Quad-Model Imaging-Guided High-Efficiency Phototherapy Based on Upconversion Nanoparticles and ZnFe₂O₄ Integrated...

The strategy of diagnosis-to-therapy to realize the integration of imaging and high antitumor efficiency has become the most promising method. Light-induced therapeutic technologies have drawn considerable interest. However, the limited penetration depth of UV/vis excitation and relatively low efficiency are the main obstacles for its further clinic application. For this concern, we presented a facile method to anchor ultrasmall ZnFe₂O₄ nanoparticles and upconversion luminescence nanoparticles (UCNPs) on graphene oxide (GO) nanosheets (GO/ZnFe₂O₄/UCNPs, abbreviated as GZUC). To solve the penetration question, here we introduced Tm³⁺-doped UCNPs to convert the high-penetrated near-infrared (NIR) light into UV/vis photons to activate the photodynamic process. In this system, the dual phototherapy from GO and ZnFe₂O₄ has been realized upon NIR laser irradiation. Combined with the photodynamic therapy (PDT) based on Fenton reaction that ZnFe₂O₄ nanoparticles react with excessive H₂O₂ in tumor microenvironment to produce toxic hydroxyl radicals (·OH), an excellent anticancer efficiency has been achieved. Furthermore, 4-fold imaging including upconversion luminescence (UCL), computed tomography (CT), magnetic resonance imaging (MRI) and photoacoustic tomography (PAT) has been obtained due to its intrinsic properties, thereby successfully realizing diagnosis-monitored therapy. Our demonstration provided a feasible strategy to solve the main problems in current light-triggered theranostic.