纳米抗菌剂及其在粉末涂料中的应用

在环氧／聚酯，聚酯／TGIC粉末体系中添加1．0％－3．0％的无机银离子抗菌剂后，采用原有的制粉设备和静电喷涂工艺，形成的涂层具有优良的杀灭细菌的功能，涂层本身对人体无害。

纳米农药国际管理现状及挑战

近年来,纳米农药因同时具有“增效”和“减量”的双重优势,赢得了业界广泛关注,发展势头强劲。但因其“纳米”特性可能对人体健康和环境安全造成危害,也给各国农药管理部门带来了一定的挑战。本文从纳米农药定义入手,对有关国际组织和欧美等发达国家的纳米农药管理现状进行了介绍,同时从理化特性、健康风险评估以及环境风险评估等角度总结了纳米农药管理的主要特点及面临的挑战,供相关管理部门和行业参考。

DNA疫苗的研究现状

DNA疫苗的概念提出已有十几年的时间,其间针对DNA疫苗的研究工作取得了很大进展,其有效性已在动物体内得到了验证,而且部分疫苗已进入临床试验阶段,但在取得进展的同时也遇到了许多制约其发展的难题。本文对DNA疫苗发展现状,遇到的问题,采取的策略及可能引起的副反应加以综述。

N-doped ordered mesoporous carbon as a multifunctional support of ultrafine Pt nanoparticles for hydrogenation of nitroarenes

Due to the advantages of high surface areas, large pore volumes and pore sizes, abundant nitrogen content that favored the metal-support interactions, N-doped ordered mesoporous carbons are regarded as a kind of fascinating and potential support for the synthesis of effective supported cat-alysts. Here, a N-doped ordered mesoporous carbon with a high N content （9.58 wt%）, high surface area （417 m^2/g）, and three-dimensional cubic structure was synthesized successfully and used as an effective support for immobilizing Pt nanoparticles （NPs）. The positive effects of nitrogen on the metal particle size enabled ultrasmall Pt NPs （about 1.0 ± 0.5 nm） to be obtained. Moreover, most of the Pt NPs are homogeneously dispersed in the mesoporous channels. However, using the ordered mesoporous carbon without nitrogen as support, the particles were larger （4.4 ± 1.7 nm） and many Pt NPs were distributed on the external surface, demonstrating the important role of the nitrogen species. The obtained N-doped ordered mesoporous material supported catalyst showed excellent catalytic activity （conversion 100%） and selectivity （〉99%） in the hydrogenation of halogenated nitrobenzenes under mild conditions. These values are much higher than those achieved using a commercial Pt/C catalyst （conversion 89% and selectivity 90%）. This outstanding catalytic perfor-mance can be attributed to the synergetic effects of the mesoporous structure, N-functionalized support, and stabilized ultrasmall Pt NPs. Moreover, such supported catalyst also showed excellent catalytic performance in the hydrogenation of other halogenated nitrobenzenes and nitroarenes. In addition, the stability of the multifunctional catalyst was excellent and it could be reused more than 10 times without significant losses of activity and selectivity. Our results conclusively show that a N-doped carbon support enable the formation of ultrafine metal NPs and improve the reaction ac-tivity and selectivity.

Alginate-Coated Fe3O4 Hollow Microspheres for Drug Delivery

Novel hollow Fe3O4 nanoparticles for drug delivery were synthesized via a one-step template- free approach. These nanoparticles were obtained by modifing the Fe3O4 nanoparticles with 3-aminopropyltrimethoxy silane, and then grafting alginate onto the surface of amine magnetic. The hollow structure of Fe3O4 spheres was characterized by TEM, XRD, and XPS. The M-H hysteresis loop indicated that the magnetic spheres exhibit snperparamagnetic characteristics at room temperature. Daunorubicin acting as a model drug was loaded into the carrier, and the maximum percent of envelop and load were 28.4% and 14.2% respectively. The drug controlled releasing behaviors of the carriers were compared in different pH media.

Synthesis of Pd nanoparticles supported on CeO_2 nanotubes for CO oxidation at low temperatures

Developing efficient supported Pd catalysts and understanding their catalytic mechanism in CO oxidation are challenging research topics in recent years.This paper describes the synthesis of Pd nanoparticles supported on CeO2 nanotubes via an alcohol reduction method.The effect of the support morphology on the catalytic reaction was explored.Subsequently,the performance of the prepared catalysts was investigated toward CO oxidation reaction and characterized by Nitrogen sorption,X-ray diffraction,X-ray photoelectron spectroscopy,transmission electron microscopy,and CO-temperature-programmed desorption techniques.The results indicated that the catalyst of Pd on CeO2 nanotubes exhibits excellent activity in CO oxidation at low temperatures,due to its large surface area,the high dispersion of Pd species,the mesoporous and tubular structure of the CeO2-nanotube support,the abundant Ce3＋,formation of Pd–O–Ce bonding,and enhanced metal–support interaction on the catalyst surface.

A review of applications of poly(diallyldimethyl ammonium chloride) in polymer membrane fuel cells: From nanoparticles to support materials

Polymer membrane fuel cells represent important sustainable energy devices because their operation involves zero emissions and low temperatures and their components exhibit low toxicity. Among the various components of such cells, the electrocatalyst plays the vital role of enhancing the output power density and/or working lifetime. Over the past several decades, numerous strategies have been proposed to address the challenges of electrocatalyst activity and/or durability. Herein, we review the applications of polyelectrolytes in electrocatalysts, including the enhancement of both catalytic nanoparticles and support materials. The effects of polyelectrolytes with regard to controlling the size, composition and morphology of catalytic nanoparticles, as well as the modification of support materials were summarized. In addition, the future possibilities for the research and development of polyelectrolytes in the field of catalyst design and synthesis are discussed.

Effect of Tb/Mg doping on composition and physical properties of hydroxyapatite nanoparticles for gene vector application

Transfection efficiency of hydroxyapatite nanoparticles(HAnps)is relative to the particle size,morphology,surface charge,surface modifier and so on.This study prepared HAnps with doped Tb/Mg by hydrothermal synthesis method(HTSM)and investigated the effects of different Tb/Mg contents on the morphology,particle size,surface charge,composition and cellular endocytosis of HAnps.The results showed that Mg-HAnps possessed better dispersion ability than Tb-HAnps.With increasing doping content of Tb/Mg-HAnps,the granularity of Tb-HAnps increased,while that of Mg-HAnps declined.Both particle size and zeta potential of Mg-HAnps were lower than those of Tb-HAnps.7.5%Mg-doping HAnps presented relatively uniform slender rod morphology with average size of30nm,while10%Mg-doping HAnps were prone to agglomeration.Moreover,Mg-HAnps-GFP(green fluorescent protein)endocytosed by MG63cells was dotted in the perinuclear region,while Tb-HAnps were more likely to aggregate.In conclusion,as gene vectors,Mg-HAnps showed enhanced properties compared to Tb-HAnps.

Catalytic performance enhancement by alloying Pd with Pt on ordered mesoporous manganese oxide for methane combustion

Ordered mesoporous Mn2O3 (meso‐Mn2O3) and meso‐Mn2O3‐supported Pd, Pt, and Pd‐Pt alloy x(PdyPt)/meso‐Mn2O3; x = (0.10?1.50) wt%; Pd/Pt molar ratio (y) = 4.9?5.1 nanocatalysts were prepared using KIT‐6‐templated and poly(vinyl alcohol)‐protected reduction methods, respectively.The meso‐Mn2O3 had a high surface area, i.e., 106 m2/g, and a cubic crystal structure. Noble‐metalnanoparticles (NPs) of size 2.1?2.8 nm were uniformly dispersed on the meso‐Mn2O3 surfaces. AlloyingPd with Pt enhanced the catalytic activity in methane combustion; 1.41(Pd5.1Pt)/meso‐Mn2O3gave the best performance; T10%, T50%, and T90% (the temperatures required for achieving methaneconversions of 10%, 50%, and 90%) were 265, 345, and 425 °C, respectively, at a space velocity of20000 mL/(g?h). The effects of SO2, CO2, H2O, and NO on methane combustion over1.41(Pd5.1Pt)/meso‐Mn2O3 were also examined. We conclude that the good catalytic performance of1.41(Pd5.1Pt)/meso‐Mn2O3 is associated with its high‐quality porous structure, high adsorbed oxygen species concentration, good low‐temperature reducibility, and strong interactions between Pd‐Pt alloy NPs and the meso‐Mn2O3 support.

Phenylboronic acid modified mucoadhesive nanoparticle drug carriers facilitate weekly treatment of experimentally- induced dry eye syndrome

Topical formulations, commonly applied for treatment of anterior eye diseases, require frequent administration due to rapid clearance from the ocular surface, typically through the lacrimal drainage system or through over-spillage onto the lids. We report on a mucoadhesive nanoparticle drug delivery system that may be used to prolong the precorneal residence time of encapsulated drugs. The nanoparticles were formed from self-assembly of block copolymers composed of poly（D, L-lactide） and Dextran. The enhanced mucoadhesion properties were achieved by surface functionalizing the nanoparticles with phenylboronic acid. The nanoparticles encapsulated up to 12 wt.% of Cyclosporine A （CycA） and sustained the release for up to five days at a clinically relevant dose, which led us to explore the therapeutic efficacy of the formulation with reduced administration frequency. By administering CycA-loaded nanoparticles to dry eye-induced mice once a week, inflammatory infiltrates were eliminated and the ocular surface completely recovered. The same once a week dosage of the nanoparticles also showed no signs of physical irritation or inflammatory responses in acute （1 week） and chronic （12 weeks） studies in healthy rabbit eyes. These findings indicate that the nanoparticles may significantly reduce the frequency of administration for effective treatment of anterior eye diseases without causing ocular irritation.

Gene silencing-mediated immune checkpoint blockade for tumor therapy boosted by dendrimer-entrapped gold nanoparticles

Immune checkpoint blockade(ICB) has been regarded as one promising approach for tumor immunotherapy. Here, we report a functional nanoplatform based on generation 5(G5) poly(amidoamine)(PAMAM)dendrimer-entrapped gold nanoparticles(Au DENPs) as a nonviral vector to deliver programmed death-ligand 1(PDL1) small interfering RNA(siPD-L1) for subsequent PD-L1 gene silencing-mediated tumor immunotherapy. In this work,G5 dendrimers with amine termini were partially decorated with methoxy polyethylene glycol(m PEG) on their periphery,entrapped Au NPs within their interiors, and were eventually labeled with fluorescamine. The generated functional Au DENPs possess desired dispersibility in water and colloidal stability, satisfactory cytocompatibility after complexation with siPD-L1, and efficient gene delivery performance. Strikingly, the functional Au DENPs enabled the delivery of siPDL1 to cancer cells to efficiently knock down the PD-L1 protein expression, thus boosting the ICB-based immunotherapy of a xenografted melanoma mouse tumor model with a tumor inhibition efficiency much higher than the PD-L1 antibody.The immune responses were also well demonstrated by downregulation of PD-L1 protein on the tumor cell surface and abundant distribution of CD8+and CD4+T cells in the infiltrating tumor tissue and spleen organ. The developed functional dendrimer-based nanoplatform may be promising to boost ICB-based immunotherapy of other tumor types.

Versatile functionalization of amylopectin for effective biomedical applications

Successful gene vectors should be with high transfection efficiency and minimal cytotoxicity. Natural polysaccharides, due to their good biocompatibility and biodegradability, have been widely studied and applied. Amylopectin is one of polysaccharides with dendritic structure and numerous hydroxyl groups that could be used for subsequent modification. In this work, a series of dendritic cationic gene vectors comprising amylopectin backbones and poly(2-(dimethylamino) ethyl methacrylate)(PDMAEMA) side chains with different lengths(termed as AMY-PDs) were readily prepared by atom transfer radical polymerization(ATRP). The gene condensation ability, cytotoxicity and gene transfection of AMY-PDs carriers were investigated. In comparison with "gold-standard" poly(ethyleneimine)(PEI, 25 k Da), the AMY-PDs exhibited higher transfection efficiency with lower cytotoxicity. AMY-PDs could be further modified with Au nanoparticles(termed as AMY-PD@Au). The potential of the AMY-PD@Au vectors to be utilized as a CT contrast agent for imaging of cancer cells was investigated. Such AMY-PD@Au vectors may realize gene therapy with the ability of real-time imaging.