrating cell array positioning with in situ single-cell impedance measurement

Area of Science:

• Biomedical Engineering
• Microfluidics
• Cellular Biophysics

Background:

• Single-cell impedance measurement is crucial for understanding cellular behavior.
• Small electrode surface areas limit sensitivity in current impedance measurement techniques.
• Real-time, long-term monitoring of single cells requires advanced microfluidic platforms.

Purpose of the Study:

• To develop a novel microarray chip for integrated single-cell positioning and real-time impedance measurement.
• To enhance the sensitivity of impedance measurements on single cells.
• To monitor and analyze the adherence behavior of single cells over time.

Main Methods:

• Fabrication of a microchip with quadrupole positioning electrodes and planar measuring electrodes.
• Utilizing negative dielectrophoresis (nDEP) for precise cell trapping on measuring electrodes.
• Surface modification of measuring electrodes with gold nanostructures to increase effective surface area and double-layer capacitance.
• Real-time impedance spectroscopy of single HeLa cells during adherence.

Main Results:

• The developed microchip successfully integrated cell positioning and impedance measurement.
• Surface modification with gold nanostructures increased electrode double-layer capacitance by approximately one order of magnitude.
• Real-time impedance data revealed cellular electrical parameter changes during cell adherence.
• The study observed that cells compress the electrical double layer during adherence, completing the process within 4-5 hours.

Conclusions:

• The novel microchip enables sensitive, real-time, long-term impedance analysis of single cells.
• Surface-enhanced electrodes significantly improve measurement sensitivity for cellular biophysical studies.
• The findings provide insights into the biophysical mechanisms of cell adhesion at the single-cell level.