Functionalized ImmunoFET for Detection of Phosphatidyl-L-serine

This paper presents an ion-sensitive field-effect transistor (ISFET)-based biosensor for detecting phosphatidylserine (PS), a key apoptosis marker. The sensor, featuring a silicon nitride (Si<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>N<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf>) membrane functionalized with Annexin V, achieved sensitivities of 20 mV/decade for Ag/AgCl electrodes and 52 mV/decade for gold electrodes, with a limit of detection down to 10 nM. Surface modification was validated via fluorescence microscopy, showing a twofold increase in signal intensity upon PS binding. Compared to fluorescence microscopy and enzyme-linked immunosorbent assay (ELISA), which require extensive processing, the ISFET-based approach offers a rapid, label-free, and miniaturizable alternative. Optimized surface treatment enhanced performance, making it suitable for real-time apoptotic marker detection and integration into portable diagnostics.