title: Detection of prostate specific antigen based on electrocatalytic platinum nanoparticles conjugated to a recombinant scFv antibody.
abstract: Highly sensitive and label free detection of prostate specific antigen (PSA) still remains a challenge in prostate cancer diagnosis. In this paper, we propose a sensitive electrochemical immunosensor based on electrocatalytic platinum nanoparticles conjugated to a recombinant scFv antibody. Gold disc electrodes functionalised with a l-Cysteine (Cys) self-assembled monolayer (SAM) were used to covalently bind PSA specific monoclonal antibody (anti-PSA) using N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide (EDC/NHS) chemistry. Immunosensing was completed using sandwich-type immunoreaction of the PSA-antigen (1-30 ng/mL) between anti-PSA immobilized on the l-Cys modified electrode using label free electrochemical impedance (EIS) technique. Furthermore, highly specific in-house generated scFv fragments as receptor proteins were utilised for one step site-directed immobilisation on the surface of platinum nanoparticles (PtNPs). To improve the sensitivity of the immunoassay, these scFV labelled electrocatalytic PtNPs were then used for covalent hybridisation to the PSA modified electrode and then applied in a hybridisation assay to determine the concentration of the PSA by measuring the faradaic current associated with reduction of peroxide in solution. Semi-log plots of the PSA concentration vs. faradaic current are linear from 1 to 30 ng/mL and pM concentrations can be detected without the need for molecular, e.g., PCR or NASBA, amplification.
authors.affiliation: Biomedical Diagnostic Institute, Dublin City University, Dublin 9, Ireland; School of Chemical Sciences, National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland. Electronic address: elainespain@gmail.com.
authors.forename: Elaine
authors.initials: E
authors.lastname: Spain
authors.affiliation: School of Biotechnology, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Sarah
authors.initials: S
authors.lastname: Gilgunn
authors.affiliation: School of Biotechnology, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Shikha
authors.initials: S
authors.lastname: Sharma
authors.affiliation: School of Chemical Sciences, National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland.
authors.forename: Kellie
authors.initials: K
authors.lastname: Adamson
authors.affiliation: School of Chemical Sciences, National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland.
authors.forename: Eadaoin
authors.initials: E
authors.lastname: Carthy
authors.affiliation: School of Biotechnology, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Richard
authors.initials: R
authors.lastname: O'Kennedy
authors.affiliation: School of Chemical Sciences, National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Forster
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology; D014408:Biomarkers, Tumor / Q000032:analysis; D002384:Catalysis; D003217:Conductometry / Q000295:instrumentation*; D004595:Electroplating / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D058726:Nanoconjugates / Q000737:chemistry* / Q000648:ultrastructure; D017430:Prostate-Specific Antigen / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D057127:Single-Chain Antibodies / Q000737:chemistry* / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D058726:Nanoconjugates; D057127:Single-Chain Antibodies; D017430:Prostate-Specific Antigen
keywords: Electrocatalytic platinum nanoparticles; Electrochemical impedance immunosensor; Label-free immunosensor; Prostate specific antigen (PSA); Recombinant scFv antibody