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Abstract: Flower-like SnO2 porous microspheres self-assembled by hollow nanospheres have been successfully synthesized via a sucrose-assisted solvothermal method. The morphology, structure and composition of the as-prepared product have been characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED) and X-ray diffraction (XRD). The results show that the microspheres are self-assembled completely by well-defined SnO2 hollow nanospheres with porous wall composed of single crystalline nanoparticles. A growth mechanism has been proposed to explain the growth processes for such novel structures. First ever study on hydrogen absorption characteristics of the flower-like SnO2 microspheres performed at 373K shows a good absorption capacity of 0.92wt%. [Copyright &y& Elsevier]

The combination of photodynamic therapy (PDT) and photothermal therapy (PTT) has emerged as a promising strategy for complete tumor ablation therapy. Herein, a boron dipyrromethene (BODIPY)-conjugated hyaluronic acid polymer that can self-assemble to form the nanoparticles (BODIPY-HA NPs) was prepared for combined cancer PDT and PTT. The fluorescence emission and reactive oxygen species (ROS) generation of BODIPY-HA NPs were inhibited because of the π-π stacking behavior of BODIPY, resulting in photothermal effect under 808 nm light irradiation. Upon the internalization by cancer cells, the BODIPY-HA NPs could disassemble into BODIPY-HA molecules, with the recovery of the fluorescence and ROS generation for PDT. Importantly, in vitro results confirmed that combined PTT and PDT have exhibited better anticancer effect than PTT alone upon 808 nm laser irradiation. These results showed that the self-assembled BODIPY-HA NPs may be a promising nanomedicine for synergistic cancer PDT and PTT.

In this study, we recruited chitosan (CS) both for selenium nanoparticles (SeNPs) synthesis and for the development of a thermoresponsive nanocomposite hydrogel with the addition of glycerol phosphate (GP). Considering that SeNPs are toxic at high concentrations, five different ingredients of the nanocomposite hydrogel system with low concentrations of SeNPs (1.25-20 μg/mL) were prepared. The gelation conditions, structural characteristics, and mechanical properties of SeNPs-loaded thermosensitive CS/GP hydrogels were investigated. We also evaluated their antioxidizing activities and biocompatibility of the CS/GP/SeNPs hydrogels. Our study demonstrated that the incorporation of SeNPs in the hydrogel improved its mechanical properties, antioxidant activity, and degree of swelling. According to the properties of SeNPs and CS/GP thermosensitive hydrogels, the combination of these two technologies in an appropriate manner would be a promising antioxidant system for drug delivery and tissue engineering.

Unlike stable atherosclerotic plaques, vulnerable plaques are very likely to cause serious cardio-cerebrovascular diseases. Meanwhile, how to non-invasively identify vulnerable plaques at early stages has been an urgent but challenging problem in clinical practices. Here, we propose a macrophage-targeted and in situ stimuli-triggered T 1 -T 2 switchable magnetic resonance imaging (MRI) nanoprobe for the non-invasive diagnosis of vulnerable plaques. Precisely, single-dispersed iron oxide nanoparticles (IONPs) modified with hyaluronic acid (HA), denoted as IONP-HP, show macrophage targetability and T 1 MRI enhancement (r 2 /r 1 = 3.415). Triggered by the low pH environment of macrophage lysosomes, the single-dispersed IONP-HP transforms into a cluster analogue, which exhibits T 2 MRI enhancement (r 2 /r 1 = 13.326). Furthermore, an in vivo switch of T 1 -T 2 enhancement modes shows that the vulnerable plaques exhibit strong T 1 enhancement after intravenous administration of the nanoprobe, followed by a switch to T 2 enhancement after 9 h. In contrast, stable plaques show only slight T 1 enhancement but without T 2 enhancement. It is therefore imperative that the intelligent and novel nanoplatform proposed in this study achieves a substantial non-invasive diagnosis of vulnerable plaques by means of a facile but effective T 1 -T 2 switchable process, which will significantly contribute to the application of materials science in solving clinical problems.