Photothermal ablation (PTA) therapy has a great potential to revolutionize conventional therapeutic approaches for cancers, but it has been limited by difficulties in obtaining biocompatible photothermal agents that have low cost, small size (<100 nm), and high photothermal conversion efficiency. Herein, we have developed hydrophilic plate-like Cu(9)S(5) nanocrystals (NCs, a mean size of ∼70 nm × 13 nm) as a new photothermal agent, which are synthesized by combining a thermal decomposition and ligand exchange route. The aqueous dispersion of as-synthesized Cu(9)S(5) NCs exhibits an enhanced absorption (e.g., ∼1.2 × 10(9) M(-1) cm(-1) at 980 nm) with the increase of wavelength in near-infrared (NIR) region, which should be attributed to localized surface plasmon resonances (SPR) arising from p-type carriers. The exposure of the aqueous dispersion of Cu(9)S(5) NCs (40 ppm) to 980 nm laser with a power density of 0.51 W/cm(2) can elevate its temperature by 15.1 °C in 7 min; a 980 nm laser heat conversion efficiency reaches as high as 25.7%, which is higher than that of the as-synthesized Au nanorods (23.7% from 980 nm laser) and the recently reported Cu(2-x)Se NCs (22% from 808 nm laser). Importantly, under the irradiation of 980 nm laser with the conservative and safe power density over a short period (∼10 min), cancer cells in vivo can be efficiently killed by the photothermal effects of the Cu(9)S(5) NCs. The present finding demonstrates the promising application of the Cu(9)S(5) NCs as an ideal photothermal agent in the PTA of in vivo tumor tissues.

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Photothermal nanomaterials have recently attracted significant research interest due to their potential applications in biological imaging and therapeutics. However, the development of small-sized photothermal nanomaterials with high thermal stability remains a formidable challenge. Here, we report the rational design and synthesis of ultrasmall (<10 nm) Fe3O4@Cu2-xS core-shell nanoparticles, which offer both high photothermal stability and superparamagnetic properties. Specifically, these core-shell nanoparticles have proven effective as probes for T2-weighted magnetic resonance imaging and infrared thermal imaging because of their strong absorption at the near-infrared region centered around 960 nm. Importantly, the photothermal effect of the nanoparticles can be precisely controlled by varying the Cu content in the core-shell structure. Furthermore, we demonstrate in vitro and in vivo photothermal ablation of cancer cells using these multifunctional nanoparticles. The results should provide improved understanding of synergistic effect resulting from the integration of magnetism with photothermal phenomenon, important for developing multimode nanoparticle probes for biomedical applications.

Fluorescence targeted imaging in vivo has proven useful in tumor recognition and drug delivery. In the process of in vivo imaging, however, a high autofluorescence background could mask the signals from the fluorescent probes. Herein, a high contrast upconversion luminescence (UCL) imaging protocol was developed for targeted imaging of tumors based on RGD-labeled upconversion nanophosphors (UCNPs) as luminescent labels. Confocal Z-scan imaging of tissue slices revealed that UCL imaging showed no autofluorescence signal even at high penetration depth (approximately 600 microm). More importantly, region of interest (ROI) analysis of the UCL signal in vivo showed that UCL imaging achieved a high signal-to-noise ratio (approximately 24) between the tumor and the background. These results demonstrate that the UCL imaging technique appears particularly suited for applications in tracking and labeling components of complex biological systems.

The synthesis of hollow opening polyhedral cages has always been an attractive but challenging goal, especially with regard to inorganic polyhedral cages. Herein, we present a novel, 240-nuclearity giant polymolybdate cage prepared via hydrothermal synthesis. This cage is composed of 20 tripod-shaped [Mo6O22(SO3)] n−/[Mo6O21(SO4)] n− building blocks with three connected vertices and 30 cubane-type [Mo4O16] n− edge building blocks, featuring a rare, nearly regular pentagonal dodecahedron with a large inner cavity (diameter up to 1.8 nm) and 12 opening pentagonal windows. This is the highest nuclearity hollow opening dodecahedral cage reported to date. Importantly, this cage exhibits good stability in solution, as revealed by scanning transmission electron microscopy (STEM), TEM, UV–vis, and Raman spectra. In addition, the bulk sample of this compound exhibits an ultrahigh proton conductivity of 1.03 × 10–1 S cm–1 at 80 °C and 98% relative humidity, which is the highest among polyoxometalate-based crystalline proton conductors.