Spherical Nucleic Acid Probes on Floating-Gate Field-Effect Transistor Biosensors for Attomolar-Level Analyte Detection

Field-effect transistor (FET) sensors are attractive for the label-free detection of target biomolecules, offering ultrahigh sensitivity and a rapid response. However, conventional methods for modifying biomolecular probes on sensors often involve intricate and time-consuming procedures that require specialized training. Herein, we propose a simple and versatile approach to functionalize floating-gate (FG) FET sensors by exploiting the strong binding ability of polyvalent interactions and the three-dimensional structure of densely functionalized spherical nucleic acids (SNAs). Crucially, the SNAs can be easily deposited onto a dielectric layer under mild conditions, ensuring stable immobilization of the probes. Further, the SNAs show efficient and robust immobilization on various dielectric layers including Y