Single neuron detectors using 3D electrode micro-arrays

Cell culturing using microelectromechanical devices offers more efficient analysis than conventional cell culture methods. Microsieve-based electrode arrays are useful for detection of electrically-active cells such as neurons and cardiac cells and have the further advantage of providing electrical readout without the use of labels.

Yagmur Demircan Yalcin and Regina Luttge report a feasibility study for a simple polymeric microsieve structure that could be used as a disposable plug-in unit for a reusable 3D electrode array. Their group previously developed a fabrication technique for silicon microsieves and a pumping method capable of trapping neurons in the microsieve. Using a replica molding protocol and subsequent laser ablation, they have been able to develop a cost-effective method for creating these plug-in units.

The investigators carried out finite element method simulations of the micropore with and without cells to determine if an impedance-based detection protocol could be used. Since biological cells are dielectric particles, they change the impedance of any solution that contains them.

At low frequencies, the impedance change is related to cell diameter, while at higher frequencies, the cell’s electrical properties also affect the impedance change. When a cell moves into a microsieve pore, the impedance will change and the trend of this change differs with the movement direction of the cell.

“If a cell goes into a microsieve and then moves out of it, the impedance change will have a characteristic footprint,” said Demircan Yalcin.

The simulation results showed that 3D electrodes can be integrated into a microsieve system without compromising cell detection efficiency.

Source: “3D-electrode integrated microsieve structure as a rapid and cost-effective single neuron detector,” by Yagmur Demircan Yalcin and Regina Luttge, Journal of Vacuum Science and Technology B (2020) The article can be accessed at https://doi.org/10.1116/6.0000518 .