Gold nanoparticles on chitosan functionalized graphene oxide: Catalytic reduction of nitroarenes and anti-bladder carcinoma activity

This work describes a simple and environmentally friendly process for creating a graphene-chitosan/gold (GO-CS/Au) nanocomposite. This green synthesis method includes the reduction of gold ions onto graphene oxide that had previously been functionalized with chitosan, using pomegranate juice as a bio-reductant and capping agent. The pomegranate juice’s natural polyphenolic components helped to stabilize and reduce gold nanoparticles (AuNPs) on the GO-CS surface. To verify the GO-CS/Au nanocomposite’s successful synthesis and structure, a wide range of analytical methods were used. These techniques included X-ray diffraction (XRD), transmission electron microscopy (TEM), inductively coupled plasma (ICP) analysis, energy-dispersive X-ray spectroscopy (EDX) with elemental mapping, and field-emission scanning electron microscopy (FE-SEM). GO-CS/Au nanocomposite was subsequently assessed
in vitro
for biological applications. Using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, its potential as an anti-cancer drug was evaluated against two bladder cancer cell lines, 5637 and transitional cell carcinoma, SUPINSKI (TCCSUP). The nanocomposite reduced cell viability in a dose-dependent manner; it’s computed IC
50
values were 458 and 648 µg mL
-1
, respectively. The antioxidant capacity of the GO-CS/Au nanocomposite was also investigated via the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, which revealed a notable antioxidant activity with an IC
50
value of 98 µg mL
-1
. Furthermore, chemical catalysis of the material was explored in the reduction of different nitroarenes with sodium borohydride, being monitored over UV-Vis. The material demonstrated excellent reusability, holding onto roughly 85% of its conversion efficiency after seven runs.