Graphene oxide and adenosine triphosphate as a source for functionalized carbon dots with applications in pH-triggered drug delivery and cell imaging

A folate-functionalized carbon dot-based nanocarrier system has been successfully synthesized for cancer cell targeted drug delivery. We hydrothermally synthesized blue photoluminescent N,P-CDs using adenosine triphosphate and graphene oxide as the starting materials. The particle size of the N,P-CDs was ca. 3.8 nm. An anticancer drug, doxorubicin (DOX), was grafted onto the carbon dots via electrostatic interactions, and a more specific anticancer agent (DOX/N,P-CDs) was obtained. The DOX/N,P-CDs were characterized by H-NMR, C-NMR and UV-vis analysis. In addition, the DOX/N,P-CDs showed a pH-dependent release and were easily absorbed by cells. When compared to DOX, DOX/N,P-CDs nanoparticles exhibited the same cytotoxicity towards human cervical cancer cells (HeLa cells) and human pulmonary adenocarcinoma cells (A549 cells). Hemolysis test results indicated that DOX/N,P-CDs were safe for blood-contact applications and were suitable for intravenous administration. Owing to their intrinsic biocompatibility, N,P-CDs can be used for cell imaging and drug delivery with excellent targeting property.