磁性纳米SO4^2-／Fe3O4-ZrO2固体超强酸催化合成己二酸二正辛酯

利用磁性对纳米固体超强酸组合，制备出磁性纳米SO4^2-／Fe3O4-ZrO2固体超强酸催化剂，并用TEM、IR、Hammett指示剂检测磁性纳米固体超强酸催化剂性能。将其用于己二酸二正辛酯（DOA）的合成反应中。得到最佳反应条件为负压下，反应温度155℃，n（正辛醇）：n（己二酸）=3．2：1，反应时间2h，w（催化剂）=1．5％，己二酸的转化率达99％。利用催化剂的磁性可将纳米颗粒催化剂迅速分离，回收率达93．8％，并能重复使用。     

负载钯的磁性复合纳米颗粒的制备及其催化性能研究

本文首先合成SiO2包覆的磁性Fe3O4纳米颗粒(Fe3O4@SiO2),再通过硅烷偶联剂得到氨基修饰的纳米颗粒(Fe3O4@SiO2-NH2),该纳米颗粒再与Na2[Pd Cl4]反应将Pd负载在磁性纳米颗粒上,最后通过Na BH4还原得到了磁性纳米复合物Fe3O4@SiO2-NH2-Pd。利用红外、TEM和XRD技术对产物进行了表征。用UV-Vis对其催化4-硝基苯酚还原反应的性能进行了研究。结果表明,该纳米颗粒具有很好的催化性及重复利用性。     

磁性纳米SO42-/Fe3O4-ZrO2固体超强酸催化合成己二酸二正辛酯

利用磁性进行了纳米固体超强酸组合,制备出磁性纳米SO4^2-／Fe3O4-ZrO2固体超强酸催化剂,并将其用于己二酸二正辛酯(DOA)的合成反应中。得到最佳反应条件：在负压下,反应温度155℃,正辛醇和己二酸的摩尔比为3.2：1,反应时间2h,催化剂用量1．5％(质量),在此条件下己二酸的转化率达99．4％。实验结果表明,利用催化剂的磁性可将纳米颗粒催化剂迅速分离,回收率达93．8％,并能重复使用。     

原位复合法制备磁性纤维素纤维及其性能研究

以天然棉纤维为基材,用原位复合法在上沉积磁性Fe3O4纳米粒子,制备出磁性纤维素纤维,利用X射线衍射仪、傅立叶变换红外光谱仪、扫描电子显微镜等方法对所得产物中磁性粒子进行表征。探究了预处理方法以及铁离子（Fe^3＋/Fe^2＋=2）浓度对制得的纤维磁性能的影响,并对磁性纳米粒子与纤维的结合牢度进行了讨论。结果表明：两个因素均会对纤维的磁性能产生影响,当用5%Na OH处理棉纤维原料,在铁离子总浓度为0.10 mol/L（Fe^3＋/Fe^2＋=2）反应时,最有利于磁性纳米颗粒在其表面的沉积,制得棉纤维复合材料的磁性能可以达到11.90 eum/g;经多次洗涤后磁性纤维的磁性能稍有下降,说明磁性纳米粒子对纤维附着力较好,期望被用作功能材料。     

分散聚合法制备环氧基磁性复合微球

采用化学共沉淀法制备了油酸包覆的Fe3O4磁性纳米粒子,以此为核·采用分散聚合法制备了表面带有环氧基团的Fe3O4／聚甲基丙烯酸缩水甘油酯（PGMA）磁性复合微球,探讨了聚合工艺、聚合条件对甲基丙烯酸缩水甘油酯（GMA）利用效率的影响规律,并用傅立叶变换红外光谱仪（FTIR）、热重分析仪（TGA）、振动样品磁强计（VSM）和扫描电镜（SEM）等对磁性复合微球的结构、磁性能和包覆量进行了表征．采用盐酸一丙酮法测定了磁性复合微球表面环氧基的含量。结果表明,在优化的条件下。GMA利用效率高达61．26％。磁性复合微球具有良好的单分散性·粒径为1～2μm．具有超顺磁性．比饱和磁强度为17．12emu·g^-1。环氧基含量达3．5mmol·g^-1。     

双醛淀粉修饰的磁性Fe3O4制备及其除去水中Pb2＋的研究

使用油相水热法制备了50nm左右的Fe3O4纳米颗粒,并在其表面包裹上双醛淀粉（DSA）,使纳米颗粒表面具有丰富的羟基基团,通过化学方法将乙二胺四乙酸（EDTA）键合在其表面。通过透射电镜（TEM）和XRD表征分析,说明成功合成了粒径为50nm左右的Fe3O4磁性纳米颗粒,并且在其表面用物理吸附的方式包裹了双醛淀粉（DSA）;通过红外光谱分析表明,EDTA被成功地键合在纳米复合体的表面;通过磁回滞线（VSM）,得出Fe3O4-NH2和Fe3O4@DAS—EDTA的饱和磁性分别为83和62emu·g-1。并将这一材料应用于吸附不同pH值水中的重金属离子Pb2＋,实验结果表明,在pH值为5时,该纳米复合材料对Pb2＋吸附效果最为显著,除去率可达到98．5％,重复使用6次后,除去率仅降低3％。     

羧甲基淀粉包覆Fe_3O_4磁性纳米颗粒的制备与表征

利用共沉淀法制备了CMS@Fe3O4磁性纳米颗粒。利用扫描电子显微镜、红外光谱、Zeta电位分析仪以及振动样品磁强计表征了纳米颗粒的形态以及性质。磁性纳米颗粒类似于球状,平均直径为(35±10)nm。结果表明,在较高的pH范围内粒子有较高的负电顺磁性。30 d后考察了CMS@Fe3O4磁性纳米颗粒的稳定性,CMS@Fe3O4磁性纳米颗粒在pH值为11时保持较好的稳定性。     

共沉淀法合成小粒径单分散Fe3O4纳米颗粒

研究以FeSO4·7H2O和FeCl3·6H2O为原料,NH3·H2O作为沉淀剂,采用共沉淀法制备纳米Fe3O4颗粒,利用IR（红外光谱）、XRD（X射线衍射）等表征手段对割得的纳米颗粒进行了表征。结果表明：制备的纳米Fe3O4粒子粒径较细,且粒径分布较窄。据此找出制备纳米Fe3O4粒子的最佳实验条件为：铁盐溶液浓度为0．5mol／L,沉淀剂溶液浓度为0．2mol／L,Fe^2＋：Fe^3＋：OH^-=1．00：1．00：6．00,反应温度为30℃。制备纳米Fe3O4粒子粒径在10-20mm,且分散性较好;通过XRD谱图可以得出产物为具有立方晶系的纳米Fe3O4粒子。     

功能化磁性纳米颗粒固定化脂肪酶研究

用葡萄糖酸对Fe3O4磁性纳米颗粒表面进行修饰,然后用水溶性碳化二亚胺（EDC）作偶联剂,对脂肪酶进行固定化。考察了偶联剂浓度、给酶量和反应时间对脂肪酶固定化过程的影响。结果表明,制备功能化磁性颗粒固定化酶的最佳条件为：偶联剂浓度为12．5mg／mL磷酸缓冲液（PBS）,给酶量为2．5mg／mLPBS,反应时间为24h。固定化脂肪酶表现出优异的热稳定性,60℃时酶活为游离酶的6倍。重复使用10次后,酶促活力依然保持80％以上。     

磁性纳米颗粒的制备及表面改性

采用化学共沉淀法合成Fe3O4纳米颗粒,用葡萄糖酸对磁性纳米颗粒表面进行了修饰,并利用扫描电子显微镜(SEM)、傅立叶转变红外光谱仪(FT-IR)、X-射线衍射(XRD)对修饰前后的Fe3O4纳米颗粒进行了表征,实验结果表明:磁性纳米颗粒粒径分布均匀、单分散性好,改性后其表面具有相应的官能团。     

The effect of two novel amino acid-coated magnetic nanoparticles on survival in vascular endothelial cells,bone marrow stromal cells,and macrophages

Magnetic nanoparticles (MNPs) have been popularly used in many fields. Recently, many kinds of MNPs are modified as new absorbents, which have attracted considerable attention and are promising to be applied in waste water. In our previous study, we synthesized two novel MNPs surface-coated with glycine or lysine, which could efficiently remove many anionic and cationic dyes under severe conditions. It should be considered that MNP residues in water may exert some side effects on human health. In the present study, we evaluated the potential nanotoxicity of MNPs in human endothelial cells, macrophages, and rat bone marrow stromal cells. The results showed that the two kinds of nanoparticles were consistently absorbed into the cell cytoplasm. The concentration of MNPs@Gly that could distinctly decrease survival was 15 μg/ml in human umbilical vascular endothelial cells (HUVECs) or bone marrow stromal cells (BMSCs) and 10 μg/ml in macrophages. While the concentration of MNPs@Lys that obviously reduced viability was 15 μg/ml in HUVECs or macrophages and 50 μg/ml in BMSCs. Furthermore, cell nucleus staining and cell integrity assay indicated that the nanoparticles induced cell apoptosis, but not necrosis even at a high concentration. Altogether, these data suggest that the amino acid-coated magnetic nanoparticles exert relatively high cytotoxicity. By contrast, lysine-coated magnetic nanoparticles are more secure than glycine-coated magnetic nanoparticles.     

Radioiodinated Magnetic Nanoparticles Conjugated With Moxifloxacin: Synthesis and In Vitro Biological Affinities

Magnetic nanoparticles (MNPs) were synthesized and coated with tetraethyl orthosilicate and aminosilane to create functional amino groups. Moxifloxacin (MXF) was conjugated to the modified MNPs using glutaraldehyde as crosslinker. Finally, MXF conjugated magnetic nanoparticles were radiolabeled and their biological affinities such as cell incorporation ratio, cytotoxicity, and their potential as cell imaging probe were investigated using A-549 cells.     

Preparation and Characterization of Stimuli-Responsive Magnetic Nanoparticles

In this work, the main attention was focused on the synthesis of stimuli-responsive magnetic nanoparticles (SR-MNPs) and the influence of glutathione concentration on its cleavage efficiency. Magnetic nanoparticles (MNPs) were first modified with activated pyridyldithio. Then, MNPs modified with activated pyridyldithio (MNPs-PDT) were conjugated with 2, 4-diamino-6-mercaptopyrimidine (DMP) to form SR-MNPs via stimuli-responsive disulfide linkage. Fourier transform infrared spectra (FTIR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize MNPs-PDT. The disulfide linkage can be cleaved by reduced glutathione (GHS). The concentration of glutathione plays an important role in controlling the cleaved efficiency. The optimum concentration of GHS to release DMP is in the millimolar range. These results had provided an important insight into the design of new MNPs for biomedicine applications, such as drug delivery and bio-separation.     

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.     

Facile synthesis of monodispersed silica-coated magnetic nanoparticles

Silica-coated magnetic nanoparticles (MNPs) have great potential for use in field of biotechnology owing to their unique properties, which can be manipulated by an external magnetic field gradient. Herein, we describe a method for facile synthesis of monodispersed silica-coated MNPs (MNP@SiO₂ NPs). Commercially available oleate-MNPs were successfully converted to polyvinylpyrrolidone-MNPs (PVP-MNPs), and then coated with silica by the modified Stöber method. More than 95% of MNPs were individually coated with a silica shell; non-magnetic core silica nanoparticles (NPs) were not detected. Notably, the MNP@SiO₂ NPs are highly monodispersed in size (size distribution < 2.5%) and synthesis at the scale of grams was easily obtained by a simple scale up process. Moreover, aggregation was not detected upon storage of over three months.     

Transmittance Measurements in Non-alternating Magnetic Field as Reliable Method for Determining of Heating Properties of Phosphate and Phosphonate Coated Fe3O4 Magnetic Nanoparticles

Different phosphates and phosphonates have shown excellent coating ability toward magnetic nanoparticles, improving their stability and biocompatibility which enables their biomedical application. The magnetic hyperthermia efficiency of phosphates (IDP and IHP) and phosphonates (MDP and HEDP) coated Fe₃O₄ magnetic nanoparticles (MNPs) were evaluated in an alternating magnetic field. For a deeper understanding of hyperthermia, the behavior of investigated MNPs in the non-alternating magnetic field was monitored by measuring the transparency of the sample. To investigate their theranostic potential coated Fe₃O₄-MNPs were radiolabeled with radionuclide ¹⁷⁷Lu. Phosphate coated MNPs were radiolabeled in high radiolabeling yield (>?99%) while phosphonate coated MNPs reached maximum radiolabeling yield of 78%. Regardless lower radiolabeling yield both radiolabeled phosphonate MNPs may be further purified reaching radiochemical purity of more than 95%. In vitro stabile radiolabeled nanoparticles in saline and HSA were obtained. The high heating ability of phosphates and phosphonates coated MNPs as sine qua non for efficient in vivo hyperthermia treatment and satisfactory radiolabeling yield justifies their further research in order to develop new theranostic agents.

     

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.     

The Interplay between Fe3O4 Superparamagnetic Nanoparticles,Sodium Butyrate,and Folic Acid for Intracellular Transport

Combined treatments which use nanoparticles and drugs could be a synergistic strategy for the treatment of a variety of cancers to overcome drug resistance, low efficacy, and high-dose-induced systemic toxicity. In this study, the effects on human colon adenocarcinoma cells of surface modified Fe₃O₄ magnetic nanoparticles (MNPs) in combination with sodium butyrate (NaBu), added as a free formulation, were examined demonstrating that the co-delivery produced a cytotoxic effect on malignant cells. Two different MNP coatings were investigated: a simple polyethylene glycol (PEG) layer and a mixed folic acid (FA) and PEG layer. Our results demonstrated that MNPs with FA (FA-PEG@MNPs) have a better cellular uptake than the ones without FA (PEG@MNPs), probably due to the presence of folate that acts as an activator of folate receptors (FRs) expression. However, in the presence of NaBu, the difference between the two types of MNPs was reduced. These similar behaviors for both MNPs likely occurred because of the differentiation induced by butyrate that increases the uptake of ferromagnetic nanoparticles. Moreover, we observed a strong decrease of cell viability in a NaBu dose-dependent manner. Taking into account these results, the cooperation of multifunctional MNPs with NaBu, taking into consideration the particular cancer-cell properties, can be a valuable tool for future cancer treatment.     

金磁纳米颗粒的制备与表征

金作为一种惰性贵金属,具有生物相容性好,易于功能化等特点,目前已被广泛应用于磁性纳米颗粒的表面的功能化.利用反胶束方法制备了金包铁(Fe/Au)结构的磁性纳米复合颗粒,表征结果显示Fe/Au具有明显的核壳结构,其平均粒径为15 nm.无磁滞现象,其剩余磁化强度与矫顽力均为零.这表明所得的Fe/Au MNPs为超顺磁性颗...     

Synthesis of MIL-Modified Fe3O4 Magnetic Nanoparticles for Enhancing Uptake and Efficiency of Temozolomide in Glioblastoma Treatment

A nanometric hybrid system consisting of a Fe₃O₄ magnetic nanoparticles modified through the growth of Fe-based Metal-organic frameworks of the MIL (Materials Institute Lavoiser) was developed. The obtained system retains both the nanometer dimensions and the magnetic properties of the Fe₃O₄ nanoparticles and possesses increased the loading capability due to the highly porous Fe-MIL. It was tested to load, carry and release temozolomide (TMZ) for the treatment of glioblastoma multiforme one of the most aggressive and deadly human cancers. The chemical characterization of the hybrid system was performed through various complementary techniques: X-ray-diffraction, thermogravimetric analysis, FT-IR and X-ray photoelectron spectroscopies. The nanomaterial showed low toxicity and an increased adsorption capacity compared to bare Fe₃O₄ magnetic nanoparticles (MNPs). It can load about 12 mg/g of TMZ and carry the drug into A172 cells without degradation. Our experimental data confirm that, after 48 h of treatment, the TMZ-loaded hybrid nanoparticles (15 and 20 μg/mL) suppressed human glioblastoma cell viability much more effectively than the free drug. Finally, we found that the internalization of the MIL-modified system is more evident than bare MNPs at all the used concentrations both in the cytoplasm and in the nucleus suggesting that it can be capable of overcoming the blood-brain barrier and targeting brain tumors. In conclusion, these results indicate that this combined nanoparticle represents a highly promising drug delivery system for TMZ targeting into cancer cells.