title: Integrated amperometric affinity biosensors using Co2+-tetradentate nitrilotriacetic acid modified disposable carbon electrodes: application to the determination of β-lactam antibiotics.
abstract: A novel strategy for the construction of disposable amperometric affinity biosensors is described in this work. The approach uses a recombinant bacterial penicillin binding protein (PBP) tagged by an N-terminal hexahistidine tail which was immobilized onto Co(2+)-tetradentate nitrilotriacetic acid (NTA)-modified screen-printed carbon electrodes (SPCEs). The biosensor was employed for the specific detection and quantification of β-lactam antibiotics residues in milk, which was accomplished by means of a direct competitive assay using a tracer with horseradish peroxidase (HRP) for the enzymatic labeling. The amperometric response measured at -0.20 V versus the Ag pseudoreference electrode of the SPCE upon the addition of H2O2 in the presence of hydroquinone (HQ) as redox mediator was used as the transduction signal. The developed affinity sensor allowed limits of detection to be obtained in the low part-per-billion level for the antibiotics tested in untreated milk samples. Moreover, the biosensor exhibited a good selectivity against other antibiotics residues frequently detected in milk and dairy products. The analysis time was of approximately 30 min.
authors: Departamento de Química Analítica, Universidad Complutense de Madrid, Madrid, Spain.
authors: Felipe
authors: F
authors: Conzuelo
authors: María
authors: M
authors: Gamella
authors: Susana
authors: S
authors: Campuzano
authors: Paloma
authors: P
authors: Martínez-Ruiz
authors: María
authors: M
authors: Esteban-Torres
authors: Blanca
authors: B
authors: de las Rivas
authors: A Julio
authors: AJ
authors: Reviejo
authors: Rosario
authors: R
authors: Muñoz
authors: José M
authors: JM
authors: Pingarrón
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002244:Carbon / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D004209:Disposable Equipment; D004566:Electrodes; D009571:Nitrilotriacetic Acid / Q000737:chemistry*; D047090:beta-Lactams / Q000032:analysis*
chemical_list: D047090:beta-Lactams; D003035:Cobalt; D002244:Carbon; D009571:Nitrilotriacetic Acid