Seed-mediated growth of gold nanoparticles using self-assembled monolayer of polystyrene microspheres as nanotemplate arrays

Arrays of noble metal nanoparticles show potential applications in （bio-）sensing, optical storage, surface-enhanced spectroscopy, and waveguides. For all such potential devices, controlling the size, morphology, and interparticle spacing of the nanoparticles is very important. Here, we combine seed-mediated growth with nanosphere lithography to study the controllable growth of gold nanoparticles （Au NPs）, in which the self-assembly monolayer of polystyrene （PS） on a silicon surface is used to guide the modification of allaunesilanes and the subsequent adsorption of gold seeds; seed-mediated growth is applied to controlling the morphology and size of Au NPs. The size of adsorption region （determining the number of adsorbed gold seeds） is controlled by etching PS microspheres with oxygen plasma or annealing PS microspheres at the glass transition temperature. The size and morphology of the Au NPs are controlled by changing growth conditions. In such a way, we have achieved the dual control of the obtained Au NPs. Preliminary results show that this strategy holds a great promise. This approach can also be extended to a wide range of materials and substrates.

Self-assembled Nanoparticles based on Folic Acid Modifi ed Carboxymethyl Chitosan Conjugated with Targeting Antibody

Nanoparticles conjugated with antibody were designed as active drug delivery system to reduce the toxicity and side effects of drugs for acute myeloid leukemia（AML）.Moreover,methotrexate（MTX）was chosen as modeldrug and encapsulate within folic acid modified carboxymethylchitosan（FACMCS）nanoparticles through self-assembling.The chemicalstructure,morphology,release and targeting of nanoparticles were characterized by routine detection.It is demonstrated that the mean diameter is about 150 nm,the release rate increases with the decreasing of p H,the binding rate of CD33 antibody and FA-CMCS nanoparticles is about 5：2,and nanoparticles can effectively bind onto HL60 cells in vitro.The experimentalresults indicate that the FA-CMCS nanoparticles conjugated with antibody may be used as a potentialp Hsensitive drug delivery system with leukemic targeting properties.

Three-Dimensional Hexagram Gold Nanoparticles: Synthesis and Growth Mechanism

This study explained a procedure to synthesize 3 D hexagram gold nanoparticles using a specific morphologically controlled gold precursor reduction. Acetaldehyde acted as the reducing agent along with polyvinyl pyrrolidone as the stabilizing agent with a limited reaction temperature range observed to be near to 25 °C. The resulting special gold nanoparticles were physically characterized and observed to possess an average planar size of 420 nm, an average central thickness of 200 nm, and an average edge thickness of 18 nm. Furthermore, a mechanism model was proposed to describe the oriented growth of gold nanoparticles employing published accounts of the mechanisms involved in the growth of gold hexagonal nanoplates. Moreover, the two major factors that controlled the morphology of synthesized gold nanoparticles were elaborated to provide reference for future fabrication methods of metal nanoparticles in both academia and industry.

Nanoparticle mediated controlled delivery of dual growth factors

Peripheral nerve functional recovery after nerve injury generally requires multiple growth factors by synergistic effect.However,the optical combination of multiple synergistic growth factors for axonal regeneration has been scarcely considered up to now.Meanwhile,the use of growth factors in promoting nerve regeneration was limited by its short biological half-life in vivo,its vulnerability to structure disruption or hydrolyzation,leading to loss of bioactivity.Herein,a novel polymeric nanoparticle delivery system composed of heparin andε-poly-L-lysine(PL)was prepared for control release of nerve growth factor(NGF)and basic fibroblast growth factor(bFGF).The nanoparticles were synthesized by polyelectrolyte complexation in aqueous solution at room temperature,followed by cross-linking with biological genipin.The obtained nanoparticles had a spherical shape,with a mean diameter of about 246 nm,and high growth factors encapsulation efficiency as well as good stability.NGF and bFGF were encapsulated in the nanoparticles and showed a continuous and slow release behavior in vitro.The bioactivities of the released growth factors were evaluated,and exhibited the synergistic effect.The controlled release of the dual synergistic growth factors would improve the treatment of peripheral nerve injury to mimic the natural cellular microenvironments.

Amphiphilic poly(ethylene glycol)-b-poly(ethylene brassylate)copolymers: One-pot synthesis, self-assembly, and controlled drug release

A set of amphiphilic poly（ethylene glycol）-b-poly（ethylene brassylate）（PEG-b-PEB） copolymers based on the PEB hydrophobic block was first synthesized by ring-opening polymerization of ethylene brassylate with an organic catalyst. The EB/PEG molar ratios and reaction times were adjusted to achieve different chain lengths of PEB. Block copolymers that were characterized by1 H NMR and GPC could selfassemble into multimorphological aggregates in aqueous solution, which were characterized by DLS and TEM. The hydrophobic doxorubicin（DOX） was chosen as a drug model and successfully encapsulated into the nanoparticles. The release kinetics of DOX were investigated.

化学还原法制备纳米银粒子的研究进展

导电银浆因其具有优异的导电性能,被用作印刷太阳能电池板的电极栅线材料。银粉作为导电银浆中的导电相,其性能直接影响到太阳能电池的光电转换效率。不同形貌、尺寸的微纳米银粉作为导电相,可以提高银浆的烧结活性和服役性能。其中,成本低廉、操作简便的液相还原法是合成不同形貌与尺寸的银粒子的主要方法。本文概括了银粒子的性质与应用,介绍了三种常用的银粒子液相合成方法,以及纳米晶形核生长理论,总结了银粒子的生长调控方式,并对光伏银浆领域银粒子的制备与调控等研究进行了分析和展望。

Colloidal AgCl induced-growth of thorny gold nanoparticles and their SERS activity

In this paper,we exploited a unique procedure for obtaining thorny gold nanoparticles(Au NPs)with controllable length of thorns without using seeds and surfacta nts.A larger number of Ag+ions was added into the reaction system containing with HAuCI4 and NH2 OH·HCl,so as to forming colloidal AgCl.AgCl could induce the growth of thorny Au NPs.The morphology of Au NPs changed from short-thorns,longthorns to no-thorns,as the amount of AgNO3 increased.The obtained Au NPs exhibited shapedetermined surface-enhanced Raman spectroscopy(SERS)activity toward rhodamine 6 G(R6 G);indicating their potential for use in SERS-based detections and analysis.

Evolution of stellated gold nanoparticles:New conceptual insights into controlling the surface processes

Understanding the surface processes(deposition and surface diffusion)that occur at or close to the surface of growing nanoparticles is important for fabricating reproducibly stellated or branched gold nanoparticles with precise control over arm length and spatial orientation of arms around the core.By employing a simple seed-mediated strategy,we investigate the key synthetic variables for precise tuning of in situ surface processes(competition between the deposition and surface diffusion).These variables include the reduction rate of a reaction,the packing density of molecules/ions on the high surface energy facets,and temperature.As a result,the thermodynamically stabilized nanoparticles(cuboctahedron and truncated cube)and kinetic products(cube,concave cube,octapod,stellated octahedron,and rhombic dodecahedron)in different sizes with high quantitative shape yield(>80%)can be obtained depending on the reduction rate of reaction and the packing density of molecules/ions.With computer simulation,we studied the stability of stellated(branched structure)and non-stellated(non-branched structure)gold nanoparticles at high temperature.We construct a morphology phase diagram by varying different synthetic parameters,illustrating the formation of both stellated and non-stellated gold nanoparticles in a range of reaction conditions.The stellated gold nanoparticles display shape-dependent optical properties and can be self-assembled into highly ordered superstructures to achieve an enhanced plasmonic response.Our strategy can be applied to other metal systems,allowing for the rational design of advanced new stellated metal nanoparticles with fascinating symmetry dependent plasmonic,catalytic,and electronic properties for technological applications.

纳米粒子的控制生长和自组装研究进展

由于在纳米器件上有潜在应用，通过化学方法控制的纳米粒子生长，以及纳米粒子自组装的一维、二维和三维点阵受到人们的广泛关注。本文介绍了近年来纳米粒子的控制生长和组装研究的现状。主要探讨了有机稳定剂对纳米粒子形状和尺寸控制的影响。含配位基团和长链烷烃的有机化合物不但可以用作控制纳米粒子生长的稳定剂，而且可以用作纳米粒子自组装的模板剂。

形貌可控贵金属纳米颗粒的合成、光学性质及生长机制

近二十年来,贵金属纳米颗粒由于其独特的性质,已成为人们广泛研究的课题.研究人员应用多种方法来合成纳米尺度的贵金属材料并且探讨了纳米材料的性质与尺寸和形状的关系.本文简单回顾贵金属纳米颗粒的合成方法,主要讨论纳米颗粒的形状对其光学性质的影响和颗粒的生长机制,最后简述贵金属纳米材料的应用前景.

纳米银的合成与表征——三种微乳体系的比较研究

利用SDS-环己烷-异辛醇-水、AOT-环己烷-水和AOT-十二烷-水等3种微乳体系分别制备纳米银溶胶,利用紫外-可见光谱和透射电镜对形成粒子进行表征,进而探讨纳米银粒子的形成机制。3种体系中纳米银的共振吸收强度依次减小,半峰宽依次增大,最大吸收波长分别为400,428和435nm;形成粒子均为球形结构,无团聚现象,但粒子的平均粒度和粒度分布存在明显的差异;3种体系中形成粒子的平均粒度分别为6.46,4.03和1.78nm。微乳体系中球形胶束为纳米银的形成提供一种独特的微观环境,但由于碰撞导致团聚,微乳液中形成粒子的粒度与形貌和胶束的尺寸和形状并不完全一致,实际形成的纳米银粒子具有一定的粒度分布宽度。

单分散纳米金尺寸的分步晶种生长控制

以聚乙烯吡咯烷酮(poly(vinylpyrrolidone),PVP)为保护剂,硼氢化钠为还原剂,合成了尺寸为(1.9±0.4)nm的单分散金胶体,再以其作为一级晶种,并分别用抗坏血酸和PVP为还原剂和保护剂,通过改变各步晶种尺寸和氯金酸与晶种的摩尔比分步逐级合成了尺寸为3.2、4.7、6.3、8.0、10.3、14.0nm的系列金纳米颗粒.以LaMer模型为基础,对分步晶种生长过程中影响金胶体产物尺寸分布(单分散性)的主要因素进行了讨论.缓慢加入抗坏血酸并降低氯金酸对晶种的相对量对于单分散金纳米颗粒的控制合成有决定性作用.快速加入抗坏血酸会因二次成核而导致金颗粒尺寸分布范围变宽.

银纳米颗粒的物理可控生长技术

目前纳米颗粒的合成方法基本都无法实现纳米颗粒的高纯度可控生长,制约着纳米颗粒的应用发展需求,我们课题组采用全新技术,利用物理合成法——气相凝聚法,通过调节气相凝聚工艺中的工艺参数,制备了粒径可控、密度可控、可重复性的银纳米颗粒,实现了物理方法对纳米颗粒生长的可控制,且该方法简单、有效、可重复操作。接着采用龙胆紫生物大分子作为探针,进一步研究了粒径、密度不同的银纳米颗粒薄膜的表面增强拉曼散射(SERS)和表面增强荧光(SEF)效应,结合理论,验证了该物理方法对纳米颗粒的可控生长,同时进行了纳米颗粒薄膜在生化传感方面的高灵敏检测应用探索。

N-乙烯基吡咯烷酮可控合成多形貌金纳米颗粒

为了探究在N-乙烯基吡咯烷酮(NVP)体系下其对金纳米颗粒形貌的影响,分别在不同的操作条件下进行了金纳米颗粒合成实验,并通过TEM、UV-vis、XRD等手段对合成的金纳米颗粒进行了表征分析。随后,以三角片状金纳米颗粒为例对合成机理进行了探讨。结果表明:N-乙烯基吡咯烷酮不仅可以同时作为还原剂和稳定剂制备出能够稳定存在的金纳米颗粒,而且还能够诱导金纳米颗粒发生非均向生长,产生三角形和六边形金纳米片。在此发现的基础上,针对不同反应条件对该体系制备金纳米颗粒的影响进行了全面系统的实验研究,发现该方法还能制备出棒状和带有支脚的金纳米颗粒。

纳米控释系统在组织工程领域的应用

纳米控释系统作为药物、基因传递和控释的载体,由于它的超微小体积,使其具有特殊的重要性。对纳米控释系统在组织工程领域的研究进行评述,表明纳米粒子作为生长因子控制释放、信号分子传递和基因转染的载体在组织工程领域具有广阔的应用前景。

纳米粒子控制生长的研究进展

介绍了球形、棒状、三角形、四边形、六边形纳米粒子控制生长的发展现状,并对该法的制备原理、工艺条件等进行了阐述,还对发展方向进行了展望。

Flash nanocomplexation (FNC): A new microvolume mixing method for nanomedicine formulation

The application of nanotechnologies in formulation has significantly promoted the development of mod-ern medical and pharmacological science,especially for nanoparticle-based drug delivery,bioimaging,and theranostics.The advancement of engineering particle design and fabrication is largely supported by a better understanding of how their apparent characteristics(e.g.,size and size distribution,surface mor-phology,colloidal stability,chemical composition)influence their in vivo biological performance,which raises an urgent need for practical nanoformulation methods.Based on turbulent flow mixing and the self-assembly of molecules in fluids,flash technologies emerged as effective bottom-up fabrication strate-gies for effective nanoformulation.Among the flash technology family,flash nanocomplexation(FNC)is considered a novel and promising candidate that can promote and optimize formulation processes in a precise spatiotemporal manner,thus obtaining excellent fabrication efficiency,reproducibility and ex-pandability.This review presents an overview of recent advances in fabricating drug-delivery nanoparti-cles using FNC platforms.Firstly,brief introductions to the basic principles of FNC technology were car-ried out,followed by descriptions of turbulent microvolume mixers that have significantly promoted the efficiency of FNc-based fabrications.Applications of real formulation cases were then categorized accord-ing to the self-assembly-driven interactions(including electrostatic interaction,coordination interaction,hydrogen bonding and hydrophobic interaction)and discussed to reveal the progressiveness of fabricat-ing nanoparticles and discuss how its flexibility will provide advances and replenish the philosophy of nanomedicine formulation.In the end,the commercial potential,current limitations,and prospects of FNC technology for nanoformulation will be s rizedanddiscussed.

Perspective on how laser-ablated particles grow in liquids

Laser ablation in liquids has emerged as a new branch of nanoscience for developing various nanomaterials with different shapes.However, how to design and control nanomaterial growth is still a challenge due to the unique chemical-physical process chain correlated with nanomaterial nucleation and growth, including plasma phase(generation and rapid quenching), gas(bubble) phase,and liquid phase. In this review, through summarizing the literature about this topic and comparing with the well-established particle growth mechanisms of the conventional wet chemistry technique, our perspective on the possible nanoparticle growth mechanisms or routes is presented, aiming at shedding light on how laser-ablated particles grow in liquids. From the microscopic viewpoint, the nanoparticle growth contains six mechanisms, including LaMer-like growth, coalescence, Ostwald ripening, particle(oriented) attachment, adsorbate-induced growth and reaction-induced growth. For each microscopic growth mechanism, the vivid growth scenes of some representative nanomaterials recorded by TEM and SEM measurements are displayed. Afterwards,the scenes from the macroscopic viewpoint for the large submicro-and micro-scale nanospheres and anisotropic nanostructures formation and evolution from one nanostructure into another one are presented. The panorama of how diverse nanomaterials grow during and after laser ablation in liquids shown in this review is intended to offer a overview for researchers to search for the possible mechanisms correlated to their synthesized nanomaterials, and more expectation is desired to better design and tailor the morphology of the nanocrystals synthesized by LAL technique.

负载纳米粒子的壳聚糖单向缓释膜的制备及理化性质研究

目的 将壳聚糖纳米粒子与壳聚糖单向缓释膜结合,制备得到负载纳米粒子的壳聚糖单向缓释膜,并对其理化性质及体外释放性能进行研究.方法 采用反相乳化法制备壳聚糖纳米粒子,采用流延法制备壳聚糖单向缓释膜,通过透射电镜、扫描电镜和粒度分析仪检测纳米粒子的形态、大小及壳聚糖单向缓释膜表面形貌,MTT法检测其生物相容性,荧光显微镜观察纳米粒子在壳聚糖单向缓释膜中的分布,体外释放实验检测单向缓释膜的缓释性能.结果 4种水溶性壳聚糖纳米粒子呈球状且粒径均一,其中类透明质酸壳聚糖纳米粒子平均粒径为（255.40±39.10） nm,具有最好的生物相容性及缓释性能.壳聚糖单向缓释膜外层膜致密,内层膜疏松,纳米粒子在内层膜中均匀分布,体外释放实验证明,壳聚糖单向缓释膜为单向释放,且具有较好的缓释性能.结论 包载纳米粒子的壳聚糖单向缓释膜具有较好的缓释和单向控释性能,在生长因子类药物载体方面有一定应用前景.