Abstract: The graphene-based materials have been used
as a potential coating material for nanoparticles due to
their excellent passivation. Herein, we report for the first
time the colloidal stability, photothermal profile, thermal
stability, cytotoxicity, and photo-cytotoxicity of graphene
quantum dots (GQDs) coupled with the second infrared
window (NIR-II) absorbing gold nanorods (AuNRs/GQDs)
and compare it to graphene oxide (GO)-coated NIR-II
absorbing AuNRs (AuNRs/GO). The composites were achieved
by electrostatic interaction of the GO or GQDs with AuNRs.
The results revealed that (i) AuNRs/GQDs were more stable
in the aqueous phosphate buffer and cell culture media than
AuNRs/GO and AuNRs; (ii) GO enhanced the photothermal
efficiency of the AuNRs, whereas GQDs reduced it; (iii) GQDs
enhanced the photothermal stability of AuNRs than GO;
(iv) both AuNRs/GO and AuNRs/GQDs were biocompatible
with mouse colon carcinoma (C26) cell lines and malignant
fibrous histiocytoma‐like, expressing a fusion of the
luciferase and enhanced green fluorescent protein genes
(KM-Luc/GFP) cell lines; and (v) photo-cytotoxicity of
AuNRs/GO and AuNRs/GQDs conducted against C26 cell
lines showed significantly improved cell death compared
to laser irradiation alone; however, AuNRs/GO exhibited
high photo-toxicity than AuNRs/GQDs. This study shows
that AuNRs/GO and AuNRs/GQDs composites possess unique
properties to improve AuNRs and be utilised in photothermal
applications
