Non-Invasive Biofluid Sensing Using Partially Symmetric Multi-Layered Metallic Metasurfaces

Blood tests are commonly used for disease diagnosis, but they are invasive, uncomfortable, and sometimes impractical. This paper presents a non-invasive approach employing a partially symmetric, multilayered metasurface biosensor to detect subtle variations in key sweat analytes. Since sweat composition reflects various physiological and biochemical states, monitoring it can provide useful indicators of health conditions. The reflection response of the proposed structure is analyzed to identify small changes in sweat permittivity with high sensitivity. The results demonstrate that the biosensor effectively distinguishes between normal and abnormal conditions, offering a simple and painless method for disease detection and monitoring. Moreover, its fully metallic structure combines low fabrication cost with mechanical robustness, long-term stability, and strong electromagnetic performance for reliable sweat analysis. These findings highlight the potential of metasurface-based sensing for continuous, wearable health monitoring and early diagnosis without invasive procedures or laboratory testing.