Bevacizumab and folic acid dual-targeted gadolinium-carbon dots for fluorescence/magnetic resonance imaging of hepatocellular carcinoma

Abstract

In this study, single- and dual-targeted gadolinium-carbon dots (Gd-CDs) with Bevacizumab (BEV) and/or folic acid (FA) were developed as dual-modal fluorescence and magnetic resonance (FL/MR) imaging nanoprobes. Gd-CDs were prepared by a single-pot hydrothermal route using citric acid, ethylenediamine, and Gd-DO3A-butrol (Gadovist) as the starting materials. Mouse hepatocellular carcinoma (Hepa1-6) cell line was selected as cancer cells, while mouse fibroblast (L929) was used as a normal cell line. Gd-CDs, Gd-CDs-FA, Gd-CDs-BEV, and Gd-CDs-FA-BEV exhibited the high relaxivities (r1) of 7.98, 7.83, 7.61, and 6.03 mM−1 s−1, respectively, being considerably more than the clinical Gd-DO3A-butrol contrast agent (r1 = 4.01 mM−1 s−1). Moreover, they exhibited strong fluorescence with a fluorescence quantum yield (QY) of 49.94%, 61.22%, 82.5%, and 83.67%, respectively. MTT assays on cancer and normal cells showed that various synthesized Gd-CDs on both cell lines have low toxicity. Inductively coupled plasma optical emission spectrometry (ICP-OES) analysis revealed that Gd-CDs-FA-BEV uptake by Hepa1-6 cells was 5-fold as much as the non-targeted Gd-CDs after 24 h incubation. Functionalization of Gd-CDs with Bevacizumab and/or folic acid improves the diagnostic sensitivities and specificities, making them ideal contrast agents for MRI as well as ideal fluorophores for fluorescence imaging.