Electrical detection of Troponin i based on aptamer as a probe molecule

Abstract

Rapid detection of cardiac biomarkers is an important factor for the diagnosis of acute myocardial infarction (AMI). The cardiac troponin I (cTnI) is at present a promising biomarker for diagnosis of AMI.<br/> In this dissertation, we demonstrate an effect of electrical control approach for a carbon nanotube network (CNN) based biosensor platform to detect the cTnI. <br/> The carbon nanotube (CNT) channel between the concentric electrodes is formed by the dip-coating method. The CNN channel region is decorated with gold nanoparticels (GNPs), which act as attaching sites of the probe molecules.<br/> The contribution of this dissertation can be summarized in three approaches.<br/> First, we employ aptamer as the probe molecule in this research since it has high affinity and specificity to cTnI for biosensing application. The aptamer is immobilized on the AuNP by forming the gold-thiol chemical bonds. The method of AC electrothermal flow (ACEF) was first introduced to our biosensor platform improve the affinity between the probe and the target molecules.<br/> Second, the pulse measurement was used as the method of electrical detection and the current change was analyzed in the transient state. To enhance the performance of the sensor platform, the method of integration current was proposed in this study.<br/> Third, in order to demonstrate the applicability of the technology for point of care testing (POCT), we conducted validation studies with the biosensor platform to detect cTnI in the human serum conditions. As a result, the detection limit of the sensor platform is a low as 4.5pg/ml in a human serum added solution (cut off value of cTnI: 45pg/ml~1pM).<br/>