Tip-assisted Si nanowire MOSFET aptasensor for cardiac biomarker detection

https://doi.org/10.1016/j.microc.2025.114358

Miniature electronic sensors manufactured using modern silicon technology have been intensively studied as candidates for replacing chemical and biological test systems used in medicine for precision detection of proteins and molecules in liquids and gases. Selective recognition of low concentrations of biomarkers will make it possible to diagnose dangerous diseases at early stages, thereby ensuring their successful treatment. In this study, a method for electrical detection of a heart-type fatty acid-binding protein (hFABP) in air is proposed. To enhance the selectivity, silicon nanowire field-effect transistors (Si-NW FETs) with channel widths of 0.4, 1, and 3 μm have been fabricated and pre-functionalized with an anti-hFABP DNA aptamer (FABPAp1c-t38). It has been found that the FABPAp1c-t38 and hFABP protein induce opposite shifts of threshold voltage V_th of the Si-NW FET. For a detected target, the voltage V_th shifts from +0.2 to +2.8 V. It has been established that the voltage V_th is a better signal as compared with other electrical characteristics of the transistor. This has allowed the hFABP detection at concentrations of 1 pM in a model buffer system. It is expected that the proposed cardio target sensors and method for detection under dry conditions will contribute to the development and production of various electronic devices for application in medicine and other fields.