Highly Sensitive Micropatterned Interdigitated Electrodes for Enhancing the Concentration Effect Based on Dielectrophoresis

Abstract

The concentration effect of dielectrophoresis (DEP) enables detection of biomolecules with high sensitivity. In this study, microstructures were patterned between the interdigitated microelectrodes (IMEs) to increase the concentration effect of DEP. The microstructures increased the electric field gradient (∇|E2|) between the IMEs to approximately 6.61-fold higher than in the bare IMEs with a gap of 10 μm, resulting in a decreased optimal voltage to concentrate amyloid beta 42 (Aβ42, from 0.8 Vpp to 0.5 Vpp) and tau-441 (from 0.9 Vpp to 0.6 Vpp) between the IMEs. Due to the concentration effect of DEP, the impedance change in the optimal condition was higher than the values in the reference condition at 2.64-fold in Aβ42 detection and at 1.59-fold in tau-441 detection. This concentration effect of DEP was also verified by counting the number of gold (Au) particles which conjugated with the secondary antibody. Finally, an enhanced concentration effect in the patterned IMEs was verified by measuring the impedance change depending on the concentration of Aβ42 and tau-441. Our results suggest that microstructures increase the concentration effect of DEP, leading to enhanced sensitivity of the IMEs.

Recent Advancements in Bipolar Electrochemical Methods of Analysis

“…Another promising research avenue is the integration of BPEs with interdigitated electrodes (IDEs), which are already employed separately for pDEP cell capture and for redox cycling. For example, Huang and co-workers integrated microscale BPEs between the fingers of a pair of IDEs, which resulted in enhanced dielectrophoretic attraction of antigens to surface-immobilized antibodies . In this context, a dual function of the BPEs for DEP and sensing would provide a spatially defined visual readout of the immunoassay.…”

“…For example, Huang and co-workers integrated microscale BPEs between the fingers of a pair of IDEs, which resulted in enhanced dielectrophoretic attraction of antigens to surface-immobilized antibodies. 141 In this context, a dual function of the BPEs for DEP and sensing would provide a spatially defined visual readout of the immunoassay.…”

Toward low‐voltage dielectrophoresis‐based microfluidic systems: A review

“…In 2019, Kim et al. [46] reported a DEP device capable of detecting Alzheimer's disease biomarkers, Aβ42 and tau‐441, by capturing them using voltages between 0.5 and 0.9 V pp . Two designs were used.…”

Electric-Field-Mediated In-Sensor Alignment of Antibody’s Orientation to Enhance the Antibody–Antigen Binding for Ultrahigh Sensitivity Sensors

“…Biosensing technology can be used to predict and diagnose diseases qualitatively or quantitatively based on complementary binding between biomarkers and receptors immobilized on the surface of the biosensor. − Therefore, biosensing technology must be highly sensitive and specific, and continuous development and optimization of both biomarkers and receptors is essential. For biomarkers, applying an electrostatic force, such as via electrophoresis or dielectrophoresis, , can help derive higher concentrations of the target biomarkers in a biomatrix to establish highly sensitive and selective detection. Conversely, for the receptors, uniform immobilization, typically an antibody binding to a biomarker on the surface of the biosensor, can enhance sensor sensitivity and specificity by increasing the binding probability and biological activity between biomarker and antibody …”