title: Electrochemical Impedance Spectroscopy (bio)sensing through hydrogen evolution reaction induced by gold nanoparticles.
abstract: A new gold nanoparticle (AuNP) based detection strategy using Electrochemical Impedance Spectroscopy (EIS) through hydrogen evolution reaction (HER) is proposed. This EIS-HER method is used as an alternative to the conventional EIS based on [Fe(CN)6](3-/4-) or [Ru(NH3)6](3+/2+) indicators. The proposed method is based on the HER induced by AuNPs. EIS measurements for different amounts of AuNP are registered and the charge transfer resistance (Rct) was found to correlate and be useful for their quantification. Moreover the effect of AuNP size on electrical properties of AuNPs for HER using this sensitive technique has been investigated. Different EIS-HER signals generated in the presence of AuNPs of different sizes (2, 5, 10, 15, 20, and 50 nm) are observed, being the corresponding phenomena extendible to other nanoparticles and related catalytic reactions. This EIS-HER sensing technology is applied to a magneto-immunosandwich assay for the detection of a model protein (IgG) achieving improvements of the analytical performance in terms of a wide linear range (2-500 ng mL(-1)) with a good limit of detection (LOD) of 0.31 ng mL(-1) and high sensitivity. Moreover, with this methodology a reduction of one order of magnitude in the LOD for IgG detection, compared with a chroamperometric technique normally used was achieved.
authors: Nanobioelectronics & Biosensors Group, Institut Catala de Nanociencia i Nanotecnologia (ICN2), Edifici ICN2, Campus UAB, Bellaterra (Barcelona) 08193, Spain.
authors: Carmen C
authors: CC
authors: Mayorga-Martinez
authors: Nanobioelectronics & Biosensors Group, Institut Catala de Nanociencia i Nanotecnologia (ICN2), Edifici ICN2, Campus UAB, Bellaterra (Barcelona) 08193, Spain; Autonomous University of Barcelona, UAB Campus, 08193 Bellaterra, Spain.
authors: Alejandro
authors: A
authors: Chamorro-Garcia
authors: Nanobioelectronics & Biosensors Group, Institut Catala de Nanociencia i Nanotecnologia (ICN2), Edifici ICN2, Campus UAB, Bellaterra (Barcelona) 08193, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, 08010 Barcelona, Spain. Electronic address: arben.merkoci@icn.cat.
authors: Arben
authors: A
authors: Merkoçi
mesh_terms: D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D006046:Gold / Q000737:chemistry; D006801:Humans; D006859:Hydrogen / Q000737:chemistry*; D007074:Immunoglobulin G / Q000276:immunology / Q000302:isolation & purification*; D018189:Immunomagnetic Separation; D053768:Metal Nanoparticles / Q000737:chemistry
chemical_list: D007074:Immunoglobulin G; D006046:Gold; D006859:Hydrogen
keywords: Electrochemical Impedance Spectroscopy; Gold nanoparticles; Hydrogen evolution reaction; Magneto-immunoassay