Synthesis and cytotoxic evaluation of gum arabic surface modified cadmium telluride quantum dots

Water-soluble cadmium telluride (CdTe) quantum dots (QDs) were capped with gum Arabic (GA) is a non-toxic, water-soluble glycoprotein polymer commonly used in the food and pharmaceutical industries. The GA was used to stabilise cadmium telluride quantum dots (GA-QDs) and provides functional groups for other molecules such as nucleic acids, peptides and antibodies to be attached to the QDs for biological and biomedical applications. In this study, the GA was used to cap and stabilise QDs using two different methods. These QDs were characterised using Ultraviolet-visible (UV-vis) and Photoluminescence (PL) spectroscopy, X-powder ray diffraction (XRD), High-resolution transmission electron microscopy, zeta potential and particle size distributions. Cytotoxicity of these QDs was also investigated using four different human cell lines; HeLa, MCF-7, PC-3 and U87 cancer cells. The QDs-MPA was capped with 3-mercaptopropionic acid, QDs-GA2 was stabilized and capped with GA at 60 degrees C for two hours, and QDs-GA12 was stabilized and capped with GA for twelve hours at room temperature (25 degrees C) with continuous stirring; These QDs were found to be highly luminescent with PL values of 675 nm, 678 nm and 677 nm respectively. The average polydispersity index (PDI) were 0.36 +/- 0.02, 0.27 +/- 0.02, 0.35 +/- 0.01 for QDs-MPA, QDs-GA2 and QDs-GA12, respectively. The average particles size from HRTEM, XRD and hydrodynamic size showed that the QDs-GA have bigger particles sizes; (56.12 nm +/- 1.14), (68.69 nm +/- 2.08) and (77.85 nm +/- 1.69) for QDs-MPA, QD-GA2 and QD-GA12 respectively. Cytotoxicity studies of these QDs were carried out using WST-1 cell proliferation assay on four different tumour cell line. The results showed that these cells were over 50 per cent viable and the QDs-GA capped had higher cell percentage viability.