Novel SOI-Biosensor Topology for the Detection of an Acute Myocardial Infarction Marker - Troponin I

A biosensor based on field-effect transistors on silicon-on-insulator structures (SOI-biosensor) is a high-potential device for detection of biological molecules, for instance, such as troponin I; the biosensor allows conducting label-free real-time analysis. The aim of the study is the development of SOI-biosensor design for detection of acute myocardial infarction marker - troponin I. A notable feature of this design was the integration of two grounding electrodes directly onto the biosensor surface, which effectively nullified the static potential of the liquid sample and minimized physical breakdowns of biosensor elements.

The highly specific anti-troponin I DNA aptamer was used as a receptor for specific detection of protein marker. Aptamer immobilization on the biosensor surface was carried out by physical adsorption. The analyzed range of target troponin I molecules concentration in the sample varied within 10^-11 to 10^-9 mol/L, mirroring clinical levels observed in myocardial infarction cases. During the experiment, a constant voltage of V_ds=0.15 V was maintained.

The developed SOI-biosensor successfully detected target troponin I molecules at a concentration of 10^-11 mol/L. The detection process exhibited an effective time of approximately 200-300 s per sample. Moreover, analysis of the detection process revealed a noticeable decrease in current within the source-drain circuit, indicative of the negatively charged complex formed by troponin I and anti-troponin I DNA-aptamer at the "liquid sample-nanowire" phase interface.