PO-088 A modified electrochemical biosensor for sensitive detection of human chorionic gonadotropin (hCG) biomarker

Abstract

IntroductionHuman chorionic gonadotropin (hCG) is a 37 kDa glycoprotein hormone synthesised naturally in the body during pregnancy in women. Finding this hormone in men is considered as a tumour marker for selected tumours such as lung, pancreas, and stomach. Indeed, in women, combining blood and urine tests of hCG is considered to be an efficient diagnostic assay for cervical and ovarian cancers. Hence, fabrication of selective and sensitive assays for the early detection of tumour biomarkers is in high demand for successful diagnosis, treatment and improvement of survival rates. Micro and nano-fabricated electrochemical sensors are widely used as sensing devices due to their low-cost, high selectivity and sensitivity, and the possibility to be integrated into smart systems enabling sampling and fluidic handling. This work is aimed at developing a microelectrode sensor functionalized with anti-hCG antibody that enables rapid, selective and sensitive recognition of hCG biomarker.Material and methodsScreen printed carbon macroelectrode (400 µm diameter) was modified with a layer of 1-pyrenebutyric acid-N-hydroxysuccinimide ester (PANHS) to enhance the sensing performance of the fabricated sensor. Anti-hCG antibodies were immobilised onto the modified surface and then bovine serum albumin was dropped to minimise unspecific adsorption on the electrode surface. Functionality of the developed sensor was examined by measuring cyclic voltammetry (CV) and square wave voltammetry (SWV) after addition of hCG proteins at different concentrations.Results and discussionsIn immunesensors, generation of an electrochemical signals is based on formation of a stable complex between an analyte and antibody that recognise the analyte specifically. When hCG protein was added at different concentrations to the developed sensor, SWV electrochemical signals were changed. The peak current reduced with higher hCG concentrations which is attributed to formation of an antigen-antibody complex onto the fabricated sensor. The limit of detection was approximately 1 pg/ml.ConclusionIn this work, an electrode with a micropatterning was used to enhance the sensitivity of the sensor since the surface area directly affects the sensing mechanism. The fabricated microelectrode exhibited a good detection limit. In the future, the proposed sensor will be modified using nanomaterials such as graphene and carbon nanotubes to enhance the sensitivity which can be further exploited in the diagnostic applications for early detection of different disease biomarkers.