Lumi-HOF@Tb as Probes for Multiple Ratiometric Fluorescence and Chemiluminescence Sensing of α-Glucosidase

The innovative assembly of luminescent hydrogen-bonded organic frameworks (HOFs) into multifunctional optical sensors is of great significance for developing advanced materials. Herein, we report a facile room-temperature synthesis strategy for the luminol HOF modified by Tb³⁺ (Lumi-HOF@Tb) and featuring sensitive chemiluminescence and fluorescence characteristics. Lumi-HOF@Tb is further pioneered as a dual-signal sensor for selective detection of α-glucosidase, a type of enzyme that plays a crucial role in the digestion of carbohydrates, and screening of its inhibitors. The sensor is constructed by combining the dual optical characteristics of luminol from the HOF and lanthanide ion assistance. From the hydrolysis of α-glucosidase and the 4-nitrophenyl-α-d-glucopyranoside (pNGP) substrate emerges the fluorescent luminol-p-nitrophenol (pNP) complex at 466 nm and changes the inner filter absorption to recover Tb³⁺ characteristic fluorescence at 546 nm; luminol also produces a chemiluminescence signal driven by H₂O₂ from additional glucose oxidase-catalyzed hydrolysis of α-d-glucose. Fluorescence and chemiluminescence assays for α-glucosidase activity have therefore been established and exhibit detection limits as low as 0.04 and 0.005 U L^-1, respectively. This study not only presents the possibility of Ln³⁺-HOF-based sensors as intelligent optical materials by integration of fluorescence and chemiluminescence techniques but also demonstrates great potential for future applications in biosensing.