Sonochemical-assisted green synthesis of nitrogen-doped carbon dots from crab shell as targeted nanoprobes for cell imaging

A one-pot sonochemical method was developed for the green synthesis of highly fluorescent carbon dots with nitrogen dopants (N@C-dots) derived from crab shells. The synthesized N@C-dots exhibited excellent water solubility with a fluorescence quantum yield of 14.5%. The N@C-dots then conjugated with folic acid (FA) to construct the N@C-dots-FA nanoprobe with the ability to selectively target folate-receptor positive cancer cells. Moreover, in vitro cytotoxicity studies showed excellent biocompatibility. Cellular uptake of the N@C-dots-FA was further studied via in vitro confocal microscopy studies. Results showed that N@C-dots-FA nanoprobes were mostly localized in the cytoplasm of the folate receptor-overexpressing Human cervical cancer cell (HeLa) while cellular uptake by human embryo lung cell (HEL) cells (folate receptor-deficient control) was negligible. Based on their improved diagnostic imaging and enhanced targeting effect, the N@C-dots-FA probe has high potential in the theranostic applications. This study demonstrates an economically viable approach to synthesize N@C-dots-FA probe using seafood waste. (C) 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.