Microwave synthesis of chitosan-based carbon dots for Al³⁺ detection and biological application

Yellow fluorescent carbon dots (Y-CDs) were prepared via microwave method using chitosan and o-phenylenediamine as the main raw materials. The obtained Y-CDs possesses good water solubility, excellent biocompatibility and luminous stability. During the microwave pyrolysis carbonization process, the surface of Y-CDs was modified with the functional groups such as amino and carboxyl, which can bind to Al³⁺ by forming complexes, further improving the selectivity and sensitivity of the Al³⁺ detection. And the fluorescence of Y-CDs was quenched by Al³⁺ by static quenching process. More importantly, Y-CDs as fluorescent sensor was further applied for the determination of Al³⁺ in the real water samples with high reliability and accuracy. In addition, Y-CDs present potential application in biological imaging. The cultivated zebrafish embryos with Y-CDs displayed clearly in vivo uptake and metabolic fluorescence images, further confirming its low toxicity and excellent biocompatibility.