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Multifunctional biodegradable inorganic theranostic nano-agents are of great interest to the field of nanomedicine. Upon lipid modification, VS2 nanosheets could be converted into ultra-small VS2 nanodots encapsulated inside polyethylene glycol (PEG) modified lipid micelles. Owing to paramagnetism, high near-infrared (NIR) absorbance, and chelator-free 99mTc4+ labeling of VS2, such VS2@lipid-PEG nanoparticles could be used for T1-weighted magnetic resonance (MR), photoacoustic (PA),and single photon emission computed tomography (SPECT) tri-modal imaging guided photothermal ablation of tumors. Importantly, along with the gradual degradation of VS2, our VS2@lipid-PEG nanoparticles exhibit effective body excretion without appreciable toxicity. The unique advantages of VS2 nanostructures with highly integrated functionalities and biodegradable behaviors mean they are promising for applications in cancer theranostics. [ABSTRACT FROM AUTHOR]

Despite extensive use of radiotherapy in cancer treatment, there has been huge demand to improve its efficacy and accuracy in tumor destruction. To this end, nanoparticle-based radiosensitizers, particularly those with high-Z elements, have been explored to enhance radiotherapy. Meanwhile, imaging is an essential tool prior to the individual planning of precise radiotherapy. Here, hollow tantalum oxide (H-TaOx) nanoshells are prepared using a one-pot template-free method and then modified with polyethylene glycol (PEG), yielding H-TaOx-PEG nanoshells for imaging-guided synergistically enhanced radiotherapy. H-TaOx-PEG nanoshells show strong intrinsic binding with metal ions such as Fe3+ and 99mTc4+ upon simple mixing, enabling magnetic resonance imaging and single photon emission computed tomography imaging, respectively, which are able to track in vivo distribution of those nanoshells and locate the tumor. With mesoporous shells and large cavities, those H-TaOx-PEG nanoshells show efficient loading of 7-ethyl-10-hydroxycamptothecin (SN-38), a hydrophobic chemotherapeutic drug. By means of the radiosensitization effect of Ta to deposit X-ray energy inside tumors, as well as SN-38-induced cell cycle arrest into radiation-sensitive phases, H-TaOx-PEG@SN-38 can offer remarkable synergistic therapeutic outcome in the combined chemoradiotherapy. Without appreciable systemic toxicity, such hollow-TaOx nanostructure may therefore find promising applications in multimodal imaging and enhanced cancer radiotherapy. [ABSTRACT FROM AUTHOR]

Molybdenum oxide (MoOx) nanosheets with high near-infrared (NIR) absorbance and pH-dependent oxidative degradation properties were synthesized, functionalized with polyethylene glycol (PEG), and then used as a degradable photothermal agent and drug carrier. The nanosheets, which are relatively stable under acidic pH, could be degraded at physiological pH. Therefore, MoOx-PEG distributed in organs upon intravenous injection would be rapidly degraded and excreted without apparent in vivo toxicity. MoOx-PEG shows efficient accumulation in tumors, the acidic pH of which then leads to longer tumor retention of those nanosheets. Along with the capability of acting as a photothermal agent for effective tumor ablation, MoOx-PEG can load therapeutic molecules with high efficiencies. This concept of inorganic theranostic nanoagent should be relatively stable in tumors to allow imaging and treatment, while being readily degradable in normal organs to enable rapid excretion and avoid long-term retention/toxicity. [ABSTRACT FROM AUTHOR]

Theranostic agents with both imaging and therapeutic functions have attracted enormous interests in cancer diagnosis and treatment in recent years. In this work, we develop a novel theranostic agent based on Prussian blue nanocubes (PB NCs), a clinically approved agent with strong near-infrared (NIR) absorbance and intrinsic paramagnetic property, for in vivo bimodal imaging-guided photothermal therapy. After being coated with polyethylene glycol (PEG), the obtained PB-PEG NCs are highly stable in various physiological solutions. In vivo T 1 -weighted magnetic resonance (MR) and photoacoustic tomography (PAT) bimodal imaging uncover that PB-PEG NCs after intravenous (i.v.) injection show high uptake in the tumor. Utilizing the strong and super stable NIR absorbance of PB, in vivo cancer treatment is then conducted upon i.v. injection of PB-PEG NCs followed by NIR laser irradiation of the tumors, achieving excellent therapeutic efficacy in a mouse tumor model. Comprehensive blood tests and careful histological examinations reveal no apparent toxicity of PB-PEG NCs to mice at our tested dose, which is two-fold of the imaging/therapy dose, within two months. Our work highlights the great promise of Prussian blue with well engineered surface coating as a multifunctional nanoprobe for imaging-guided cancer therapy. [ABSTRACT FROM AUTHOR]