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

Abstract

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 appli- cations. 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 distribu- tions. 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 °C for two hours, and QDs-GA12 was stabilized and capped with GA for twelve hours at room temperature (25 °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.