Magnetic Excitations in Silver Nanocrescents at Visible and Ultraviolet Frequencies

We study magnetic excitations at optical frequencies in disordered crescent-form split-ring resonators made of silver. The resonators that are less than 100 nm in diameter are fabricated on a 4 in. quartz wafer by using a simple, fast, and inexpensive fabrication technique. The measured transmission and polarization-rotation spectra of the resonators reveal the excitation of circulating electric currents that give rise to magnetic dipole moments in the structures at visible and ultraviolet light frequencies. These frequencies have higher values than the limiting magnetic-resonance frequency predicted by the conventional LC resonance model presumably due to the plasmonic nature of the excitations.     

Bioinspired Ultrastrong Nanocomposite Membranes for Salinity Gradient Energy Harvesting from Organic Solutions

Efforts to extract energy from waste organic solutions can not only support clean environments but also help to alleviate the energy crisis. Here, a bioinspired ultrastrong nanocomposite membrane is developed via the layer‐by‐layer method based on aramid nanofiber‐graphene oxide (AGO) with good mechanical properties for salinity gradient energy harvesting from organic solutions. Benefiting from the 1D and 2D network interlocking arrangement, the AGO membrane shows an unprecedented mechanical stress of 688 MPa and maintains its integrity after soaking in organic solvents for 24 h. Impressively, when LiCl is diluted in methanol, the AGO membrane device with a working area of 113 mm² produces a current and a measured power generation of 28 ± 11 µA and 3140 ± 960 nW (C_feed = 2 mol L^?1), respectively. Thus, the working area of the AGO membrane for salinity gradient energy harvesting and temperature‐related energy harvesting enables its use in practical applications. In addition, 14 cells with the methanol‐LiCl solution (C_feed = 1 mol L^?1) can produce a voltage up to 1.82 V to light a liquid crystal display. Therefore, this AGO nanocomposite membrane presents a promising avenue to harvest salinity gradient energy from organic solutions.     

硝酸铵水凝胶分子印迹聚合物的制备

目的:目前安全问题成为世界各国的首要问题,尤其是对炸药分子的检测。硝酸铵是硝铵炸药的主要成分。研究水凝胶分子印迹法对硝铵炸药分子的检测。方法:水凝胶分子印迹方法制备硝酸铵水凝胶分子印迹聚合物,运用静态结合实验对其结合率进行了测定。结果:聚合物对硝酸铵具有良好的识别和吸附性能。印迹聚合物的解离常数为4.08g/L,最大吸附量为3.51mg/g。结论:水凝胶分子印迹法可合成水溶性炸药分子印迹聚合物,并且识别及吸附性能良好。     

Preparation and characterisation of silicone-based coatings filled with carbon nanotubes and natural sepiolite and their application as marine fouling-release coatings

This article reports on the preparation and partial characterisation of silicone-based coatings filled with low levels of either synthetic multiwall carbon nanotubes (MWCNTs) or natural sepiolite (NS). The antifouling and fouling-release properties of these coatings were explored through laboratory assays involving representative soft-fouling (Ulva) and hard-fouling (Balanus) organisms. The bulk mechanical properties of the coatings appeared unchanged by the addition of low amounts of filler, in contrast to the surface properties, which were modified on exposure to water. The release of Ulva sporelings (young plants) was improved by the addition of low amounts of both NS and MWCNTs. The most profound effect recorded was the significant reduction of adhesion strength of adult barnacles growing on a silicone elastomer containing a small amount (0.05%) of MWCNTs. All the data indicate that independent of the bulk properties, the surface properties affect settlement, and more particularly, the fouling-release behaviour, of the filled materials.     

Enhanced tissue adhesiveness of injectable gelatin hydrogels through dual catalytic activity of horseradish peroxidase

Development of bioadhesives with tunable mechanical strength, high adhesiveness, biocompatibility, and injectability is greatly desirable in all surgeries to replace or complement the sutures and staples. Herein, the dual catalytic activity of horseradish peroxidase is exploited to in situ form the hydroxyphenyl propionic acid‐gelatin/thiolated gelatin (GH/GS) adhesive hydrogels including two alternative crosslinks (phenol‐phenol and disulfide bonds) with fast gelation (few seconds – several minutes) and improved physicochemical properties. Their elastic moduli increase from 6.7 to 10.3 kPa by adding GS polymer that leads to the better stability of GH/GS hydrogels than GH ones. GH/GS adhesive strength is respectively 6.5‐fold and 15.8‐fold higher than GH‐only and fibrin glue that is due to additional disulfide linkages between hydrogels and tissues. Moreover, in vitro cell study with human dermal fibroblast showed the cell‐compatibility of GH/GS hydrogels. Taken together, GH/GS hydrogels can be considered as promising potential adhesive materials for various biomedical applications.     

Graphene oxide-methylene blue nanocomposite in photodynamic therapy of human breast cancer

The interaction of methylene blue (MB) as a photosensitizer with graphene oxide nano-sheets (GO) was examined in aqueous solution using UV-vis spectrophotometric techniques. MB–GO composites were prepared by mixing the solutions of GO nano-sheets and methylene blue due to interacting of the cationic methylene blue photosensitizer via electrostatic and π–π stacking or hydrophobic cooperative interactions. The cell killing potential of nanocomposite was examined on the MDA-MB-231 breast cancer cells in the absence and presence of red LED irradiation. The results demonstrated that the MB-GO nanocomposite has good performance in photodynamic therapy (PDT) during red LED irradiation. The cytotoxicity of nanocomposite caused reducing cell viability up to 20%. These effects would be due to the nano size structure of composite that could lead to effective cellular penetration. Also the significant difference has seen in lower concentrations of MB and MB-GO nanocomposite. The results show more than 40% increases in cell killing potential in lower concentrations of nanocomposite by using 2.5 μg/mL of each compound. The ratio of GO/MB can affect the interaction and higher ratios of graphene oxide (GO/MB > 1) can induce dimerization of MB. In lower concentrations and ratios of (GO/MB < 1) the free MB concentration increases and the electron shuttling effect of GO in photo activity decreases – which could affect the photocatalytic yield in PDT. The cell viability measurements confirm these effects on cancer cell killing potential of nanocomposite. According to microscopic and PDT assay results, the nanocomposite distribution and diffusion in cells enhanced the photochemical reaction yield in photodynamic therapy of MDA-MB-231 breast cancer cell line.