Cardiac troponin I biosensing on dipole-electrodes mediated interdigitated-zeolite transducer

Cardiovascular disease (CVD), also known as heart disease, is a general term used for disorders that affect the blood and heart vessels and are associated with a significant rate of mortality. In general, examinations and immunoassays are performed to identify and predict CVD-related diseases, but these tests are inconvenient, time-consuming, and require a specific instrument. Researchers have focused on quantifying CVD biomarkers as a substitute for conventional methods and have developed various biosensors for diagnosing CVD. In this study, a highly sensitive zeolite–cardiac troponin I (cTnI)-transducing biosensor was developed on an interdigitated electrode (IDE). Silane-modified zeolite was used on the IDE, and then glutaraldehyde (GLU) premixed with anti-cTnI was attached to the IDE through bonding between aldehyde and amine groups. Premixing GLU with the antibody improved antibody attachment on the IDE, and the zeolite-modified IDE attracted a greater amount of GLU premixed with the antibody. This antibody-modified IDE identified cTnI at concentrations as low as 1 fM on a linear regression curve (1 fM to 1 nM) with R
2
= 0.9417 [y = 4.8325x - 7.9957]. In addition, cTnI-spiked serum enhanced the current by increasing the cTnI concentration, and specificity experiments conducted with relevant proteins (NTproBNP, myoglobulin, fibrinogen, c-reactive protein (CRP), and albumin) and nonimmune antibodies did not change the current responses, confirming the selective and specific detection of cTnI. This cTnI immunoassay quantifies cTnI at a lower level than conventional methods and can be used to diagnose CVD-related issues.