Electrochemical immunoassay for serum parathyroid hormone using screen- printed carbon electrode and magnetic beads

Using magnetic beads (MBs) in electrochemical immunosensors has been shown to improve their sensitivity, reduce analysis time, and minimize reaction volume. The antigen-antibody interaction can be improved with the correct orientation of the antibody using aminophenyl boronic acid (APBA) as the immobilized ligand. In this work, a highly sensitive magneto immunosensor to detect parathyroid hormone (PTH) was reported. The analysis was based on the immobilization of anti-PTH antibodies onto MBs followed by immunocapture, voltammetric and impedimetric assay. We introduce a facile two-step method to detect PTH by using MBs modified by APBA and antibody-peroxidase complex. Immunocapture of PTH by the antibodies takes place on the modified MBs, and the immunocomplexes are separated by a magnet on a screen-printed electrode. Electrochemical detection was performed by measuring the catalytic current and impedance. The APBA coating, antibody-peroxidase ratio, MB characterization, and electrochemical parameters were systematically investigated in this study. The PTH immunosensor exhibited a linear range between 10 and 300 pg mL-1, with a limit of detection of 11.56 pg mL-1 by voltammetry and 49.30 pg mL-1 by impedance spectroscopy. A magneto immunosensor was successfully prepared by using modified MBs and a disposable electrode, which can be applied to analyze PTH quickly as a point of care device.

Automated summary

A highly sensitive magneto immunosensor for detecting parathyroid hormone (PTH) was successfully developed using MBs modified by APBA and a disposable electrode, allowing for rapid point-of-care testing for PTH. The sensor exhibited a linear detection range and low limits of detection by both voltammetry and impedance spectroscopy, showcasing its potential for practical diagnostic applications.