Ultrasensitive Terahertz Label-Free Metasensors Enabled by Quasi-Bound States in the Continuum

• Published in: Research (Washington) Vol. 7; p. 0483
• Main Authors: Wang, Ride, Song, Lingyu, Ruan, Hao, Yang, Quanlong, Yang, Xiao, Zhang, Xiaobao, Jiang, Rundong, Shi, Xiangmin, Shkurinov, Alexander P
• Format: Journal Article
• Language: English
• Published: United States AAAS 2024; American Association for the Advancement of Science (AAAS)
• Subjects: Advanced Materials
• ISSN: 2639-5274; 2639-5274
• DOI: 10.34133/research.0483

Advanced sensing devices based on metasurfaces have emerged as a revolutionary platform for innovative label-free biosensors, holding promise for early diagnostics and the detection of low-concentration analytes. Here, we developed a chip-based ultrasensitive terahertz (THz) metasensor, leveraging a quasi-bound state in the continuum ( BIC) to address the challenges associated with intricate operations in trace biochemical detection. The metasensor design features an open-ring resonator metasurface, which supports magnetic dipole -BIC combining functionalized gold nanoparticles (AuNPs) bound with a specific antibody. The substantial enhancement in THz-analyte interactions, facilitated by the potent near-field enhancement enabled by the -BICs, results in a substantial boost in biosensor sensitivity by up to 560 GHz/refractive index units. This methodology allows for the detection of conjugated antibody-AuNPs for cardiac troponin I at concentrations as low as 0.5 pg/ml. These discoveries deliver valuable insight for AuNP-based trace biomolecule sensing and pave the path for the development of chip-scale biosensors with profound light-matter interactions.