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

Abstract

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 16min. 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 3.0nm 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-yl)-2,5-diphenyltetrazolium bromide (MTT) mitochondrial 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.