Green Synthesis of Indole-pyrazole-capped Cadmium Sulphide Quantum Dots and Evaluation of Their Cytotoxicity Activity and Protein Interaction

Abstract

Plant extracts play an essential role in bioreducing metal ions and capping the resultant nanomaterials. We report the green synthesis of indole pyrazole-capped cadmium sulfide quantum dots (TRPIDC-CH 3 CdSQDs) using Moringa oleifera leaf extract and indole pyrazole ligand. Morphological analysis using a high-resolution electron microscope indicated the presence of spherical particles with an average diameter of 4.5 nm. The ultraviolet-visible (UV-Vis) spectroscopy results exhibited a bandgap energy of 2.95 eV, and phytochemical deposition on the TRPIDC-CH 3 CdSQDs was confirmed by Fourier transform infrared (FTIR). The cytotoxicity analysis was conducted using the 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay on two cancer ((breast (MCF-7) and lung (A549)) cells and a normal human embryonic kidney (HEK293) cell. Low cytotoxic activity was found for TRPIDC-CH 3 CdSQDs against all three cell types, the highest activity percentage being 63.80% against MCF-7 and TRPIDC-CH 3 CdSQDs show a dose-dependent increase in cytotoxic activity. Spectroscopic interaction studies were undertaken with human serum albumin using UV-Vis and fluorescence spectroscopy. The interactions between TRPIDC-CH 3 CdSQDs and human serum albumin were hydrophobic. Using corrected fluorescence data, the Stern-Volmer constant and binding constant were 2.06 × 10 3 and 2.85 × 10 3 mol•L −1 , respectively. The findings indicate its potential to be used in drug delivery.