Curcuminoid-Linked Lemon-Derived Carbon Dots for pH-Triggered Drug Release

The supramolecular architectures were designed from lemon-derived carbon dots (LCDs) and curcuminoids. Curcuminoids were used to link the carbon dots to create a supramolecular architecture via an ester linkage. The optical characteristics of curcuminoid-linked lemon carbon dots (CL-LCDs) demonstrated that CL-LCDs-1 can be used for bioimaging applications among all of the LCD derivatives. The HR-TEM and FEG-SEM images showed that the size of all CL-LCD derivatives is nearly 10 nm, which is ideal for the development of effective drug delivery systems. The CL-LCDs were used to encapsulate the anticancer drug methotrexate, which demonstrated a sustained drug release profile under pH stimulus. CL-LCDs-3 exhibited a 27.50% cumulative release at pH 5.5 after 7 days. At pH 7.4, CL-LCDs-3 showed a 19.73% cumulative drug release. MTX-loaded CL-LCDs-1 showed the best anticancer activity against HeLa cells, and the photoluminescence was recovered after the drug release, showing its promising application in the field of tumor imaging.