多孔磁性明胶微球的制备与结构表征

首先通过乳化法得到磁性明胶微球, 然后在高速搅拌条件下向乳液中直接加入正硅酸乙酯(TEOS), 制备出多孔磁性明胶微球. 用SEM, TEM观察了微球的微观形貌, 发现微球呈疏松多孔状结构. 用FT-IR, TGA, VSM等测试手段对微球的结构和性能进行表征. 结果表明, 二氧化硅掺杂于磁性明胶微球中. TEOS在反应中作为明胶微球的交联固化剂, 推测其固化机理是物理交联固化. 实验证实二氧化硅改性后, 磁性明胶微球内部磁性颗粒氧化速度有所降低. 所得到的多孔磁性明胶微球表现出铁磁性.     

聚合物基磁性复合微球的研究近况

磁性聚合物微球作为一种新兴起的复合功能材料,由于具有纳米尺寸、超顺磁性、良好的生物相容性、低毒性诸多优点,受到了人们广泛而深入的研究。本文简要介绍了无机磁性粒子的制备方法和磁性聚合物微球的分类,主要对磁性高分子微球的传统制备方法和涌现新方法新技术进行了阐述,并分析了各种制备磁性聚合物微球方法的优缺点及主要影响因素。除此之外,本文也介绍了磁性聚合物微球近年来最新研究成果及应用领域,并对高分子微球未来发展趋势和存在的问题进行了分析。     

内含Fe_3O_4和金纳米粒子的碳化微球的制备及其催化性能

通过蒸馏-沉淀聚合制备了丙烯酸-二乙烯苯共聚物微球,经离子交换吸附Fe2+离子,然后通过空气中加热、氩气气氛中高温碳化得到了含Fe3O4纳米粒子的多孔磁性碳化微球。在水介质中多孔磁性碳化微球吸附氯金酸,然后还原得到内含金纳米粒子的磁性碳化微球。以硼氢化钠还原对硝基苯酚生成对氨基苯酚反应为例,研究了内含金纳米粒子的磁性碳化微球的催化作用。结果表明,内含金纳米粒子的磁性碳化微球对该反应有很好的催化作用。通过外磁场很容易将磁性微球从反应液相中分离出来,微球重复使用10次后其催化活性基本未变。     

Merrifield树脂负载咪唑基离子液体磁性微球的制备与表征

制备了Merrifield树脂负载丙酸甲酯基咪唑基离子液体磁性微球。 采用FT-IR和XRD对结构进行了表征,采用TGA和VSM分别进行了热稳定性和磁性测试。 结果表明,丙酸甲酯基咪唑基离子液体成功负载到Merrifield树脂微球上,并通过共沉淀的方法实现了微球的磁性化,其磁组分为FeOOH和γ-Fe2O3混合物。 磁性微球的热稳定性优于无磁性的Merrifield树脂负载丙酸甲酯基咪唑基离子液体微球,在200 ℃以下不发生分解。 磁性微球的磁化强度为11.364 emu/g,显示出超顺磁性,无外磁场存在时不发生团聚。 沉降实验结果表明,在磁感应强度为3.0×10-4 T电磁场作用下,磁性微球10 s内即可从水相中基本分离完全,而没有磁场作用时磁性微球粒子基本不从水相中分离。     

疏水性磁性微球的制备及对盐藻的吸附研究

采用疏水性材料制备微米级磁性微球,并应用于对盐藻的吸附分离研究,考察了pH值,吸附作用时间,NaCl浓度以及磁性微球添加量对盐藻吸附的影响.结果显示磁性微球对盐藻的吸附受溶液的离子强度影响较大;pH值在一定范围内对盐藻的吸附有较大影响;延长吸附作用时间和加大磁性微球的添加量可以增加对盐藻的吸附量.通过调节pH和施加机械搅拌,磁性微球上吸附的盐藻可以很好被洗脱下来,磁性微球可以多次重复使用.     

功能化磁性高分子复合微球的研究进展

功能化磁性高分子复合微球作为一种新型功能材料,在许多领域具有广阔的应用前景。本文对近年来功能化磁性高分子复合微球的制备方法进行了总结,对当前不同方法的优缺点进行了评价与分析;对功能化磁性高分子复合微球在生物工程领域,医学领域,环境、食品领域和功能材料领域进行了阐述。并综合分析了磁性微球在各个领域的优势及已经取得的成果。最后,展望了功能化磁性高分子复合微球的发展前景,提出自己的观点,并列出亟待解决的四个问题。     

两种磁性复合微球的制备及其性能对比

为了得到蛋白吸附性能良好的免疫磁性载体,文章用反相微乳的方法合成了壳聚糖磁性复合微球(Chitosanmagneticcompositemicrospheres简称CMCM),与常用的单体聚合法制备的聚苯乙烯磁性复合微球(Polystyrenemagneticcompositemicrospheres,简称PMCM)从粒径和表观形貌、微球铁含量、磁响应性、表面官能基团等性质做了对比表征,结果表明,CMCM是一种比PMCM更理想的免疫磁性微球载体材料。     

磁性壳聚糖微球的制备及对Cr(Ⅵ)的吸附性能研究

用壳聚糖包埋磁流体,用戊二醛交联制成磁性壳聚糖微球,并用红外光谱表征其结构。用制备的磁性壳聚糖微球吸附Cr(Ⅵ)离子,考察了其对Cr(Ⅵ)离子的吸附性能;探讨了吸附时间、溶液pH值、吸附剂用量、温度、Cr(Ⅵ)起始浓度以及其他离子存在对Cr(Ⅵ)离子去除率的影响。实验结果表明,磁性壳聚糖微球吸附Cr(Ⅵ)离子的最佳条件为:吸附平衡时间40 min,最佳吸附pH值6左右,磁性壳聚糖微球用量10 mg,温度升高有利于提高磁性壳聚糖微球的吸附效率,Cr(Ⅵ)离子起始质量浓度为12μg/mL,无机盐的存在引起磁性壳聚糖微球的吸附性能降低。并且考察了吸附剂的再生性能,实验结果表明磁性壳聚糖微球具有良好的重复使用性。     

磁性微球与牛血清白蛋白的相互作用

以纳米级四氧化三铁为磁性载体,以苯乙烯为单体,用微悬浮聚合法制备了聚苯乙烯磁性微球;以牛血清白蛋白(BSA)为模型蛋白,用荧光光谱仪和紫外-可见吸收光谱仪研究了磁性微球与BSA的相互作用.结果表明,磁性微球与BSA结合反应的猝灭机理为静态猝灭.     

磁性聚苯乙烯微球的制备与性能研究

以聚苯乙烯和二氯甲烷为油相,十二烷基苯磺酸钠 (SDBS) 为表面活性剂,采用溶剂挥发法制备了磁性聚苯乙烯微球.研究了温度、搅拌速度、Fe3O4用量和pH值等操作因素对磁性微球的形貌、粒径和磁学性能的影响.结果表明,采用溶剂挥发法可以制备含有磁性颗粒Fe3O4的磁性微球.磁性微球的粒径,磁响应性能与制备磁性微球的温度、搅拌速率、水溶液的pH值、磁粉用量等操作参数有关.综合考虑微球的粒径大小、分布以及磁响应性得出,在本实验体系中,20℃的操作温度、1000r/min的搅拌速率、弱碱性的水相溶液以及1.5:10 (磁粉:聚苯乙烯) 的比例是制备磁性微球的适宜操作条件.     

磁微球及其在生化分离分析中的应用

磁微球是以金属或金属氧化物为核,外面包被带有活性基团物质的一种新型生物分离材料。目前制备磁微球的方法有包埋法、聚合法、浸渍法、挤压法和生物合成法等。这种微球通过其活性基团与化学、生化和生物物质连接后,利用其顺磁性外加一定磁场可实现与介质分离。本文全面地介绍了磁微球的制备,详尽评述了其在免疫分析、核酸杂交分析、基因测序、细胞分离、酶的固定、受体分离等各个领域的应用。     

Boronic acid functionalized Fe3O4 magnetic microspheres for the specific enrichment of glycoproteins

Glycoproteins are useful biomarkers and therapeutic targets for a number of diseases, including infections and cancer. However, identification and isolation of low‐abundant glycoproteins remains a significant challenge that limits their application. Thus, methods of specific and selective glycoprotein enrichment are required. In this study, novel phenylboronic acid functionalized magnetic microspheres were successfully synthesized. Fe₃O₄ microspheres were synthesized by using a hydrothermal method and were coated with tetraethyl orthosilicate using an ultrasonic method to form a core‐shell structure. Compared to the conventional mechanical stirring for 12 h, the ultrasonic method saved about 7 h in processing time, and the home‐made magnetic microspheres had better dispersibility and homogeneity. Subsequently, the magnetic microspheres were modified by addition of an amino group and a carboxyl group, in sequence. Finally, 3‐aminophenylboronic acid, as the functional monomer, was linked to the magnetic microspheres for capturing glycoprotein/glycopeptides. The results of this study indicate that phenylboronic acid functionalized magnetic microspheres show excellent adsorption performance toward glycoprotein/glycopeptides. The maximum absorbing capacity of the microspheres for fetuin was 108 mg/g, and the enrichment efficiency reached 89.7%, indicating their potential to separate and enrich glycoproteins from the complex biological samples.     

磁性二氧化硅微球的表面修饰及其在植物基因组核酸纯化中的应用

在利用自主研发的专利技术制备球形磁性硅胶微球的基础上,对磁性硅胶微球进行表面改性,使其表面分别键合硅羟基、环氧基、邻二醇基和羧基等官能团,并对表面官能团进行了定量研究。以小牛胸腺基因组脱氧核糖核酸(DNA)为模型化合物,研究了核酸在不同表面官能团的磁性硅胶上的吸附和脱附行为,发现表面具有硅醇基的磁球对DNA的回收率最高。将改性后磁性微球应用于玉米DNA的提取,得到了平均长度大于8kb的高纯度基因组DNA。与传统的有机溶剂抽提法相比,基于磁性微球的核酸固相萃取法具有快速简便、省时省力、易于自动化的特点,适合于大规模植物基因组DNA的样品制备。     

Streptavidin-modified magnetic poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) microspheres for selective isolation of bacterial DNA

The dispersion copolymerization of 2-hydroxyethyl methacrylate (HEMA) with glycidyl methacrylate (GMA) in a toluene/2-methylpropan-1-ol mixture in the presence of Fe₃O₄ nanoparticles coated with oleic acid, produced monodisperse magnetic poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (P(HEMA-GMA)) microspheres. Oxirane groups of the microspheres were ammonolyzed and then functionalized with streptavidin using cyanuric chloride. The final product contained 0.67 mg of streptavidin per gram of wet magnetic P(HEMA-GMA) microspheres. The microspheres were characterized by elemental analysis, scanning electron microscopy, IR, UV–VIS and atomic absorption spectroscopy. The streptavidin-modified magnetic P(HEMA-GMA) microspheres were used for immobilization of biotinylated DNA and subsequent selective isolation of target DNA from complex samples using DNA/DNA hybridisation. Based on the highly selective recognition of streptavidin with a biotin-labeled DNA probe, DNA sensor was constructed for magnetic separation of DNA from real samples.     

多孔磁性硅胶微球的制备及其在基因组脱氧核糖核酸提取中的应用

采用模板法制备了多孔磁性硅胶微球,用于生物样品中基因组脱氧核糖核酸(DNA)的分离纯化。以球形和无定型硅胶为对照,考察了吸附液组成和洗脱时间等实验参数对小牛胸腺基因组DNA在磁性硅胶固相载体上的提取回收率的影响。实验结果表明:20%(W/V)聚乙二醇和2 mol/L氯化钠,洗脱10 m in,DNA的回收率可达80%;采用简单的细胞裂解体系和合适的吸附液组成,磁性微球应用于酿酒酵母中基因组DNA的提取,得到了平均长度约为5 kb、A260/A280大于1.77的高纯度DNA片段。     

磁性高分子微球

对磁性高分子微球的研究现状进行了综述,详细探讨了目前常用的各种合成制备方法,并对各种方法的优缺点进行了分析。在此基础上,对磁性高分子微球在细胞分离、有机合成、环境/食品微生物检测等领域的最新应用进展及存在的问题进行了分析,指出了该领域今后的研究方向。     

Fe3O4@Al2O3 magnetic core-shell microspheres for rapid and highly specific capture of phosphopeptides with mass spectrometry analysis

Selective detection of phosphopeptides from complex biological samples is a challenging and highly relevant task in many proteomics applications. In this study, a novel phosphopeptide enrichment approach based on the strong interaction of Fe(3)O(4)@Al(2)O(3) magnetic core-shell microspheres with phosphopeptides has been developed. With a well-defined core-shell structure, the Fe(3)O(4)@Al(2)O(3) magnetic core-shell microspheres not only have a shell of aluminum oxide, giving them a high-trapping capacity for the phosphopeptides, but also have magnetic property that enables easy isolation by positioning an external magnetic field. The prepared Fe(3)O(4)@Al(2)O(3) magnetic core-shell microspheres have been successfully applied to the enrichment of phosphopeptides from the tryptic digest of standard phosphoproteins beta-casein and ovalbumin. The excellent selectivity of this approach was demonstrated by analyzing phosphopeptides in the digest mixture of beta-casein and bovine serum albumin with molar ratio of 1:50 as well as tryptic digest product of casein and five protein mixtures. The results also proved a stronger selective ability of Fe(3)O(4)@Al(2)O(3) magnetic core-shell microspheres over Fe(3+)-immobilized magnetic silica microspheres, commercial Fe(3+)-IMAC (immobilized metal affinity chromatography) resin, and TiO(2) beads. Finally, the Al(2)O(3) coated Fe(3)O(4) microspheres were successfully utilized for enrichment of phosphopeptides from digestion products of rat liver extract. These results show that Fe(3)O(4)@Al(2)O(3) magnetic core-shell microspheres are very good materials for rapid and selective separation and enrichment of phosphopeptides.     

Magnetic hydrophilic methacrylate-based polymer microspheres for genomic DNA isolation

Carboxyl groups containing magnetic and non-magnetic microspheres were used in solid-phase reversible immobilization (SPRI) of genomic DNA. Magnetic non-porous poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate)--P(HEMA-co-EDMA), poly(glycidyl methacrylate)--PGMA and P(HEMA-co-GMA) microspheres with hydrophilic properties were prepared by dispersion copolymerization of the respective monomers in the presence of colloidal iron oxides. DNA from chicken erythrocytes and DNA isolated from bacterial cells of Bifidobacterium longum was used for testing of adsorption/desorption properties of magnetic microspheres. The occurrence of false negative results in polymerase chain reaction (PCR) caused by the presence of extracellular inhibitors in DNA samples has been solved using SPRI. The P(HEMA-co-EDMA) and P(HEMA-co-GMA) microspheres were used for isolation of DNA from different dairy products followed by PCR identification of Bifidobacterium strains.     

Ferrite supports for isolation of DNA from complex samples and polymerase chain reaction amplification

The influence of cobalt ferrite particles, with non-modified or modified surface, on the course of polymerase chain reaction (PCR) was investigated. DNA isolated from bacterial cells of Bifidobacterium bifidum was used in PCR evaluation of magnetic microspheres. The presence of cobalt ferrite particles inhibits PCR amplification. The effect is not dependent on the functional groups of the modifying reagents used (none, amino, carboxyl). Amplification was improved after the magnetic separation of magnetic particles. Proposed indirect method enabled verification of the suitability of designed particles for their application in PCR assays. Magnetic particles coated with alginic acid under high PEG and sodium chloride concentration were used for the isolation of PCR-ready bacterial DNA from various dairy products. DNA was isolated from crude bacterial cell lysates without phenol extraction of samples. Bifidobacterium and Lactobacillus DNAs were identified in dairy products using PCR.     

Establishment and implications of a characterization method for magnetic nanoparticle using cell tracking velocimetry and magnetic susceptibility modified solutions

Magnetic micro and nanoparticles conjugated to affinity labels have become a significant, commercial reagent. It has been demonstrated that the performance of cell separation systems using magnetic labels is a function of the magnitude of the magnetic force that can be generated through labeling. This magnetic force is proportional to the number of magnetic particles bound to the cell, the magnetic energy gradient, and the particle-field interaction parameter. This particle-field interaction parameter, which is the product of the relative volumetric, magnetic susceptibility and the volume of the micro or nanoparticle, is a fundamental parameter which can be used to characterize the magnetic particles. An experimental technique is presented which measures the volumetric magnetic susceptibility of particles through the use of susceptibility modified solutions and an experimental instrument, Cell Tracking Velocimetry, CTV. Experimental studies were conducted on polystyrene microspheres alone and those bound to four different magnetic nanoparticles. The experimentally determined values of the magnetic susceptibility of the polystyrene microspheres are consistent with values found from literature. Consequently, magnetic susceptibility measurements of these polystyrene microspheres bound with the magnetic nanoparticles combined with particle size measurements using commercial dynamic light scattering instrument allowed estimates of the particle-field interaction parameter to be made for four commercial, magnetic nanoparticles. The value found for MACS beads is close to what is reported from an independent study. The values for MACS beads and Imag beads are found to agree with what is observed from experiments. Finally, an experimental demonstration of the impact that differences in this field interaction parameter has on the labeling of human lymphocytes is presented.