Synthesis, properties, and optical applications of noble metal nanoparticle-biomolecule conjugates

Noble metal nanoparticles, such as gold or silver nanoparticles and nanorods, exhibit unique photonic, electronic and catalytic properties. Functionalization of noble metal nanoparticles with biomolecules (e.g., protein and DNA) produces systems that possess numerous applications in catalysis, delivery, therapy, imaging, sensing, constructing nanostructures and controlling the structure of biomolecules. In this paper, the recent development of noble metal nanoparticle-biomolecule conjugates is reviewed from the following three aspects: (1) synthesis of noble metal nanoparticle-biomolecule systems by electrostatic adsorption, direct chemisorption of thiol derivatives, covalent binding through bifunctional linkers and specific affinity interactions; (2) the photonic properties and bioactivation of noble metal nanoparticle-biomolecule conjugates; and (3) the optical applications of such systems in biosensors, and medical imaging, diagnosis, and therapy. The conjugation of Au and Ag nanoparticles with biomolecules and the most recent optical applications of the resulting systems have been focused on.     

新型银-二氧化硅核-壳型复合纳米粒子的合成与表征

利用正四甲氧基硅在微乳液介质中的水解反应合成新型银 -二氧化硅核 -壳型复合纳米粒子 .通过化学反应调控 ,直径为 5～ 1 0 nm的金属银纳米粒子可以以单核或多核形式嵌入并分布于球型二氧化硅粒子中 .透射电子显微镜照片表明 ,该复合粒子具有高度均匀的粒径分布 .     

溶胶-凝胶法制备FePt纳米颗粒及其性质研究

通过溶胶-凝胶法制备了L10相FePt纳米颗粒,并利用X射线衍射(XRD)、振动样品磁强计(VSM)、透射电子显微镜(TEM)等测试手段对所制备的样品进行了结构和磁性表征.XRD及TEM分析表明,700℃所制备的FePt纳米颗粒为面心四方(FCT)结构,颗粒形状为球形且分散性较好,晶粒尺寸约为12 nm.磁性测试结果表明,L10相的FePt纳米颗粒室温下具有铁磁性,其矫顽力为1 887 Oe.     

Magnetic Films on Self-assembled Nanospheres

1 Results Nanoparticle media using arrays of monodisperse nanoparticles with high magneticanisotropy are assumed to be the ideal future magnetic recording media. However,key requirements like control of the magnetic anisotropy orientation along with magnetic domain isolation have not been achieved so far. Here, we report on a combination of a two-dimensional topographic pattern formed of self-assembled nanoparticles with sizes as small as 20 nm and magnetic multilayer film deposition[1]. The so formed n...     

Au, Ag and Au:Ag colloidal nanoparticles synthesized by pulsed laser ablation as SERS substrates

Chemically pure colloidal suspensions of gold and silver nanoparticles were synthesized using pulsed laser ablation.The dependence of laser fl uence on the surface plasmon characteristics of the nanoparticles was investigated.Au:Ag colloidal suspensions were prepared by mixing highly monodisperse Au and Ag nanocolloids.The plasmon band of these mixtures was found to be highly sensitive to Au:Ag concentration ratio and wavelength of the laser beam used in the ablation process.The Au:Ag mixture consists of almost spherical shaped nanostructures with a tendency to join with adjacent ones.The surface enhanced Raman scattering activity of the Au,Ag and Au:Ag colloidal suspensions was tested using crystal violet as probe molecules.Enhancement in Raman signal obtained with Au:Ag substrates was found to be promising and strongly depends on its plasmon characteristics.     

Preparation of monodisperse,superparamagnetic, luminescent,and multifunctional PGMA microspheres with amino-groups

Micron-sized, monodisperse, superparamagnetic, luminescent composite poly（glycidyl methacrylate） （PGMA） microspheres with functional amino-groups were successfully synthesized in this study. The process of preparation was as follows： preparation of monodisperse poly（glycidyl methacrylate） microspheres by dispersion polymerization method; modification of poly（glycidyl methacrylate） microspheres with ethylene diamine to form amino-groups; impregnation of iron ions （Fe^2＋ and Fe^3＋） inside the microspheres and subsequently precipitating them with ammonium hydroxide to form magnetite （Fe3O4） nanoparticles within the polymer microspheres; infusion of CdSe/CdS core-shell quantum dots （QDs） into magnetic polymer microspheres. Scanning electron microscopy （SEM） was used to characterize surface morphology and size distribution of composite microspheres. The average size of microspheres was 1.42 μm with a size variation of 3.8%. The composite microspheres were bright enough and easily observed using a conventional fluorescence microscope. The composite microspheres were easily separated from solution by magnetic decantation using a permanent magnet. The new multifunctional composite microspheres are promising to be used in a variety of bioanalyUcal assays involving luminescence detection and magnetic separation.     

单分散性的Q态CdS 纳米粒子的制备与分离

采用十二硫醇作配体，十六烷基三甲基溴化铵作有机阳离子保护层，通过加入不同量的饱和H2S溶液与CdSO4在室温条件下搅拌反应，制备出3种不同粒径的Q态CdS纳米粒子．在合成CdS纳米微粒过程中，采用后沉淀尺寸分离技术，使用无水乙醇对初制备的CdS纳米微粒进行分步沉降分离，得到单分散性的Q态CdS纳米粒子．通过紫外可见光谱测定对其进行表征和研究。     

PVA-Chitosan-SiO2荧光复合纳米粒子的制备与表征

采用反相微乳液法制备了PVA-Chitosan-SiO2荧光复合纳米粒子,利用透射电子显微镜、红外光谱、荧光光谱等对复合纳米粒子进行表征,并进行了分散性、光稳定性及荧光分子泄露等实验,结果表明该复合纳米粒子单分散性良好,呈规则球状、粒径为80 nm左右,由于高分子材料PVA的加入,复合纳米粒子水溶性、分散性及化学稳定性得到改善。     

2022年纳米颗粒精确自组装热点回眸

构筑具有特定功能的复杂物质是纳米颗粒自组装的重要目标之一。聚焦于纳米颗粒自组装的基本原则,讨论了纳米粒子间的相互作用力驱动自组装具有理想性能的纳米结构和材料,精确制备从零维到三维的高质量结构,如胶体分子、纳米链、胶体晶体和光子晶体等;回顾了2022年纳米颗粒组装体在传感、光电器件、显示、药物递送和生物医疗诊断领域所取得的重要进展,并提出了该领域在构筑新物质方面面临的挑战。     

A facile and general approach for the synthesis of fluorescent silica nanoparticles doped with inert dyes

A general and facile approach was developed for the synthesis of almost monodisperse fluorescent silica nanoparticles (NPs) doped with inert dyes, which are organic fluorophores that are strongly fluorescent but are hydrophobic or lack a covalent binding group. The prepared NPs were mesoporous and the dye molecules were encapsulated in the pores via hydrophobic interaction with the CTAB template. The NPs were stable and highly fluorescent in aqueous solution, and have potential applications in bioanalysis a...     

Fe3O4/SiO2磁性微球的制备研究

报道了Fe3O4/SiO2纳米复合材料的可控合成方法.研究并探讨了乙醇-水体系配比及氨水和硅酸四乙酯的用量对纳米粒子形貌的影响,利用柠檬酸作分散剂,控制反应条件对Fe3O4纳米粒子进行表面修饰改性后,又对其进行SiO2包覆.然后运用X射线衍射仪（XRD）、透射电子显微镜（TEM）、红外（IR）对合成的纳米微粒的粒径、结构进行了表征.实验结果表明,产物为粒径均匀的单分散Fe3O4/SiO2复合纳米粒子,平均粒度约为100 nm.     

Controlling anisotropic nanoparticle growth through plasmon excitation

Inorganic nanoparticles exhibit size-dependent properties that are of interest for applications ranging from biosensing and catalysis to optics and data storage. They are readily available in a wide variety of discrete compositions and sizes. Shape-selective synthesis strategies now also yield shapes other than nanospheres, such as anisotropic metal nanostructures with interesting optical properties. Here we demonstrate that the previously described photoinduced method for converting silver nanospheres into triangular silver nanocrystals--so-called nanoprisms--can be extended to synthesize relatively monodisperse nanoprisms with desired edge lengths in the 30-120 nm range. The particle growth process is controlled using dual-beam illumination of the nanoparticles, and appears to be driven by surface plasmon excitations. We find that, depending on the illumination wavelengths chosen, the plasmon excitations lead either to fusion of nanoprisms in an edge-selective manner or to the growth of the nanoprisms until they reach their light-controlled final size.     

金胶/碳球复合纳米材料的制备及表征

通过微波水热法,以葡萄糖水溶液为原料,制备了单分散的溶胶碳球,用自组装方法把金胶纳米粒子修饰在碳球表面合成了金胶/碳球纳米复合材料。通过扫描电镜、透射电镜、红外光谱及循环伏安等技术对最终产物的形貌、组成和光学性质进行了表征。由于所得到的金胶/碳球复合材料具有很好的化学稳定性与无毒性,同时金胶纳米粒子具有生物相容性,该复合材料可作为载体材料应用于生物分析。     

A facile strategy to prepare monodisperse nanocrystalswith init iative assembl y into superla ttice

A facile green strategy,low temperature in-situ chemical conversion,is reported to prepare nanocrystals with initiative "bottom-up" assembly into large-scale superlattice.The appropriate organic chalcogen precursors were chosen to control the kinetics of these reactions to keep monodisperse morphology.They also provide the capping ligands to acquire van der Waals interactions between ligands and dipole moment to self-assemble into large-scale superlattice.This strategy could flexibly modulate the composition of semiconductor nanostructures,such as cations,anions and even the heterostructures with metal nanoparticles.This bottom-up assembly behavior is necessary for the development of optoelectronic devices of Ⅱ-Ⅵ semiconductor nanocrystals.     

纳米CeO2的表面改性及其在水介质中的分散性能

采用阴离子型表面活性剂十二烷基硫酸钠对纳米CeO₂进行表面修饰,考察了表面改性工艺条件对纳米CeO₂在水介质中粒度分布及Zeta电位的影响,确定了适宜的表面改性工艺条件：改性剂质量浓度60g/L、改性温度25℃、改性时间4h、搅拌速率150r/min,pH 9~11。采用TEM、FT-IR、XRD对改性前后的纳米CeO₂颗粒进行了表征,结果表明改性后纳米CeO₂表面包裹了一层改性剂分子,颗粒在水介质中分散性良好,达到了单分散。此外,采用溶液共混法制备聚乙烯醇（PVA）/ CeO₂纳米复合膜材料,利用UV-Vis分光光度计表征了复合膜材料的光学性能,发现纳米复合膜具有良好的紫外屏蔽性能以及高的可见光透过率,在300~400nm的近紫外光区,复合膜的紫外屏蔽率可达97%,添加5%纳米粒子的复合膜在650nm处的可见光透过率比纯PVA膜降低了3%,保证了复合膜的透明度。     

单分散聚苯乙烯/二硫化钼纳米复合微球的制备与分散性

以二硫化钼为核,聚苯乙烯为壳,通过种子乳液聚合方法,成功制备了具有核壳结构的聚苯乙烯/二硫化钼(PS/MoS2)有机-无机纳米复合微球。利用紫外可见吸收光谱、透射电镜、扫描电镜、能量色散谱仪等多种方法,对PS/MoS2纳米微球的形貌、结构进行了表征,同时,利用分散性试验考察了PS/MoS2纳米微球在油溶性单体双环戊二烯(DCPD)中的分散性。试验结果表明:聚苯乙烯包覆在MoS2的表面,形成核壳结构;纳米粉体呈球形且粒径尺寸均一。分散性试验表明PS/MoS2纳米微球在DCPD中具有极佳的分散性。     

Self-directed self-assembly of nanoparticle/copolymer mixtures

The organization of inorganic nanostructures within self-assembled organic or biological templates is receiving the attention of scientists interested in developing functional hybrid materials. Previous efforts have concentrated on using such scaffolds to spatially arrange nanoscopic elements as a strategy for tailoring the electrical, magnetic or photonic properties of the material. Recent theoretical arguments have suggested that synergistic interactions between self-organizing particles and a self-assembling matrix material can lead to hierarchically ordered structures. Here we show that mixtures of diblock copolymers and either cadmium selenide- or ferritin-based nanoparticles exhibit cooperative, coupled self-assembly on the nanoscale. In thin films, the copolymers assemble into cylindrical domains, which dictate the spatial distribution of the nanoparticles; segregation of the particles to the interfaces mediates interfacial interactions and orients the copolymer domains normal to the surface, even when one of the blocks is strongly attracted to the substrate. Organization of both the polymeric and particulate entities is thus achieved without the use of external fields, opening a simple and general route for fabrication of nanostructured materials with hierarchical order.     

均分散二氧化硅微球生长速度与粒径的相关性

分散体系形成过程中，颗粒生长速度与颗粒尺寸的关系是决定分散体系颗粒大小分布的十分重要的因素。本文利用均分散体系颗粒大小均一这一重要特征，提出了适用于确定均分散体系颗粒生长速度与颗粒尺寸相关性的方法，并研究了二氧化硅微球的生长速度与其粒径的关系。研究表明，二氧化硅微球的生长速度与其粒径无关，符合表面反应控制生长机理。     

单分散二氧化硅体系制备中正硅酸乙酯水解与成核及颗粒生长的关系

用透射电镜对乙醇介质中氨催化下正硅酸乙酯（ＴＥＯＳ）水解制各单分散二氧化硅微粒过程中颗粒的生长过程进行了跟踪，通过对ＴＥＯＳ的水解速率与成核及颗粒生长速率间关系的研究，发现水解是整个反应的控制步骤，影响水解的因素也同样影响成核及颗粒的生长。     

SiO2/PMMA无机-有机复合材料的制备与性能

以苯乙烯磺酸钠（NaSS）为离子单体,将其介入甲基丙烯酸甲酯（MMA）与正硅酸乙酯（TEOS）的原位分散聚合体系,以获得较少分散剂用量下的多功能二氧化硅/聚甲基丙烯酸甲酯(SiO2/PMMA)复合体系的单分散微球,采用XRD、SEM、TEM、FTIR、TGA和DSC对所获SiO2/PMMA复合微球进行了表征,并对其防水性能及单体合成机理进行了研究。研究结果表明：在分散聚合体系中加入正硅酸乙酯（TEOS）获得的纳米SiO2颗粒,可提高聚合物PMMA的疏水性能,且对该复合材料的透光率影响不大,仍具有很高的透明度。