Gas vortex discovery in butterfly microcavities for constructing ultrasensitive gas sensors

Gas sensors are pivotal for environmental monitoring and medical diagnostics but usually face the sensitivity-stability trade-off in trace-gas detection. Conventional sensitivity-enhancement strategies rely on reactive surface modifications, which may risk long-term stability, whereas inefficient gas-solid interaction time limits detection sensitivity. Here, we find gas vortex effects in butterfly wings that can prolong molecular residence time and apply this bioinspired mechanism to gas sensor design to resolve this trade-off. We establish a universal design rule: Periodic microcavities with diameter-to-height ratios of 1 to 1.33 generate centralized vortices that prolong molecular residence time by 85% and optimize mass transfer efficiency, as validated through computational fluid dynamics, fluorescence tracking, and Sherwood number analysis. This geometric principle enables metal oxide (ZnO, In₂O₃, Co₃O₄, and WO₃) sensors to achieve ultralow detection limits (0.8 to 30 parts per billion) while maintaining long-period stability. A four-channel microsensor array leveraging vortex-enhanced microstructures enables real-time profiling of human breath biomarkers. This work resolves the classical sensitivity-stability conflict through geometric fluidic control rather than material chemistry.