Terahertz Let-7a specific sensing and DNA differentiation enabled by Q-BIC metasurface and phenylboronic acid-gold...

Nucleic acids are genetic molecules that carry biological information, the development of accurate nucleic acid detection technology is of great significance for the treatment of some diseases. Here, we proposed a novel scheme to specific detect Let-7a (miRNA) and simultaneous discrimination from DNA based on terahertz (THz) metasurface. The metasurface is designed for supporting quasi-bound states in continuum (Q-BIC) resonance, which can effectively improve the sensing performance. Numerical simulation consistent with experimental results confirms the Q-BIC is induced by the symmetry broken between the metal wires. To specific detect trace amount Let-7a, the PBA-AuNPs probe developed by modifying Au nanoparticles (AuNPs) with phenylboronic acid (PBA), is integrated into metasurface for signal amplification. Our results show that highly sensitive and selective detection of Let-7a is achieved, the detection limit can reach to 0.01 nM. More importantly, due to the selective binding of the nanoprobe, the sensitivity for Let-7a is more than 3 times that of DNA sharing the same sequence. Even in serum samples, the frequency shift of resonance still maintains a good linear relationship with the logarithm of the Let-7a concentration. This miRNA-targeted PBA-AuNPs amplification technology offers a versatile platform with translational potential across disciplines, particularly advancing emerging THz metasurface-based biosensing.