Development of a novel label-free amperometric immunosensor for the detection of okadaic acid

Okadaic acid (OA), a lipophilic phycotoxin is mainly produced by toxigenic dinoflagellates. The need to develop high performing methods for OA analysis able to improve the traditional ones is evident. In this work, a novel experimental methodology for label-free detection of OA was developed. Protein G magnetic beads (protein-G-MBs) modified gold electrode was used to immobilize anti-OA monoclonal antibody (anti-OA-MAb). Preliminary, colorimetric tests were performed in order to validate protein-G-MBs and anti-OA-MAb reaction. Electrochemical detection was carried out by differential pulse voltammetry in ferri/ferrocyanide solution. The limit of detection value obtained (0.5 μg L−1) validated the developed electrochemical immunosensor as a promising tool for routine use. The matrix effect and the recovery rate were also assessed with real samples, showing a good percentage of recovery.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlight► This work described a new approach for label-free amperometric detection of OA. ► The use of protein G MBs provided large surface area for immunochemical reaction. ► The specific interaction between immobilized anti-OA-MAb and OA increased Ret without any amplification step. ► DPV was carried out to perform a calibration curve.