title: Love-wave bacteria-based sensor for the detection of heavy metal toxicity in liquid medium.
abstract: The present work deals with the development of a Love-wave bacteria-based sensor platform for the detection of heavy metals in liquid medium. The acoustic delay-line is inserted in an oscillation loop in order to record the resonance frequency in real-time. A Polydimethylsiloxane (PDMS) chip with a liquid chamber is maintained by pressure above the acoustic wave propagation path. Bacteria (Escherichia coli) were fixed as bioreceptors onto the sensitive surface of the sensor coated with a polyelectrolyte (PE) multilayer using a simple and efficient layer-by-layer (LbL) electrostatic self-assembly procedure. Poly(allylamine hydrochloride) (PAH cation) and poly(styrene sulfonate) (PSS anion) were alternatively deposited so that the strong attraction between oppositely charged polyelectrolytes resulted in the formation of a (PAH-PSS)(n)-PAH molecular multilayer. The real-time characterization of PE multilayer and bacteria deposition is based on the measurement of the resonance frequency perturbation due to mass loading during material deposition. Real-time response to various concentrations of cadmium (Cd(2+)) and mercury (Hg(2+)) has been investigated. A detection limit as low as 10(-12) mol/l has been achieved, above which the frequency increases gradually up to 10(-3) mol/l, after a delay of 60 s subsequent to their introduction onto bacterial cell-based biosensors. Beyond a 10(-3) mol/l a steep drop in frequency was observed. This response has been attributed to changes in viscoelastic properties, related to modifications in bacteria metabolism.
authors.affiliation: Université de Bordeaux, IMS, IPB-ENSEIRB, CNRS UMR 5218, Talence 33405, France.
authors.forename: I
authors.initials: I
authors.lastname: Gammoudi
authors.forename: H
authors.initials: H
authors.lastname: Tarbague
authors.forename: A
authors.initials: A
authors.lastname: Othmane
authors.forename: D
authors.initials: D
authors.lastname: Moynet
authors.forename: D
authors.initials: D
authors.lastname: Rebière
authors.forename: R
authors.initials: R
authors.lastname: Kalfat
authors.forename: C
authors.initials: C
authors.lastname: Dejous
mesh_terms: D000162:Acoustics; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D002104:Cadmium / Q000633:toxicity; D018914:Cells, Immobilized; D003470:Culture Media; D004129:Dimethylpolysiloxanes; D004573:Electrolytes; D004926:Escherichia coli / Q000187:drug effects*; D008628:Mercury / Q000633:toxicity; D019216:Metals, Heavy / Q000633:toxicity*; D011073:Polyamines; D011137:Polystyrenes; D055672:Static Electricity
chemical_list: D003470:Culture Media; D004129:Dimethylpolysiloxanes; D004573:Electrolytes; D019216:Metals, Heavy; D011073:Polyamines; D011137:Polystyrenes; D002104:Cadmium; C063994:polyallylamine; C013830:baysilon; C003321:polystyrene sulfonic acid; D008628:Mercury