Synthesis of immunomagnetic nanoparticles and their application in the
separation and puri?cation of CD34+hematopoietic stem cells
Wei Chen a ,Hebai Shen a ,*,Xingyu Li a ,Nengqin Jia a ,Jianming Xu b
a
Life and Environment Science College,Shanghai Normal University,Shanghai 200234,PR China
b
Zhongshan Hospital of FuDan University,Shanghai 200030,PR China
Received 31October 2005;accepted 6March 2006
Available online 18April 2006
Abstract
The silica-coated superparamagnetic nanoparticles with the uniform diameter of about 60nm were synthesized by reverse microemulsions method.And the magnetic nanoparticles were modi?ed with N -(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPS).The immunomagnetic nanoparticles were then successfully prepared by covalently immobilizing anti-CD34+monoclonal antibodies to the surface of amino silane modi?ed magnetic particles.The cell separation results showed that the synthesized immunomagnetic nanoparticles could rapidly and conveniently separate the CD34+cells with high ef?ciency and speci?city than normal ones.The surface morphology of separated target cells was examined by scanning electron microscope (SEM).Atomic force microscope (AFM)also characterized the magnetic materials on the surface of the separated target cells for the ?rst time,which further con?rmed that the target cells were separated by the immunomagnetic nanoparticles.The viability of the separated cells was studied by culturing method and Beckman Vi-cell viability analyst.Therefore,our experiments provided a new,direct,rapid mode to separate target cells.#2006Elsevier B.V .All rights reserved.
PACS:75.50.-y;07.79.LH;87.17.E
Keywords:Immunomagnetic separation;CD34+;Monoclonal antibody (MAbs);Atomic force microscopy (AFM);Scanning electron microscopy (SEM)
1.Introduction
Nanoscience is one of the most important research and development frontiers in modern science [1].The use of nanoparticle materials offers many advantages due to their unique size,physical properties,large surface area/volume and so on [2,3].Among all these materials,the magnetic particles are paid more attention.As their special trait of magnetism,they have been widely applied in various ?elds of bioseparation and medicine,such as protein and enzyme immobilization [4,5],immunoassay,RNA and DNA puri?cation,cell isolation and recognition [6–8],target drug [9–11]and the PCR reaction [12].Using magnetic particles is advantageous for full automation,resulting in minimizing manual labor and providing more precise results [13].Use of nanomagnetic particles also has the advantages in assay sensitivity,rapidity and precision [14].All these bioseparation and medicine applications require that these nanoparticles have high magnetization and small diameter
with narrow particle size distribution so that the particles have uniform physical and chemical properties [15].
It is well known that the hematopoietic stem cells (HSC)are the source of all blood cells [16].They are very important for generating all kinds of cells and maintaining the number of cells in peripheric blood.Since the ?rst successful treatment of Fanconi’s anemia by the using of human umbilical cord blood in 1988,more and more researches have been done about the transplanting of human umbilical cord blood [17].Human umbilical cord blood transplanting has been applied in curing many malignancy hematonosis,such as acute lymphocytic leukaemia,chronic granulocyte leukaemia,Hodgkin’s disease and so on.Now,it has been revealed that the human umbilical cord blood is rich in HSC.In order to study the HSC,the ?rst thing that should be done is to separate the HSC from hematopoietic tissue.The normal way is utilizing the marker protein on the surface of HSC.Nowadays,CD34+is the most widely used marker protein of HSC.Among all those methods,the immunomagnetic separation is a very attractive method [7].Immunomagnetic separation can separate the target cells from the crude cells directly,conveniently and rapidly.As early
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Applied Surface Science 253(2006)1762–1769
*Corresponding author.Tel.:+862164322516;fax:+862164321800.E-mail address:shenhb@https://www.doczj.com/doc/e62798071.html, (H.Shen).
0169-4332/$–see front matter #2006Elsevier B.V .All rights reserved.doi:10.1016/j.apsusc.2006.03.012
as in1980’s,people had begun to research the magnetic cell separation[18–20].Until now,the mainly used magnetic particles are microparticles and the antibodies modi?ed on the magnetic particles are mainly second antibodies.These kinds of immunomagnetic particles may have some disadvantages, such as fast sedimentation rate,cell damni?cation and so on. And also the using of the second antibodies maybe increase the cost of the experiment and require higher experimental techniques and conditions.However,there are very limited literature reports about the direct application of monoclonal antibody modi?ed immunomagnetic nanoparticles in the separation and puri?cation of CD34+hematopoietic stem cells.By using this method,it can separate and purify the target cells from the complicated mixed system with high ef?ciency rather than with cumbersome experimental steps and high cost.
In this study,we have developed a powerful technique, which allows a simple and fast isolation and enrichment of CD34-positive cells by using nano-scale superparamagnetic particles with the virtue of cost-effective.The superparamag-netic nanoparticles used to prepare immunomagnetic nano-particles have been prepared and characterized by some advanced means.The morphology,structure and character of the nanoparticles were studied by TEM and FT-IR.We modi?ed the prepared nanoparticles with the active group of–NH2on the surface of the nanoparticles.By this active group, the CD34+monoclonal antibodies were directly connected to the surface of the nanoparticles.The modi?ed nanoparticles were used to separate the HSC from the human umbilical cord blood.The surface morphology,purity and viability of the separated HSCs were characterized by scanning electron microscopy(SEM),atomic force microscope(AFM)and Hematopoietic Colony Assay method,respectively.
2.Experiments
2.1.Materials
The ferrous chloride heptahydrate(FeCl2á7H2O),ferric chloride hexahydrate(FeCl3á6H2O),sodium hydrate,tetraethyl orthosilicate(TEOS),ammonium hydroxide(28%,w/w)were purchased from the sino-pharm chemical reagent limited company in Shanghai.N-(2-aminoethyl)-3-aminopropyltri-methoxysilane(AEAPS)and glutaraldehyde were purchased from J&Kchemica Company.RPMI-1640medium were purchased from Sino-American Biotechnology Company. The mouse anti-human monoclonal antibody against CD34+cell surface antigen was obtained from Biomeda Company.All the chemicals,used in the experiment,were commercial available and were of analytical reagent grade. Double distilled water was used for all the experiments.
2.2.Synthesis of silica-coated superparamagnetic nanoparticles
The g-Fe2O3magnetic nanoparticles were prepared by our reported method[21].Typically,2.5M NaOH solution was dropped into the solution of mixture of FeCl3(0.2M)and FeSO4(0.12M)with violently stirring.Then the obtained precipitation was aged at the temperature of608C for2h and washed with water for several times.Finally,the magnetic nanoparticles were dried at608C for24h.To coat the magnetic nanoparticles with silica,we adopted the water-in-oil reverse microemulsions of water/Triton X-100/n-hexylalcohol/cyclo-hexane.0.1g g-Fe2O3was dispersed in the60ml above microemulsion with3-min ultrasonication,then the solution was poured into three-necked?ask with vigorous stirring at 228C.Concentrated ammonia and tetraethoxysilane(TEOS) were added dropwise into the system in turn.The reaction ended after10h.The nanoparticles were aged overnight and then washed with ethanol three times.At last,the silica-coated g-Fe2O3nanoparticles were got after sintered at6508C for2h.
2.3.Modi?cation of silica-coated superparamagnetic nanoparticles with AEAPS
Twenty milligrams of g-Fe2O3nanoparticles were dispersed in the mixture of25ml methanol and15ml glycerol with 30-min ultrasonication.Then1.5ml AEAPS was added into the mixture and dispersed by vigorous stirring.Through the whole experiment,the temperature was retained at608C.The amino-silane modi?ed nanoparticles were washed with meth-anol and double distilled water for three times,respectively. Then the nanoparticles were dried in the vacuum oven.The amino-silane modi?ed silica-coated maghemite was used to immobilize the monoclonal antibody against CD34+cell. 2.4.Characterization of magnetic nanoparticles
2.4.1.Transmission electron microscope(TEM) characterization of the silica-coated magnetic nanoparticles
The size,distribution and morphology of the silica-coated magnetic nanoparticles were studied by using a Hitachi-600 TEM.The sample of the silica-coated magnetic nanoparticles was drop-cast onto a carbon coated copper grid and air dried at the room temperature.
2.4.2.Fourier transformed infrared(FT-IR) characterization of the silica-coated magnetic nanoparticles
The FT-IR spectrum was recorded in the transmission mode on a Nicolet Avatar370spectrometer.The dried sample of magnetic nanoparticles was grounded with KBr and the mixture was compressed into a pellet.The spectrum was scanned from 4000to400cmà1.
2.5.Preparation of antibody immobilized amino-silane modi?ed silica-coated magnetic nanoparticles
Before immobilizing the antibody,we adopted the reported way to activate the nanoparticles by glutaraldehyde method for the application in bioseparation[2,3].The activated nanoparticles were then dispersed in the phosphate buffered saline(PBS,0.1M,pH7.4)with identical concentrations
W.Chen et al./Applied Surface Science253(2006)1762–17691763
of 0.5mg/ml.The 0.3mg/ml monoclonal antibody against CD34+cell surface antigen was added into 1ml maghemite-PBS solution.The mixture was incubated at 48C for 2h.The mixture was washed carefully with PBS three times.Finally,the antibody-immobilized maghemite nanoparticles were redispersed in the PBS with concentration of 0.5mg/ml.2.6.Puri?cation of mononuclear cells
The human umbilical cord blood was obtained from the International Maternity and Child Hygiene Station of Shanghai.The heparin was added into the sample blood to prevent the blood coagulating.The sample blood would be separated in https://www.doczj.com/doc/e62798071.html,ing lymphocyte separation media,the cell suspension was centrifuged at 2000r/min for 30min to collect mono-nuclear cells at the pasma-histopaque interface.The interface containing the mononuclear cell was transferred to a sterile tube and washed twice with RPMI-1640for further using.2.7.Magnetic separation of stem cell maker positive cells (CD34+)
Two hundred microliters of antibody-immobilized maghe-mite nanoparticles were added into the cell suspension,which contained 1?106cells.The mixture was incubated at 48C for 30min with continuous mixing.Then,the cells were magnetically separated by using a magnet for 5min.The magnetically separated cells were resuspended in 1ml RPMI-1640.The total cells before separation were measured by direct cell count using a microscope and Beckman Vi-cell analyst,the number of target cells after separation was also measured by the same methods.
2.8.Scanning electron microscope and atomic force microscopy characterization of the separated target cells The scanning electron microscopy photographs were obtained by using a S-2700SEM at the voltage of 15kV.The cell sample was ?rstly ?xed with 1.5%glutaraldehyde for 1h.After washing with PBS (pH 7.4)twice,the cells were post-?xed in 1%osmium tetroxide.Then the cell sample was dehydrated through a series of alcohol concentrations (50%,70%,90%,95%and dry alcohol).Following,the sample was immersed in the acetate isopentyl ether for 0.5h three times.Once the sample air-dry,the sample was sputter coated with gold before SEM morphology observation.In order to further con?rm the SEM result,the atomic force microscopy images were got by using Veeco AFM (USA).The magnetic scanning of the AFM can detect the magnetic nanoparticles on the surface of the separated target cells.The glutaraldehyde ?xed cells were drop-cast onto the mica before loading into the atomic force microscope.2.9.Hematopoietic colony assays
Hematopoietic colony assay was carried out as described previously [14,22–25].In the experiment,about 1?105
CD34+cells separated from total cells were used for hematopoietic colony assays each time.This assay method was carried out by growing cells in the mixed media which consisting of 1%methylcellulose,50ng/ml stem cell factor (FCS),2ng/ml erythropoietin (EPO),20ng/ml IL-1,20ng/ml IL-3,20ng/ml IL-6,20ng/ml granulocyte colony stimulating factor (G-CSF),30%fetal bovine serum (FBS)and RPMI-1640.The whole volume of the mixed media was 2ml.The media was aliquoted in four wells of 24-well plate.The control team was using the blood mononuclear cells before magnetic separation.After 14days of incubation at 378C in 5%CO 2,colony forming was observed by inverted microscope.3.Results and discussion
3.1.Characterization of synthesized magnetic nanoparticles
The g -Fe 2O 3magnetic nanoparticles used in the experiment were synthesized by coprecipitation of ferrous and ferric ion solutions.It had been reported that magnetite nanoparticles synthesized by the coprecipitation method had quite a lot of hydroxyl groups on the surface of nanoparticles from contacting with the aqueous phase [3,24].Fourier transform infrared spectroscopy was used to characterize the magnetic nanoparticles.The FT-IR spectrum of the particles is shown in Fig.1(a).
It was reported that the characteristic absorption bands of the g -Fe 2O 3were in 632and 585cm à1[25].However,in Fig.1(a)these two bands shift to high wavenumbers of about 641.67and 590.31cm à1.The possible reason is that owing to the effect of ?nite size of nanoparticles,the bonds of surface atoms are breaking.Therefore,the inlocalized electrons on the surface of particles are rearranged and the lattice constric-tions occur.Meanwhile,the surface bond force constant increases while the synthesized particles are small to nano-scale dimension.All that leads to the shifting of the adsorp-tion bands of FT-IR spectrum to the higher wavenumbers.So the blue shift of the adsorption band of Fe–O bond was observed.Although the superparamagnetic nanoparticles
W.Chen et al./Applied Surface Science 253(2006)1762–1769
1764Fig.1.FT-IR spectrum of (a)magnetic nanoparticles and (b)silane-coated magnetic nanoparticles.
have the potential to be widely used in biology and medicine,owing to the limitation of tending to aggregate into large clusters,the uncoated nanoparticles lose the speci?c properties of the nanoparticles and cannot be used directly [26].In our work,the g -Fe 2O 3nanoparticles were coated with silica in order to make the particles with high dispersion and compatibility with biology [27,28].The FT-IR method was also applied to characterize the silica-coating.Fig.1(b)is the IR spectrum of the silica-coated magnetic nanoparticles.From the spectrum,it can be seen that there are three main peaks on the spectrum at 1110.08,806.89and 475.70cm à1.The strong and wide absorption band at 1110.08cm à1is due to the asymmetry stretching vibration of Si–O bond.And the bands at
806.89and 475.70cm à1are due to the symmetry stretching vibration of Si–O bond.Meanwhile,the characteristic absorption bands of the Fe–O bond are still appearing at 641.67and 561.22cm à1.All these results indicate that the silica-coated g -Fe 2O 3has been successfully synthesized.The TEM method was also taken to characterize the coating result.The TEM image of the silica-coated g -Fe 2O 3(Fig.2)shows that the coated particles are with uniform dispersity and the average diameter of the particles is about 60nm.
As reported that magnetite nanoparticles synthesized by the coprecipitation method had quite a lot of hydroxyl groups on the surface of nanoparticles from contacting with the aqueous phase.AEAPS was used to immobilize the antibody on the silica magnetic nanoparticles with reaction with hydroxyl groups on the nanoparticle surface.Fig.3shows the FT-IR
W.Chen et al./Applied Surface Science 253(2006)1762–1769
1765
Fig.2.TEM micrograph of the silica-coated g -Fe 2O 3
.
Fig. 3.FT-IR spectrum of the unmodi?ed (a)and AEAPS-modi?ed (b)magnetic
nanoparticles.
Fig.4.Scheme diagram of immunomagnetic separation of CD34+cells.
spectrum of the AEAPS modi?ed nanoparticles.From the spectrum,compared with the unmodi?ed nanoparticles,the modi?ed nanoparticles posses the adsorption band in 3434.31cm à1due to the stretching vibration of N–H bond,and at 1648.79and 1545.96cm à1attributed to the bending vibra-tion of the N–H bond.After the amino groups were grafted on the particle surface by silanization,the antibody was bonded to the amino groups on the particle surface with glutaraldehyde through the Schiff base generating reaction.
In order to successfully separate the target CD34+cells,the cell separation process was designed as shown in Fig.4.
The key step in the cell separation process is to immobilize the CD34+monoclonal antibodies onto the surface of the mag-netic nanoparticles,which made the separation with high ef?ciency and speci?city.The scheme for the immobilization of antibody is shown in Fig.5.
W.Chen et al./Applied Surface Science 253(2006)1762–1769
1766Fig.5.Schematic procedure of antibody immobilized to the silica-coated magnetic
nanoparticles.
Fig.8.The atomic force image of the separated CD34+cells.(a)The altitude image of the separated target cell (normal scanning)and (b)the magnetic scanning image of the separated target cell (magnetic scanning;the brown spots on the image stand for the immunomagnetic nanoparticles and unmagnetic materials including the cell cannot be seen in the
image).
Fig.6.Percentage of CD34+cells before and after
separation.
Fig.7.The SEM photo of the separated CD34+cells.
3.2.Magnetic separation of CD34+cells
According to the report,there are about1–4%the stem cell maker positive cells in the human umbilical cord blood[29].As the results of direct cell counting by hemocytometer and Beckman Vi-cell viability analyst,there were about1?107 mononuclear cells before separation.After magnetic separation using magnetic nanoparticles binding with CD34+monoclonal antibody,there were about3?105cells left.The effect of the separation was determined by the same method and the results are shown in Fig.6.After cell separation using immunomag-netic nanoparticles,the percentage of the CD34+cells increased greatly from about1%before separation to about75%, indicating that the immunomagnetic nanoparticles can effec-tively separate the target cells,which maintain the high viability.The result was con?rmed by the method of hemato-poietic colony assay[22].3.3.Morphology of cells separated by immunomagnetic nanoparticles
SEM was used to directly observe the morphology of cells separated by the immunomagnetic nanoparticles.Fig.7is the SEM photo of the separated cell.It can be seen that the separated cell still maintains the morphology of normal cells. Besides,the following result can also be known that there are many particles on the surface of the separated cell.These particles are most possibly the immunomagnetic nanoparticles. It also can be seen that the magnetic nanoparticles attached onto the surface of the separated cells have the aggregation phenomenon.The reason may be possible that when the magnetic nanoparticles were bounded to the monoclonal antibodies,the obtained immunomagneitc nanoparticles aggre-gated because of the attraction of the unmodi?ed surface of the nanoparticles to the antibodies.See from the photo that this
W.Chen et al./Applied Surface Science253(2006)1762–1769
1767 Fig.9.Microscopic photographs of hematopoietic colonies.CD34+hematopoietic stem cells puri?ed from human umbilical cord blood mononuclear cells formed colonies in semisolid media(A and C)for14days and(B and D)for21days.(A and B)Colony-forming granulocyte/macrophage;(C and D)burst-forming erythroid.
aggregation phenomenon did not in?uence the shape of the target cells and the separation effect.
In order to further con?rm the particles’properties on the surface of the separated cells,the method of atomic force microscope was adopted.The magnetic scanning can induce the magnetic materials by the function of the magnetic?eld. The materials with the magnetism can be seen from the AFM magnetic scanning images with the fuscous color while the materials without magnetism cannot be found from the AFM magnetic scanning images.By this way,the magnetic nanoparticles on the surface of the separated cells can be easily detected.
Fig.8shows the AFM image of the separated cell.The image(a)of Fig.8is the altitude image of the separated cell. From this image,it can be clearly observe that the separated cell still maintains the normal shape,which is in accord with the result gotten from the SEM photo.The right image(b)is the magnetic scanning AFM image of the separated cell.The magnetic scanning can induce the magnetic material by the function of the magnetic?eld.The brown spots on this image mean these particles have the characteristics of magnetism, indicating that the particles on the surface of the separated cell are immunomagnetic nanoparticles.Therefore,from the magnetic scanning image and the SEM photo,it can be?rmly ensured that the immunomagnetic nanoparticles were bound to the surface of the target cells.
3.4.Hematopoietic colony assay of the CD34+cells after magnetic separation
The method of hematopoietic colony assay of CD34+cells was adopted in order to analyze the proliferation and differentiation ability of the CD34+cells separated by the immunomagnetic nanoparticles.After the separated cells were incubated in the mixed media for14days and21days,the colony forming of granulocyte/macrophage and burst forming of erythroid were observed.The microscopic photo of hematopoietic colonies is shown in Fig.9.Fig.9A and C for 14days,Fig.9B and D for21days.
All these results indicate that the CD34+cells separated by immunomagnetic nanoparticles still maintained the capability of colony formation as the hematopoietic stem cells with-out inhibition of the proliferation and differentiation abilities [14].
4.Conclusions
The superparamagnetic nanoparticles with a mean dia-meter of50nm were synthesized by coprecipitation from ferrous and ferric iron solutions.The magnetic nanoparticles were coated with silica by water-in-oil reverse microemul-sions method.These nanoparticles have an average size of about60nm diameter.The AEAPS was coupled to the nanoparticles by chemical reaction.The immunomagnetic nanoparticles could be made by bonding the CD34+ monoclonal antibodies to the magnetic nanoparticles,and then the imunomagnetic nanoparticles were used to separate the CD34+hematopoietic stem cell.The result showed that the immunomagnetic nanoparticles can separate the target cell effectively.The SEM and AFM characterization results can further con?rm that the target cells can be effectively separated by the immunomagnetic nanoparticles.The sepa-rated target hematopoietic stem cells showed high viability and capability of colony formation as hematopoietic stem cells without inhibition of the proliferation and differentia-tion abilities.All the studies,therefore,supply us a very convenient,rapid method to effectively separate the CD34+ hematopoietic stem cells.Further studies on the using of separated CD34+hematopoietic stem cells in vivo models and in clinic using are in progress.
Acknowledgements
This work has been supported by the National Natural Science Foundation of China(No.20443005),the key project of Shanghai educational committee(No.O4DA01)and the Nanotechnology special project of Shanghai(No.352nm123). The author would also like to thank the International Maternity and Child Hygiene Station of Shanghai for offering the human umbilical cord blood.
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毕业设计（论文）题目磁性多壁碳纳米管的制 备及其性能研究 系（院）化学与化工系 专业化学工程与工艺 班级2009级2班 学生姓名韩方欣 学号2009022608 指导教师张岩 职称讲师 二〇一三年六月十八日
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磁性多壁碳纳米管的制备及性能研究 摘要 本研究以多壁碳纳米管为实验材料，综合论述了磁性多壁碳纳米管的制备方法及其性能研究，还通过响应面分析方法探讨了磁性多壁碳纳米管吸附去除染料废水中罗丹明B的最佳工艺条件，采用紫外可见分光光度计测定了染料废水中罗丹明B的吸光度，以确定染料废水中罗丹明B的去除率，进而研究吸附时间，罗丹明B浓度，pH值及吸附温度对磁性多壁碳纳米管吸附性能的的影响。具体研究内容和研究结果如下： (1)本实验采用浸渍法将多壁碳纳米管制备成带有磁性的磁性多壁碳纳米管。 (2)采用单因素实验和响应面实验初步确定了磁性多壁碳纳米管吸附去除染料废水中罗丹明B的工艺条件，即吸附时间为12.00 h，罗丹明B浓度为3.7 mg/L，吸附温度为30 ℃，pH值为4.50。 (3)经测定优化后得到的罗丹明B的去除率为0.993717。 关键词：磁性多壁碳纳米管；响应面；吸附；罗丹明Ｂ
磁性纳米材料的应用 磁性纳米颗粒是一类智能型的纳米材料，既具有纳米材料所特有的性质如表面效应、小尺寸效应、量子效应、宏观量子隧道效应、偶连容量高，又具有良好的磁导向性、超顺磁性类酶催化特性和生物相容性等特殊性质，可以在恒定磁场下聚集和定位、在交变磁场下吸收电磁波产热。基于这些特性，磁性纳米颗粒广泛应用于分离和检测等方面。 （一）生物分离 生物分离是指利用功能化磁性纳米颗粒的表面配体与受体之间的特异性相互作用（如抗原-抗体和亲和素 -生物素等）来实现对靶向性生物目标的快速分离。 传统的分离技术主要包括沉淀、离心等过程，这些纯化方法的步骤繁杂、费时长、收率低，接触有毒试剂，很难实现自动化操作。磁分离技术基于磁性纳米材料的超顺磁性，在外加磁场下纳米颗粒被磁化，一旦去掉磁场，它们将立即重新分散于溶液中。因此，可以通过外界磁场来控制磁性纳米材料的磁性能，从而达到分离的目的，如细胞分离、蛋白质分离、核酸分离、酶分离等，具有快速、简便的特点，能够高效、可靠地捕获特定的蛋白质或其它生物大分子。此外，由于磁性纳米材料兼有纳米、磁学和类酶催化活性等特性，不仅能实现被检测物的分离与富集，而且能够使检测信号放大，具有重要的应用前景。 通常磁分离技术主要包括以下两个步骤：（ 1）将要研究的生物实体标记于磁性颗粒上；（2）利用磁性液体分离设备将被标记的生物实体分离出来。 ①细胞分离：细胞分离技术的目的是快速获得所需的目标细胞。传统的细胞分离技术主要是根据细胞的大小、形态以及密度差异进行分离，如采用微滤、超滤和超滤离心等方法。这些方法虽然操作简单，但是特异性差，而且纯度不高，制备量偏小，影响细胞活性。但是利用磁性纳米材料可以避免一定的局限性，如在磁性纳米材料表面接上具有生物活性的吸附剂或配体（如抗体、荧光物质和外源凝结素等），利用它们与目标细胞特异性结合，在外加磁场的作用下将细胞分离、分类以及对数量和种类的研究。 磁性纳米材料作为不溶性载体，在其表面上接有生物活性的吸附剂或其它配体等活性物，利用它们与目标细胞的特性结合，在外加磁场作用下将细胞分离。 温惠云等的地衣芽孢杆菌实验结果表明，磁性材料 Fe3O4 的引入对地衣芽孢杆菌的生长没有影响；Kuhara等制备了人单克隆抗体anti-hPCLP1,利用 anti-hPCLP1 修饰的磁纳米颗粒从人脐带血中成功分离了成血管细胞，PCLP1 阳性细胞分离纯度达到了 95%。 ②蛋白质分离：利用传统的生物学技术（如溶剂萃取技术）来分离蛋白质程序非常复杂，而磁分离技术是分离蛋白分子便捷而快速的方法。 基于在磁性粒子表面上修饰离子交换基团或亲和配基等可与目标蛋白质产生特异性吸附作用的功能基团 , 使经过表面修饰的磁性粒子在外加磁场的作用下从生物样品中快速选择性地分离目标蛋白质。 王军等采用络合剂乙二胺四乙酸二钠和硅烷偶联剂KH-550寸磁性Fe3O4粒 子进行表面修饰改性 , 并用其对天然胶乳中的蛋白质进行吸附分离。结果表明 , 乙二胺四乙酸通过化学键合牢固地结合在磁性粒子表面 , 并通过羰基与蛋白质反应, 达到降低胶乳氮含量的目的。 ③核酸分离 经典的DNA/RN分离方法有柱分离法和一些包括沉积、离心步骤的方法，这些方法的缺点是耗时多，难以自动化，不能用于分析小体积样品，分离不完全。
关于磁性纳米材料的研究应用 文献综述 姓名：于辉 学号：2013155048 学院：理学院 专业：材料化学 年级：2013级
关于磁性纳米材料的研究应用 【前言】 磁性纳米材料的应用可谓涉及在机械，电子，光学，磁学，化学和生物学领域的应用前景，纳米科学技术的诞生将对人类社会产生深远的影响，并有可能从根本上解决人类面临的许多问题。 下一世纪初的主要任务是依据纳米材料各种新颖的物理和化学特性设计出顺应世纪的各种新型的材料和器件，通过纳米材料科学技术对传统产品的改性，增加其高科技含量以及发展纳米结构的新型产品[1]。磁性纳米材料将成为纳米材料科学领域一个大放异彩的明星，在新材料，能源，信息，生物医学等各个领域发挥举足轻重的作用。 磁性纳米材料由于其独特的磁学性能、小尺寸效应，在化学设计与合成、表面功能化方法,及其在核磁共振成像、磁控治疗、磁热疗和生物分离等领域都有应用[2]。
【磁性纳米材料的发展历程和现状】 （一）关于磁性纳米材料 纳米材料又称纳米结构材料,是指在三维空间中至少有一维处于纳米尺度范围内的材料(1-100nm),或由它们作为基本单元构成的材料,是尺寸介于原子、分子与宏观物体之间的介观体系,因此,纳米磁性材料的特殊磁性可以说是属于纳米磁性，而纳米磁性材料和纳米磁性又分别是纳米科学技术和纳米物性的一个组成部分。 （二）关于颗粒磁性的研究 颗粒的磁性，根据磁畴理论与实验表明:当磁性微粒处于单畴尺寸时,矫顽力将呈现极大值[3]。铁磁材料,在应用上,可以作为高矫顽力的永磁材料和磁记录材料。由于颗粒磁性与其尺寸有关,若尺寸进一步减小,颗粒将在一定的温度范围内将呈现出超顺磁性。利用微粒的超顺磁性,提出了磁宏观量子隧道效应的概念,并研制成了磁性液体。非晶态磁性材料的诞生为磁性材料增添了新的一页,也为纳米微晶磁性材料(纳米微晶软磁材料、纳米复合永磁材料)的问世铺平了道路。（三）磁性纳米材料的特点和制备方法[4] 磁性纳米材料有量子尺寸效应、小尺寸效应、宏观量子隧道效应的特点。 制备方法： <1>磁流体的制备方法 物理法：研磨法、热分解法、超声波法。 化学法：化学沉淀法、水热法。 <2>磁性微粒的制备方法 分散法、单体聚合法。 <3>纳米磁性微晶的制备方法 非晶化法、深度塑性变形法。 <4>纳米磁性结构复合材料的制备方法 溶胶-凝胶法、化学共沉淀法、磁控溅射法和激光脉冲沉积法。 （四）磁性纳米材料的应用范围[4] 磁记录方面的应用、纳米永磁材料方面的应用、纳米软磁材料方面的应用、纳米吸波材料领域的应用、生物医学领域的应用、金属有机高分子磁性材料方面的应用。
2011412690 应用化学董会艳 题目纳米材料的磁学性质、发展及其应用前景 内容摘要：磁性纳米材料的特性不同于一般的磁性材料，当与磁性相关联的特征物理长度恰好出于纳米量级，以及电子平均自由路程等大致处于1~100nm量级，或磁性体的尺寸与这些特征物理长度相当时，就会呈现反常的磁学与电学性质。不同分类的磁性纳米材料有着大不相同的特性。从纳米科技诞生的那一刻起就对人类产生着深远的影响。同时磁性材料一直是国民经济，国防工业的重要支柱与基础，与此同时在信息化高度发展的今天，磁性纳米材料的地位显的更加的重要与不可替代。 关键词：磁性，纳米，磁性纳米材料，应用 Abstract：Characteristics of magnetic nanomaterials is different from the general magnetic materials and magnetic properties associated with the characteristics of the physical length of just for the nanoscale, and the electron mean free path, etc. generally in the 1 ~ 100nm orders of magnitude, or magnetic body size and characteristicsphysical length is quite showing the anomalous magnetic and electrical properties. Different classification of magnetic nanomaterials differ materially from those features. The moment of the birth of nanotechnology on humans with far-reaching impact. Magnetic materials has been an important pillar and foundation of the national economy, defense industry, at the same time in the development of information technology today, the status of magnetic nanomaterials significantly more important and irreplaceable. Key words：Magnetic ，Nano ，Magnetic nanomaterials，Application 前言：在社会发展和科技进步的同时，磁性纳米材料的研究和应用也有了很大的突 破。磁性纳米材料在于与磁性相关联的特征物理长度恰好出于纳米量级，例如，磁单畴尺寸，超顺磁性临界尺寸以及电子平均自由路程等大致处于1~100nm量级，当磁性体的尺寸与这些特征物理长度相当时，就会呈现反常的磁学与电学性质。 当磁性微粒处于单畴尺寸时, 矫顽力将呈现极大值。铁磁材料, 如铁、钻等磁性单畴临界尺寸大约在l0 nm 量级,可以作为高矫顽力的永磁材料和磁记录材料。由于颗粒磁性与其尺寸有关, 如果尺寸进一步减小, 颗粒将在一定的温度范围内呈现出超顺磁性。利用微粒的这个特性, 人们在开始对镍纳米微粒进行低温磁性研究, 并提出磁宏观量子隧道效应的概念, 随后在60年代末期研制成了磁性液体。80 年代以后, 在理论与实验二方面, 开始研究纳米磁性微粒的磁宏观量子隧道效应,在1988 年首先在Fe/ Cr 多层膜中发现了巨磁电阻效应, 也为磁性纳米材料的研究奠定了更夯实的基础。 正文 磁性纳米材料的特性不同于常规的磁性材料，其原因在于与磁性相关联的特征物理长度恰好出于纳米量级，例如，磁单畴尺寸，超顺磁性临界尺寸，交换作用长度，以及电子平均自由路程等大致处于1~100nm量级，当磁性体的尺寸与这些特征物理长度相当时，就会呈现反常的磁学与电学性质。利用这些新特性已涌现出一系列新材料，尤其在信息存储，处理与传输中已成为不可或缺的组成部分，广泛地应用于电信，自动控制，通讯，家用电器等领域，信息化发展的总趋势是向小，轻，薄以及多功能方
磁性纳米材料的研究进展 Progress of magnetic nanoparticles 李恒谦﹡贾雪珂李艳周康佳 （合肥工业大学，安徽宣城） （Hefei University of Technology, Xuancheng, Anhui, China) 摘要：纳米技术是近年来发展起来的一个覆盖面极广、多学科交叉的科学领域。而磁性纳米材料因其优异的磁学性能，也逐渐发挥出越来越大的作用。随着科学工作者在制备、应用领域的拓展逐渐深入，也使得纳米材料的外形、尺寸的控制日趋完善。因此，磁性纳米材料在机械、电子、化学和生物学等领域有着广泛的应用前景。文章综述磁性纳米材料的制备方法、性能及其近年来在不同领域的应用状况。 关键词：磁性；纳米；制备；性能；应用 Abstract: Nanotechnology is developed in recent years as a kind of science with wide coverage and multidisciplinary. Magnetic nanoparticles also play an increasing role due to its excellent magnetic properties．As scientists research take them deeper along the aspects of synthesis and application．the control of shape and dimensions of magnetic nanoparticles has become more mature．Therefore, magnetic nanoparticles have wide application propects in machinery, electronics, chemistry, biology, etc. In this paper，the synthesis method is discussed, the character is mentioned and the application of magnetic nanoparticles is summarized． Keywords：magnetic；nanoparticles；synthesis；character; application 1.引言 磁性纳米材料的特性不同于常规的磁性材料，其原因是关联于与磁相关的特征物理长度恰好处于纳米量级，例如：磁单畴尺寸，超顺磁性临界尺寸，交换作用长度，以及电子平均自由路程等大致处于1-100nm量级，当磁性体的尺寸与这些特征物理长度相当时，就会呈现反常的磁学性质。 纳米表征技术是高新材料基础理论研究与实际应用交叉融合的技术。对我国高新材料产业的发展有着重要的推动作用，其在全国更广泛的推广应用，能加速我国高新材料研究的进程，为我国高新技术产业的发展作出更大的贡献。在纳米表征技术下，磁性纳米材料的应用日显勃勃生机。例如磁性材料与信息化、自动化、机电一体化、国防，国民经济的方方面面紧密相关，磁记录材料至今仍是信息工业的主体。 磁性纳米材料的应用可谓涉及到各个领域。在机械，电子，光学，磁学，化学和生物学领域有着广泛的应用前景。纳米科学技术的诞生将对人类社会产生深远的影响。并有可能从根本上解决人类面临的许多问题。特别是能源，人类健康和环境保护等重大问题。下一世纪初的主要任务是依据纳米材料各种新颖的物理和化学特性设计出顺应世纪的各种新型的材料和器件，通过纳米材料科学技术对传统产品的改性，增加其高科技含量以及发展纳米结构的新型产品。已出现可喜的苗头，具备了形成下一世纪经济新增长点的基础。磁性纳米材料将成为纳米材料科学领域一个大放异彩的明星，在新材料，能源，信息，生物医学等各个领域发挥举足轻重的作用。 2.制备 在人们所熟知的大量磁性材料中，由于不能同时满足高饱和磁化强度和稳定性高的要求，饱和磁化强度高但稳定性低的材料应用在一定程度上受到了限制。目前可选作磁性微粒的仅有少数几种，主要为金属氧化物，如三氧化二铁（Fe2O3）、MFe2O4(M为Co，Mn，Ni)、四氧化三铁（Fe3O4），二元和三元合金，如金属铁、钴、镍及其铁钴合金、镍铁合金，以及钕
高姗姗等：磷灰石/硅灰石生物玻璃基骨水泥的溶胶–凝胶法制备及性能· 1247 ·第36卷第9期 新型碳纳米管磁性复合材料的制备及磁性能 曹慧群1，邵科1，李耀刚2，朱美芳2 (1. 深圳大学化学与化工学院，深圳 518060；2. 东华大学材料科学与工程学院，纤维改性国家重点试验室，上海 200051) 摘要：采用水热–沉淀法制备了ZnFe2O4包覆碳纳米管(carbon nanotubes，CNTs)磁性复合材料。采用X射线衍射、扫描电镜、透射电镜、M?ssbauer 谱仪和振动样品磁强计等仪器表征制备样品的结构与性能。200℃是制备纳米ZnFe2O4包覆CNTs磁性复合材料的较好的反应条件，温度过高或过低都生成较多的γ-Fe2O3。包覆在CNTs上的ZnFe2O4纳米粒子为球形，粒径为13～20nm。M?ssbauer谱结果表明：大部分ZnFe2O4纳米粒子表现出超顺磁性，少量表现出铁磁性。磁滞回线结果表明：复合材料的矫顽力值为254215.85A/m。 关键词：磁性复合材料；碳纳米管；铁酸锌；磁性能 中图分类号：TB33 文献标识码：A 文章编号：0454–5648(2008)09–1247–04 SYNTHESIS AND MAGNETIC PROPERTIES OF NOVEL CARBON NANOTUBES MAGNETIC COMPOSITES CAO Huiqun1，SHAO Ke1，LI Yaogang2，ZHU Meifang2 (1. College of Chemistry and Chemical Engineering, Shenzhen University, Shenzhen 518060; 2. College of Material Science and Engineer, State Key Laboratory for Modification of Chemical Fibers and Polymer Material, Donghua University, Shanghai 200051, China) Abstract: Novel magnetic composites of carbon nanotubes(CNTs) coated with ZnFe2O4 nanoparticles were synthesized by a precipi-tation-hydrothermal method. The composites were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, M?ssbauer spectrum(MS), and vibrating sample magnetometry. A temperature of about 200 was identified to ℃ be an appropriate reactive condition to obtain CNTs coated with ZnFe2O4. It is concluded that more γ-Fe2O3 existed in composites when the temperature is higher or lower than 200. The ZnFe ℃2O4 nanoparticles coated on surface of CNTs are round, and the size of the nanoparticles ranges from 13nm to 20nm. The MS results reveal that most of the ZnFe2O4 nanoparticles show superparamagnetic relaxation, and some of them exhibit ferrite magnetic relaxation. The sample demonstrates good magnetic properties with a coercive strength of 254215.85A/m. Key words: magnetic composites; carbon nanotubes; ferrite znic; magnetic property 碳纳米管(carbon nanotubes，CNTs)具有独特的物理化学性质，在很多领域都具有良好的应用前景，自1991年发现CNTs以来，引起了人们极大的兴趣。[1–3] 将纳米材料与CNTs结合来制备CNTs复合材料已经有大量报道，其中磁性纳米材料与CNTs复合材料的制备引起了人们特别的关注，用具有磁性的金属及其氧化物填充CNTs的研究相对较多，[4–14] 对于磁性纳米材料包覆CNTs。Jiang等[15]采用溶剂热的方法制备了磁性四氧化三铁/CNTs复合材料，并研究了复合材料的电性能。Liu等[16]采用水热法合成的NiFe2O4/CNTs复合材料，研究了复合材料的电性能，相对于NiFe2O4的电性能提高5倍。Correa- Duarte等[17]采用聚合物包覆和层–层组装技术合成出氧化铁纳米颗粒包覆的CNTs功能材料，并在低磁场中将制备的磁性纳米管材料定向排列后，复合材料表现出超顺磁行为，温度为5K时的矫顽力(H c)为22288.00A/m，不存在剩磁；或室温下不存在矫顽力。He等[18]制备的多壁CNTs–Fe2+复合材料在5 K时，H c=20696.00A/m，饱和磁化强度(M s)为0.016 Am2/kg。 收稿日期：2007–12–13。修改稿收到日期：2008–03–19。基金项目：国家自然科学基金(50473002)项目资助。 第一作者：曹慧群(1976—)，女，博士，讲师Received date:2007–12–13. Approved date: 2008–03–19. First author: CAO Huiqun (1976–), female, Doctor, lector. E-mail: chq0524@https://www.doczj.com/doc/e62798071.html, 第36卷第9期2008年9月 硅酸盐学报 JOURNAL OF THE CHINESE CERAMIC SOCIETY Vol. 36，No. 9 September，2008
磁性纳米粒子的制备与应用 孙超 （上海大学环境与化工工程学院，上海200444） 摘要：磁性纳米材料（magnetic nanoparticle）是由Fe，Co，Ni等过渡金属及其氧化物组成的打下尺度介于1~100nm间的一种新型功能材料，磁性纳米材料具有磁性特征，还具有纳米材料的独特效应和生物亲和性，因而成为目前生物医学研究的热点之一。本文简要介绍了磁性纳米颗粒的制备方法，和目前磁性纳米颗粒在医用载药方面的研究进展。 关键词：磁性纳米材料；氧化铁；载药 Preparation and Application of Magnetic Nanoparticles Sunchao (School of Environmental and Chemical Engineering，Shanghai University，Shanghai 200444，China) Abstract: Magnetic nanoparticles are a kind of magnetic material with diameter of l～1 00nm，which are made of transition metal and their oxide such as Fe、Co、Ni and so on．They are new type of functional materials with characterization of special effect，magnetic responsibility and bioaffinity，and have been one of hot spots in recent biomedicine research．This paper introduces the preparation of magnetic nanoparticles and some recent studies about drug loading of magnetic nanoparticles in medicine。 Key words: Magnetic nanoparticles；Iron oxide；Drug loading 1.引言
第25卷第2期大学化学2010年4月 今日化学 磁性纳米材料的化学合成、功能化 及其生物医学应用 侯仰龙 (北京大学工学院先进材料与纳米技术系北京100871) 摘要从纳米材料的生长动力学模型出发,讨论磁性纳米材料的控制合成原理。总结磁性纳米材料的化学设计与合成、表面功能化及其在核磁共振成像和多模式影像等方面的应用研究最新 进展。 磁性材料在信息存储、传感器和磁流体等传统学科领域有着重要的应用。近年来,随着纳米材料科学与技术的发展,纳米磁性材料的应用开发日益引起人们的关注,特别是在提高信息存储密度、微纳米器件和生物医学领域的应用潜力巨大。本文将从纳米磁学开始,回顾磁性材料的基本概念、化学设计与合成、表面功能化及其在生物医学领域的潜在应用[1]。 1纳米磁学 在磁场中,铁磁体的磁化强度M或磁感应强度B与磁场强度H的关系可用曲线来表示。当外磁场作周期变化时,铁磁体中的磁感应强度随磁场强度的变化而形成一条闭合线,即磁滞回线,图1(a)为铁磁物质磁滞现象的曲线。一般说来,铁磁体等强磁物质的磁化强度M(或B)不是磁场强度H的单值函数而依赖于其所经历的磁状态。以磁中性状态为起始态,当磁状态沿起始磁化曲线磁化时,此时磁化强度逐渐趋于饱和,曲线几乎与H轴平行,将此时的磁化强度称为M s。此后若减小磁场强度,则从某一磁场强度开始,M随H的变化偏离原先的起始磁化曲线,M的变化落后于H。当H减小至0时,M并未同步减小到0,而存在剩余磁化强度 M r 。为使M减至0,需加一反向磁场,称为矫顽力H c 。反向磁场继续增大时,磁体内的M将沿 反方向磁化到趋于饱和(M s),反向磁场减小至0再施加正向磁场时,按相似的规律得到另一支偏离反向起始磁化曲线的曲线。当外磁场完成如上变化时,铁磁体的磁状态可由图1(a)所示的闭合回线描述。当温度高于居里点时,磁性材料将变成顺磁体,其磁性很容易随周围磁场的改变而改变。如果温度进一步提高,或者磁性颗粒的粒度很小时,即便在常温下,当尺寸达到临界畴时,材料中电子的热运动将逐渐占主导作用,热运动引起的扰动能超过磁能,使得原有的磁有序发生无序化,该现象称为超顺磁现象,如图1(b)所示,此时材料矫顽力和剩磁为0。对于纳米颗粒的超顺磁转变温度,称为B loc k i n g温度。其磁学性质随尺寸的变化,如图2所示,与块体磁性材料的多畴结构相比,纳米颗粒具有单畴结构,当颗粒尺寸小于临界畴尺寸时,纳米颗粒的磁自旋将无序排列。在单畴区域,矫顽力随着颗粒尺寸的增加而增加,在颗粒 1
目录 1前言 (1) 1.1纳米磁性空心微球概述 (2) 1.1.1纳米磁性空心微球研究现状 (2) 1.1.2纳米磁性空心微球的制备方法 (2) 1.1.3纳米磁性空心微球的应用 (8) 1.2稀土掺杂铁氧体吸波材料的研究现状 (10) 1.3碳纳米管的研究现状 (10) 1.4磁性碳纳米管复合材料的研究现状 (11) 1.5论文选题目的及意义 (12) 1.5.1论文选题目的及意义 (12) 1.5.2论文主要研究内容 (13) 2实验药品与仪器设备 (14) 2.1实验药品 (14) 2.2实验仪器 (15) 2.3样品的表征手段及条件 (15) 2.3.1X射线衍射分析(XRD) (15) 2.3.2扫描电镜分析(SEM) (16) 2.3.3透射电镜分析(TEM） (16) 2.3.4振动样品磁强计(VSM) (16) 2.3.5矢量网络分析仪 (16) 3钴铁氧体空心微球的制备及性能研究 (18) 3.1钴铁氧体空心微球的制备 (18) 3.1.1以聚苯乙烯(PS)球为模板法 (18) 3.1.2以碳微球为模板法 (18)
3.1.3溶剂热法 (19) 3.2钴铁氧体空心微球的表征与分析 (19) 3.2.1XRD分析 (19) 3.2.2形貌和粒径分析 (21) 3.2.3磁性能研究 (24) 3.2.4吸波性能研究 (26) 3.3本章小结 (27) 4钴锌、钴镍铁氧体空心微球的制备及性能研究 (28) 4.1钴锌、钴镍铁氧体空心微球的制备及性能研究 (28) 4.1.1钴锌铁氧体空心微球的制备 (28) 4.1.2钴镍铁氧体空心微球的制备 (28) 4.2钴锌、钴镍铁氧体空心微球的表征与分析 (28) 4.2.1XRD分析 (28) 4.2.2形貌和粒径分析 (29) 4.2.3磁性能研究 (31) 4.2.4吸波性能研究 (34) 4.3本章小结 (37) 5稀土掺杂钴锌铁氧体微球的制备及性能研究 (38) 5.1稀土掺杂钴锌铁氧体微球的制备 (38) 5.1.1镧掺杂钴锌铁氧体微球的制备 (38) 5.1.2铈掺杂钴锌铁氧体微球的制备 (38) 5.1.3钕掺杂钴锌铁氧体微球的制备 (38) 5.2稀土掺杂钴锌铁氧体微球的表征与分析 (38) 5.2.1XRD分析 (38) 5.2.2形貌和粒径分析 (39) 5.2.3磁性能研究 (40) 5.2.4吸波性能研究 (44)
无论是三氧化二铁还是四氧化三铁等都是常用的磁性纳米材料，其中又以纳米磁性四氧化三铁应用尤其广泛。而随着纳米技术的进步由各种各样大分子修饰的四氧化三铁磁性纳米材料的应用也在逐渐增加，本次就分享油酸修饰的四氧化三铁磁性纳米颗粒。 油酸修饰的磁性Fe3O4纳米颗粒（OA@Fe3O4），具有优异的磁性、分散性和稳定性，可广泛应用于纳米探针构建、磁共振造影与分子影像、磁热疗、药物载体及靶向诊疗一体化研究等。OA@Fe3O4纳米颗粒为油溶性，可分散在环己烷、氯仿、四氢呋喃等溶剂中，用于掺杂水包油纳米乳、修饰纳米脂质体、构建磁性纳米药物等。高温热解法所制备的油酸修饰的磁性Fe3O4纳米颗粒，磁性更强、尺寸更均一。 油酸修饰的四氧化三铁磁性纳米颗粒制备方法主要有：微乳液法、水热合成法、热分解铁有机物法、化学共沉淀合成法、凝胶-溶胶法等。四氧化三铁纳米颗粒通过表面修饰过程可以降低磁性纳米粒子的表面能，从而改善提高磁性纳米粒子的分散性，还可以通过特定的修饰方法引入功能性基团实现磁性纳米微粒的
功能化。 经油酸修饰的四氧化三铁磁性纳米粒子晶体的晶体结构为反立方的尖晶石型结构。用方程d=Xk/(Bcos0)可估算出四氧化三铁磁性纳米粒子的晶体粒径，在方程中λ=0.15406,0为衍射角，β为半峰宽，k=0.89。有研究表明油酸修饰未改变磁性四氧化三铁纳米粒子晶体结构；修饰后的磁性四氧化三铁纳米粒子的粒径约2Inm；其饱和磁化强度在50ermu/g以上，磁响应性能佳、具有超顺磁性。 以上是对油酸修饰的四氧化三铁磁性纳米颗粒的相关介绍，下面介绍一家生产纳米材料的公司。南京东纳生物科技有限公司，是一家集产学研于一体的高新技术型企业，主要从事纳米材料及生物医学纳米技术，功能微球、体外诊断试剂
磁性纳米材料的制备及应用前景 摘要：磁性纳米材料因其具有独特的性质，在现代社会中有着广泛的应用，并越来越受到人们的关注。本文主要介绍了磁性纳米材料的制备及应用前景，概述了纳米磁性材料的制备方法，如机械球磨法，水热法，微乳，液法，超声波法等，总结了纳米磁性材料在实际中的应用，并对其研究前景进行了展望。 Abstract: magnetic nanomaterials due to their unique properties, in the modern society has a wide range of applications, and people pay more and more attention. This paper mainly introduces the magnetic nanometer material preparation and application prospect of nano magnetic materials, summarized the preparation methods, such as mechanical ball milling method, hydrothermal method, microemulsion, liquid method, ultrasonic method, summarizes the nanometer magnetic materials in practical application, and the research prospect.
前言 纳米材料因其尺寸小而具有普通块状材料所不具有的特殊性质，如表面效应、小尺寸效应、量子效应和宏观量子隧道效应等，从而与普通块状材料相比具有较优异的物理、化学性能。磁性纳米材料由于其在高密度信息存储，分离，催化，靶向药物输送和医学检测等方面有着广泛的应用，已经受到了广泛关注。磁性复合纳米材料是以磁性纳米材料为中心核，通过键合、偶联、吸附等相互作用在其表面修饰一种或几种物质而形成的无机或有机复合材料。由于社会的发展和科学的进步，磁性纳米材料的研究和应用领域有了很大的扩展。磁性材料在信息存储、传感器和磁流体等传统学科领域有着重要的应用。随着纳米材料科学与技术的发展，纳米磁性材料的应用开发日益引起人们的关注，特别是在提高 信息存储密度、微纳米器件和生物医学领域的应用潜力巨大。目前普遍采用化学法制备铁氧体磁性纳米颗粒，具体有溶胶～凝胶法、化学共沉淀法等，而由于生物合成的磁性纳米颗粒表现出更优良的性质。 1.磁性纳米材料的特点 量子尺寸效应：材料的能级间距是和原子数N 成反比的，因此，当颗粒尺度小到一定的程度，颗粒内含有的原子数N 有限，纳米金属费米能级附近的电子能级由准连续变为离散，纳米半导体微粒则存在不连续的最高被占据分子轨道和最低未被占据的分子轨道，能隙变宽。当这能隙间距大于材料物性的热能，磁能，静电能，光子能等等时，就导致纳米粒子特性与宏观材料物性有显著不同。例如，导电的金属在超微颗粒时可以变成绝缘体，磁矩的大小和颗粒中电子是奇数还是偶数有关，比热亦会反常变化，光谱线会产生向短波长方向的移动，这就是量子尺寸效应的宏观表现。 小尺寸效应：当粒子尺度小到可以与光波波长，磁交换长度，磁畴壁宽度，传导电子德布罗意波长，超导态相干长度等物理特征长度相当或更小时，原有晶体周期性边界条件破坏，物性也就表现出新的效应，如从磁有序变成磁无序，磁矫顽力变化，金属熔点下降等。 宏观量子隧道效应：微观粒子具有穿越势垒的能力，称为量子隧道效应。而在马的脾脏铁蛋白纳米颗粒研究中，发现宏观磁学量如磁化强度，磁通量等也具有隧道效应，这就是宏观量子隧道效应。它限定了磁存储信息的时间极限和微电子器件的尺寸极限。 2. 磁性复合纳米材料的制备方法 2.1水热合成法 水热合成法是液相中制备纳米粒子的一种新方法。一般是在100~300摄氏度温度下和高气压环境下使无机或有机化合物与水化合，通过对加速渗透析反应和物理过程的控制，得到改进的无机物，再过滤，洗涤，干燥，从而得到高纯，超细的各类微粒子。研究发现以FeC13为铁源，AOT为表面活性剂，N2H4·H20（50%）为还原剂水热合成 Fe3O4纳米颗粒时，反应温度和时间，表面活性剂和还原剂浓度对最终产物的尺寸形貌、分散性和磁性有明显影响。还有通过调节水热反
磁性吸附碳纳米管复合材料在军事方面的应用 前言 自碳纳米管发现以来，由于其独 特的力学、磁学、电学等性能，已 迅速成为世界科学研究的前言和热 点。随着现时代的发展，为了现代 高科技战争的需要，越来越多的磁 性材料被应用到了军事方面，特别 是以磁性吸附纳米管复合材料为主 的材料更是各位军事大国所首选的 研究领域。纳米吸波材料是一种高科技、高性能的纳米功能材料，磁性吸附碳纳米管复合材料就是利用了碳纳米管能把微小颗粒吸入管腔并且紧密排列的特质，将磁性材料吸附在其管内，使其具有一定的磁损耗，也就是能吸收入射的电磁波能量，并将其电磁能转化为热能而消耗掉，或是电磁波受到干扰而消失，从而减少雷达散射截面积，达到隐形的目的。与传统的吸波材料相比，磁性吸附纳米管复合材料拥有比较优良的机械、电性能，其比重小、高温抗氧化、介电性能可调、稳定性好、在高频和宽频吸收段吸收比较强，能够满足现代战争的需求。目前有很多隐形战斗机也应用了这种材料，比如说B-2A幽灵、F22A猛禽、F35A~C雷电II、F-15SE沉默鹰、UH-60S沉默黑鹰，这更是给其战斗能力提升到了一个全新的档次。 磁性吸附碳吸附纳米管复合材料的制备 磁性吸附碳纳米管主要是通过两个步骤来完成，其第一步是先用化学方法使碳纳米管开口，然后再用物理、化学的方法或者是两者相结合的方法将磁性材料填充到碳纳米管中。下面介绍第二步的两种方法： 一、物理法填充法 所谓物理法填充法也可称为毛细管作用诱导填充法，也就是通过毛细作用力将液体或者熔化金属填充到碳纳米管腔内的一种方法，这就是一个润湿的问题。显
然，只有低表面张力的液体或熔融物才 能润湿碳管表面，而高于分界点 200mN/m 的物质无法润湿碳管，就不能 用毛细填充法。1992年美国海军实验室 的Pedeson等人利用局域密度泛涵理论 对碳纳米管和HF分子进行了计算机模 拟。根据计算结果他们预言：开口的碳 纳米管作为可高度化的“分子吸管”，可 以通过毛细作用力将HF等极性分子填 充到其管腔内，而从理论上证明了对碳 纳米管进行毛细填充的可能性。1993年Ajayan和Iijma用碳纳米管做“模具”，制备出碳纳米管内填充Pb的纳米导线。其制备方法是：将用电弧法制备的MWCNTs和金属Pb在400度空气炉中退火，首先将MWCNTs端帽打开，随后金属Pb填充到MWCNTs空腔内。由于碳纳米管端帽的富勒烯半球中存在碳原子围成的五元结构，在空气炉中加热是，这种五元环缺陷比围成碳管管体的六元环更易于金属发生反应而使碳管端口优先打开，随后熔融态的金属Pb便可填充到MWCNTs内。 二、化学法填充法 化学法填充法即溶液化学法，通常是指将碳纳米管和待填充金属的盐类一起加到强酸熔液中，通过强酸熔液的作用打开碳纳米管的端帽进行填充的一种方法。碳纳米管的端帽打开后，金属盐 溶液的溶质在毛细作用力驱动 下填入管内，然后再在惰性气体 中进行退火处理，即可得到金属 氧化物填充的碳纳米管。如果要 制备纯金属填充的碳纳米管，可以将中间产物在还原气体中进行退火处理，即可使之还原成纯金属。牛津大学的Tsang等人率先提出熔液化学法，制备了NiO填充的碳纳米管。对碳纳米管进行NiO填充的试验过程如下：将碳纳米管分散在含有水和硝酸镍的硝酸熔液中。接下来将得到的黑色不溶物在100度下干燥一夜。然后，将得到的样品在氦气保护下进行退火处理。电镜观测表面，经过硝酸处理后，约30%的碳纳米管的端部被打开，这些端部打开的碳纳米管中60%~70%都填充了NiO。在碳纳米管的外表面也发现了NiO的纳米粒子的存在，但未观测到碳纳米管有插层现象发生。将得到的填充有NiO的碳纳米管在氢气气体中退火处理后，得到金属Ni填充的碳纳米管。 结束语 虽然目前的碳纳米管的研究取得了很大的进展，但还是存在很多的问题，比如说碳纳米管的提纯、碳纳米管在溶剂中贵大分散性很差等等，这都是现代研究的重点领域，也是要想让磁性吸附碳纳米复合材料对军事贡献的一个重要前提。我相信，以后的磁性吸附碳纳米复合材料不仅在对战斗机隐形方面有应用，在更多的军事方面也得到更大的推广，造福我们社会。
磁性Fe304纳米粒子 1 磁性Fe304纳米粒子的表面修饰及功能化 与磁性Fe304纳米粒子尺寸相关联的一个不可避免的问题是其在较长一段时间内固有的不稳定性，这主要表现在两个方面：(1)分散性的降低，小粒径的纳米粒子聚集并形成大的颗粒以降低表面能，从而降低了粒子的分散性能；(2)磁性能的损耗，裸的磁性Fe304纳米粒子由于其高化学活性容易在空气中氧化，进而损失部分磁性能。因此，在Fe304纳米粒子的应用中(后)重要的是要制定一个保护策略来保护Fe304不受损坏。尤其在生物医学应用方面，需要获得亲水性的纳米Fe304颗粒，因为大多数生物介质是接近中性的水溶液，因此更有必要对Fe304颗粒表面进行有效的修饰及功能化。近年来，各种材料已被用来对Fe304颗粒表面进行修饰及功能化，主要分为有机材料和无机材料(图3.1)。 图3.1 Fe304颗粒表面修饰及功能化材料分类图 1.1 有机材料修饰 表面经一些有机材料修饰后的磁性纳米粒子主要用于磁记录，电磁屏蔽，磁共振成像，尤其是生物领域的药物靶向，磁性细胞分离，生物监测等。外加高磁场下磁性纳米粒子的稳定性对其在生物体内应用以及其他领域的应用是非常重要的。采用有机材料对磁性纳米粒子的表面修饰及功能化的方法有很多，包括原位涂层法和合成后涂层法。此外，为防止团聚及确保纳米粒子具有好的生物相容性，使用不同的有机材料对磁性纳米粒子表面进行修饰，比如葡萄糖，淀粉，聚乙二醇(PEG)，聚(D，L-丙交酯)(PLA)，聚乙烯亚胺(PEI)，特别是一些亲水性的有机材料。 1.1.1 小分子及表面活性剂
经适当的表面改性后，磁性纳米粒子的表面带有一些特殊官能团(例如-OH，-COOH，-NH2，-SH)，有利于通过连接不同的生物活性分子做进一步修饰从而适应各种应用。 作为小分子，硅烷常被用来修饰磁性纳米粒子及对裸露的磁核表面有效官能团化，常见的硅烷修饰剂有3-氨基丙基三乙氧基硅烷(APTES)，p-氨基苯基三甲氧基硅烷(APTS)及巯基丙基三甲氧基硅烷(MPTES)。Shen等人报道了采用一步水热法将APTS加入到含有Fe2+的溶液中，134℃下反应3h制备了可用于生物医学领域的APTS修饰的磁性氧化铁纳米粒子(Fe304@APTS)。细胞毒性和溶血分析结果表明氧化铁纳米粒子表面上的氨基基团乙酰化后显著改善了粒子的细胞相容性和血液相容性。此外，Wu等人研究发现，APTES在对Fe304纳米粒子进行表面修饰的过程中能够有效维持纳米粒子的形貌，而MPTES修饰时会导致磁化强度值的减少。 此外，对于亲油性磁性纳米粒子一般都具有很好的单分散性，而常见的赋予磁性纳米粒子亲油性的表面修饰剂主要有油酸及油胺。通常情况下，油酸及油胺用在高温热分解反应过程中，例如，Salas等人研究发现，高温分解油酸铁化合物能够得到超顺磁性纳米晶体，且粒子的尺寸约为10nm，能稳定地分散在非极性溶剂中。 为直接获得亲水性磁性纳米粒子，一种方法就是在反应过程中加入小分子(如氨基酸，柠檬酸，维生素，环糊精等)。比如，Gao等人使用改进的一步溶剂热法制备了平均粒径为195nm的亲水性超顺磁性纳米团簇凝胶。反应中含有磺酸酯和羧酸酯基的阴离子聚电解质聚(4-苯乙烯磺酸-共-马来酸)钠盐(PSSMA)作为稳定剂，经PSSMA修饰的磁性纳米团簇能够很好的分散在水溶液、磷酸盐缓冲溶液(PBS)及乙醇中。 1.1.2 聚合物 与小分子及表面活性剂相比，聚合物不仅能够提供多官能团以及更好的胶体稳定性，还能对有关磁性纳米粒子在生物学(即药代动力学和生物分布)方面的应用起到了显著的作用。此外，大量的天然及合成的生物可降解的聚合物，如聚天冬氨酸盐，多糖，明胶，淀粉，藻酸盐，聚丙烯酸(PAA)，聚乙二醇(PEG)，聚(D，L-丙交酯)(PLA)，壳聚糖以及聚甲基丙烯酸甲酯(PMMA)等，是目前使用较多的用于磁性纳米粒子表面功能化的聚合物。 Dresco等人报道了采用单个反相微乳液法制备了聚合物包覆的磁性纳米粒子。首先，在含有水/双(2-乙基己基)钠/甲苯的反相微乳液中合成Fe304纳米粒子，然后将水，单体(甲基丙烯酸和羟乙基甲基丙烯酸酯)，交联剂(N，N’-亚甲基二(丙烯酰胺))及引发剂(2，2’-偶氮二(异丁腈))加入到反应体系中，55℃下通氮气反应。聚合反应结束后，经过量丙酮／甲醇混合物(9:1)析出收集。所制得的产物具有超顺磁性性能，粒径约为80nm且粒径分布窄，