Biocompatible luminescent carbon dots embedded in crosslinked chitosan/gelatin for in vitro dopamine release

Abstract

The present work elucidates the synthesis and properties of chitosan/gelatin/carbon dot nanocomposite. The synthesized carbon dots are incorporated into the chitosan-gelatin matrix in the ratio of 1:1. This ratio was chosen as it showed better release, anti-bacterial and antioxidant properties. The integration of carbon dots and dopamine into the chitosan-gelatin matrix was confirmed by XRD, UV, IR analysis and TEM micrographs. Toxicity studies of the composite were examined with the help of the IC-21 macrophage cell line. The release of the drug was tabulated in-vitro, and Korsmeyer - Peppas Case II transport release kinetics was observed over a period of 30 h in pH 7. After 30 h, 90 % of the encapsulated dopamine was released from the matrix. The addition of carbon dots enhances the controlled and extended release of the drug. The system is also tested for antibacterial and antioxidant properties. The highlight of this work is the facile synthesis and luminescent property of chitosan-derived carbon dots. The embryos and larvae of zebrafish were treated with the synthesized carbon dots, which provided them with an incubation period of 24 h. They were then observed under a fluorescent microscope with DAPI, FTIC and TRITC filters. Excitation-dependant emission, i.e., blue, green, and red emission, was seen in the sample when excited with UV, blue and green wavelengths, respectively. Its fluorescence properties help in its use as a tracer in monitoring the flow and movement of the drug-loaded composite.