Toward greener electrochemical synthesis of composition-tunable luminescent CdX-based (X= Te, Se, S) quantum dots for bioimaging cancer cells

A novel versatile and clean colloidal processing route was developed for synthesizing CdX(X = Te, Se or S) quantum dots (QDs) based on the simultaneous production of the respective precursors via cadmium sacrificial anode electrochemical methodology. The CdX QDs stabilized by 3-mercaptopropionic acid (MPA) were synthesized in one-pot electrochemical process using aqueous medium at room temperature with full reaction time of approximately 16 min. The CdX quantum dots conjugates were extensively characterized by UV-vis, PL, FTIR, TEM-EDS, XRD, DLS, XPS, and Zeta potential, evidencing that very stable colloidal quantum dots were produced with uniform narrow-size distributions and average nanoparticle diameter of approximately 3.0 nm and quantum yield (QY) of approximately 10%. The cell viability response of HeLa cells toward the CdX-MPA conjugates clearly demonstrated that they are non-toxic based on the 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide (MTT) mitochondria) metabolic activity assay for 24h of incubation with HeLa cervical cancer cells. Moreover, they showed effective fluorescent activity with time-dependent intensities for evaluating continuous endocytosis of cancer cells, thus, offering innumerous possibilities to be used as fluorescent nanoprobes for bioimaging and biosensing of cancer cells. (C) 2017 Elsevier B.V. All rights reserved.