A Multifunctional Mesoporous Silica-Coated UCNP/Au Nanoplatform for Near-Infrared Light-Triggered Photothermal Conversion/Photoluminescence and Drug Delivery

The combination of near-infrared (NIR) light-triggered photoluminescence, photothermal conversion, and drug delivery in a single multifunctional nanoplatform has attracted a great deal of attention. In this work, a novel multifunctional nanoplatform (UCNP/Au@SiO2 NPs) was developed to construct a multifunctional drug nanocarrier by incorporating Au-doped upconversion nanoparticles (UCNP/Au NPs) and mesoporous SiO2. In our design, UCNP/Au NPs can provide dual photoluminescence and photothermal conversion. After that, the prepared UCNP/Au NPs were further coated with a mesoporous SiO2 shell. The UCNP/Au@SiO2 NPs were investigated by using different characterization methods. As a multifunctional nanoplatform, the photothermal conversion and photoluminescence properties were evaluated in detail. The results showed that UCNP/Au@SiO2 NPs had good photothermal conversion ability in both the NIR-I and NIR-II regions. Additionally, UCNP/Au@SiO2 NPs showed an effective photoluminescence performance under 808 nm laser excitation. Benefiting from mesoporous SiO2, the UCNP/Au@SiO2 NPs proved to be an effective nanocarrier for drug loading and controlled release. Overall, this study described a novel NIR light-triggered nanoplatform for intelligent photoluminescence, photothermal conversion, drug delivery, etc.