figshare.xlsx

Technologies capable of quantitatively detecting various molecules at trace concentrations without the need for external labels or amplification are crucial for early identification of disease biomarkers in medical diagnostics. In this context, label-free field-effect transistor biosensors based on two-dimensional (2D) materials are highly desired for their exceptional sensitivity. However, the instability of non-covalent interface engineering and variations in device performance lead to poor reproducibility, limiting their use in quantitative analysis. To address these challenges, we functionalize only the edges of graphene by protecting its basal plane with a ceramic material and reversibly modifying the edges using diazonium chemistry. Remarkably, the resulting edge-enhanced graphene quantum capacitor (eGQC) exhibits reusability for up to 100 cycles with reproducible working curves. This achievement enables the robust detection of miRNA-21 molecules, a promising biomarker for early cancer diagnosis, at femtomolar concentrations. The sensing response exhibits a standard deviation of only 41% over 100 continuous miRNA detections, significantly outperforming current state-of-the-art graphene biosensor arrays.<br><br>