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Facile preparation of multifunctional theranostic nanoplatforms with well-controlled morphology and sizes remains an attractive in the area of nanomedicine. Here, a new kind of 2D transition metal dichalcogenide, rhenium disulfide (ReS2) nanosheets, with uniform sizes, strong near-infrared (NIR) light, and strong X-ray attenuation, is successfully synthesized. After surface modification with poly(ethylene glycol) (PEG), the synthesized ReS2-PEG nanosheets are stable in various physiological solutions. In addition to their contrasts in photoacoustic imaging and X-ray computed tomography imaging because of their strong NIR light and X-ray absorptions, respectively, such ReS2-PEG nanosheets can also be tracked under nuclear imaging after chelator-free labeling with radioisotope ions, 99mTc4+. Efficient tumor accumulation of ReS2-PEG nanosheets is then observed after intravenous injection into tumor-bearing mice under triple-modal imaging. The combined in vivo photothermal radiotherapy is further conducted, achieving a remarkable synergistic tumor destruction effect. Finally, no obvious toxicity of ReS2-PEG nanosheets is observed from the treated mice within 30 d. This work suggests that such ultrathin ReS2 nanosheets with well-controlled morphology and uniform sizes may be a promising type of multifunctional theranostic agent for remotely triggered cancer combination therapy. [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]

Photothermal therapy (PTT), as a minimally invasive and highly effective cancer treatment approach, has received widespread attention in recent years. Tremendous effort has been devoted to explore various types of photothermal agents with high near-infrared (NIR) absorbance for PTT cancer treatment. Despite many exciting progresses in the area, effective yet safe photothermal agents with good biocompatibility and biodegradability are still highly desired. In this work, a new organic PTT agent based on polyethylene glycol (PEG) coated micelle nanoparticles encapsulating a heptamethine indocyanine dye IR825 is developed, showing a strong NIR absorption band and a rather low quantum yield, for in vivo photothermal treatment of cancer. It is found that the IR825-PEG nanoparticles show ultra-high in vivo tumor uptake after intravenous injection, and appear to be an excellent PTT agent for tumor ablation under a low-power laser irradiation, without rendering any appreciable toxicity to the treated animals. Compared with inorganic nanomaterials and conjugated polymers being explored in PTT, the NIR-absorbing micelle nanoparticles presented here may have the least safety concern while showing excellent treatment efficacy, and thus may be a new photothermal agent potentially useful in clinical applications. [ABSTRACT FROM AUTHOR]