Bound States in the Continuum Metasurfaces for Biomolecular Detection: A Review of Advances and Applications

The demand for high-sensitivity, label-free sensing has driven the development of metasurface-based optical biosensors. While traditional architectures suffer from broad resonances and limited sensitivity due to radiative and dissipative losses, bound states in the continuum (BICs) offer a pathway to achieve extreme field enhancement and narrow resonance linewidths. By harnessing quasi-BIC modes, metasurfaces can significantly improve the limit of detection and facilitate device miniaturization. This Review synthesizes current advancements in BIC-enabled biomolecular sensing, covering fundamental physics, symmetry-breaking strategies, and sensing modalities. Furthermore, we categorize recent developments based on material platforms-ranging from dielectrics to hybrids-and highlight their specific applications in life sciences. The Review concludes with an outlook on bridging the gap between laboratory research and commercial point-of-care diagnostics.