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Silver nanoparticles (Ag NPs) were widely explored for antimicrobial applications, whereas the translation into drugs and implantable antibacterial devices provoked serious concerns about their potential cytotoxicity. Herein, Ag NPs with diameters ranging from 4 to 19 nm were in situ fabricated and immobilized on titanium by using a plasma immersion ion implantation process. The particles have a population-dependent capability in activating the integrin α5 orchestrated MAPK/ERK signal cascade of osteoblast differentiation in rat bone marrow stem cells (BMSCs), and promoting osteointegration of titanium. It was demonstrated that the titanium-supported Ag NPs played an important role in motivating integrin α5 through triggering the galvanic hydrogen evolution reactions, which was found in positive correlation with the distribution density of the immobilized Ag NPs. Since cellular uptake is a key factor determining the cytotoxic performance of Ag NPs, the extracellular effects of immobilized Ag NPs on promoting osteogenesis provided new insights into the safe application of nanomaterials, and into designing and developing renewed antibacterial devices with selective toxicity.

Excessive perfluorooctane sulfonate (PFOS) in natural water ecosystem has the potential to detrimentally affect immune system, but little is known of such effects or underlying mechanisms in fish. In the present study, we evaluated the effects of PFOS on growth performance, organizational microstructure, activities of immune-related enzymes and expressions of immune-related genes in male zebrafish (Danio rerio) exposed to different concentrations of 0, 0.02, 0.04 and 0.08 mg/L of PFOS for 7, 14, and 21 days or cotreatment with PFOS and PDTC to investigate the effects of PFOS on immune system and the potential toxic mechanisms caused by PFOS. The results indicated that PFOS accumulated in livers after exposure, and remarkably elevations were found in three exposure groups compared with the control group at three stages. The growth of the adult zebrafish in the experiments was significantly inhibited, the microstructures of liver were serious damaged. The ROS levels were remarkably increased. The activities of ACP, AKP, and lysozyme were obviously decreased, while the activities of MPO and NF-κB were significantly increased. The expressions of immune-related mRNA were significantly affected. After co-treatment with PFOS and PDTC, the growth inhibition, the morphological damage, the ROS induction, and the expressions of immune-related mRNA were reversed. Taken together, the results indicated that PFOS can significantly inhibit the growth, disturb the immune system by changing the normal structure of liver, the activities of immune-related enzymes, and a series of gene transcriptions involved in immune regulation in liver of male zebrafish. PFOS-induced pro-inflammatory effect of hepatocytes was observed, and the involvement of NF-κB signaling pathway was participated in its action mechanism. These findings provide further evidence that PFOS interferes with the immune regulation of liver of male zebrafish under in vivo conditions.

Al + Fe2O3 + BaO2 and NaNO3 as the reactive system and the foaming agent, respectively, are used to prepare barium ferrite hollow microspheres (BFHMs) by self-reactive quenching technology based on flame spraying technology, self-propagating high-temperature synthesis (SHS) technology and quick chilling technology. Effects of NaNO3 on the particle size, morphology, phase structure and microwave absorption properties of BFHMs are investigated through SEM, XRD, particle size analyzer, high-speed camera and vector network analyzer. The results show that, after adding 10 wt.% NaNO3, the average particle size of BFHMs decreases initially from 28 μm to 6 μm, as well as the particle distribution gets narrower. Micro-nano lamellar crystals appear on the surface of BFHMs, with the dimension ranging from 500 nm to 2 μm. BaFe2O4 and Fe3O4, which have spinel structures, can be seen in XRD, and they are beneficial for microwave absorption properties. The real part (ɛ′), imaginary part (ɛ″) of permittivity, and the imaginary part of permeability (μ″) increases in 0.5–18 GHz. The real part (μ′) of permeability increases in 0.5–10.3 GHz, while decreases in 10.3–18 GHz. The microwave absorption properties are improved greatly, and the minimum reflectivity decreases from −3.1 dB to −9.8 dB. The reasons for improvement of microwave absorption properties after adding NaNO3 foaming agent may be the decreasing of the particle size of BFHMs, the appearance of ferrites (BaFe2O4 and Fe3O4) with spinel structure and special micro-nano tabular crystals. Magnetoplumbite-type barium ferrites (BaFe12O19) hollow microspheres are obtained after heat-treatment and the microwave absorption properties are further improved.