B/N modified GDY as a rare base 2D sensor: a first-principles study

Detecting DNA rare bases is essential for diagnosing genetic disorders and cancers. However, their low abundance and high structural similarity make selective and sensitive detection challenging. The two-dimensional functionalized carbon material graphdiyne (GDY) holds great promise for enhancing sensor performance due to its excellent electronic properties, biocompatibility, and ease of functionalization. This study employs density functional theory (DFT) to investigate the adsorption behavior of rare bases on GDY and R-GDY (R = B/N) surfaces. Essential factors, including adsorption energy, bandgap, charge transfer, and density of states, are systematically analyzed. Additionally, critical sensor performance metrics, such as deposition time, sensitivity, and selectivity are predicted, providing valuable insights into the potential applications of these materials. The results indicate that while pure GDY can specifically recognize 5-hydroxymethylcytosine, its sensitivity is limited. In contrast, R-GDY stably adsorbs rare bases via π-π interactions, exhibiting good reversibility and moderate charge transfer, which significantly enhance its sensitivity. R-GDY effectively distinguishes between rare bases based on translocation time, making it ideal for the development of efficient and reusable electrochemical biosensors, thus providing a reliable approach for clinical diagnostics.