Synthesis of molecularly imprinted polymer encapsulated with quantum dots for detection of crocin as an alternative approach for quality estimation of saffron

Molecularly Imprinted Polymers (MIPs) are widely used for their selective recognition capabilities, synthesized through interactions between template molecules, functional monomers, crosslinkers, and solvents. In this study, MIPs encapsulated with Carbon Quantum Dots (CQDs) were synthesized for detection of crocin, a bioactive carotenoid responsible for saffron’s vivid colour. CQDs were synthesized via thermal pyrolysis and characterized using TEM, FTIR, XRD, XPS, and fluorescence spectroscopy. The MIP-CQDs nanocomposite was prepared by integrating CQDs with functional monomers and crosslinkers, followed by template removal. Comparative non-imprinted polymers (NIPs) were also synthesized. The nanocomposites exhibited excellent optical and morphological properties, with fluorescence quenching used to evaluate crocin interaction. The MIP-CQDs displayed high sensitivity and selectivity for crocin in a linear range of 2–175 μM, with a detection limit of 2.1 μM. Optimal conditions included pH 7.0 and a 5-minute incubation time. The fluorescence quenching mechanism was attributed to Forster Resonance Energy Transfer (FRET) between crocin and MIP-CQDs. Notably, MIP-CQDs showed strong resistance to interference from structurally similar compounds and co-existing ions, ensuring reliable performance in complex matrices. The study underscores the significance of tailored nanocomposite designs for advancing molecular sensing applications.