title: Electrochemical detection of Salmonella using gold nanoparticles.
abstract: A disposable immunosensor for Salmonella enterica subsp. enterica serovar Typhimurium LT2 (S) detection using a magneto-immunoassay and gold nanoparticles (AuNPs) as label for electrochemical detection is developed. The immunosensor is based on the use of a screen-printed carbon electrode (SPCE) that incorporates a permanent magnet underneath. Salmonella containing samples (i.e. skimmed milk) have been tested by using anti-Salmonella magnetic beads (MBs-pSAb) as capture phase and sandwiching afterwards with AuNPs modified antibodies (sSAb-AuNPs) detected using differential pulse voltammetry (DPV). A detection limit of 143 cells mL(-1) and a linear range from 10(3) to 10(6) cells mL(-1) of Salmonella was obtained, with a coefficient of variation of about 2.4%. Recoveries of the sensor by spiking skimmed milk with different quantities of Salmonella of about 83% and 94% for 1.5×10(3) and 1.5×10(5) cells mL(-1) were obtained, respectively. This AuNPs detection technology combined with magnetic field application reports a limit of detection lower than the conventional commercial method carried out for comparison purposes in skimmed milk samples.
authors.affiliation: Nanobioelectronics & Biosensors Group, Catalan Institute of Nanotechnology, CIN2 (ICN-CSIC), Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain.
authors.forename: André S
authors.initials: AS
authors.lastname: Afonso
authors.forename: Briza
authors.initials: B
authors.lastname: Pérez-López
authors.forename: Ronaldo C
authors.initials: RC
authors.lastname: Faria
authors.forename: Luiz H C
authors.initials: LH
authors.lastname: Mattoso
authors.forename: Manuela
authors.initials: M
authors.lastname: Hernández-Herrero
authors.forename: Artur Xavier
authors.initials: AX
authors.lastname: Roig-Sagués
authors.forename: Marisa
authors.initials: M
authors.lastname: Maltez-da Costa
authors.forename: Arben
authors.initials: A
authors.lastname: Merkoçi
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation; D002417:Cattle; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000295:instrumentation*; D005506:Food Contamination / Q000032:analysis; D006046:Gold; D018189:Immunomagnetic Separation / Q000295:instrumentation*; D053768:Metal Nanoparticles; D008892:Milk / Q000382:microbiology*; D015203:Reproducibility of Results; D019779:Salmonella enterica / Q000302:isolation & purification*; D012680:Sensitivity and Specificity
chemical_list: D006046:Gold