自组装金纳米粒子薄膜SERS研究

采用静电自组装技术制备了金纳米粒子薄膜,研究了薄膜的表面增强拉曼散射(SERS)活性。自组装金纳米粒子薄膜具有明显的SERS效应,其中2双层薄膜的增强效应最强。金纳米粒子相互靠近但又不至于连通的状态具有最强的增强效果。若金纳米粒子通过点、面接触形成连通网络,将导致入射光激发表面等离子体波的机率下低,使增强效果降低。     

金纳米棒合成与自组装的研究进展

与球形金颗粒相比,各向异性的金纳米棒同时具有化学和光学上的各向异性,其更为特殊的表面等离子共振（SPR）特性和基于表面SPR的强吸收和发光特性,在材料科学和生物医学领域中存在着巨大的应用前景。本文主要评述了金纳米棒合成与组装的最新研究进展,具体内容包括：金纳米棒的合成、模板诱导的金纳米棒的自组装、表面张力诱导的金纳米棒的自组装及应用。     

光触发金纳米颗粒低聚体的可逆自组装研究

利用聚乙二醇(PEG,亲水)和含有螺吡喃结构单元的聚甲基丙烯酸酯(PSPMA,疏水)修饰金纳米颗粒(AuNP)表面,成功制备出光响应双亲性金纳米颗粒。由于螺吡喃结构单元的光敏感性,在光触发条件下,该双亲性金纳米颗粒容易实现可控调节的组装和解离。在可见光作用下,螺吡喃结构为相邻的AuNP之间提供较弱分子间作用力,可以在溶剂中彼此解离。而在紫外光作用下,聚甲基丙烯酸酯中的螺吡喃结构单元发生螺-部花青异构化,该异构体中含有共轭结构和两性离子态,通过π-π键重叠和静电吸引等强作用力促进相邻AuNP的自组装,进一步促进AuNP低聚物的形成。智能可逆的AuNP低聚物表现出可切换的等离子体耦合性能,在基于表面增强拉曼散射的传感器和光学成像领域具有非常广阔的应用前景。     

“核—卫星”状金纳米粒子组装体的自组装方法与应用

"核—卫星"状金纳米粒子组装体(CSNAs)因其新颖的构型和特殊的性能而备受关注,在表面增强拉曼光谱(SERS)、光电器件、生化传感器和特异材料方面引起了科学家们的极大兴趣。文章总结了目前用于构建CSNAs的几种主要的自组装方法,并对组装体的应用进行了介绍。     

金纳米粒子修饰玻碳电极的电化学行为研究

利用层层自组装技术,通过有机偶联层胱胺将金纳米粒子修饰在玻碳电极上,得到金纳米粒子/胱胺/玻碳电极,并通过循环伏安法和电化学阻抗谱对修饰电极的电化学行为进行研究,结果表明该修饰电极具有优于裸玻碳电极的良好的电化学性能,可用于进一步的应用。     

液晶金纳米粒子的研究进展

液晶金纳米粒子是一类非常重要的功能材料。液晶金纳米粒子不仅能自组装成一维(1D)、二维(2D)和三维(3D)有序的定向排列还能增强液晶材料的导电性。液晶金纳米粒子在非线性光学、物理化学传感器和分子识别等领域有着广泛的应用前景。综述了近年来液晶硫醇金纳米粒子的研究进展。     

有序纳米金颗粒的多层组装

采用LB技术组装了一种三维有序的由十八胺修饰的纳米金颗粒多层结构．这是一种新的组装纳米颗粒三维有序聚集体的方法．为了扩大这种方法的适用范围，在组装过程中，将有机小分子1-苯基-5-巯基四氮唑引进结构，形成了新的纳米金颗粒多层聚集体．这两种多层膜经透射电子显微镜和小角X射线衍射测量证明构成多层膜的单层膜上的纳米金颗粒是有序的，并且颗粒在层与层之间的排列也是有序的．     

自组装膜技术及应用研究进展

对自组装膜技术的概念和近年的应用和研究进展做了较全面的综述,介绍了自组装膜的形成机理,自组装膜技术在纳米薄膜、表面修饰、金属防护、生物医学、催化剂和药物传送等方面的应用.对相关研究领域的杰出研究成果进行分析,为更加深入探索和研究自组装膜技术提供了有用的参考信息.     

两亲性肽自组装纳米结构及其应用

自然界中许多生物大分子都可以通过小分子以分子自组装的方式有机地组织起来,分子自组装技术在制备纳米结构生物材料等方面具有独特的优势,尤其是以能自组装成各种纳米结构的两亲性肽分子自组装材料近来备受关注。文章就目前国内外两亲性肽自组装成纳米结构及其多种生物医学方面应用进行了综述,并对影响两亲性肽自组装的因素进行了探讨。     

碳纳米管表面铜和银纳米粒子的修饰

利用非共价修饰的方法,先在碳纳米管表面包裹上表面活性剂十六烷基三甲基溴化铵（CTAB）和聚丙烯酸钠（PAA）,然后原位修饰上铜和银纳米粒子,制备出MWCNT/CTAB/PAA/M（M：Cu或Ag）纳米复合材料,最后通过XRD、SEM和TEM等技术对其进行表征。结果表明,利用这种简单的层层自组装方法能够在碳管上均匀地修饰金属纳米粒子,并且这两种金属纳米粒子的尺寸都小于5 nm。     

A Centrifugation-based Method for Preparation of Gold Nanoparticles and its Application in Biodetection

Gold nanoparticles (AuNPs) have found widespread applications in life sciences. While synthesis of monodispersed AuNPs has been fairly convenient by using chemical reduction of chloroauric acid by sodium citrate, we found that AuNPs of high quality and high concentrations were not readily obtained via this method. As an example, we showed that monodispersed 13-nm AuNPs were readily synthesized at relatively low concentrations (e.g. 3.5 nM); in contrast, 13-nm AuNPs of 17 nM obtained by the direct reduction method were irregularly shaped and not well dispersed. In this work, we demonstrated that AuNPs of high concentration could be prepared by a two-step approach, i.e. chemical reduction at low concentrations and subsequent centrifugation. Compared to the direct reduction method, this new two-step method led to AuNPs with high salt resistance and high stability, which are essential for the preparation of DNA-AuNPs conjugates for DNA biodetection.     

二氧化钛纳米粒子的表面修饰及表征

本文利用溶胶-凝胶法制备了6-氨基己酸修饰的TiO2纳米粒子,并对所得产物进行FT-IR、UVVis、XRD和TEM表征,结果证明所得产物表面包覆有有机层,产物的粒径范围为50～60nm,颗粒形状为球形,品型主要为锐钛矿型。在醇溶胶中,产物对紫外光的吸收性能大大提高。     

Self-Assembly Nanoparticles of Natural Bioactive Abietane Diterpenes

Different approaches have been reported to enhance penetration of small drugs through physiological barriers; among them is the self-assembly drug conjugates preparation that shows to be a promising approach to improve activity and penetration, as well as to reduce side effects. In recent years, the use of drug-conjugates, usually obtained by covalent coupling of a drug with biocompatible lipid moieties to form nanoparticles, has gained considerable attention. Natural products isolated from plants have been a successful source of potential drug leads with unique structural diversity. In the present work three molecules derived from natural products were employed as lead molecules for the synthesis of self-assembled nanoparticles. The first molecule is the cytotoxic royleanone 7α-acetoxy-6β-hydroxyroyleanone (Roy, 1) that has been isolated from hairy coleus (Plectranthus hadiensis (Forssk.) Schweinf). ex Sprenger leaves in a large amount. This royleanone, its hemisynthetic derivative 7α-acetoxy-6β-hydroxy-12-benzoyloxyroyleanone (12BzRoy, 2) and 6,7-dehydroroyleanone (DHR, 3), isolated from the essential oil of thicket coleus (P. madagascariensis (Pers.) Benth.) were employed in this study. The royleanones were conjugated with squalene (sq), oleic acid (OA), and/or 1-bromododecane (BD) self-assembly inducers. Roy-OA, DHR-sq, and 12BzRoy-sq conjugates were successfully synthesized and characterized. The cytotoxic effect of DHR-sq was previously assessed on three human cell lines: NCI-H460 (IC₅₀ 74.0 ± 2.2 µM), NCI-H460/R (IC₅₀ 147.3 ± 3.7 µM), and MRC-5 (IC₅₀ 127.3 ± 7.3 µM), and in this work Roy-OA NPs was assayed against Vero-E6 cells at different concentrations (0.05, 0.1, and 0.2 mg/mL). The cytotoxicity of DHR-sq NPs was lower when compared with DHR alone in these cell lines: NCI-H460 (IC₅₀ 10.3 ± 0.5 µM), NCI-H460/R (IC₅₀ 10.6 ± 0.4 µM), and MRC-5 (IC₅₀16.9 ± 0.5 µM). The same results were observed with Roy-OA NPs against Vero-E6 cells as was found to be less cytotoxic than Roy alone in all the concentrations tested. From the obtained DLS results, 12BzRoy-sq assemblies were not in the nano range, although Roy-OA NP assemblies show a promising size (509.33 nm), Pdl (0.249), zeta potential (−46.2 mV), and spherical morphology from SEM. In addition, these NPs had a low release of Roy at physiological pH 7.4 after 24 h. These results suggest the nano assemblies can act as prodrugs for the release of cytotoxic lead molecules.     

纳米改性聚合物材料研究进展

综述了纳米改性聚合物材料的研究进展,包括纳米粒子的结构与性质,纳米粒子的表面改性,纳米粒子对聚合物的改性机理和方法及纳米技术在高分子材料领域中的应用。     

Methanobactin-Mediated One-Step Synthesis of Gold Nanoparticles

Preparation of gold nanoparticles with a narrow size distribution has enormous importance in nanotechnology. Methanobactin (Mb) is a copper-binding small peptide that appears to function as an agent for copper sequestration and uptake in methanotrophs. Mb can also bind and catalytically reduce Au (III) to Au (0). In this study, we demonstrate a facile Mb-mediated one-step synthetic route to prepare monodispersed gold nanoparticles. Continuous reduction of Au (III) by Mb can be achieved by using hydroquinone as the reducing agent. The gold nanoparticles have been characterized by UV-visible spectroscopy. The formation and the surface plasmon resonance properties of the gold nanoparticles are highly dependent on the ratio of Au (III) to Mb in solution. X-ray photoelectron spectroscopy (XPS), fluorescence spectra and Fourier transform-infrared spectroscopy (FT-IR) spectra suggest that Mb molecules catalytically reduce Au (III) to Au (0) with the concomitant production of gold nanoparticles, and then, Mb statically adsorbed onto the surface of gold nanoparticles to form an Mb-gold nanoparticles assembly. This avoids secondary nucleation. The formed gold nanoparticles have been demonstrated to be monodispersed and uniform by transmission electron microscopy (TEM) images. Analysis of these particles shows an average size of 14.9 nm with a standard deviation of 1.1 nm. The gold nanoparticles are extremely stable and can resist aggregation, even after several months.     

Dispersion Function of a Protein,DP-1, Identified in Collimonas sp. D-25, for the Synthesis of Gold Nanoparticles

Collimonas sp. (D-25), found in the soil of Akita Prefecture, is a gram-negative bacterium with the ability to synthesize gold nanoparticles (AuNPs). During the synthesis of AuNPs, one specific protein (DP-1) was found to have disappeared in the sonicated solution of the bacterium. Recombinant DP-1 (rDP-1) from Escherichia coli BL21 (DE3) was used to study the effect of DP-1 on the synthesis of AuNPs. AuNPs synthesized with rDP-1 result in small, stabilized nanoparticles. AuNPs synthesized by DP-1 retained the stability of both the dispersion and nano-size particles under high salt concentrations. Isothermal titration calorimetry was employed to investigate the bonding ratio of rDP-1 to AuNPs. Several thousand rDP-1 proteins are attached to the surface of an AuNP to form a protein corona containing multiple layers. These results suggest that DP-1 obtained from D-25 has a size and stability control function during AuNP synthesis.     

二硫化钼纳米微粒改性聚乙烯研究

通过红外、热重、差热等分析手段及拉伸实验,研究了二硫化钼(MoS2)纳米球与纳米片对聚乙烯(PE)塑料性能的影响。发现添加MoS2后,PE塑料的降解温度、结晶峰温度与玻璃化温度均有提高,同时材料的拉伸强度也得到明显提升,其中MoS2纳米片对PE的改性效果最佳。MoS2纳米球与MoS2纳米片的微观结构不同,因而导致了它们改性PE塑料效果的差别。     

Dose Rate Effects on the Selective Radiosensitization of Prostate Cells by GRPR-Targeted Gold Nanoparticles

For a while, gold nanoparticles (AuNPs) have been recognized as potential radiosensitizers in cancer radiation therapy, mainly due to their physical properties, making them appealing for medical applications. Nevertheless, the performance of AuNPs as radiosensitizers still raises important questions that need further investigation. Searching for selective prostate (PCa) radiosensitizing agents, we studied the radiosensitization capability of the target-specific AuNP-BBN in cancer versus non-cancerous prostate cells, including the evaluation of dose rate effects in comparison with non-targeted counterparts (AuNP-TDOTA). PCa cells were found to exhibit increased AuNP uptake when compared to non-tumoral ones, leading to a significant loss of cellular proliferation ability and complex DNA damage, evidenced by the occurrence of multiple micronucleus per binucleated cell, in the case of PC3 cells irradiated with 2 Gy of γ-rays, after incubation with AuNP-BBN. Remarkably, the treatment of the PC3 cells with AuNP-BBN led to a much stronger influence of the dose rate on the cellular survival upon γ-photon irradiation, as well as on their genomic instability. Overall, AuNP-BBN emerged in this study as a very promising nanotool for the efficient and selective radiosensitization of human prostate cancer PC3 cells, therefore deserving further preclinical evaluation in adequate animal models for prostate cancer radiotherapy.