AIE-active metal–organic frameworks: facile preparation, tunable light emission, ultrasensitive sensing of copper(II) and visual fluorescence detection of glucose

By binding aggregation-induced emission luminogens (AIEgens) with nanoscale ZIF-8, a series of novel Luminescent metal-organic frameworks (LMOFs) with good photostability and excellent dispersibility have been facilely fabricated. The developed AIE-active MOFs not only can inherit the intriguing AIE properties of AIEgens, that including excited-state intramolecular proton transfer (ESIPT) properties, intense solid-state luminescence and large stokes shifts (115-202 nm), but also show surprising boosted fluorescent emission efficiency (over 16 times) when compared with original fluorescence of AIEgens. Meanwhile, the emission of AIE-active MOFs could also be finely engineered by varying the substituents on AIEgens. And as a proof of concept, the selected AIE-active MOF-2 (LMOF-2) was served as a novel fluorescent probe for detecting copper ion (Cu2+), a considerable response range (1-100 nM) and a sensitive picomolar detection limit (550 pM) were favorably obtained. More importantly, based on a glucose oxidase (GOD) catalyzed cascade redox reaction of LMOF-2/GOD nanocomposites, a fluorescent allochroic test strip was favourably developed for visual detection of glucose within a normal concentration range of fasting blood-glucose in human sera (3-8 mM), and has great potential to be applied in on-site assay of glucose in real serum samples due to its praiseworthy specificity and selectivity.