Synthesis of luminescent chitosan-based carbon dots for Candida albicans bioimaging

In this work, we used chitosan as a raw material to synthesize carbon dots using fast microwave carbonization. We studied the influence of the synthesis time, doping agent, and the molar ratio between the reactants on the quantum yield of carbon dots. Chitosan-based carbon dots displayed stable blue fluorescence emission with excitation-dependent behavior and quantum yield values ranging from 1.16 to 7.07 %. ANOVA results showed that the interaction factor between the doping agent and the molar ratio of the reactants was a significant combination to produce carbon dots with higher quantum yield. The presence of the doping agent improved the carbon dots optical properties by obtaining higher fluorescence intensity values. Confocal laser microscope images showed that the carbon dots internalized in the Candida albicans cellular membrane, exhibiting blue, green, and red emissions, acting as a promising agent for bioimaging. •Chitosan-based carbon dots are synthesized by a fast and simple microwave approach.•Synthesis conditions modulation is essential to improve the fluorescent properties.•Statically, the synergy of molar ratio and doping agent leads higher quantum yields.•Chitosan-based carbon dots bind specifically with ergosterol from Candida albicans.•Chitosan-based carbon dots functioned as a bioimaging agent for Candida albicans.