All‐Optical Nanoscale Heating and Thermometry with Resonant Dielectric Nanoparticles for Controllable Drug Release in Living Cells

All‐dielectric nanophotonics becomes a versatile tool for various optical applications, including nanothermometry and optical heating. Its general concept includes excitation of Mie resonances in nonplasmonic nanoparticles. However, the potential of resonant dielectric nanoparticles in drug delivery applications still has not been fully realized. Here, optically resonant dielectric iron oxide nanoparticles (α‐Fe₂O₃ NPs) are employed for remote rupture of microcontainers used as a drug delivery platform. It is theoretically and experimentally demonstrated that α‐Fe₂O₃ NPs have several advantages in light‐to‐heat energy conversion comparing to previously used materials, such as noble metals and silicon, due to the broader spectral range of efficient optical heating, and in enhancement of thermally sensitive Raman signal. The α‐Fe₂O₃ NPs embedded into the wall of universal drug carriers, polymer capsules, are used to experimentally determine the local temperature of the capsule rupture upon laser irradiation (170 °C). As a proof of principle, the delivery and remote release of anticancer drug vincristine upon lowered laser irradiation (4.0× 10⁴ W cm⁻²) using polymer capsules modified with the α‐Fe₂O₃ NPs is shown. The biological tests are performed on two primary cell types: i) carcinoma cells, as an example of malignant tumor, and ii) human stem cells, as a model of healthy cells.