Fabrication and characterization of microwave-assisted synthesis of carbon dots crosslinked sodium alginate hydrogel films

In this study, potassium-incorporated carbon dots (K-CDs) and nitrogen-incorporated carbon dots (N-CDs) were composted using the microwave-assisted method, in which the carbon source is citric acid. Subsequently, the prepared CDs were added into sodium alginate (NaAlg)/CaCO₃ to form a hydrogel film. The Ca²⁺ in the system is tend to be released in the presence of acidic CDs to promote the cross-linking of NaAlg. This study presents a NaAlg hydrogel film preparation process that requires no additional acid and is natural and environmentally friendly. Moreover, it gives the NaAlg hydrogel film excellent antioxidant and antimicrobial properties and also improves its mechanical properties and gel strength. The release behaviors of the CDs in the hydrogel films were also explored. The prepared CD-incorporated NaAlg hydrogel films have potential applications in medical, biological engineering, food preservation, and other fields owing to their functional properties.