Synthesis, Characterization, and Application in HeLa Cells of an NIR Light Responsive Doxorubicin Delivery System Based on NaYF₄:Yb,Tm@SiO₂‑PEG Nanoparticles

Herein, we present a phototriggered drug delivery system based on light responsive nanoparticles, which is able to release doxorubicin upon NIR light illumination. The proposed system is based on upconversion fluorescence nanoparticles of β-NaYF₄:Yb,Tm@SiO₂-PEG with a mean diameter of 52 ± 2.5 nm that absorb the NIR light and emit UV light. The UV radiation causes the degradation of photodegradable <i>ortho</i>-nitrobenzyl alcohol derivates, which are attached on one side to the surface of the nanoparticles and on the other to doxorubicin. This degradation triggers the doxorubicin release. This drug delivery system has been tested “<i>in vitro</i>” with HeLa cells. The results of this study demonstrated that this system caused negligible cytotoxicity when they were not illuminated with NIR light. In contrast, under NIR light illumination, the HeLa cell viability was conspicuously reduced. These results demonstrated the suitability of the proposed system to control the release of doxorubicin via an external NIR light stimulus