title: A novel electrochemical aptamer-antibody sandwich assay for lysozyme detection.
abstract: In this paper, we have reported a novel electrochemical aptamer-antibody based sandwich biosensor for the detection of lysozyme. In the sensing strategy, an anti-lysozyme aptamer was immobilized onto the carbon electrode surface by covalent binding via diazonium salt chemistry. After incubating with a target protein (lysozyme), a biotinylated antibody was used to complete the sandwich format. The subsequent additions of avidin-alkaline phosphatase as an enzyme label, and a 1-naphthyl phosphate substrate (1-NPP) allowed us to determine the concentration of lysozyme (Lys) via Differential Pulse Voltammetry (DPV) of the generated enzyme reaction product, 1-naphthol. Using this strategy, a wide detection range from 5 fM to 5 nM was obtained for a target lysozyme, with a detection limit of 4.3 fM. The control experiments were carried out by using bovine serum albumin (BSA), cytochrome c and casein. The results showed that the proposed biosensor had good specificity, stability and reproducibility for lysozyme analysis. In addition, the biosensor was applied for detecting lysozyme in spiked wine samples, and very good recovery rates were obtained in the range from 95.2 to 102.0% for lysozyme detection. This implies that the proposed sandwich biosensor is a promising analytical tool for the analysis of lysozyme in real samples.
authors.affiliation: Sensors and Biosensors Group, Department of Chemistry, UniversitatAutònoma de Barcelona, 08193 Bellaterra, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Ocaña
authors.forename: Akhtar
authors.initials: A
authors.lastname: Hayat
authors.forename: Rupesh
authors.initials: R
authors.lastname: Mishra
authors.forename: Alina
authors.initials: A
authors.lastname: Vasilescu
authors.forename: Manel
authors.initials: M
authors.lastname: del Valle
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Marty
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology*; D052157:Aptamers, Nucleotide / Q000378:metabolism*; D015374:Biosensing Techniques / Q000379:methods*; D002417:Cattle; D004563:Electrochemistry; D057230:Limit of Detection; D009113:Muramidase / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D015203:Reproducibility of Results; D014920:Wine / Q000032:analysis
chemical_list: D000906:Antibodies; D052157:Aptamers, Nucleotide; D009113:Muramidase