Silica/antibody-conjugated microcomb electrode sensor for cardiac biomarker analysis

Myocardial infarction (MI), which is generally known as a heart attack, occurs when there is a lack of blood supply to the heart. Electrocardiogram (ECG) is commonly used for the initial screening of MI but is not sufficiently sensitive. With ECG, cardiac biomarkers help to efficiently assess MI. The cardiac troponin I level has a high correlation with MI and is one of the gold standard biomarkers to identify MI. This study focuses on detecting cardiac troponin I by its parent antibody on a microcomb interdigitated electrode (IDE) sensor. To improve the detection, silica nanoparticles (SiNps) were complexed with antibody and immobilized on the IDE sensing surface. Amine-modified SiNps help to hold more antibodies on the sensing surface and interact with more cardiac troponin I molecules, leading to sensitive detection with a limit of detection of 1 fM (24 pg/mL). Moreover, the control proteins were failed to specifically interact, indicating the genuine detection of cardiac troponin I. This study helps to more easily and efficiently quantify the cardiac troponin I level to diagnose MI.