title: Microfluidic-based electrochemical genosensor coupled to magnetic beads for hybridization detection.
abstract: This paper describes the development of a rapid and sensitive enzyme-linked electrochemical genosensor using a novel microfluidic-based platform. In this work, hybridization was performed on streptavidin-coated paramagnetic micro-beads functionalized with a biotinylated capture probe. The complementary sequence was then recognized via sandwich hybridization with a capture probe and a biotinylated signaling probe. After labeling the biotinylated hybrid with a streptavidin-alkaline phosphatase conjugate, the beads were introduced in a disposable cartridge composed of eight parallel microchannels etched in a polyimide substrate. The modified beads were trapped with a magnet addressing each microchannel individually. The presence of microelectrodes in each channel allowed direct electrochemical detection of the enzymatic product within the microchannel. Detection was performed in parallel within the eight microchannels, giving rise to the possibility of performing a multiparameter assay. Quantitative determinations of the analyte concentrations were obtained by following the kinetics of the enzymatic reaction in each channel. The chip was regenerated after each assay by removing the magnet and thus releasing the magnetic beads. The system was applied to the analytical detection of PCR amplified samples with a RSD%=6. A detection limit of 0.2 nM was evaluated.
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Firenze, Sesto Fiorentino, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Berti
authors.forename: Serena
authors.initials: S
authors.lastname: Laschi
authors.forename: Ilaria
authors.initials: I
authors.lastname: Palchetti
authors.forename: Joël S
authors.initials: JS
authors.lastname: Rossier
authors.forename: Frédéric
authors.initials: F
authors.lastname: Reymond
authors.forename: Marco
authors.initials: M
authors.lastname: Mascini
authors.forename: Giovanna
authors.initials: G
authors.lastname: Marrazza
mesh_terms: D002138:Calibration; D004247:DNA / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D015342:DNA Probes / Q000032:analysis* / Q000737:chemistry* / Q000235:genetics; D004563:Electrochemistry; D004798:Enzymes / Q000378:metabolism; D008280:Magnetics; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*
chemical_list: D015342:DNA Probes; D004798:Enzymes; D004247:DNA