Development of a Re-usable and Disposable Sensor for the Rapid Determination of Human Chorionic Gonadotrophin (hCG) Biomarker

Abstract

Herein we have developed a previously undescribed electrochemical nanoMIP-based sensor for the sensitive, re-usable and accurate determination of human chorionic gonadotrophin (hCG). Using a proprietary rapid and scalable method, hCG-selective polyacrylamide nanoMIP particles were produced within 2hrs at high yields of 11 mg per 1 mL reaction batch upon hCG modified magnetic nanoparticles (MNPs@CHO@hCG). The MNPs were re-usable for 5 sequential cycles of nanoMIP production. The nanoMIPs were integrated with gold screen printed electrodes by electropolymerisation within an electrochemically grown polyacrylamide layer. The ensuing hcG sensor was interrogated using cyclic voltammetry and electrochemical impedance spectroscopy. Both electrochemical modes were shown to be suitable for determining the selective binding of biomarker. The sensor was also tested using a non-target protein (SARS-CoV2 nucleocapsid protein) and was shown to be 20x more selective for target hCG compared with non-target. The linear range was shown to be 1.5 to 384 mIU with a LOD of 3 mIU and saturation occurring beyond 1000 mIU. We also electrochemically determined the equilibrium dissociation constant with EIS to be 1.4 x 10-10 M which is on a par with monoclonal antibodies produced for hCG. Sensor re-usability studies demonstrated that the same sensor once regenerated after sodium dodecyl sulphate/acetic acid treatment, could be used for 3 subsequent measurements. We present an effective method that can me used for both pregnancy testing and testicular cancer monitoring.