Synergistic Integration of 2D MOF Films and Gold Nanoparticles for Multifunctional Surface Plasmon Resonance Sensing

Metal-organic frameworks (MOFs), known for their high porosity and tunable properties, have attracted significant interest in enhancing the sensitivity and functionality of plasmonic optoelectronic devices. However, their application in surface plasmon resonance (SPR) fiber-optic sensors remains challenging due to difficulties in preparing and transfer of large-area two-dimensional (2D) MOFs. Here, a large-area continuous ultrathin MOF film was successfully fabricated using an interfacial synthesis strategy and seamlessly adhered to tilted fiber Bragg gratings (TFBG). The resulting 2D MOF film not only exhibited excellent optoelectronic properties, thereby enhancing the plasmonic response in the sensing region, but also, due to its exceptionally high specific surface area, facilitated molecular enrichment within the effective sensing region. Subsequently, gold nanoparticles (AuNPs) were uniformly grown in situ on the 2D MOF films, leveraging the localized surface plasmon resonance (LSPR) effect of AuNPs to amplify the sensing signal, which significantly improved the sensor's performance for trace analysis. Concurrently, the AuNPs and the MOF-constructed nanozymes facilitated ultrasensitive glucose detection through a cascade catalytic reaction, obviating the need for additional receptors. The prepared sensor demonstrates excellent detection capabilities for glucose and DNA molecules in complex biological samples, such as serum. It exhibits strong performance in stability, reproducibility, and scalability, and holds potential for transformation in industrial testing applications. This design fully leverages the synergistic effects among diverse materials, enhancing the sensor's detection capabilities and providing valuable insights for the development of next-generation sensors.