title: Electrochemical Immunosensor Based on Polythionine/Gold Nanoparticles for the Determination of Aflatoxin B₁.
abstract: An aflatoxin B₁ (AFB₁) electrochemical immunosensor was developed by the immobilisation of aflatoxin B₁-bovine serum albumin (AFB₁-BSA) conjugate on a polythionine (PTH)/gold nanoparticles (AuNP)-modified glassy carbon electrode (GCE). The surface of the AFB₁-BSA conjugate was covered with horseradish peroxidase (HRP), in order to prevent non-specific binding of the immunosensors with ions in the test solution. The AFB₁ immunosensor exhibited a quasi-reversible electrochemistry as indicated by a cyclic voltammetric (CV) peak separation (ΔEp) value of 62 mV. The experimental procedure for the detection of AFB₁ involved the setting up of a competition between free AFB₁ and the immobilised AFB₁-BSA conjugate for the binding sites of free anti-aflatoxin B₁ (anti-AFB₁) antibody. The immunosensor's differential pulse voltammetry (DPV) responses (peak currents) decreased as the concentration of free AFB₁ increased within a dynamic linear range (DLR) of 0.6 - 2.4 ng/mL AFB₁ and a limit of detection (LOD) of 0.07 ng/mL AFB₁. This immunosensing procedure eliminates the need for enzyme-labeled secondary antibodies normally used in conventional ELISA-based immunosensors.
authors.affiliation: SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa.
authors.forename: Joseph H O
authors.initials: JH
authors.lastname: Owino
authors.affiliation: SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa.
authors.forename: Omotayo A
authors.initials: OA
authors.lastname: Arotiba
authors.affiliation: SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa.
authors.forename: Nicolette
authors.initials: N
authors.lastname: Hendricks
authors.affiliation: SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa.
authors.forename: Everlyne A
authors.initials: EA
authors.lastname: Songa
authors.affiliation: SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa.
authors.forename: Nazeem
authors.initials: N
authors.lastname: Jahed
authors.affiliation: SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa.
authors.forename: Tesfaye T
authors.initials: TT
authors.lastname: Waryo
authors.affiliation: SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa.
authors.forename: Rachel F
authors.initials: RF
authors.lastname: Ngece
authors.affiliation: SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa.
authors.forename: Priscilla G L
authors.initials: PG
authors.lastname: Baker
authors.affiliation: SensorLab, Department of Chemistry, University of Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa. eiwuoha@uwc.ac.za.
authors.forename: Emmanuel I
authors.initials: EI
authors.lastname: Iwuoha
keywords: Aflatoxin B1; Gold nanoparticles; Horseradish peroxidise (HRP); Immunosensor; Polythionine