Nanoelectrode ensembles as recognition platform for electrochemical immunosensors

Abstract

a b s t r a c tIn this study we demonstrate the possibility to prepare highly sensitive nanostructured electrochemical immunosensors by immobilizing biorecognition elements on nanoelectrode ensembles (NEEs) prepared in track-etch polycarbonate membranes. The gold nanodisk electrodes act as electrochemical transducers while the surrounding polycarbonate binds the antibody-based biorecognition layer. The interaction between target protein and antibody is detected by suitable secondary antibodies labelled with a redox enzyme. A redox mediator, added to the sample solution, shuttles electrons from the nanoelectrodes to the biorecognition layer, so generating an electrocatalytic signal. This allows one to fully exploit the highly improved signal-to-background current ratio, typical of NEEs. In particular, the receptor protein HER2 was studied as the target analyte. HER2 detection allows the identification of breast cancer that can be treated with the monoclonal antibody trastuzumab. NEEs were functionalized with trastuzumab which interacts specifically with HER2. The biorecognition process was completed by adding a primary antibody and a secondary antibody labelled with horseradish peroxidase. Hydrogen peroxide was added to modulate the label electroactivity; methylene blue was the redox mediator generating voltammetric signals. NEEs functionalized with trastuzumab were tested to detect small amounts of HER2 in diluted cell lysates and tumour lysates.

Arrays of copper nanowire electrodes: Preparation, characterization and application as nitrate sensor

“…In the last years the properties and advantageous characteristics of array of nanoelectrodes to be employed as sensitive voltammetric sensors have been demonstrated [1][2][3][4][5][6][7]. The largest part of these studies was developed using ensembles of gold nanoelectrodes (NEEs) prepared via electroless deposition.…”

Electrochemical immunosensor for the analysis of the breast cancer biomarker HER2 ECD

“…To date two electrochemical immunosensing methods for the analysis of HER2 have been published [14,15]. Mucelli et al [14] used nanoelectrode ensembles as the transducer and a sandwich immunoassay for the detection of HER2 in diluted cell lysates and tumor lysates.…”

“…Mucelli et al [14] used nanoelectrode ensembles as the transducer and a sandwich immunoassay for the detection of HER2 in diluted cell lysates and tumor lysates. The lowest concentration they analyzed was 40 ng/ mL.…”

Electroanalysis of Trace Inorganic Arsenic with Gold Nanoelectrode Ensembles

“…It was indeed demonstrated that, thanks to dramatically improved signal to background current ratio and enhanced diffusion [24,25], NEEs can be successfully applied to trace analysis of a variety of redox analytes ranging from small organics [26,27] to large redox proteins and antigens [28,29], from antibiotics [30] to iodide [31,32].…”