Printed Flexible Microelectrode for Application of Nanosecond Pulsed Electric Fields on Cells

Abstract

Medical treatment is increasingly benefiting from biomedical microsystems, especially the trending telemedical application. A promising modality for tumor therapy showed the application of nanosecond pulsed electric fields (nsPEF) on cells to achieve nanoporation, cell death, and other cell reactions. A key technology for this method is the generation of pulsed fields in the nanosecond range with high-field strengths in the range of several kilovolts per centimeter. For further biomedical applications, state-of-the-art setups need to decrease in size and improve their capability of integration into microsystems. Due to demanding electronic requirements, i.e., using high voltages and fast pulses, miniaturization and low-cost fabrication of the electrode is first considered. This paper proposes a proof-of-concept for a miniaturized printed flexible electrode that can apply nsPEF on adherent fibroblast cells. The interdigital gold electrode was printed on polyimide with line-width of about 10 µm using an electrohydrodynamic inkjet printer. Furthermore, an electrical circuit was developed to generate both electrical pulses in the nano-second range and voltages up to 180 V. The electrode was integrated into an experimental setup for in-vitro application to human fibroblasts. Field strengths up to 100 kV/cm with 45 ns pulse duration were applied, depending on the degree of cell confluence. The cells show contraction, detachment from the electrode, and lethal reactions after the nsPEF treatment. Furthermore, this printed miniaturized electrode was found to be suitable for subsequent microsystem integration and further cell experiments to optimize pulse parameters for control of cell reaction and behavior.

Fabrication of Electronics by Electrohydrodynamic Jet Printing

“…After applying voltage of 100 kV cm −1 and 45 ns pulse duration, they found that the cell contracted, detached from the electrode, and almost died. [ 63 ]…”

“…After applying voltage of 100 kV cm −1 and 45 ns pulse duration, they found that the cell contracted, detached from the electrode, and almost died. [63] Besides metal NPs, carbon materials are also used for the fabrication of the electrodes by e-jet printing.…”

Precise Electrohydrodynamic Direct-Write Micro-Droplets Based on a Designed Sinusoidal High-Voltage AC Power

“…In recent years, the AC electric field has been introduced into the EDW process for the fabrication of precise micro/nano structures [11,12]. The AC electric field can reduce the accumulation of the charges on the nozzle by neutralizing the electric polarity, which can help to suppress the charge repulsion interferences under the DC electric field and promote jet stability and deposition precision [13][14][15]. Under the AC electric field, the free charges reciprocate along the jet and the polarity of the electric field force on the jet changes periodically, then micro/nano droplets can be obtained at a corresponding frequency [16,17].…”