Molecular imprinting-based triple-emission ratiometric fluorescence sensor with aggregation-induced emission effect for visual detection of doxycycline

The development of high-performance sensors for doxycycline (DOX) detection is necessary because its residue accumulation will cause serious harm to human health and the environment. Here, a novel tri-emission ratiometric fluorescence sensor was proposed by using “post-mixing” strategy of different emissions fluorescence molecularly imprinted polymers with salicylamide as dummy template (DMIPs). BSA was chosen as assistant functional monomer, and also acted as sensitizers for the aggregation-induced emission (AIE) effect of DOX. The blue-emitting carbon dots and the red-emitting CdTe quantum dots were separately introduced into DMIPs as the response signals. Upon DOX recognition within 2min, blue and red fluorescence of the tri-emission DMIPs sensor were quenched while green fluorescence of DOX was enhanced, resulting in a wide range of color variations observed over bluish violet-rosered-light pink-orange-yellow-green with a detection limit of 0.061μM. The sensor possessed highly selective recognition and was successfully applied to detect DOX in complicated real samples. Moreover, with the fluorescent color collection and data processing, the smartphone-assisted visual detection of the sensors showed satisfied sensitivity with low detection limit. This work provides great potential applications for rapid and visual detection of antibiotics in complex substrates. Environmental Implication Doxycycline (DOX) has been used for the prevention and treatment of diseases, and can also be added to animal feeds to promote animal growth. However, owing to its incomplete degradation, the continued accumulation of DOX residues will have the serious impacts on human health and the environment. To detect trace DOX in complex matrices, a molecular imprinting-based triple-emission ratiometric fluorescence sensor was constructed by using a “post-mixing” strategy, enabling highly sensitive and selective detection of DOX with a wide range of color variations observed. The developed sensor provides a promising approach in DOX determination and environmental protection.