浅谈纳米粒子在生物学和医学中的应用

介绍了纳米粒子的基本特征及其在生物学和医学中的应用。     

磁性纳米粒子的合成及在石油乳化中的应用

对磁性纳米粒子的制备方法进行了总结,目前常用的方法有水热法、共沉淀法、溶胶凝胶法、溶剂热合成法、声化合成法和一些绿色合成方法。对影响磁性纳米粒子稳定乳状液因素的研究进行了简单介绍,最后对MNPs进一步的研究进行了展望。     

磁性纳米粒子的制备和包覆

磁性纳米粒子由于其广泛的应用一直以来都是研究的热点。随着合成技术的不断发展,各种磁性纳米粒子均已成功制得,特别是合成形貌可控,高度稳定和单分散性的磁性纳米粒子。综述了磁性纳米粒子的几种比较常见的合成方法及其包覆措施,并对磁性纳米材料的应用进行了展望。     

浅谈纳米材料在生物学及医学领域的应用

纳米材料粒径在1～100nm内,位于单个原子、分子和体相材料间,能够同时发挥小尺寸效应、量子尺寸效应、宏观量子隧道效应、表面效应及体积效应等。通过物理、化学、生物、电子学等方法调节纳米材料粒径、形貌、表面特性、带隙等,能够产生一些特异性质,并应用于生物学、医学等领域。本文从纳米材料在细胞与生物分子研究、MRI对比剂、靶向药物载体、组织工程及肿瘤治疗等方面,阐述纳米材料在生物学与医学领域中的应用。     

磁性纳米粒子的制备、表面修饰及其在药物方面的应用

文章综述了各种常用的磁性纳米粒子的制备方法,概述了磁性纳米粒子的表面修饰方法,并阐述r表面修饰过的磁性纳米粒子在药物作用和药物传输方面的应用,最后对磁性纳米粒子的应用前景进行了展望。     

磁性纳米粒子在分离植物有效成分中的应用研究

用传统方法分离提取植物中的有效成分,其操作过程繁琐复杂,并且容易造成资源浪费和环境污染。因此,制备出功能化的吸附材料,以提高植物中有效成分的分离效果,已成为广大研究者探索的热门领域。有相关研究表明,一些具有功能化的磁性纳米粒子已经成功被应用于植物成分分离中,并且得到了较好的效果。     

联氨还原法制备磁性钴纳米粒子

在表面活性剂聚乙烯吡咯烷酮(PVP)的保护下,采用水合肼于乙醇体系中还原CoCl2·6H2O而得到磁性钴纳米粒子,通过X射线衍射检验确认该种方法合成的钴纳米粒子同时具有hcp相和fcc相.X射线光电子能谱的表征结果显示钴粒子表面价态为零价,说明制备过程中没有被氧化.用透射电镜和激光光散射仪对粒子的表面形貌和粒径进行了表征分析,结果显示粒径在30nm左右,近似圆球形,在正己烷中分散效果较好.     

新型磁性纳米级油酸改性铁氧磁流体磁性粒子的制备及表征

用油酸钠作为表面活性剂,采用化学共沉淀法制备纳米级油酸改性铁氧体磁性粒子,从温度T、碱的过量比y、表面活性剂的用量比n、反应时间t4个方面进行研究。确定高纯度、小粒径、强磁性、均匀分散的Fe3O4磁性粒子的合理工艺条件:t=180 min,T=80℃,y=0.25,n=0.6。红外光谱测试,证明产品为表面活性剂油酸包裹的纳米级磁性粒子,粒径<10 nm,XRD分析证实了产品为铁氧体磁性粒子,古埃磁天平对产品进行了性能测试。     

磁性纳米催化剂的研究进展

介绍了磁性纳米催化剂的特性,综述了近年来磁性纳米催化剂在在氢化催化、加氢甲酰化催化、C-C键偶联反应催化、氧化和环氧化催化、酯化反应催化、缩合反应催化、烯烃复分解催化、光催化、生物催化等领域应用的研究进展,旨在探讨磁性纳米催化剂制备方法和应用领域,同时提出其应用过程中存在的问题,并对发展前景进行了展望。     

SiO_2复合磁性纳米粒子的合成及表面性质的研究

采用溶胶凝胶法合成具有快速磁场响应能力的SiO2复合磁性纳米粒子。用表面电位仪研究了不同包覆层厚度对粒子表面性质的影响。用AFM对粒子的表面形貌进行了表征。并考察了不同SiO2包覆层厚度粒子的抗酸性。结果表明生长3层SiO2后复合粒子的表面完全被SiO2所包覆,粒子具有高的磁含量和快速的磁场响应能力,并具有高的抗酸性。     

Syntheses of Fe-Ni Magnetic Nanoparticles and Their Applications on Biologic Labeling

In this study, we compared FeNi alloy magnetic nanoparticles (MNPs) prepared by either combustion or chemical precipitation methods. We found that the FeNi MNPs generated by combustion method have a rather high saturation magnetization Ms of～180 emu/g and a coercivity field Hc of near zero. However, the alloy nanoparticles are easily aggregated and are not well dispersive such that size distribution of the nanoparticle clusters is wide and clusters are rather big (around 50～700 nm). To prepare a better quality and well dispersed Fe-Ni MNPs, we also developed a thermal reflux chemical precipitation method to synthesize FeNi3 alloy MNPs. The precursor chemicals of Fe(acac)3 and Ni(acac)2 in a molecular ratio 1,2-hexadecandiol and tri-n-octylphosphine oxide (TOPO) were used as reducer and surfactant, respectively. The chemically precipitated FeNi3 MNPs are well dispersed and have well-controlled particle sizes around 10～20 nm with a very narrow size distribution (±1.2 nm). The highly monodispersive FeNi3 MNPs present good uniformity in particle shape and crystallinity on particle surfaces. The MNPs exhibit well soft magnetism with saturation magnetization of ～61 emu/g and Hc～0. The biomedically compatible FeNi MNPs which were coated with biocompatible polyethyleneimine (PEI) polymer were also synthesized. We demonstrated that the PEI coated FeNi MNPs can enter the mammalian cells in vitro and can be used as a magnetic resonance imagine (MRI) contrast agent. The results demonstrated that FeNi MNPs potentially could be applied in the biomedical field. The functionalized magnetic beads with biocompatible polymer coated on MNPs are also completed for biomedical applications.     

Chemical Biology Towards Precision Medicine

Organic chemistry is primed to fill a much-needed gap in our understanding of human biology and disease on the one hand and our ability to treat disease effectively on the other. The key challenge is to discover compounds having the novel mechanisms of action demanded by these new patient-derived insights.     

磁性流体组成及其应用前景

简述了磁性流体的组成,重点介绍了磁性流体在生物医学和工程上的应用。     

Enzymatic Synthesis of Magnetic Nanoparticles

We report the first in vitro enzymatic synthesis of paramagnetic and antiferromagnetic nanoparticles toward magnetic ELISA reporting. With our procedure, alkaline phosphatase catalyzes the dephosphorylation of l-ascorbic-2-phosphate, which then serves as a reducing agent for salts of iron, gadolinium, and holmium, forming magnetic precipitates of Fe_45±14Gd_5±2O_50±15 and Fe_42±4Ho_6±4O_52±5. The nanoparticles were found to be paramagnetic at 300 K and antiferromagnetic under 25 K. Although weakly magnetic at 300 K, the room-temperature magnetization of the nanoparticles found here is considerably greater than that of analogous chemically-synthesized Ln_xFe_yO_z (Ln = Gd, Ho) samples reported previously. At 5 K, the nanoparticles showed a significantly higher saturation magnetization of 45 and 30 emu/g for Fe_45±14Gd_5±2O_50±15 and Fe_42±4Ho_6±4O_52±5, respectively. Our approach of enzymatically synthesizing magnetic labels reduces the cost and avoids diffusional mass-transfer limitations associated with pre-synthesized magnetic reporter particles, while retaining the advantages of magnetic sensing.     

Exploiting Size-Dependent Drag and Magnetic Forces for Size-Specific Separation of Magnetic Nanoparticles

Realizing the full potential of magnetic nanoparticles (MNPs) in nanomedicine requires the optimization of their physical and chemical properties. Elucidation of the effects of these properties on clinical diagnostic or therapeutic properties, however, requires the synthesis or purification of homogenous samples, which has proved to be difficult. While initial simulations indicated that size-selective separation could be achieved by flowing magnetic nanoparticles through a magnetic field, subsequent in vitro experiments were unable to reproduce the predicted results. Magnetic field-flow fractionation, however, was found to be an effective method for the separation of polydisperse suspensions of iron oxide nanoparticles with diameters greater than 20 nm. While similar methods have been used to separate magnetic nanoparticles before, no previous work has been done with magnetic nanoparticles between 20 and 200 nm. Both transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis were used to confirm the size of the MNPs. Further development of this work could lead to MNPs with the narrow size distributions necessary for their in vitro and in vivo optimization.     

Microfluidic Biosensing Systems Using Magnetic Nanoparticles

In recent years, there has been rapidly growing interest in developing hand held, sensitive and cost-effective on-chip biosensing systems that directly translate the presence of certain bioanalytes (e.g., biomolecules, cells and viruses) into an electronic signal. The impressive and rapid progress in micro- and nanotechnology as well as in biotechnology enables the integration of a variety of analytical functions in a single chip. All necessary sample handling and analysis steps are then performed within the chip. Microfluidic systems for biomedical analysis usually consist of a set of units, which guarantees the manipulation, detection and recognition of bioanalytes in a reliable and flexible manner. Additionally, the use of magnetic fields for performing the aforementioned tasks has been steadily gaining interest. This is because magnetic fields can be well tuned and applied either externally or from a directly integrated solution in the biosensing system. In combination with these applied magnetic fields, magnetic nanoparticles are utilized. Some of the merits of magnetic nanoparticles are the possibility of manipulating them inside microfluidic channels by utilizing high gradient magnetic fields, their detection by integrated magnetic microsensors, and their flexibility due to functionalization by means of surface modification and specific binding. Their multi-functionality is what makes them ideal candidates as the active component in miniaturized on-chip biosensing systems. In this review, focus will be given to the type of biosening systems that use microfluidics in combination with magnetoresistive sensors and detect the presence of bioanalyte tagged with magnetic nanoparticles.     

磁性纳米粒子的制备及脂肪酶的固定化

建立了以纳米级磁性粒子为载体固定化脂肪酶的方法,优化了脂肪酶的固定化条件,考察了固定化酶的性质. 制备的磁性载体平均粒径20 nm,具有超顺磁性,分散和再分散效果好. 固定化酶的最适吸附时间为60 min,酶用量:载体量为1:1,固定化酶的酶活达到718 U/g. 结果表明,经纳米磁性粒子固定化后,脂肪酶得到活化,固定化酶比活为游离酶的1.8倍. 同时,固定化脂肪酶的pH稳定性显著提高.     

氧化铁磁性纳米粒子的表面修饰及应用

氧化铁磁性纳米粒子因其优异的性能,广泛应用于环境分离、生物活性物质的富集和分离等领域,近年来引起了广泛的关注和研究。文章总结了氧化铁肱性纳米粒子表面修饰方法及相关应用,并对其前号进行了展望。     

Magnetic Organosilica Nanoparticles for Localized Polymer Surface Modification

Magnetic organosilica nanoparticles are synthesized by grafting MPB‐POSS/MMA‐based block copolymers from magnetic iron nanoparticles via surface‐initiated ATRP. The hybrid nanoparticles consist of a magnetic iron core and a PMMA/POSS composite shell. A small amount of the nanoparticles is added as “smart additive” in casting PMMA sheets for localized surface modification. It is demonstrated that the particles are readily brought to the surface of the cast piece by applying a magnet field to the molding. At 1 wt% loading, the sample has a 50‐time higher particle content in a 100 µm‐thick surface layer than in the bulk. The indentation hardness of the modified surface is increased by 30%.

     

葡聚糖磁性微球在生物医学领域的应用

葡聚糖磁性微球作为一种新型功能材料,在生物医学、细胞学和生物工程学等领域有着广泛的应用前景.着重介绍了葡聚糖磁性微球在固定化酶、靶向药物、细胞分离与免疫分析、临床诊断和治疗等领域的应用,并展望了今后的研究方向.