2.1 Synthesis of the CDs
The CDs were synthesized by a
one-step hydrothermal method
using CA and PEI (M. W. = 10k) as the raw materials, as shown inFigure 1 . In brief, CA (1.0 g) and PEI (2.0 g) were dissolved
in water (10 mL). Then, the mixture was transferred into a Teflon-lined
hydrothermal reactor and reacted at 200°C for 2 h. After cooling to room
temperature, the system appearing yellow was dialyzed against water for
24 h with a dialysis bag (1000 Da). Finally, the filtrate was
lyophilized to obtain a yellow powder of the CDs.