Simulations of Interdigitated Electrode Interactions with Gold Nanoparticles for Impedance-Based Biosensing Applications

Abstract

In this paper, we describe a point-of-care biosensor design. The uniqueness of our design is in its capability for detecting a wide variety of target biomolecules and the simplicity of nanoparticle enhanced electrical detection. The electrical properties of interdigitated electrodes (IDEs) and the mechanism for gold nanoparticle-enhanced impedance-based biosensor systems based on these electrodes are simulated using COMSOL Multiphysics software. Understanding these properties and how they can be affected is vital in designing effective biosensor devices. Simulations were used to show electrical screening develop over time for IDEs in a salt solution, as well as the electric field between individual digits of electrodes. Using these simulations, it was observed that gold nanoparticles bound closely to IDEs can lower the electric field magnitude between the digits of the electrode. The simulations are also shown to be a useful design tool in optimizing sensor function. Various different conditions, such as electrode dimensions and background ion concentrations, are shown to have a significant impact on the simulations.

An aptasensor for the detection of Mycobacterium tuberculosis secreted immunogenic protein MPT64 in clinical samples towards tuberculosis detection

“…The geometry of the IDE (digit width and spacing) played an important role in the aptasensor sensitivity. The sensitivity of the sensor increases with a decreasing distance between the digits 20,21 . Therefore, analytes with different sizes (bacteria 22 , virus 23 , protein 24 , DNA 25 ) could be detected using the IDE with different interdigit spacing (100–250 µm, 15 µm, 5–10 µm, 150 nm, respectively).…”

Immuno-impedimetric Biosensor for Onsite Monitoring of Ascospores and Forecasting of Sclerotinia Stem Rot of Canola

“…A custom designed IDE sensor chip, with digit parameters optimized for nanoparticle-enhanced impedimetric sensors 51 , was fabricated on a silicon wafer with 500 nm thermal oxide following a standard photolithography process flow involving sputter deposition of chromium (10 nm) and gold (100 nm), photoresist and photomask pattern transfer followed by development, reactive ion etching and lift-off. Each of the sensor chips has eight 3 mm × 3 mm square IDEs with digit length, width, thickness, and gap of 3 mm, 3 µm, 110 nm, and 3 µm respectively.…”

Using Impedance Measurements to Characterize Surface Modified with Gold Nanoparticles

“…Modifications have been characterized through impedance spectroscopy and with an atomic force microscope (AFM). These results are compared with simulation results that have been performed using the design of the chip, which have been previously reported [ 16 , 36 ]. COMSOL Multiphysics software was used to create simulations of IDEs with a range of dimensions, buffers, and nanoparticle positions.…”