Cardiovascular biomarker troponin I biosensor: Aptamer-Gold-Antibody Hybrid on a metal oxide surface.

Myocardial infarction (MI) is highly related to the cardiac arrest leading to death and damage of the organs. Radiological techniques and electrocardiography have been used as the preliminary tests to diagnose MI; however, these techniques are not sensitive enough for the early-stage detection. A blood biomarker-based diagnosis is the immediate solution, and due to the high correlation of troponin with MI, it has been considered to be a gold-standard biomarker. In the present research, cardiac biomarker troponin I (cTnI) was detected on an interdigitated electrode sensor with varied surface interfaces. To detect cTnI, a capture aptamer-conjugated gold nanoparticle probe and detection antibody probe were utilized and compared through an alternating the sandwich pattern. The surface metal oxide morphology of the developed sensor was proved by microscopic assessments. The limit of detection with the aptamer-gold-cTnI-antibody sandwich pattern was 100 aM, while it was 1 fM with antibody-gold-cTnI-aptamer, representing 10-folds differences. Further, high performance of the sensor was confirmed by selective cTnI determination in serum, exhibiting a superior nonfouling. These methods of determination provide options for generating novel assays for diagnosing MI. This article is protected by copyright. All rights reserved.