CuFeS2chalcopyrite nanoparticles (NPs) can
generate
heat under exposure to near-infrared laser irradiation. Here, we develop
a protocol to decorate the surface of CuFeS2NPs (13 nm)
with a thermoresponsive (TR) polymer based on poly(ethylene glycol
methacrylate) to combine heat-mediated drug delivery and photothermal
heat damage. The resulting TR-CuFeS2NPs feature a small
hydrodynamic size (∼75 nm), along with high colloidal stability
and a TR transition temperature of 41 °C in physiological conditions.
Remarkably, TR-CuFeS2NPs, when exposed to a laser beam
(in the range of 0.5 and 1.5 W/cm2) at NP concentrations
as low as 40–50 μg Cu/mL, exhibit a high heating performance
with a rise in the solution temperature to hyperthermia therapeutic
values (42–45 °C). Furthermore, TR-CuFeS2NPs
worked as nanocarriers, being able to load an appreciable amount of
doxorubicin (90 μg DOXO/mg Cu), a chemotherapeutic agent whose
release could then be triggered by exposing the NPs to a laser beam
(through which a hyperthermia temperature above 42 °C could be
reached). In anin vitrostudy performed on U87 human
glioblastoma cells, bare TR-CuFeS2NPs were proven to be
nontoxic at a Cu concentration up to 40 μg/mL, while at the
same low dose, the drug-loaded TR-CuFeS2-DOXO NPs displayed
synergistic cytotoxic effects due to the combination of direct heat
damage and DOXO chemotherapy, under photo-irradiation by a 808 nm
laser (1.2 W/cm2). Finally, under a 808 nm laser, the TR-CuFeS2NPs generated a tunable amount of reactive oxygen species
depending on the applied power density and NP concentration.