MIL-53(Al)-functionalized terahertz metasurface sensor for specific detecting lung cancer biomarker of styrene

A MIL-53(Al)-functionalized terahertz metasurface sensor was developed for the room-temperature detection of styrene, a potential volatile biomarker associated with lung cancer. The sensor combines the localized electromagnetic field enhancement of the terahertz metasurface with the adsorption enrichment capability of MIL-53(Al). Benefiting from the flexible one-dimensional channels, the size-compatible pore environment of MIL-53(Al), and the possible π–π and host–guest interactions between styrene molecules and the terephthalate linkers, the functionalized metasurface exhibits an enhanced sensing response toward styrene. APTES was introduced as an interfacial coupling layer to improve the immobilization and dispersion of MIL-53(Al) nanocrystallites on the metasurface. SEM and FTIR characterizations confirmed the formation of a nanocrystallite-stacked MIL-53(Al) coating and the successful introduction of both APTES and MIL-53(Al) onto the sensor surface. The optimized sensor achieved a sensitivity of 0.37 GHz/ppm and a limit of detection of 1 ppm within the concentration range of 1–100 ppm. In addition, the sensor showed good selectivity against several interfering VOCs, as well as acceptable repeatability and stability. This work provides a feasible strategy for integrating flexible MOF adsorbents with terahertz metasurfaces, offering a potential platform for rapid, label-free, and room-temperature detection of trace aromatic VOCs.