Stress-Enhanced MEMS Trapezoidal Microcantilever Sensor for Enhanced Detection of Respiratory Syncytial Virus

Early detection of disease-causing antigens plays a crucial role in preventive healthcare. Biosensors are devices that monitor and diagnose human health by converting biological interactions into measurable signals. In recent years, microcantilever-based biosensors have gained significant attention due to their high sensitivity, miniaturization capability, and rapid response characteristics. This paper focuses on detecting the RSV-G protein of Respiratory Syncytial Virus using a paddle-type trapezoidal microcantilever with different stress concentration regions. The cantilever is designed using SU-8 polymer material with a density of 1123 kg/m³, Young’s modulus of 5 GPa, and Poisson’s ratio of 0.22. The sensing mechanism is modeled in static mode, where antigen–antibody binding is represented as an equivalent surface-stress-induced loading condition in the finite element simulation. Comparative analysis of different SCR geometries shows that the rectangular SCR configuration yields a maximum displacement of 6.8 × 10⁻¹⁸ µm, demonstrating a nearly fourfold enhancement over the conventional design without an SCR. This improvement is attributed to localized stress concentration and reduction in effective structural stiffness under identical loading conditions. The results indicate that geometry-driven stress concentration significantly enhances the mechanical sensitivity of the microcantilever sensor and provides an effective approach to structural optimization for viral biosensing applications.