abstract
This work describes a sensitive voltammetric immunosensor for label-free electroanalysis of the prostate specific antigen (PSA), the main biomarker of prostate cancer. A gold electrode was firstly modified with the optimum self-assembled monolayer (SAM), 1,6-hexanedithiol, followed by the subsequent adsorption of gold nanoparticles (AuNPs) and, then, the monoclonal antibody to recognize PSA was immobilized. The influence of the most significant experimental variables (SAM type and incubation time, AuNPs deposition, antibody concentration and bovine serum albumin immobilization) on the biosensor response was studied by microscopy and voltammetry techniques. The electroanalytical detection was based on the interaction between PSA antibody and PSA via square-wave voltammetry using ferrocyanide/ferricyanide as electrochemical redox indicator. Using the proposed immunosensor, PSA was specifically detected within the linear range between 0.2 and 200 ng mL(-1) with 0.01 ng mL(-1) as limit of detection. The immunosensor allows accurate, reproducible and sensitive (22.7 % reduction mL ng(-1)) detection in a concentration range useful for clinical purposes.
keywords
FREE ELECTROCHEMICAL IMMUNOSENSOR; SELF-ASSEMBLED MONOLAYERS; GOLD NANOPARTICLES; SILICA NANOPARTICLES; CANCER BIOMARKER; IMMUNOASSAY; ELECTRODE; QUANTIFICATION; BIOSENSORS; ANTIBODY
subject category
Chemistry; Electrochemistry
authors
Oliveira, N; Costa-Rama, E; Viswanathan, S; Delerue-Matos, C; Pereira, L; Morais, S
our authors
Maria de Lourdes Gomes Pereira
Associate Professor with Aggregationacknowledgements
The authors are grateful for financial support from the European Union (FEDER funds through COMPETE) and National Funds (FCT) through projects UID/QUI/50006/2013 and UID/CTM/50011/2013. The authors also thank financial support by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF): projects Norte-01-0145-FEDER-000011, Norte-01-0145-FEDER-000024 and POCI-01-0145-FEDER-007679.