Nanoscaled interdigitated electrode arrays for biochemical sensors

Abstract

Nanoscaled interdigitated electrode arrays were made with Deep U.V. lithography. Electrode widths and spacings from 500 nm down to 250 nm were achieved on large active areas (OS mm x 1 mm). These electrodes allow for the detection of affinity binding of biomolecular structures (e.g. antigens, DNA) by impedimetric measurements. Such sensor is developed, theoretically analyzed, experimentally characterized, and will be demonstrated as an affinity biosensor.

A Self-Oscillating System to Measure the Conductivity and the Permittivity of Liquids within a Single Triangular Signal

“…In every system implementation, the circuit elements are nonideal and limit the system performances. Our major concern is to insure the good quality of the analog output signal to detect capacitances and resistances on the largest measurement range; it means that the probed wave has to fit as most as possible the modeling equation (9). Therefore all parasitic impacts on the analog output voltage have to be discussed.…”

“…The bulk and fluid capacitances and the fluid resistance are given by (5). The height of the resolution domain is set to be twice the cell width to enclose 99% of the electric energy [9]. FEM has been chosen because the IDE classical analytical formulas given in [9] do not consider the finger height and make the cell constant estimation less accurate:…”

“…The application of the inverse Laplace transform on the ( ) ( ) product gives the time domain voltage response wave expression given by (9), introducing three shaping parameters named in Table 2 as , , and . The plots sketched in Figure 5 illustrate the time progression of the current wave and the voltage output wave for several values of the model electrical components:…”

Culture‐Independent Rapid Detection Methods for Bacterial Pathogens and Toxins in Food Matrices

“…The advantages of impedimetric biosensors include their rapid response and the capability of both labeled and label‐free bacterial detection, since cell membranes and microbial metabolism can result in changes in electrical impedance. The sensitivity of impedimetric biosensors has been improved by using high‐density electrodes (such as interdigitated array micro/nano‐electrodes) for larger active areas and enhanced capability to monitor the changes in the immediate proximity of electrode surface (Van Gerwen and others ; Yang and others ; Wang and others ; Wang and others ), and nanomaterials for efficient immobilization of biomolecules and signal amplification (Wang and others ; Suni ; Dong and others ). An interdigitated array microelectrode‐based impedance immunosensor was reported for the detection of E. coli O157:H7 in ground beef with magnetic separation (Varshney and Li ).…”

Lithography of high spatial density biosensor structures with sub-100 nm spacing by MeV proton beam writing with minimal proximity effect

“…• The sensitivity is enhanced for d ∼ 10-200 nm compared to conventional sensors with d on a scale of 0.5-1000 µm because of the geometric effect associated with the high electrode spatial density [7,8] and also because the current flow in the cell is confined to a thin surface layer with thickness of the order of the electrode gap, within which the receptor molecules are immobilized [9]. • The electric field for a modest 100 mV voltages with d = 100 nm yields 1 MV m −1 electric fields that may induce non-linear dipole effects that can be exploited to enhance specificity and sensitivity as well as shifting relaxation phenomena to an accessible region of the frequency spectrum [7].…”