Preparation and Characterization of Quercetin/Cyclodextrin/Carbon Quantum Dot Nanocomplexes and Evaluation of their Stability and In Vitro Digestive Properties

In this study, α-, β-, γ-cyclodextrin (CD) and carbon quantum dots (CQs) nanocomplexes loaded with quercetin (Qu) were prepared successfully. The results showed that incorporation of CQs increased the Qu encapsulation efficiency and the stability of the nanocomplexes. Fourier transform infrared spectra showed that Qu, CQs and CD were mainly linked by hydrogen bonds. X-ray diffraction results showed that the crystal structures of Qu/CD-CQs were completely different from those of Qu, CD and Qu/CD. The results from differential scanning calorimetry, thermogravimetric analysis and scanning electron microscopy provided evidence for the formation of Qu/CD-CQs. Moreover, compared with Qu, the synthesized Qu/CD-CQs exhibited better physicochemical stabilities, and CD and CQs synergistically improved the stability and bioavailability of Qu. The release of Qu from Qu/CD-CQs was controlled. These results suggested that Qu was efficiently encapsulated by α-, β-, γ-CD and CQs, and the resulting nanocomplexes have great potential for use as nanofunctional foods.