title: Improved electrochemical detection of a transthyretin synthetic peptide in the nanomolar range with a two-electrode system integrated in a glass/PDMS microchip.
abstract: An alternative to a three-electrode set-up for electrochemical detection and analysis in microfluidic chips is described here. The design of the electrochemical sensor consists of the surface of the glass substrate covered with a PDMS block which bears the microfluidic channels. A band microelectrode which acts as a working electrode surrounded by a large counter electrode is obtained at the micrometric level to propose a simple and efficient sensing area for on-a-chip analysis. The counter-electrode with a surface area about 22-fold greater than the working-microelectrode can also be considered as a pseudo reference since its current density is low and thus limits the potential variations around the rest potential. To this purpose, the [Fe(III)(CN)₆]³⁻/[Fe(II)(CN)₆]⁴⁻ redox couple was used in order to set a reference potential at 0 V since both electrodes were platinum. The electrochemical microchip performance was characterized using differential pulse voltammetric (DPV) detection and quantification of the optically multi-labelled transthyretin synthetic peptide mimicking a tryptic fragment of interest for the diagnosis of familial transthyretin amyloidosis (ATTR). The limit of detection of the peptide by the working microelectrode was 25 nM, a value 100-fold lower than the one reported with conventional capillary electrophoresis coupled with laser-induced fluorescence under the same analytical conditions.
authors.affiliation: CNRS, UMR 8235, LISE, F-75005, Paris, France. Jean.gamby@upmc.fr.
authors.forename: Mathilde
authors.initials: M
authors.lastname: Faure
authors.forename: Antoine
authors.initials: A
authors.lastname: Pallandre
authors.forename: Syrine
authors.initials: S
authors.lastname: Chebil
authors.forename: Isabelle
authors.initials: I
authors.lastname: Le Potier
authors.forename: Myriam
authors.initials: M
authors.lastname: Taverna
authors.forename: Bernard
authors.initials: B
authors.lastname: Tribollet
authors.forename: Claude
authors.initials: C
authors.lastname: Deslouis
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Haghiri-Gosnet
authors.forename: Jean
authors.initials: J
authors.lastname: Gamby
mesh_terms: D000682:Amyloid / Q000032:analysis* / Q000737:chemistry; D028227:Amyloid Neuropathies, Familial / Q000175:diagnosis; D002138:Calibration; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004867:Equipment Design; D005292:Ferricyanides / Q000737:chemistry; D005295:Ferrocyanides / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D008422:Materials Testing; D008832:Microchemistry / Q000295:instrumentation*; D008839:Microelectrodes; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000032:analysis* / Q000737:chemistry; D011228:Prealbumin / Q000032:analysis* / Q000737:chemistry; D066330:Printing, Three-Dimensional; D015203:Reproducibility of Results; D013499:Surface Properties
chemical_list: D000682:Amyloid; D004129:Dimethylpolysiloxanes; D005292:Ferricyanides; D005295:Ferrocyanides; D010446:Peptide Fragments; D011228:Prealbumin; C076571:transthyretin-related amyloid fibril protein, human; C013830:baysilon; C000170:ferric ferrocyanide; C053439:ferric ferricyanide