COMSOL-Based Impedance and Sensitivity Analysis of an Interdigitated Electrode Biosensor for Dengue NS1 Detection

Dengue remains a major global public health concern, highlighting the need for rapid and sensitive methods for the early detection of dengue virus biomarkers. In the present study, a finite element model for the detection of dengue nonstructural protein 1 (NS1) using an interdigitated electrode (IDE)-based impedimetric biosensor was developed in COMSOL Multiphysics. The proposed sensor consists of gold IDEs coated with an antibody-based biorecognition layer and immersed in a conductive aqueous sample medium. Antibody–NS1 binding was modeled using the Langmuir adsorption isotherm. Frequency-domain simulations were used to examine the impedance response over a range of NS1 concentrations from 0 to 1000 ng/cm3. The results showed that the simulated impedance magnitude decreased with increasing NS1 concentration and excitation frequency. At 10 MHz, the normalized impedance response increased rapidly at low NS1 concentrations and gradually approached saturation at higher concentrations. A linear fit to three simulated concentration points (1–3 ng/cm3) yielded a normalized response slope of 0.9223%/(ng/cm3) (R2 = 0.9963), providing a preliminary characterization of the model-predicted low-concentration response. These findings demonstrate the potential of computational modeling for characterizing the predicted electrical response of an IDE-based impedimetric NS1 biosensor, providing a basis for sensor optimization and future experimental validation. The reported sensitivity and concentration-dependent responses are simulation-based predictions and have not been experimentally validated.