ABSTRACT :
Photothermal therapy is based on producing localized enhancement of the temperature in the tumor area
after laser irradiation, with the consequent death of cancer cells. The near-infrared (NIR) light used in this
therapy shows high penetration depth in the biological tissues, less toxicity in normal cells and tissues and a
low dose of light irradiation.
Here, we design and synthesize modified nanoparticles with the ability to produce photo-hyperthermia
upon laser illumination for their application in head and neck cancer (HNC) since conventional treatments
show problems related with poor detection or surgical complexity among others. For this purpose, gold
nanoparticles, specifically nanorods (AuNRs), have been used, which after being irradiated with NIR light,
are able to induce an increase in temperature due to their aspect ratio and optical properties. AuNRs have
been synthesized and coated with silica (SiO2) in order to study their photothermic properties.
In addition, it is crucial to determine and locally control the temperature of the nanomaterials in order to
relate it with the destruction of tumor cells. Taking this into account, Y2O3·2% Er3+ particles were attached
to the AuNRs to use them as optical nanothermometers due to the fluorescence intensity ratio in the visible
spectral range. All these nanomaterials were studied in vitro, in HNC cells with and without laser irradiation.
Furthermore, AuNRs@SiO2 covered with Y2O3·2% Er3+ modify the intensity of its emission bands depending
on the temperature, so we determine in situ and non-invasively the temperature reached by the NPs inside
the cells after irradiation.
