Novel Interdigitated Electrode Conductometric Sensor for Rapid, Sensitive, and Selective Detection of cTnI Biomarkers in Saliva

Accurate and sensitive detection of cardiac troponin I (cTnI), a key biomarker of myocardial infarction, is essential for the early diagnosis and management of cardiovascular diseases. Although cTnI biosensors offer promising alternatives to conventional detection methods, many are limited by complex fabrication, insufficient sensitivity, and cumbersome detection procedures. This work presents a novel conductometric interdigitated electrode (IDE) sensor fabricated on a high‐resistivity silicon wafer for rapid, noninvasive, sensitive, and selective detection of cTnI in saliva. The sensor employs molecularly imprinted polymer nanoparticles (cTnI nanoMIPs) and features a scalable fabrication process with a simple detection approach. Six IDE configurations (1, 2, 4, 8, 16, and 32 electrode pairs) were evaluated in phosphate‐buffered saline. Among them, the 16‐pair IDE achieved the best performance, with an ultralow limit of detection of 0.08 fM. The same sensor also demonstrated excellent performance in artificial saliva and pooled human saliva. The assay requires only 15 µL of sample, with a 10 min incubation and a sensor readout time of <3 min. With the capability of miniaturization, potential for multiplexing capability, and ability to integrate with common electronic platforms for wireless detection, this conductometric IDE sensor shines as a promising futuristic medical device for point‐of‐need applications.