Topologically Protected Graphene Metamaterials for Terahertz Biosensing: A Comprehensive Review

The terahertz spectral range holds immense promise for label‐free biosensing through direct access to molecular vibrational fingerprints. However, its translation to practice is severely hampered by the dual challenges of overwhelming water absorption and the fragility of high‐sensitivity resonant sensors. This review critically analyzes an emerging paradigm that overcomes these obstacles via the synergistic integration of graphene metamaterials and topological photonics. Graphene's electrically tunable plasmons dramatically enhance light–matter interactions to counteract water absorption, while topological photonics provide a framework for creating robust, high‐Q resonant modes intrinsically immune to fabrication and environmental perturbations.We establish the foundational principles of this synergy, investigate the design of topological phases such as quantum valley/spin Hall and Floquet states within graphene‐based metamaterials, and confront the associated nanofabrication challenges. The review then explores advanced mechanisms for sensitivity enhancement, from the interplay of topological modes and plasmonic field confinement to the frontiers of quantum sensing in the strong coupling regime. By surveying state‐of‐the‐art applications in biomarker detection and charting a future outlook toward clinical translation, non‐Hermitian systems, and AI‐driven inverse design, we present a comprehensive framework for this rapidly advancing field.