Fe3O4磁性纳米颗粒的合成与接枝聚合修饰（英文）

以氨水作为沉淀剂并控制溶液的pH值,采用Fe3+和Fe2+共沉淀法制得了磁性四氧化三铁纳米颗粒。合成的磁性纳米颗粒通过高分辨透射电镜、X射线衍射仪、傅里叶变换红外光谱仪进行了表征。四氧化三铁纳米颗粒的粒径约为10nm,其表面含有丰富的羟基。为了增强磁性四氧化三铁纳米颗粒和聚合物基质之间的相互作用,在纳米颗粒的表面接枝上乙烯基单体。傅里叶变换红外光谱仪和热重分析仪的测试结果显示,聚合物链共价结合在纳米颗粒表面。表面接枝聚合后,四氧化三铁纳米颗粒由极性转变为非极性。     

A Surface‐Charge Study on Cellular‐Uptake Behavior of F3‐Peptide‐Conjugated Iron Oxide Nanoparticles

Surface‐charge measurements of mammalian cells in terms of Zeta potential are demonstrated as a useful biological characteristic in identifying cellular interactions with specific nanomaterials. A theoretical model of the changes in Zeta potential of cells after incubation with nanoparticles is established to predict the possible patterns of Zeta‐potential change to reveal the binding and internalization effects. The experimental results show a distinct pattern of Zeta‐potential change that allows the discrimination of human normal breast epithelial cells (MCF‐10A) from human cancer breast epithelial cells (MCF‐7) when the cells are incubated with dextran coated iron oxide nanoparticles that contain tumor‐homing F3 peptides, where the tumor‐homing F3 peptide specifically bound to nucleolin receptors that are overexpressed in cancer breast cells.     

Fluorescent Magnetic Fe3O4/Rare Earth Colloidal Nanoparticles for Dual‐Modality Imaging

Fluorescent magnetic colloidal nanoparticles (FMCNPs) are produced by a two‐step, seed emulsifier‐free emulsion polymerization in the presence of oleic acid and sodium undecylenate‐modified Fe₃O₄ nanoparticles (NPs). The Fe₃O₄/poly(St‐co‐GMA) nanoparticles are first synthesized as the seed and Eu(AA)₃Phen is copolymerized with the remaining St and GMA to form the fluorescent polymer shell in the second step. The uniform core–shell structured FMCNPs with a mean diameter of 120 nm exhibit superparamagnetism with saturation magnetization of 1.92 emu/g. Red luminescence from the FMCNPs is confirmed by the salient fluorescence emission peaks of europium ions at 594 and 619 nm as well as 2‐photon confocal scanning laser microscopy. The in vitro cytotoxicity test conducted using the MTT assay shows good cytocompatibility and the T₂ relaxivity of the FMCNPs is 353.86 mM^?1S^?1 suggesting its potential in magnetic resonance imaging (MRI). In vivo MRI studies based on a rat model show significantly enhanced T₂‐weighted images of the liver after administration and prussian blue staining of the liver tissue slice reveals accumulation of FMCNPs in the organ. The cytocompatibility, superparamagnetism, and excellent fluorescent properties of FMCNPs make them suitable for biological imaging probes in MRI and optical imaging.     

Bifunctional Graphene/γ‐Fe2O3 Hybrid Aerogels with Double Nanocrystalline Networks for Enzyme Immobilization

Highly porous hosting materials with conducting (favorable to electron transfer) and magnetic (favorable to product separation) bicontinuous networks should possess great potentials for immobilization of various enzymes in the field of biocatalytic engineering, but the synthesis of such materials is still a great challenge. Herein, bifunctional graphene/γ‐Fe₂O₃ hybrid aerogels with quite low density (30–65 mg cm^?3), large specific surface area (270–414 m² g^?1), high electrical conductivity (0.5–5 × 10^?2 S m^?1), and superior saturation magnetization (23–54 emu g^?1) are fabricated. Single networks of either graphene aerogels or γ‐Fe₂O₃ aerogels are obtained by etching of the hybrid aerogels with acid solution or calcining of the hybrid aerogels in air, indicative of the double networks of the as‐synthesized graphene/γ‐Fe₂O₃ hybrid aerogels for the first time. The resulting bifunctional aerogels are used to immobilize β‐glucuronidase for biocatalytic transformation of glycyrrhizin into glycyrrhetinic acid monoglucuronide or glycyrrhetinic acid, with high biocatalytic activity and definite repeatability.     

ZnO/Al_2O_3复合纳米颗粒的制备与表征

为研究ZnO/Al2O3复合纳米颗粒在涂料、化妆品等领域的应用,采用直接沉淀法制备了纳米ZnO,用硫酸铝水解生成的Al2O3对纳米ZnO进行了表面改性。采用IR、TEM、SEM、XRD等手段对改性前后的粉体进行表征。分析结果表明,改性后粉体颗粒的团聚现象减轻。粉体的光催化降解甲基橙的实验研究表明,改性后ZnO粉体的光催化活性明显下降,进一步证明纳米ZnO颗粒表面存在Al2O3的包覆层。     

Fluorescent Nanoparticles Based on Self‐Assembled π‐Conjugated Systems

π‐Conjugated molecules are interesting components to prepare fluorescent nanoparticles. From the use of polymer chains that form small aggregates in water to the self‐assembly of small chromophoric segments into highly ordered structures, the preparation of these materials allows to develop systems with applications as sensors or biolabels. The potential functionalization of the nanoparticles can lead to specific probing. This progress report describes the recent advances in the preparation of such emittive organic nanoparticles.     

Synthesis and Magnetic Properties of Fe3O4 Nanoparticles

Magnetic Fe₃O₄ nanoparticles with size below 10 nm have been prepared by the aqueous phase coprecipitation method. The Fe₃O₄ nanoparticles show typical superparamagnetism. Comparison is made between the dispersed sample and the powder sample, and the results are discussed.     

Gold Nanoparticles Downregulate Interleukin‐1β‐Induced Pro‐Inflammatory Responses

Interleukin 1 beta (IL‐1β)‐dependent inflammatory disorders, such as rheumatoid arthritis and psoriasis, pose a serious medical burden worldwide, where patients face a lifetime of illness and treatment. Organogold compounds have been used since the 1930s to treat rheumatic and other IL‐1β‐dependent diseases and, though their mechanisms of action are still unclear, there is evidence that gold interferes with the transmission of inflammatory signalling. Here we show for the first time that citrate‐stabilized gold nanoparticles, in a size dependent manner, specifically downregulate cellular responses induced by IL‐1β both in vitro and in vivo. Our results indicate that the anti‐inflammatory activity of gold nanoparticles is associated with an extracellular interaction with IL‐1β, thus opening potentially novel options for further therapeutic applications.     

EPR and Magnetic Susceptibility Investigation of Fe Ions in B2O3—SrF2 Glass Matrix

The structural and magnetic properties of an oxide-fluoride mixed vitreous matrix 2B2O3-SrF2, were explored by using Fe impurities as probes.Information about the structural units involving iron ions,their valence state,the strengths and type of interactions involving them was obtained using EPR spectroscopy and magnetic susceptibility measurements.