Cation Enrichment\nEffect Modulated Nafion/Graphene\nField-Effect Transistor for Ultrasensitive RNA Detection

The graphene field-effect transistor (GFET) biosensor\nserves as\na foundational platform for detecting biomolecules, offering high\nconductivity, label-free operation, and easy integration. These features\nhave garnered significant attention in biomarker detection. However,\nthe presence of free cations in solution often leads to electrostatic\nshielding of negatively charged biomolecules, reducing GFET detection\nsensitivity (LOD ≥ 1 fM). Additionally, the limited capacitance\nchange in GFET restricts its use as a response signal. This study\nintroduces a cation enrichment electric field modulation strategy\n(CEEFMS) to enhance capacitance and Dirac voltage response during\ndetection. The cation-enriched rough Nafion/graphene FET (CENG-FET)\nachieves RNA detection at the aM level. Utilizing total capacitance\nchange and Dirac voltage shift as response signals, the CENG-FET demonstrates\na wide linear range from 1 aM to 1 pM. These findings advance dual-signal\ndetection strategies, reducing accidental inaccuracies in biomolecular\nsensing and paving the way for further research.