Impedance Biosensor Utilizing a Si Substrate Deposited by Wet Methods

Abstract

We report an impedance biosensor utilizing a Si electrode created by wet chemical deposition atop 6061 Al alloy. The sensor electrode is created by galvanic/electroless Si deposition from an electrolyte containing 10 mM HF and 20 mM Na2SiF6 in 80 wt% formic acid, followed by antibody immobilization. The impedance response of the sensor electrode to increasing concentrations of peanut protein Ara h 1, a common food allergen, can be fit to an equivalent circuit containing three RC loops. The circuit element most sensitive to antigen binding is the charge transfer resistance, yielding a detection limit of 4 ng/mL.Biosensors that utilize electrochemical impedance spectroscopy have been employed with a wide variety of immobilized biomolecules, including antibodies, receptor proteins, aptamers, and ssDNA.

Impedance Biosensing atop MoS2 Thin Films with Mo−S Bond Formation to Antibody Fragments Created by Disulphide Bond Reduction

“…Protein immobilization through an SAM depends critically on the surface roughness being less than the SAM thickness. For cases like the current one where the substrate has a high surface roughness relative to the biomolecular film thickness, the exponent n can deviate substantially from unity .…”

Electroless Metallization of the Elements: Survey and Progress

“…% Si after deposition for 30 h at 20 °C. Falola et al 629 have used similar Si films as electrodes for an impedance biosensor to measure nanogram•mL −1 levels of peanut protein Ara h 1 food allergen. Inguanta and co-workers 630 have extended the utility of HCOOH baths to facilitate deposition of Si onto other metals, such as Au, by galvanically coupling a piece of Al to the metal to permit electron transfer from Al through the metal to reduce SiF 6…”