Carbon dots embedded metal-organic framework@molecularly imprinted nanoparticles for highly sensitive and selective detection of quercetin

A facile and efficient one-pot approach for the synthesis of carbon dots embedded metal-organic framework@molecularly imprinted polymer nanoparticles (CDs@MOF@MIP), which can be used for highly selective and sensitive optosensing of quercetin (QCT), is reported herein for the first time. Metal-organic frameworks (MOFs) with high specific surface area and porosity were first prepared via a room-temperature reaction and used as a matrix to construct MOF-based sensor. Then, highly blue luminescent carbon dots (CDs) were introduced to act as signal transducer that can sense the bonding interactions between the developed sensor and the target molecules and further transduce them to the detectable fluorescence signals. Final, through a surface molecular imprinting process, the resulting CDs@MOF@MIP was obtained. The CDs@MOF@MIP not only exhibited higher selectivity and sensitivity toward target molecular compared to carbon dots embedded metal-organic framework @non-imprinted polymer (CDs@MOF@NIP), but also showed faster reaction rate than CDs-embedded molecularly imprinted polymer (CDs@MIP) derived from the introduction of porous MOF and the optical detection. This proposed sensor was employed to sense trace QCT, and its fluorescence presented a well linear decline with the increasing concentration of QCT from 0 μM to 50.0 μM with a limit of detection of 2.9 nM (S/N = 3), and the precision for eleven replicate detections of 0.5 μM QCT was 1.9%. This developed CDs@MOF@MIP sensor was also used to determine QCT content in real Ginkgo biloba extract capsules with satisfactory performance, and the results were correlated well with those obtained using high performance liquid chromatography.