Synthesis of CuInS2 and CuInS2@ZnX (X = S, Se) nanoparticles for bioimaging of cancer cells using electrochemically generated S2- and Se2-

An electrochemical approach has been used for the aqueous synthesis of low-toxicity and eco-friendly copper indium sulfide (CuInS2) nanocrystals, and related core@shell systems (CuInS2@ZnX, where X = S2- and Se2-). The chalcogenide precursors (S2-, Se2-) were generated in electrochemical cavity cell, using a constant current electrolysis (i = 30 mA and Q = 11.5C), in the presence of metallic precursors (In3+, Cu+, Zn2+), room temperature and argon atmosphere. Firstly, In2S3 seeds were obtained in the intermediate compartment of the cell and converted to CuInS2 by thermoactivated diffusion (colloidal solution under reflux) of Cu+ ions into the In2S3 lattice. Cu+/In3+ ratios = 0.25 and 0.125 were tested for the production of CuInS2 stabilized by L-glutathione (GSH), and characterized by UV-vis and emission spectroscopy, XRD, HRTEM and zeta potential. CuInS2@ZnX nanoparticles were prepared by using the same electrochemical system, paired electrolysis and Zn sacrificial anode. Nanocrystals prepared under Cu+/In3+ = 0.125 reached 3.1% (CuInS2), 4.6% (CuInS2@ZnSe), and 9.6% (CuInS2@ZnS) quantumyields. The CuInS2@ZnX systems presented high cell viability (85%-94%) and internalization in cytosol region of HeLa cells, showing high potential for biological labeling. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

An electrochemical approach was used to synthesize low-toxicity and eco-friendly copper indium sulfide nanocrystals and core@shell systems with high quantum yields and cell viability. Different ratios of metallic precursors were tested to produce nanoparticles with potential biological labeling applications.