Interdigitated Electrodes integrated with zinc oxide nanoparticles for Cardiac Troponin I biomarker detection

In this paper, an interdigitated electrodes (IDEs) biosensor integrated with zinc oxide (ZnO) nanoparticles thin film as transducer is presented, which is capable of converting the biological interaction into electrical signal of cardiac troponin I (cTnI), a gold standard biomarker for Acute Myocardial Infarction (AMI). Conventional photolithography methods are applied to fabricate the device on a silicon wafer. The surface ZnO nanoparticles thin film is functionalized with bi-linkers and cTnI monoclonal antibodies via covalent binding for capturing the cTnI target biomarkers. The fabricated biosensor is electrically characterized by using Keithley 6487 picoammeter. The changes in the current flow are compared between before and after cTnI biomarkers binding at different concentrations. The biosensor had successfully demonstrated detection of cTnI biomarker in the concentration range of 1 ng/ml to 10 μg/mL. The achieved sensitivity and detection limit of 15.806 nA*(g/mL)-1 and 2.191 ng/mL, respectively, show that biosensor has great properties for detection of cTnI.