锂离子电池硅纳米粒子/碳复合材料

硅由于其超高的理论比容量有望取代石墨成为下一代锂离子电池负极材料,但是硅在充放电过程中巨大的体积膨胀(~300%)会导致材料粉化从集流体上脱落,同时不断形成固相电解质层,造成不可逆容量损失,而材料纳米化和碳复合是解决这些问题的有效手段。本文介绍了硅在循环过程中容量衰减机理,并综述了硅纳米粒子与碳材料复合的最新进展,主要包括包覆型、核壳型以及嵌入型硅碳负极材料,并对核壳型与嵌入型做了重点探究,最后对硅纳米粒子/碳复合材料存在的问题进行分析并展望其研究前景。     

金核壳纳米粒子的控制合成及其生物复合(英文)

合成了一系列Au/SiO2核壳纳米粒子,并详细研究了Au纳米壳层的生长过程。发现在金纳米壳层形成的过程中存在着2个竞争反应。利用这一发现,可将金纳米壳层的吸收峰从524nm连续调谐至980nm处。恩度是一种临床抗癌药物,我们首次将其生物复合于吸收峰位于808nm的Au/SiO2壳层表面,得到Au/SiO2-Endo,通过FTIR测试证明该生物复合成功。将恩度特殊的饿杀肿瘤特性以及对肿瘤具有特异识别能力,与Au/SiO2纳米壳层结构的光学可调谐特性以及良好的光热转换能力复合于一体,我们期望得到一种治疗肿瘤效果更强的新型药物。     

水/甲苯界面制备均匀可循环SERS基底

采用在沸水浴中还原硅酸钠的方法制备壳层约4nm的Au@SiO2核壳纳米粒子,利用水/ 甲苯两相界面诱捕出其单粒子层膜并将这层膜转移到Si片上.作为对比,采用化学方法自组装Au@SiO2膜至ITO玻璃表面. 以1,4-对苯二硫作为探针分子考察了它们的SERS活性以及可循环使用性能. 研究结果表明,Au@SiO2核壳粒子可避免待测分子与基底直接接触,NaBH4溶液可作为基底循环的洗涤剂,经化学组装的基底的可循环性能较差,每次洗涤SERS效应均有一定程度降低,而两相界面形成的单粒子致密膜的SERS效应稳定性较好,其循环性能较高,即使洗涤10次后,SERS效应仍未明显降低,此膜可作为循环使用的SERS基底.     

水滑石型磁性纳米载药粒子的制备及其体外药物释放性能研究

通过调变镁铁尖晶石的含量, 采用一步共沉淀法制备了一系列具有核壳结构的水滑石型磁性纳米载药粒子, 对其微结构、热稳定性、磁性和药物释放性能进行了系统的研究. 结果表明这种磁性纳米载药粒子是一种具有以镁铁尖晶石为核层、双氯酚酸(Diclofenac, DIC)插层水滑石(DIC-LDH)为壳层的复合纳米粒子, 粒径在90～180 nm之间. 其中壳层DIC-LDH的晶粒尺寸D₁₁₀和层板电荷密度随磁核含量的增大而逐渐减小. 磁性纳米载药粒子的载药量随磁核含量的增大而逐渐减小, 而其比饱和磁化强度则随着磁核含量的增大逐渐增大. 体外释放实验表明, 无外加磁场时, 磁核含量增大, 壳层DIC-LDH粒径减小, 磁性纳米载药粒子药物释放速率逐渐增大|外加1500 G磁场时, 磁核含量增大, 磁致团聚程度增大, 其药物释放速率逐渐减小.     

Au@SiO2核壳纳米粒子的制备及其表面增强拉曼光谱

采用柠檬酸钠还原氯金酸法制备金溶胶, 以正硅酸乙酯(TEOS)为硅源, 氨水作催化剂, 制备以金为核, 二氧化硅为壳的核壳纳米粒子. 金纳米粒子的粒径可以通过柠檬酸钠和氯金酸的比例控制, 通过调节TEOS的量和反应的时间可以控制二氧化硅壳层的厚度. 以苯硫酚为探针分子研究了核壳结构纳米粒子的表面增强拉曼散射(SERS)效应与二氧化硅壳层厚度之间的关系. 研究结果表明, 金内核电磁场增强效应随着二氧化硅壳层厚度的增加逐渐减弱, 且其衰减速度比具有相同尺度的双金属核壳结构纳米粒子的慢. 此外, 探针分子主要以物理作用吸附在二氧化硅的表面, 可通过洗涤方法将探针分子除去, 从而可使该复合结构基底用于循环SERS分析.     

具有可见光响应聚合物纳米粒子的制备及性能研究

利用可见光响应供体-受体Stenhouse加合物(DASAs)设计并制备了2种表面含有可见光响应单元的聚合物纳米粒子,并对纳米粒子的光响应性进行了研究.首先合成了修饰DASA分子的聚合物PGMD,研究结果表明PGMD可溶于与水互溶的有机溶剂(如DMSO)中并具有良好的光响应性,PGMD链段可在可见光刺激下响应为亲水状态.因此,含有PGMD链段的嵌段共聚物PCL-b-PGMD可在水中自组装形成胶束,并能与PCL-b-PEG在水中共组装形成复合壳层胶束,但PGMD链段在水中无法可逆响应为疏水状态.为获得具有可逆响应性的聚合物纳米粒子,利用硅烷偶联剂水解修饰的方法得到表面含有疏水三烯状态DASA分子与亲水PEG短链的复合壳层二氧化硅纳米粒子,实验结果表明复合壳层二氧化硅纳米粒子在水环境中有良好的分散稳定性,并且表面修饰的DASA分子仍具有良好的响应性.本研究为设计表面性质可调的响应性聚合物纳米粒子提供了新的设计思路.     

以胶体粒子为模板制备核壳纳米复合粒子

核壳纳米复合粒子具有许多不同于单组分胶体粒子的独特的光、电、磁、催化等物理与化学性质,是构筑新型功能复合材料的重要组元,在光子带隙材料、微波吸收材料、电磁流变液、催化剂和生物等领域有重要应用.本文从控制核壳复合粒子的微观结构及壳层均匀性与厚度的角度,详细评述了目前以胶体粒子为模板制备粒径从纳米到微米尺度的核壳复合粒子的方法.指出利用胶体粒子模板表面与壳层物质或其前驱物间的特殊相互作用(包括静电和化学相互作用),是完善现有制备方法和发展新方法来制备具有设定组成、结构和性能的核壳复合粒子的关键,同时也是将来的粒子表面纳米工程和获取有序的、先进纳米复合材料的主要方向。     

AucoreCoshell纳米粒子的制备、表征及其表面增强拉曼光谱研究

在乙醇体系中和在制备好的Au纳米粒子表面, 用水合肼还原钴盐制备Co壳, 首次通过化学还原法制得核壳结构的Au-Co纳米粒子, 并通过控制钴盐的投料, 得到不同包裹层厚度的AucoreCoshell纳米粒子. 用扫描电子显微镜(SEM)和电化学循环伏安法(CV)等测试方法对其进行表征, 并用吡啶(Py)作为探针分子研究了其SERS效应.     

刺激响应型生物医用聚合物纳米粒子研究进展

近十几年来, 纳米科学的发展极大地推动了纳米材料在生物医用领域的应用. 聚合物纳米粒子由于其独特的性能在药物传递、医学成像等医用领域备受关注. 其中, 刺激响应型聚合物纳米粒子是一类可以在外界信号刺激下(包括pH、温度、磁场、光等)发生结构、形状、性能改变的纳米粒子. 利用这种刺激响应性可调节纳米粒子的某种宏观行为, 故而刺激响应型聚合物纳米粒子也被称为智能纳米粒子. 因为其特有的“智能性”, 刺激响应型聚合物纳米粒子的研究已成为当前生物材料领域的研究热点. 本文综述了几类重要的生物医用刺激响应型聚合物纳米粒子, 侧重介绍双重及多重刺激响应型聚合物纳米粒子的制备及其生物医学应用.     

SiO2/聚合物核壳型杂化粒子及其空心结构的制备

SiO2/聚合物核壳型杂化粒子及其空心结构以其独特的形貌在药物控制释放、催化剂载体、生物医药等领域应用前景广阔,引起了人们的广泛关注。本文着重从乳液聚合法、仿生矿化法等制备方法角度阐述了SiO2/聚合物核壳型杂化粒子及其空心结构的研究进展。乳液聚合制备SiO2/聚合物核壳型杂化粒子简单易行,一般需要预先合成SiO2纳米粒子,其合成过程通常需要一些非理想的条件,如高温高压、极端pH、昂贵或有毒的有机试剂等,而且预先合成的SiO2粒子无法与聚合物实现100%匹配,即总有纯的聚合物粒子存在。相比之下,原位仿生矿化法制备SiO2杂化粒子不仅在环境条件下可进行,而且能够精确控制其纳米尺度的形态及分级有序结构。目前对材料科学家来讲,要使人工合成SiO2/聚合物杂化粒子实现像自然生物硅那样优异的性能,仍然是很大的挑战。     

Niosomes from 80s to present: The state of the art

Efficient and safe drug delivery has always been a challenge in medicine. The use of nanotechnology, such as the development of nanocarriers for drug delivery, has received great attention owing to the potential that nanocarriers can theoretically act as “magic bullets” and selectively target affected organs and cells while sparing normal tissues. During the last decades the formulation of surfactant vesicles, as a tool to improve drug delivery, brought an ever increasing interest among the scientists working in the area of drug delivery systems. Niosomes are self assembled vesicular nanocarriers obtained by hydration of synthetic surfactants and appropriate amounts of cholesterol or other amphiphilic molecules. Just like liposomes, niosomes can be unilamellar or multilamellar, are suitable as carriers of both hydrophilic and lipophilic drugs and are able to deliver drugs to the target site. Furthermore, niosomal vesicles, that are usually non-toxic, require less production costs and are stable over a longer period of time in different conditions, so overcoming some drawbacks of liposomes.     

Near-infrared spectroscopy applications in pharmaceutical analysis

Near-infrared (NIR) spectroscopy is a fast and non-destructive analytical technique that offers many advantages for a broad range of industrial applications. In this work, we reviewed recent developments in the pharmaceutical domain where it can be applied from raw material identification to final product release. The characteristics of NIR allow the technique to be implemented as a process analytical technology (PAT). Moreover, recent instrumental developments open the perspectives of numerous applications in the NIR imaging area. After “Introduction”, according to their subject, the applications are discussed in the parts “Identification”, “Water content”, “Assay” and “Other applications”.     

A two-color-change, nanoparticle-based method for DNA detection

Herein, we describe the detailed synthesis of Ag/Au core-shell nanoparticles, the surface-functionalization of these particles with thiolated oligonucleotides, and their subsequent use as probes for DNA detection. The Ag/Au core-shell nanoparticles retain the optical properties of the silver core and are easily functionalized with thiolated oligonucleotides due to the presence of the gold shell. As such, the Ag/Au core-shell nanoparticles have optical properties different from their pure gold counterparts and provide another “color” option for target DNA-directed colorimetric detection. Size-matched Ag/Au core-shell and pure gold nanoparticles perform nearly identically in DNA detection and melting experiments, but with distinct optical signatures. Based on this observation, we report the development of a two-color-change method for the detection and simultaneous validation of single-nucleotide polymorphisms in a DNA target using Ag/Au core-shell and pure gold nanoparticle probes.     

Overview on natural hydrophilic polysaccharide polymers in drug delivery

Nanotechnology is poised to make potentially revolutionary innovations in areas of biomedical science, such as gene therapy and drug therapy. A recently developed nanodelivery strategy involves the use of hydrophilic polymers as carriers of proteins and siRNA. By controlling the reaction conditions during polymer production, various degrees of anionic charge, cationic charge, and cross‐linking can be added, thereby changing their capabilities as protein and nucleic acid carriers and promoting effective cell membrane permeation. The efficiency of a specific controlled‐release polymeric system is determined in part by its unique physical and chemical properties and biodegradation rate. In this review, we will summarize recent progress in the ability to modify drug release of hydrophilic polymers nanoparticles.     

刺激响应共负载药物/基因微载体的制备

合成了聚乙烯亚胺接枝二茂铁(PEI-Fc)两亲聚合物, 采用水包油法制备包埋疏水性抗癌药阿霉素(DOX)的载药胶束, 并利用胶束表面正电荷的PEI链段有效缔合DNA, 获得尺寸合适、 表面带正电荷的阿霉素与基因共负载微载体. 在磷酸盐(PBS)缓冲溶液中, 共负载微载体能够缓慢释放出DOX. 在硝酸铈铵存在下, 二茂铁从疏水性转变为亲水性, 使载药胶束完全解离, 由于PEI-Fc与DNA之间的静电作用, 使基因超分子组装体稳定存在, 显示出很好的氧化响应特性. 细胞培养结果表明, 表面带正电荷的共负载微载体易被HepG2细胞内吞, 并可转染, 且随着DOX的释放逐渐杀死HepG2肝癌细胞, 为安全稳定、 具有刺激响应的药物与基因共负载微载体的制备提供了可行的途径.     

“Turn-off-on” fluorescent sensor for (N-methyl-4-pyridyl) porphyrin -DNA and G-quadruplex interactions based on ZnCdSe quantum dots

As a new detection model, the reversible fluorescence “turn-off-on” sensor based on quantum dots (QDs) has already been successfully employed in the detections of many biochemical materials, especially in the researches on the interactions between anticancer drugs. The previous studies, however, mainly focused on simple-structured oligonucleotides and Calf thymus DNA. G-quadruplex, an important target for anti-cancer drug with special secondary structure, has been stimulating increasing research interests. In this paper, we report a new detection method based on the fluorescence “turn-off-on” model with water-soluble ZnCdSe QDs as the fluorescent probe, to analyze the interactions between anticancer drug (N-methyl-4-pyridyl) porphyrin (TMPyP) and nucleic acid, especially the G-quadruplex. The fluorescence of QDs can be quenched by TMPyP via photo-induced electron transfer and fluorescence resonance energy transfer, while on the other hand, the combination between TMPyP and G-quadruplex releases QDs from their quenchers and thus recovers the fluorescence. Most importantly, the fluorescence “turn-off-on” model has been employed, for the first time, to analyze the impacts of special factors on the interaction between TMPyP and G-quadruplex. The excellent selectivity of the system has been verified in the studies of the interactions between TMPyP and different DNAs (double-stranded DNA, single-stranded G-quadruplex, and different types of G-quadruplexes) in Na⁺ or K⁺-containing buffer.     

Synthesis and physico-chemical characterization of Au/TiO2 nanostructures formed by novel “cold” and “hot” nanosoldering of Au and TiO2 nanoparticles dispersed in water

A novel approach to synthesize Au/TiO₂ nanostructures with interesting optical properties is presented and discussed. It is based on the nanoparticle “cold” or “hot” nanosoldering occurring when two water suspensions of Au and TiO₂ nanoparticles are merely mixed at room temperature or laser irradiated after mixing.Thanks to the high fraction and mutual reactivity of surface species, immediately after the mixing process, the encounters between Au and TiO₂ nanoparticles in liquid phase are enough for “cold” nanosoldering of gold nanoparticles onto TiO₂ nanoparticles to occur. The optical characterizations show that this fast process (timescale less than 1 min) is followed by a slower process, attributable to some change of the Au nanoparticles. This latter process is significantly accelerated by the 532 nm laser light illumination. The structural and optical properties of “cold” and “hot” nanosoldered Au-TiO₂ nanoparticles were investigated by TEM, UV-vis and fluorescence spectroscopies.Interesting optical limiting response was detected at laser fluences above 0.8 J/cm². The nature of the nonlinear effect was investigated by the Z-scan technique, determining both the nonlinear absorption coefficient and the refraction index. Such interesting non-linear optical properties are worth to be tailored for specific applications.     

聚乳酸纳米粒的改性研究进展

聚乳酸纳米粒具有控制药物释放速度以达到长效缓释、增加药物靶向性、降低毒副作用以及提高疗效等优点,在药物传输中有着广阔的研究和应用前景。但由于聚乳酸的疏水性和分子链基团的单一性,它在靶向制剂和长效制剂的应用方面受到很大制约。本文对可生物降解材料聚乳酸作为载药纳米粒的改性研究状况进行了综述,针对目前制约聚乳酸纳米粒临床应用存在的问题,介绍了亲水性修饰、靶向修饰的最新研究进展。     

Fluorescent carbon nanoparticles: A low-temperature trypsin-assisted preparation and Fe sensing

In recent years, extensive researches are focused on the fluorescent carbon nanoparticles (CNPs) due to their excellent photochemical, biocompatible and water-soluble properties. However, these synthesis methods are generally suffered from tedious processes. In this paper, fluorescent carbon nanoparticles are synthesized by a facile, one-pot, low-temperature method with trypsin and dopamine as precursors. The synthesis process avoids any heating operation and organic solvent, which provides a “green” and effective preparation route. The obtained CNPs exhibit excellent water-solubility, salt-tolerance and photostability. Based on the synergistic action of the inner filter effect and static quenching mechanism, the CNPs are exploited as a “turn-off” fluorescence sensor for sensitive and selective detection of Fe³⁺ ions. The probe shows a wide linear range from 0.1 to 500 μM, with a limit of detection of 30 nM. Furthermore, the as-fabricated fluorescent sensing system is successfully applied to the analysis of Fe³⁺ in biological samples such as human urine and serum samples with satisfactory recoveries (92.8–113.3%).