The high near infrared (NIR) absorption displayed by reduced
graphene oxide (rGO) nanostructures renders them a great potential for application in
cancer photothermal therapy. However, the production of this material often relies on the use of
hydrazine as a
reductant, leading to poor biocompatibility and environmental-related issues. In addition, to improve rGO colloidal stability, this material has been functionalized with poly(
ethylene glycol). However, recent studies have reported the immunogenicity of poly(
ethylene glycol)-based coatings. In this work, the production of rGO, by using
dopamine as the
reducing agent, was optimized considering the size distribution and NIR absorption of the attained materials. The obtained results unveiled that the rGO produced by using a 1:5
graphene oxide:
dopamine weight ratio and a reaction time of 4 h (termed as
DOPA-rGO) displayed the highest NIR absorption while retaining its nanometric size distribution. Subsequently, the
DOPA-rGO was functionalized with
thiol-terminated
poly(2-ethyl-2-oxazoline) (P-
DOPA-rGO), revealing suitable physicochemical features, colloidal stability and cytocompatibility. When irradiated with NIR light, the P-
DOPA-rGO could produce a temperature increase (ΔT) of 36 °C (75 μg/mL; 808 nm, 1.7 W/cm2, 5 min). The
photothermal therapy mediated by P-
DOPA-rGO was capable of ablating
breast cancer cells monolayers (viability < 3%) and could reduce heterotypic
breast cancer spheroids' viability to just 30%. Overall, P-
DOPA-rGO holds a great potential for application in
breast cancer photothermal therapy.