Switchable up-conversion luminescence bioimaging and targeted photothermal ablation in one core-shell-structured nanohybrid by alternating near-infrared light.

In photothermal therapy (PTT), simultaneous achievement of imaging and hyperthermia mediated by a single laser inevitably risks damaging normal tissues before treatment. Herein, a core-shell-structured GdOF:Yb/Er@(GNRs@BSA) nanohybrid was designed and fabricated by conjugating gold nanorods (GNRs) on the surfaces of GdOF:Yb/Er nanoparticles by a facile procedure. By alternating near-infrared (NIR) light appropriately, high photothermal efficiency for PTT and good up-conversion luminescence (UCL) imaging can be achieved in this structure, which can substantially solve the heat-induced risk during the theranostic process. Furthermore, good biocompatibility and phagocytosis can be realized by modifying bovine serum albumin (BSA) on the surface of the GNRs, and the conjugation of folic acid (FA) endows this nanohybrid with targeting function. It is noted that the size of the GNRs prepared by the one-pot method is much smaller than that by the seed-mediated method, which is not only conducive to uniform heat distribution during intratumoral therapy, but also contributes to the nanohybrid metabolic decomposition and fluorescence tracing after treatment. Moreover, this product can also be utilized as a good magnetic resonance imaging (MRI) and computed tomography (CT) contrast agent, which can provide versatile imaging properties in the field of cancer clinical treatment.

Multifunctional Theranostic Nanoplatform Based on Fe-mTa2O5@CuS-ZnPc/PCM for Bimodal Imaging and Synergistically Enhanced Phototherapy.

Multifunctional nanotheranostic agent with high performance for tumor site-specific generation of singlet oxygen (1O2) as well as imaging-guidance is crucial to laser-mediated photodynamic therapy. Here, we introduced a versatile strategy to design a smart nanoplatform using phase change material (PCM) to encapsulate photosensitizer (zinc phthalocyanine, ZnPc) in copper sulfide loaded Fe-doped tantalum oxide (Fe-mTa2O5@CuS) nanoparticles. When irradiated by 808 nm laser, the PCM is melted due to the hyperthermia effect from CuS nanoparticles, inducing the release of ZnPc to produce toxic 1O2 triggered by 650 nm light with very low power density (5 mW/cm2). Then, the produced heat and toxic 1O2 can kill tumor cells in vitro and in vivo effectively. Furthermore, the special properties of Fe-mTa2O5 endow the nanoplatform with excellent computed tomography (CT) and T1-weighted magnetic resonance imaging ( T1-MRI) performance for guiding and real-time monitoring of therapeutic effect. This work presents a feasible way to design smart nanoplatform for controllable generation of heat and 1O2, achieving CT/ T1-MRI dual-modal imaging-guided phototherapy.

Polypyrrole-coated UCNPs@mSiO2@ZnO nanocomposite for combined photodynamic and photothermal therapy.

Designing multifunctional nanoplatforms for the purpose of simultaneous theranostic modalities is critical to address the challenges of cancer therapy. Also, single modalities of phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT), cannot meet the requirements of highly efficient treatment. Here, a core-shell-shell nanostructure consisting of a core of upconversion nanoparticles (UCNPs), a layer of mesoporous silica with anchored ZnO nanodots, and an outer layer of polypyrrole (PPy) was developed. In the proposed construct, the emitted ultraviolet (UV) light from the UCNPs core upon 980 nm near-infrared light irradiation can trigger the ZnO nanodots to activate ambient O2 molecules around cancerous tissues to produce toxic reactive oxygen species (ROS), realizing the PDT function. On the other hand, the coated PPy layer can concurrently give rise to an obvious heat effect upon NIR light illumination, thus achieving synergistic PDT and PTT effects; this results in excellent anti-tumor efficiency in vitro and in vivo. Furthermore, in hand with the upconversion luminescence (UCL) and computed tomography (CT) imaging derived from the UCNPs core, dual-mode imaging directed cancer therapy has been realized.