A Capacitive Biosensor for the Early Detection of Pancreatic Cancer Using Carbohydrate Antigen 19-9

Pancreatic cancer has one of the highest cancer mortality rates, as it is often detected in late stages, when unresectable tumours are present. Researchers have identified a biomarker associated with the early detection of pancreatic cancer, called Carbohydrate Antigen 19-9 (CA19-9)—researchers have recommended it for pancreatic cancer screening, and for the monitoring of the efficacy of pancreatic cancer treatments. The development of a biosensor for the detection of CA19-9 is discussed in this paper. The biosensor uses capacitive spectroscopy on gold interdigitated electrodes. This electrochemical transducer mechanism was selected as appropriate due to its increased popularity in point-of-care applications. Mouse monoclonal anti-CA19-9 antibodies were covalently bound to the gold surface using cysteamine hydrochloride and glutaraldehyde, and immobilization was verified with a Zeiss AxioObserver fluorescence microscope. Next, the antigen was prepared in different concentrations, and added to the prepared electrodes. Impedance spectroscopy was carried out using the PalmSens4 Electrochemical Interface, where five different concentrations of CA19-9 were detected in this process. The concentrations ranged from 10 U/mL to 300 U/mL, which includes the threshold concentration of CA19-9 for the detection of pancreatic cancer, of 37 U/mL. This biosensor is, therefore, suited to detect the CA19-9 concentrations needed for pancreatic cancer screening.