• 【通过植物还原,一锅微波辅助绿色合成Fe2O3/Ag纳米复合材料: 作为阳光驱动的光催化剂,抗菌和抗癌剂的潜在应用。】 复制标题 收藏 收藏
    DOI:10.1016/j.jphotobiol.2020.111885 复制DOI
    作者列表:A S,Thamer A,K R,A P,V R,K M,Murad A,P M
    BACKGROUND & AIMS: :Herein, we report a one-pot microwave assisted method to prepare an efficient Fe2O3/Ag nanocomposites (NCs) using Aloe vera (A. vera) gel extract as a mild, safe, renewable and active stabilizer without any harmful reagent. The advanced characterization techniques including XRD, FT-IR, UV-DRS, PL, TGA, SEM-EDX, TEM, DLS, Elemental mapping, VSM and BET were applied to analyze the morphology and structure of the prepared Fe2O3/Ag NCs. The results exhibited that the Fe2O3/Ag NCs was successfully synthesized by greener route. Furthermore, these bio-reduced Fe2O3/Ag NCs was tested for its catalytic degradation toward methylene blue (MB) as a model contaminant and exhibited outstanding photocatalytic degradation efficiency with 88.2% removal rate in 140 min. It was worth pointing out that the Fe2O3/Ag nanoparticles facilitated the charge transportation and inhibit the charge recombination of an electron in the conduction band. Additionally, the prepared Fe2O3/Ag NCs was studied for their in-vitro antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria and anticancer properties against A549 cell lines (human lung cancer). The biological results of this study demonstrated that A. vera gel extract derived Fe2O3/Ag NCs showed significant inhibition properties against bacterial strains and also capable of achieving superior action against A549 cancer cell lines.
    背景与目标: 在这里,我们报告了一种使用芦荟 (a.vera) 凝胶提取物作为温和,安全,可再生和活性稳定剂而没有任何有害试剂的一锅微波辅助方法来制备高效的Fe2O3/Ag纳米复合材料 (NCs)。采用XRD,ft-ir,uv-drs,PL,TGA,sem-edx,TEM,DLS,元素映射,VSM和BET等先进的表征技术对制备的Fe2O3/Ag nc的形貌和结构进行了分析。结果表明,采用绿色路线成功合成了Fe2O3/Ag NCs。此外,测试了这些生物还原的Fe2O3/Ag NCs对作为模型污染物的亚甲基蓝 (MB) 的催化降解,并显示出出色的光催化降解效率,在140分钟内去除速率88.2%。值得指出的是,Fe2O3/Ag纳米颗粒促进了电荷传输并抑制了导带中电子的电荷复合。此外,还研究了制备的Fe2O3/Ag NCs对金黄色葡萄球菌 (S. aureus) 和大肠杆菌 (E. coli) 细菌的体外抗菌活性以及对A549细胞系 (人肺癌) 的抗癌特性。这项研究的生物学结果表明,A. vera凝胶提取物衍生的Fe2O3/Ag NCs对细菌菌株具有显着的抑制作用,并且能够对A549癌细胞株具有优异的作用。
  • 【用于双重热疗和紫杉醇递送的PEG-氧化铁水凝胶纳米复合材料的表征。】 复制标题 收藏 收藏
    DOI:10.1080/09205063.2012.741321 复制DOI
    作者列表:Meenach SA,Shapiro JM,Hilt JZ,Anderson KW
    BACKGROUND & AIMS: :Hyperthermia, the heating of tissue from 41 to 45 °C, has been shown to improve the efficacy of cancer therapy when used in conjunction with irradiation and/or chemotherapy. In this work, hydrogel nanocomposites have been developed that can control the delivery of both heat and a chemotherapeutic agent (e.g. paclitaxel). The nanocomposites studied involve a stealth, poly(ethylene glycol) (PEG)-based system comprised of PEG (n = 1000) methyl ether methacrylate and PEG (n = 400) dimethacrylate with iron oxide nanoparticles physically entrapped within the hydrogel matrices. The capability of the hydrogel nanocomposites to be heated in an alternating magnetic field was demonstrated. The heating of the hydrogel systems was dependent on the crosslinking of the hydrogel network where hydrogels with lower swelling ratios were found to heat to a greater extent than those with higher ratios. In addition, paclitaxel was shown to exhibit non-Fickian release from the hydrogel systems, with the amount of drug released dependent on the hydrogel network structure. Three cell lines: M059K (glioblastoma), MDA MB 231 (breast carcinoma), and A549 (lung adenocarcinoma) were exposed to paclitaxel only, hyperthermia only, and both paclitaxel and hyperthermia to determine if a synergistic cytotoxic effect was possible for these cell lines. The efficacy of paclitaxel was greater with hyperthermia for the A549 cells; however, the M059K and MDA MB 231 did not show the same response.
    背景与目标: : 热疗,将组织从41 ℃ 加热到45 ℃,已被证明与辐射和/或化学疗法结合使用时可提高癌症治疗的疗效。在这项工作中,已经开发了水凝胶纳米复合材料,该复合材料可以控制热量和化学治疗剂 (例如紫杉醇) 的传递。所研究的纳米复合材料涉及一种隐身的、基于聚 (乙二醇) (PEG) 的系统,该系统由PEG (n   =   1000) 甲基丙烯酸甲酯和PEG (n   =   400) 二甲基丙烯酸酯和物理截留在水凝胶基质内的氧化铁纳米颗粒组成。证明了水凝胶纳米复合材料在交变磁场中加热的能力。水凝胶系统的加热取决于水凝胶网络的交联,其中发现具有较低溶胀比的水凝胶比具有较高溶胀比的水凝胶加热的程度更大。此外,紫杉醇显示出从水凝胶系统中释放出非Fickian,释放的药物量取决于水凝胶网络结构。三种细胞系: M059K (胶质母细胞瘤) 、MDA MB 231 (乳腺癌) 和A549 (肺腺癌) 仅暴露于紫杉醇,仅暴露于高热,以及紫杉醇和高热,以确定这些细胞系是否可能产生协同细胞毒性作用。紫杉醇对A549细胞的热疗疗效更高; 然而,M059K和MDA MB 231没有显示出相同的反应。
  • 【前驱体衍生的t-ZrO2/SiOC(N) 纳米复合材料中纳米级异质结的设计: 跨越从UV到可见光的催化活性边界。】 复制标题 收藏 收藏
    DOI:10.1038/s41598-019-57394-8 复制DOI
    作者列表:Bhaskar S,Awin EW,Kumar KCH,Lale A,Bernard S,Kumar R
    BACKGROUND & AIMS: :In this work, nanocomposites made of nanosized zirconia crystallized in situ in an amorphous silicon oxycarbo(nitride) (SiOC(N)) matrix have been designed through a precursor route for visible light photocatalytic applications. The relative volume fraction of the starting precursors and the pyrolysis temperatures not only influences the phase fraction of zirconia crystallites but also stabilizes the tetragonal crystal structure of zirconia (t-ZrO2) at room temperature. The presence of carbon in interstitial sites of zirconia and oxygen vacancy defects led to drastic reduction in the band gap (2.2 eV) of the nanocomposite. Apart from being a perfect host avoiding sintering of the active phase and providing mechanical stability, the amorphous matrix also reduces the recombination rate by forming heterojunctions with t-ZrO2. The reduction in band gap as well as the formation of heterojunctions aids in harnessing the visible light for photocatalytic activity.
    背景与目标: : 在这项工作中,已通过用于可见光光催化应用的前体路线设计了由在非晶硅氧碳 (氮化物) (SiOC(N)) 基质中原位结晶的纳米氧化锆制成的纳米复合材料。起始前体的相对体积分数和热解温度不仅影响氧化锆微晶的相分数,而且在室温下稳定氧化锆 (t-ZrO2) 的四方晶体结构。氧化锆间隙位中碳的存在和氧空位缺陷导致纳米复合材料的带隙 (2.2  eV) 急剧减少。除了作为避免活性相烧结和提供机械稳定性的完美主体之外,非晶基质还通过与t-ZrO2形成异质结来降低复合速率。带隙的减少以及异质结的形成有助于利用可见光进行光催化活性。
  • 【具有增强光催化活性的新型碳/ZnO/Li2O纳米复合材料。】 复制标题 收藏 收藏
    DOI:10.1038/s41598-019-53335-7 复制DOI
    作者列表:Diacon A,Mocanu A,Răducanu CE,Busuioc C,Șomoghi R,Trică B,Dinescu A,Rusen E
    BACKGROUND & AIMS: :Our study was focused on the synthesis of photocatalytic materials for the degradation of organic dyes based on the valorization of biomass resources. The biochar resulted from pyrolysis process of cherry pits wastes was activated by CO2 flow. Activated and inactivated carbon was used to obtain carbon-based photocatalysts impregnated with different zinc salt precursors. The activation of carbon had no significant influence on the photodegradation process. The doping procedure used Li2CO3 and Zn(CH3COO)2 of different concentrations to impregnate the biochar. The carbon-ZnO-Li2O based nanomaterials were analysed by TEM and SEM, while the presence of hexagonal wurtzite ZnO was investigated by XRD. The solid samples were analysed by PL at 360 nm excitation fixed wavelength to correlate their morphology with the optical and photocatalytic properties. The presence of Li atoms led to photocatalytic activities of the doped ZnO similar to the undoped ZnO obtained at higher concentrations of zinc acetate precursor.
    背景与目标: : 我们的研究重点是基于生物质资源的valorization合成用于降解有机染料的光催化材料。樱桃坑废物热解过程产生的生物炭被CO2流激活。使用活化和失活的碳来获得浸渍有不同锌盐前体的碳基光催化剂。碳的活化对光降解过程没有显着影响。掺杂程序使用不同浓度的Li2CO3和Zn(CH3COO)2浸渍生物炭。通过TEM和SEM分析了carbon-ZnO-Li2O基纳米材料,而通过XRD研究了六方纤锌矿ZnO的存在。通过在360  nm激发固定波长下的PL分析固体样品,以将其形态与光学和光催化性能相关联。Li原子的存在导致掺杂的ZnO的光催化活性类似于在较高浓度的乙酸锌前体下获得的未掺杂的ZnO。
  • 【可注射聚 (丙交酯环氧乙烷富马酸酯)/羟基磷灰石纳米复合材料流变性能的建模和实验研究。】 复制标题 收藏 收藏
    DOI:10.1021/bm050958s 复制DOI
    作者列表:Sarvestani AS,Jabbari E
    BACKGROUND & AIMS: :Injectable multiphasic polymer/ceramic composites are attractive as bioresorbable scaffolds for bone regeneration because they can be cross-linked in situ and are osteoconductive. The injectability of the composite depends on the nanoparticle content and the energetic interactions at the polymer/particle interface. The objective of this research was to determine experimentally the rheological properties of the PLEOF/apatite composite as an injectable biomaterial and to compare the viscoelastic response with the predictions of a linear elastic dumbbell model. A degradable in situ cross-linkable terpolymer based on low molecular weight poly(L-lactide) and poly(ethylene oxide) linked by unsaturated fumarate groups is synthesized. The poly(L-lactide-co-ethylene oxide-co-fumarate) (PLEOF) terpolymer interacts with the surface of the apatite nanoparticles by polar interactions and hydrogen bonding. A kinetic model is developed that takes into account the adsorption/desorption of polymer chains to/from the nanoparticle surface. Rheological properties of the aqueous dispersion of PLEOF terpolymer reinforced with nanosized hydroxyapatite (HA) particles are investigated using mechanical rheometry. To this end, we performed a series of rheological experiments on un-cross-linked PLEOF reinforced with different volume fractions of HA nanoparticles. The results demonstrate that the observed nonlinear viscoelasticity at higher shear rates is controlled by the energetic interactions between the polymer chains and dispersed particle aggregates and by the rate of the adsorption/desorption of the chains to/from the surface of the nanoparticles.
    背景与目标: : 可注射多相聚合物/陶瓷复合材料作为骨再生的生物可吸收支架很有吸引力,因为它们可以原位交联并且具有骨传导性。复合材料的可注入性取决于纳米颗粒含量和聚合物/颗粒界面处的高能相互作用。这项研究的目的是通过实验确定褶皱/磷灰石复合材料作为可注射生物材料的流变特性,并将粘弹性响应与线性弹性哑铃模型的预测进行比较。合成了一种基于不饱和富马酸酯基团连接的低分子量聚L-丙交酯和聚环氧乙烷的可降解原位交联三元共聚物。聚 (L-丙交酯-co-环氧乙烷-co-富马酸酯) (PLEOF) 三元共聚物通过极性相互作用和氢键与磷灰石纳米颗粒的表面相互作用。开发了一种动力学模型,该模型考虑了聚合物链在纳米颗粒表面的吸附/解吸。使用机械流变仪研究了用纳米羟基磷灰石 (HA) 颗粒增强的褶皱三元共聚物的水分散体的流变性能。为此,我们对用不同体积分数的HA纳米颗粒增强的未交联的褶皱进行了一系列流变实验。结果表明,在较高的剪切速率下观察到的非线性粘弹性受聚合物链与分散颗粒聚集体之间的能量相互作用以及链到/从纳米颗粒表面的吸附/解吸速率控制。
  • 【基于TiO2覆盖的磁性Co3 O4的新型核壳纳米复合材料,用于生物医学应用。】 复制标题 收藏 收藏
    DOI:10.1002/jbm.b.34529 复制DOI
    作者列表:Tonelli AM,Venturini J,Arcaro S,Henn JG,Moura DJ,Viegas ADC,Bergmann CP
    BACKGROUND & AIMS: :Magnetic Co3 O4 nanoparticles (NPs) have great potential for applications in biomedicine, as contrast enhancement agents for magnetic resonance imaging, or for drug delivery. Although these NPs are so attractive, their potential toxicity raises serious questions about decreasing cellular viability. In this context, Co3 O4 NPs were prepared via sol-gel method and encapsulated with a layer of TiO2 , a biocompatible oxide, and subjected to structural, magnetic and toxicity characterization. X-ray diffractograms of the samples demonstrate the successful synthesis of the spinel and Raman spectroscopy confirms the coating of the Co3 O4 spinel with TiO2 . The Co3 O4 cores showed a very intense superparamagnetic character; however, this behavior is strongly suppressed when the material is covered with TiO2 . According to the neutral red uptake assay, the coating of the cores with TiO2 significantly decreases the cytotoxic character of the Co3 O4 particles and, as it can be observed with the zeta (ξ) potential measurements, they form a stable colloidal dispersion at cytoplasmic pH. The effect of the thermal treatment enhances the biocompatibility even further, with no statistically significant effect on cell viability even at the highest analyzed concentration. The proposed pathway presents a successful sol-gel method for the preparation of Co3 O4 @TiO2 core-shell nanoparticles. This work opens up possibilities for future application of these materials not only for magnetic resonance imaging but also in catalysis and hyperthermia.
    背景与目标: : 磁性Co3 O4纳米颗粒 (NPs) 在生物医学,磁共振成像或药物递送的造影剂中具有巨大的应用潜力。尽管这些np非常有吸引力,但它们的潜在毒性引发了有关降低细胞活力的严重问题。在这种情况下,通过溶胶-凝胶法制备Co3 O4 np,并用一层生物相容性氧化物TiO2封装,并进行结构,磁性和毒性表征。样品的x射线衍射图证明了尖晶石的成功合成,拉曼光谱证实了用TiO2涂覆Co3 O4尖晶石。Co3 O4核心显示出非常强烈的超顺磁性; 但是,当材料被TiO2覆盖时,这种行为会受到强烈抑制。根据中性红摄取测定法,用TiO2涂覆核心显着降低Co3 O4颗粒的细胞毒性特性,并且通过zeta (ξ) 电位测量可以观察到,它们在细胞质pH下形成稳定的胶体分散体。热处理的效果甚至进一步增强了生物相容性,即使在最高分析浓度下,对细胞活力也没有统计学上的显着影响。所提出的途径提出了一种成功的溶胶-凝胶方法来制备Co3 O4 @ TiO2核壳纳米颗粒。这项工作为这些材料的未来应用提供了可能性,不仅可以用于磁共振成像,还可以用于催化和热疗。
  • 【微波辅助快速制备基于锌/铁氧化物的聚合物纳米复合材料并对马成纤维细胞进行评估。】 复制标题 收藏 收藏
    DOI:10.1016/j.ijbiomac.2020.09.172 复制DOI
    作者列表:Manuja A,Kumar B,Riyesh T,Talluri TR,Tripathi BN
    BACKGROUND & AIMS: :We aimed to provide a tissue repair material, which can be synthesized rapidly, using polymers mimicking the natural environment in the extra-cellular matrix and metals/minerals. The components should have the potential to be used in tissue repair and simultaneously, reducing the side-effects of the incorporated molecules. It is challenging to manage the dispersibility of ZnO NPs in common solutions like water. Here, we report a novel method for preparing highly dispersible suspensions of ZnO NPs. In contrast to those synthesized by conventional methods, microwave assisted method allowed synthesis of dispersible ZnO NPs and the incorporation of zinc/Iron oxides NPs within alginate and gum matrix (AG) in a short span of time providing high yield of the product. The nanoformulations were characterized for size, morphology, interaction of various chemicals used during their synthesis by transmissible electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and energy dispersive X ray Spectrum. It was also evaluated for cytotoxicity and their effect on equine fibroblast cells. Microwave-assisted fabrication of zinc/iron oxides nanoparticles provided flowerlike morphology with good dispersibility and high yield in a short span of time. Our results revealed that ZnO NPs were more cytotoxic than AG ZnO NPs and doped AG Fe3O4 doped ZnO NPs at higher concentrations. Further metal nanoparticles capped with alginate/acacia with size range less than 100 nm demonstrated high stability, good biocompatibility, re-epithelization and enhanced mineralization in horse fibroblast cells.
    背景与目标: : 我们旨在提供一种组织修复材料,该材料可以使用模仿细胞外基质和金属/矿物质中的自然环境的聚合物快速合成。这些成分应具有用于组织修复的潜力,同时减少掺入分子的副作用。管理ZnO np在水等常见解决方案中的分散性具有挑战性。在这里,我们报告了一种制备ZnO np高分散性悬浮液的新方法。与通过常规方法合成的方法相反,微波辅助方法允许在短时间内合成可分散的ZnO np,并在藻酸盐和树胶基质 (AG) 中掺入锌/铁氧化物np,从而提供高收率的产品。通过透射电子显微镜,x射线衍射,傅立叶变换红外光谱和能量色散x射线光谱,对纳米制剂的尺寸,形态,合成过程中使用的各种化学物质的相互作用进行了表征。还评估了其细胞毒性及其对马成纤维细胞的影响。微波辅助制备锌/铁氧化物纳米颗粒可在短时间内提供具有良好分散性和高产率的花朵状形态。我们的结果表明,在较高浓度下,ZnO NPs比AG ZnO NPs和掺杂的AG Fe3O4掺杂的ZnO NPs更具细胞毒性。用尺寸范围小于100 nm的藻酸盐/阿拉伯胶覆盖的其他金属纳米颗粒在马成纤维细胞中表现出高稳定性、良好的生物相容性、再上皮化和增强的矿化作用。
  • 【通过多巴胺自聚合和迈克尔加成轻松合成亲水性磁性石墨烯纳米复合材料,以选择性富集N-连接的糖肽。】 复制标题 收藏 收藏
    DOI:10.1038/s41598-019-56944-4 复制DOI
    作者列表:Bi C,Yuan Y,Tu Y,Wu J,Liang Y,Li Y,He X,Chen L,Zhang Y
    BACKGROUND & AIMS: :The development of methods to effectively capture N-glycopeptides from the complex biological samples is crucial to N-glycoproteome profiling. Herein, the hydrophilic chitosan-functionalized magnetic graphene nanocomposites (denoted as Fe3O4-GO@PDA-Chitosan) were designed and synthesized via a simple two-step modification (dopamine self-polymerization and Michael addition). The Fe3O4-GO@PDA-Chitosan nanocomposites exhibited good performances with low detection limit (0.4 fmol·μL-1), good selectivity (mixture of bovine serum albumin and horseradish peroxidase tryptic digests at a molar ration of 10:1), good repeatability (4 times), high binding capacity (75 mg·g-1). Moreover, Fe3O4-GO@PDA-Chitosan nanocomposites were further utilized to selectively enrich glycopeptides from human renal mesangial cell (HRMC, 200 μg) tryptic digest, and 393 N-linked glycopeptides, representing 195 different glycoproteins and 458 glycosylation sites were identified. This study provides a feasible strategy for the surface functionalized novel materials for isolation and enrichment of N-glycopeptides.
    背景与目标: : 从复杂的生物样品中有效捕获N-糖肽的方法的开发对于N-糖蛋白质组分析至关重要。在本文中,亲水性壳聚糖官能化的磁性石墨烯纳米复合材料 (表示为Fe3O4-GO @ PDA-壳聚糖) 是通过简单的两步改性 (多巴胺自聚合和迈克尔加成) 设计和合成的。Fe3O4-GO @ PDA-壳聚糖纳米复合材料具有良好的性能,检测限低 (0.4 fmol·μL-1),良好的选择性 (牛血清白蛋白和辣根过氧化物酶胰蛋白酶消化物的混合物,摩尔比为10:1),良好的重复性 (4倍),高结合能力 (75 mg·g-1)。此外,Fe3O4-GO @ PDA-壳聚糖纳米复合材料被进一步用于从人肾系膜细胞 (HRMC,200  μ g) 胰蛋白酶消化物中选择性富集糖肽,并393代表195不同糖蛋白和458糖基化位点的N-连接糖肽被鉴定。这项研究为表面官能化新型材料隔离和富集N-糖肽提供了可行的策略。
  • 【具有Fe3O4磁芯和CdSe/ZnS量子点壳的自组装多功能纳米复合材料。】 复制标题 收藏 收藏
    DOI:10.1002/jbm.a.31609 复制DOI
    作者列表:Zhang Y,Wang SN,Ma S,Guan JJ,Li D,Zhang XD,Zhang ZD
    BACKGROUND & AIMS: :This paper describes a new method for self-assembling multifunctional nanocomposites with a magnetic core of iron oxide Fe(3)O(4) and a shell of CdSe/ZnS quantum dots (QDs). Two sol-gel processes were applied to form the uniform magnetic seeds (Fe(3)O(4)@SiO(2)-SH) and then the thiol coordination was used to bind the CdSe/ZnS QDs to the surface of the seeds. The multifunctional nanocomposites were characterized by means of transmission electron microscopy, X-ray diffraction, energy disperse spectroscopy, fluorescence spectroscopy, infrared spectroscopy, and superconducting quantum interference device (SQUID) magnetometer. The results showed that the magnetic Fe(3)O(4) nanoparticles and the CdSe/ZnS fluorescent QDs were combined together. The nanocomposites were of spherical shape with a mean diameter of 25 nm and exhibited well magnetic response, photostability, chemical activity, and water miscibility. The method put forward here can also be extended to combine systems of other metal oxides and QDs to fabricate core-shell nanocomposites with multifunction for biomedical applications.
    背景与目标: : 本文介绍了一种具有氧化铁Fe(3)O(4) 磁芯和CdSe/ZnS量子点 (QDs) 外壳的自组装多功能纳米复合材料的新方法。应用两种溶胶-凝胶工艺形成均匀的磁性种子 (Fe(3)O(4)@ SiO(2)-SH),然后使用硫醇配位将CdSe/ZnS QDs结合到种子表面。通过透射电子显微镜,x射线衍射,能量分散光谱,荧光光谱,红外光谱和超导量子干涉装置 (SQUID) 磁强计对多功能纳米复合材料进行了表征。结果表明,磁性Fe(3)O(4) 纳米颗粒和CdSe/ZnS荧光量子点结合在一起。纳米复合材料为球形,平均直径为25 nm,并表现出良好的磁响应,光稳定性,化学活性和水混溶性。此处提出的方法也可以扩展到将其他金属氧化物和量子点的系统结合起来,以制造具有多功能的核壳纳米复合材料,用于生物医学应用。
  • 【靶向结核分枝杆菌和肺癌细胞 (A-549) 的季铵化壳聚糖/银纳米复合材料的绿色合成。】 复制标题 收藏 收藏
    DOI:10.1016/j.ijbiomac.2019.09.096 复制DOI
    作者列表:Abdel-Aziz MM,Elella MHA,Mohamed RR
    BACKGROUND & AIMS: :Lung cancer (LC) is the most-deadly type of cancer representing a major public health problem worldwide. Tuberculosis TB is another infectious disease influencing lungs that causes death especially in developing countries. The present study is the first to report antimycobacterial activity of TMC/Ag nanocomposite. It aims to solve the case of lung cancer and its most associative pathogen. The current study reports one pot green biosynthesis of silver nanocomposite in presence of biodegradable biopolymer (N,N,N-trimethyl chitosan chloride, TMC) as both reducing and stabilizing agent. The structure of TMC/Ag nanocomposite was characterized with different analysis tools including TEM, XRD and UV-vis spectrophotometer techniques. TEM images showed that Ag nanoparticles were well distributed spheres and their diameter ranged from 11 to17.5 nm. While, XRD pattern of TMC/Ag nanocomposite showed diffraction peaks related to the crystalline nature of Ag nanoparticles. In addition, UV-vis spectrum revealed a broad absorption peak at 400 nm attributing to the surface Plasmon resonance (SPR) of Ag. TMC/Ag nanocomposite exhibited a promising in vitro antimycobacterial activity with MIC of 1.95 μg/mL. On the other hand, The antitumor activity results of nanocomposites against both lung carcinoma cells (A-549) and normal lung cells (WI 38) revealed that nanocomposite cytotoxicity against A-549 cells with IC50 of 12.3 μg/mL, whereas the IC50 value against normal WI 38 cells was 357.2 μg/mL.
    背景与目标: : 肺癌 (LC) 是最致命的癌症类型,代表着全球主要的公共卫生问题。结核病是影响肺部的另一种传染病,尤其是在发展中国家。本研究是首次报道TMC/Ag纳米复合材料的抗细菌活性。它旨在解决肺癌及其最相关的病原体。当前的研究报告了在可生物降解的生物聚合物 (N,N,N-三甲基壳聚糖氯化物,TMC) 作为还原剂和稳定剂的情况下,银纳米复合材料的一锅绿色生物合成。通过TEM,XRD和UV-vis分光光度计等不同分析工具对TMC/Ag纳米复合材料的结构进行了表征。透射电镜图像显示,银纳米颗粒是分布良好的球体,直径范围为11 ~ 17.5  nm。同时,TMC/Ag纳米复合材料的XRD图谱显示出与Ag纳米颗粒的结晶性质有关的衍射峰。此外,UV-vis光谱显示在400  nm处的宽吸收峰归因于Ag的表面等离子体共振 (SPR)。TMC/Ag纳米复合材料具有良好的体外抗霉菌活性,MIC为1.95  μ g/mL。另一方面,纳米复合材料对肺癌细胞 (A-549) 和正常肺细胞 (WI 38) 的抗肿瘤活性结果表明,纳米复合材料对A-549细胞的细胞毒性为12.3  μ g/mL,而对正常WI 38细胞的IC50值为357.2  μ g/mL。
  • 【羧化氧化石墨烯接枝聚乙二醇作为聚乳酸/石墨烯纳米复合材料的新型界面改性剂。】 复制标题 收藏 收藏
    DOI:10.1098/rsos.192154 复制DOI
    作者列表:Niu M,Wang H,Li J,Chen H,Li L,Yang H,Liu X,Chen Z,Liu H,Chen J
    BACKGROUND & AIMS: :Strength and toughness are both of great importance for the application of polylactic acid (PLA). Unfortunately, these two properties are often contradictory. In this work, an effective and practical strategy is proposed by using carboxylated graphene oxide (GC) grafted with polyethylene glycol (PEG), i.e. GC-g-PEG. The synthesis procedure of GC-g-PEG is firstly optimized. Then, a series of PLA nanocomposites were prepared by the melt blending method via masterbatch. In comparison to that achieved over pure PLA, these nanocomposites are of higher crystallinity, thermal stability and mechanical strength. This is mainly attributed to well-tailored interface and good dispersion. Especially, while retaining the tensile strength of the original PLA, the elongation at break increases by seven times by adding 0.3 wt% GC-g-PEG.
    背景与目标: : 强度和韧性对于聚乳酸 (PLA) 的应用都非常重要。不幸的是,这两个属性往往是矛盾的。在这项工作中,通过使用接枝聚乙二醇 (PEG) 的羧化氧化石墨烯 (GC),即GC-g-PEG,提出了一种有效且实用的策略。首先优化了gc-g-peg的合成工艺。然后,通过母料通过熔融共混法制备了一系列PLA纳米复合材料。与纯PLA相比,这些纳米复合材料具有更高的结晶度,热稳定性和机械强度。这主要归因于精心定制的界面和良好的分散性。特别是,在保持原始PLA的拉伸强度的同时,通过添加0.3重量 % 的gc-g-peg,断裂伸长率增加7倍。
  • 【使用溶胀液晶轻松合成具有非凡催化活性的原始石墨烯-钯纳米复合材料。】 复制标题 收藏 收藏
    DOI:10.1038/srep33053 复制DOI
    作者列表:Vats T,Dutt S,Kumar R,Siril PF
    BACKGROUND & AIMS: :Amazing conductivity, perfect honeycomb sp(2) arrangement and the high theoretical surface area make pristine graphene as one of the best materials suited for application as catalyst supports. Unfortunately, the low reactivity of the material makes the formation of nanocomposite with inorganic materials difficult. Here we report an easy approach to synthesize nanocomposites of pristine graphene with palladium (Pd-G) using swollen liquid crystals (SLCs) as a soft template. The SLC template gives the control to deposit very small Pd particles of uniform size on G as well as RGO. The synthesized nanocomposite (Pd-G) exhibited exceptionally better catalytic activity compared with Pd-RGO nanocomposite in the hydrogenation of nitrophenols and microwave assisted C-C coupling reactions. The catalytic activity of Pd-G nanocomposite during nitrophenol reduction reaction was sixteen times higher than Pd nanoparticles and more than double than Pd-RGO nanocomposite. The exceptionally high activity of pristine graphene supported catalysts in the organic reactions is explained on the basis of its better pi interacting property compared to partially reduced RGO. The Pd-G nanocomposite showed exceptional stability under the reaction conditions as it could be recycled upto a minimum of 15 cycles for the C-C coupling reactions without any loss in activity.
    背景与目标: : 惊人的导电性,完美的蜂窝sp(2) 排列和高理论表面积使原始石墨烯成为适合用作催化剂载体的最佳材料之一。不幸的是,该材料的低反应性使得难以与无机材料形成纳米复合材料。在这里,我们报告了一种使用溶胀液晶 (slc) 作为软模板合成原始石墨烯与钯 (Pd-G) 的纳米复合材料的简便方法。SLC模板可以控制在G和RGO上沉积尺寸均匀的非常小的Pd颗粒。与Pd-RGO纳米复合材料相比,合成的纳米复合材料在硝基酚加氢和微波辅助的c-c偶联反应中表现出更好的催化活性。硝基苯酚还原反应过程中Pd-G纳米复合材料的催化活性是Pd纳米颗粒的16倍,是Pd-RGO纳米复合材料的两倍以上。与部分还原的RGO相比,原始石墨烯负载的催化剂在有机反应中的极高活性是基于其更好的pi相互作用特性来解释的。Pd-G纳米复合材料在反应条件下显示出出色的稳定性,因为对于c-c偶联反应,它可以循环使用至少15个循环,而不会损失任何活性。
  • 【两亲性疏水缔合聚合物/蒙脱土纳米复合材料的制备及性能。】 复制标题 收藏 收藏
    DOI:10.1098/rsos.200199 复制DOI
    作者列表:Bai C,Ke Y,Hu X,Xing L,Zhao Y,Lu S,Lin Y
    BACKGROUND & AIMS: :In this research, a novel amphiphilic hydrophobically associative polymer nanocomposite (ADOS/OMMT) was prepared using acrylamide (AM), sodium 4-vinylbenzenesulfonate (SSS), N, N'-dimethyl octadeyl allyl ammonium bromide (DOAAB) and organo-modified montmorillonite (OMMT) through in situ polymerization. Both X-ray diffraction patterns and transmission electron microscopy images verified the dispersion morphology of OMMT in the copolymer matrix. Then, the effect of the introduction of OMMT layers on the copolymer properties was studied by comparing with pure copolymer AM/SSS/DOAAB (ADOS). The thermal degradation results demonstrated that the thermal stability of the ADOS/OMMT were better than pure copolymer ADOS. During the solution properties tests, ADOS/OMMT nanocomposite was superior to ADOS in viscosifying ability, temperature resistance, salt tolerance, shear resistance and viscoelasticity, which was because OMMT contributed to enhance the hydrophobic association structure formed between polymer molecules. Additionally, the ADOS/OMMT nanocomposite exhibited more excellent interfacial activity and crude oil emulsifiability in comparison to pure copolymer ADOS. These performances indicated ADOS/OMMT nanocomposite had good application prospects in tertiary recovery.
    背景与目标: : 在这项研究中,使用丙烯酰胺 (AM),4-乙烯基苯磺酸钠 (SSS),N,N'-二甲基八烷基烯丙基溴化铵 (DOAAB) 和有机改性蒙脱土 (OMMT) 通过原位聚合制备了一种新型的两亲性疏水缔合聚合物纳米复合材料 (ADOS/OMMT)。X射线衍射图和透射电子显微镜图像均验证了OMMT在共聚物基质中的分散形态。然后,通过与纯共聚物AM/SSS/DOAAB (ADOS) 进行比较,研究了引入OMMT层对共聚物性能的影响。热降解结果表明,ADOS/OMMT的热稳定性优于纯共聚物ADOS。在溶液性能测试中,ADOS/OMMT纳米复合材料在增粘能力,耐温性,耐盐性,抗剪切性和粘弹性方面优于ADOS,这是因为OMMT有助于增强聚合物分子之间形成的疏水缔合结构。此外,与纯共聚物ADOS相比,ADOS/OMMT纳米复合材料表现出更优异的界面活性和原油乳化性。这些性能表明ADOS/OMMT纳米复合材料在三次回收中具有良好的应用前景。
  • 【对Suzuki偶联反应具有增强催化活性的Pd @ 石墨烯纳米复合材料的简便合成。】 复制标题 收藏 收藏
    DOI:10.1038/s41598-020-68124-w 复制DOI
    作者列表:Khan M,Shaik MR,Adil SF,Kuniyil M,Ashraf M,Frerichs H,Sarif MA,Siddiqui MRH,Al-Warthan A,Labis JP,Islam MS,Tremel W,Tahir MN
    BACKGROUND & AIMS: :A facile and chemical specific method to synthesize highly reduced graphene oxide (HRG) and Pd (HRG@Pd) nanocomposite is presented. The HRG surfaces are tailored with amine groups using 1-aminopyrene (1-AP) as functionalizing molecules. The aromatic rings of 1-AP sit on the basal planes of HRG through π-π interactions, leaving amino groups outwards (similar like self-assembled monolayer on 2D substrates). The amino groups provide the chemically specific binding sites to the Pd nucleation which subsequently grow into nanoparticles. HRG@Pd nanocomposite demonstrated both uniform distribution of Pd nanoparticles on HRG surface as well as excellent physical stability and dispersibility. The surface functionalization was confirmed using, ultraviolet-visible (UV-Vis), Fourier transform infra-red and Raman spectroscopy. The size and distribution of Pd nanoparticles on the HRG and crystallinity were confirmed using high-resolution transmission electron microscopy and powder X-ray diffraction and X-ray photoelectron spectroscopy. The catalytic efficiency of highly reduced graphene oxide-pyrene-palladium nanocomposite (HRG-Py-Pd) is tested towards the Suzuki coupling reactions of various aryl halides. The kinetics of the catalytic reaction (Suzuki coupling) using HRG-Py-Pd nanocomposite was monitored using gas chromatography (GC).
    背景与目标: : 提出了一种易于合成高还原氧化石墨烯 (HRG) 和Pd (HRG @ Pd) 纳米复合材料的化学特异性方法。使用1-氨基芘 (1-AP) 作为功能化分子,用胺基对HRG表面进行定制。1-AP的芳环通过 π-π 相互作用位于HRG的基面上,向外留下氨基 (类似于2D衬底上的自组装单层)。氨基提供了与Pd成核的化学特异性结合位点,Pd成核随后生长成纳米颗粒。HRG @ Pd纳米复合材料显示了Pd纳米颗粒在HRG表面的均匀分布以及优异的物理稳定性和分散性。使用紫外可见 (UV-Vis),傅里叶变换红外和拉曼光谱确认了表面功能化。使用高分辨率透射电子显微镜,粉末x射线衍射和x射线光电子能谱证实了Pd纳米颗粒在HRG上的尺寸和分布以及结晶度。测试了高度还原的氧化石墨烯-芘-钯纳米复合材料 (HRG-Py-Pd) 对各种芳基卤化物的Suzuki偶联反应的催化效率。使用气相色谱 (GC) 监测使用HRG-Py-Pd纳米复合材料的催化反应动力学 (Suzuki偶联)。
  • 【良性氧化锌甜菜碱改性生物炭纳米复合材料,用于从水溶液中去除磷酸盐。】 复制标题 收藏 收藏
    DOI:10.1016/j.jenvman.2020.111048 复制DOI
    作者列表:Nakarmi A,Bourdo SE,Ruhl L,Kanel S,Nadagouda M,Kumar Alla P,Pavel I,Viswanathan T
    BACKGROUND & AIMS: :Phosphate is one of the most costly and complex environmental pollutants that leads to eutrophication, which decreases water quality and access to clean water. Among different adsorbents, biochar is one of the promising adsorbents for phosphate removal as well as heavy metal removal from an aqueous solution. In this study, biochar was impregnated with nano zinc oxide in the presence of glycine betaine. The Zinc Oxide Betaine-Modified Biochar Nanocomposites (ZnOBBNC) proved to be an excellent adsorbent for the removal of phosphate, exhibiting a maximum adsorption capacity of phosphate (265.5 mg. g-1) and fast adsorption kinetics (~100% removal at 15 min at 10 mg. L-1 phosphate and 3 g. L-1 nanocomposite dosage) in phosphate solution. The synthesis of these benign ZnOBBNC involves a process that is eco-friendly and economically feasible. From material characterization, we found that the ZnOBBNC has ~20-30 nm particle size, high surface area (100.01 m2. g-1), microporous (25.79 Å) structures, and 7.64% zinc content. The influence of pH (2-10), coexisting anions (Cl-, CO32-, NO3- and SO43-), initial phosphate concentration (10-500 mg. L-1), and ZnOBBNC dosage (0.5-5 g. L-1) were investigated in batch experiments. From the adsorption isotherms data, the adsorption of phosphate using ZnOBBNC followed Langmuir isotherm (R2 = 0.9616), confirming the mono-layered adsorption mechanism. The kinetic studies showed that the phosphate adsorption using ZnOBBNC followed the pseudo-second-order model (R2 = 1.0000), confirming the chemisorption adsorption mechanism with inner-sphere complexion. Our results demonstrated ZnOBBNC as a suitable, competitive candidate for phosphate removal from both mock lab-prepared and real field-collected wastewater samples when compared to commercial nanocomposites.
    背景与目标: : 磷酸盐是导致富营养化的最昂贵和最复杂的环境污染物之一,这会降低水质并获得清洁水。在不同的吸附剂中,生物炭是用于去除磷酸盐以及从水溶液中去除重金属的有前途的吸附剂之一。在这项研究中,在甘氨酸甜菜碱存在下,用纳米氧化锌浸渍生物炭。氧化锌甜菜碱改性的生物炭纳米复合材料 (ZnOBBNC) 被证明是去除磷酸盐的出色吸附剂,在磷酸盐溶液中表现出磷酸盐的最大吸附容量 (265.5 mg g-1) 和快速吸附动力学 (在10 mg L-1磷酸盐和3g L-1纳米复合材料剂量下15分钟去除约100%)。这些良性ZnOBBNC的合成涉及一种环保且经济可行的工艺。通过材料表征,我们发现ZnOBBNC具有〜20-30 nm的粒径,高表面积 (100.01平方米g-1),微孔 (25.79 Å) 结构和7.64% 的锌含量。在分批实验中研究了pH (2-10),共存阴离子 (Cl-,CO32-,NO3-和SO43-),初始磷酸盐浓度 (10-500 mg。L-1) 和ZnOBBNC剂量 (0.5-5g。L-1) 的影响。从吸附等温线数据来看,使用ZnOBBNC吸附磷酸盐遵循Langmuir等温线 (R2 = 0.9616),证实了单层吸附机理。动力学研究表明,使用ZnOBBNC的磷酸盐吸附遵循伪二阶模型 (R2 = 1.0000),证实了内球肤色的化学吸附机理。我们的结果表明,与商业纳米复合材料相比,ZnOBBNC是从模拟实验室制备的和实际现场收集的废水样品中去除磷酸盐的合适的,有竞争力的候选者。

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