Mercury Ion Sensing Using Aptamer-Modified Extended Gate Field-Effect Transistors and a Handheld Device

In this research, we have designed, fabricated, and characterized an Electrical double-layer (EDL) gated FET platform to detect heavy metals. The electrical double layer (EDL)-gated field-effect transistor-based sensor is garnering interest due to its sensitivity, portable configuration, selectivity, inexpensive operation, as well as their user-friendly nature. the sensing platform designed for rapid detection of Hg²⁺ using DNA-based aptamers. The investigation was carried out by introducing different concentrations of Mercury ions and a lower detection limit of 1 μM was achieved. The sensor surface was validated with Kelvin Probe Force Microscope (KPFM), which is consistent with the electrical response obtained. Sensor selectivity was studied and exhibited a high sensitivity toward Mercury ion detection. Considering its limit of detection, compatibility, and fast turnaround; the proposed system has the potential to be used to detect Mercury ions instantly for environmental monitoring, where quick and accurate detection of Mercury ions is essential.