CuS NP-based nanocomposite with photothermal and augmented-photodynamic activity for magnetic resonance...

Although many treatments have been developed for oncotherapy, the lack of effective imaging guidance in the therapeutic process is still an urgent problem to be solved. In this study, magnetic resonance contrast agent (Gd) chelated on CuS nanoparticles and glucose oxidase (GOx) were coloaded into mesoporous silica nanoparticles (MSNs) to form GOx-Gd-CuS@MSNs, in which the Gd provided magnetic resonance imaging (MRI) for therapeutic process monitor while GOx could catalyze the generation of H₂O₂ to enhance the photodynamic therapy (PDT). The in vitro results show that under near-infrared (NIR) laser irradiation (2 W·cm^-2, 5 min), temperature rapidly increased by approximately 30 °C for the accumulation of heat. At the same time, GOx on GOx-Gd-CuS@MSNs effectively consumed glucose to produce a large amount of H₂O₂, which was used to augment PDT through producing highly toxic hydroxyl radicals (·OH) and singlet oxygen (¹O₂). The photothermal and augmented-photodynamic could induce apoptosis and death of tumor cells. More importantly, the study found that GOx-Gd-CuS@MSNs had MRI performance, which provided imaging guidance during the treatment process, and it can monitor the diffusion of water molecules in the tumor tissue during the treatment and microcirculation perfusion of capillary network. These results indicate that the nanomaterial produced significant synergistic therapeutic effects through photothermal and photodynamic forces, meanwhile showed excellent spatial resolution and deep tissue penetration in imaging.