چكيده فارسي :
Molecular imprinting technique is now a common and effective strategy for production of polymeric artificial receptors for the specific molecular recognition [1]. The unique optical properties of quantum dots (QDs) including high photostability and photoluminescence efficiency, sharp emission profile and size-dependent emission wavelengths make them appealing as fluorophores in optical sensing. On the other hand, carbon dos (CDs) have recently attracted considerable attention because of a series of merits such as water solubility, biocompatibility, high photo and chemical stability and tunable emission spectra. These features make CDs especially useful for fluorescent probes [2]. Molecularly imprinting polymer-capped QD sensors can combine the excellent selectivity of MIPs with the sensitivity and stable luminescence of QDs.We report on a ratiometric fluorescent sensor based on dual-emission molecularly imprinted mesoporous silica embedded with carbon dots and CdTe quantum dots (mMIP@CDs/QDs) for celecoxib (CLX) as target molecule. Under single wavelength excitation of 360 nm, blue-emitting CDs (440 nm) embedded in silica core, produce reference signals for providing built-in correction to avoid environmental effects. Meanwhile green-emitting CdTe QDs (550 nm) embedded in imprinted mesoporous silica shell are selectively quenched by CLX resulting in a ratiometric fluorescent sensor accompanied by a visual green-to-blue color switch. This effect is much stronger for the MIP than for the non-imprinted polymer, which indicates a good recognition ability of the mesoporous MIP. The hybrid sensor also exhibited good selectivity to CLX over its structural analogs. Moreover, the high pore volume and nanosized pores of mesoporous silica provide high sensitivity and fast response time. The ratio of the intensity at two wavelength (F550/F440) proportionally decreased with the increasing of CLX concentration in the range of 0.08- 0.90 µM. A detection limit as low as 57 nM was achieved. Experimental results testified that this sensor was highly sensitive and selective for the detection of CLX in human serum samples
