查找使用阿拉丁产品的科研文献

Synthesis of polyethylenimine modified Fe3O4 nanoparticles with immobilized Cu2+ for highly efficient proteins adsorption

Tingting Xia,Yueping Guan,Mingzhu Yang,Wubin Xiong,Ning Wang,Shen Zhao,Chen Guo

We report the modification of amine-functioned Fe 3 O 4 nanoparticles (provided by the Laboratory of Bio-Medical Materials of University of Science and Technology Beijing) with polyethylenimine (PEI) using glutaraldehyde (GA) as a linker to increase the concentration of primary amine groups on the surface. The resultant Fe 3 O 4 –PEI NPs with immobilized iminodiacetic acid (IDA)–Cu 2+ groups were applied to investigate the adsorption capacity and selectivity of model proteins: bovine hemoglobin (BHb) and bovine serum albumin (BSA). The Fe 3 O 4 –PEI NPs were characterized by transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), particle analyzer, attenuated total reflection-Fourier transform infrared spectroscopy (ATR–FTIR), ninhydrin colorimetry and thermogravimetric analysis (TGA). The results showed that the well dispersed Fe 3 O 4 –PEI NPs had an average size of 172.6   nm and were super-paramagnetic with saturation magnetization of 71.11   emu/g. The characteristic peaks of PEI appeared in the ATR–FTIR spectra of Fe 3 O 4 –PEI NPs. The study of zeta potential measurement presented that the isoelectric points of the Fe 3 O 4 –PEI NPs increased to 10.5. Ninhydrin colorimetry analysis of primary amine groups showed that the concentration of primary amine groups on the surface of Fe 3 O 4 –PEI NPs increased to 0.45   mmol/g and that of TGA is 0.53   mmol/g. These results showed that PEI had been successfully modified on the surface of amine-functioned Fe 3 O 4 NPs and the concentration of primary amine groups was significantly increased. The analysis of protein adsorption indicated that the adsorption capacity of BHb was up to about 6000   mg/g and that of BSA was only about 2000   mg/g, which was about one third of that of BHb. The research on the selectivity of protein adsorption was conducted by HPLC. The result showed that the adsorption capacity of BHb was 2.5 times as high as that of BSA, which further proved Fe 3 O 4 –PEI–Cu 2+ NPs shows specific adsorption for proteins. These properties suggested the potential of the Fe 3 O 4 –PEI–Cu 2+ NPs as protein adsorbent.

Functional nanomaterials: Study on aqueous Hg(II) adsorption by magnetic Fe3O4@SiO2-SH nanoparticles

Zhuoxing Wang,Jiang Xu,Yunjun Hu,Heng Zhao,Junliang Zhou,Yu Liu,Zimo Lou,Xinhua Xu

A selective adsorbent for Hg(II) was prepared by coating Fe 3 O 4 nanoparticles with SiO 2 which was further functionalized with thiol (–SH) group. The new adsorbent (Fe 3 O 4 @SiO 2 -SH) was shown to adsorb aqueous Hg(II) species in a wide range of pH (1.0–8.0) conditions. The Hg(II) adsorption capacity q e was more than 90.0 mg g −1 at pH > 3.0, and was slightly decreased to 84.6 mg g −1 under strong acidic conditions due to the electrostatic repulsion. The Langmuir isotherm model fitted the adsorption data better than the Freundlich, Temkin, and Dubinin-Radushkevich isotherms models. The maximum adsorption capacity of Fe 3 O 4 @SiO 2 -SH for Hg(II) was 132.0 mg g −1 . The adsorption kinetics were shown to follow the pseudo-second-order kinetic model, and the kinetic constant k 2 was 2.4 × 10 −3  g mg −1  min −1 . The magnetic retrieve of the newly-developed adsorbent was easily carried out via an external magnetic field, enabling both excellent adsorbent utilization and adsorption efficiency at high Hg(II) concentrations.

The synthesis of imprinted polymers based on Fe3O4 nanomaterials and the recognition of proteins

Junxia Guo,Yuzhi Wang,Yanjin Liu,Yigang Zhou

A surface molecularly imprinted polymer (MIP-Fe3O4@AA) was prepared on a magnetic material (Fe3O4@AA) surface for the selective recognition and adsorption of bovine hemoglobin (BHb). The acrylic acid (AA) monomer was directly grafted to the surface of Fe3O4 through a simple coordination reaction between the carboxyl group of AA and unsaturated iron ions (Fe3O4@AA). Then the composite of MIP-Fe3O4@AA based on BHb was successfully synthesized by the surface grafting copolymerization method. The amounts of raw materials were optimized. The characteristics of the obtained MIP-Fe3O4@AA were determined by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), vibrating sample magnetometry (VSM) and thermogravimetric analysis (TGA). The adsorption capacity of MIP-Fe3O4@AA was evaluated and well fitted by the Langmuir model. The maximum theoretical adsorption capacity (Qmax) was calculated to be 117.27 mg g−1 for MIP-Fe3O4@AA. The selectivity experiment showed that the MIP-Fe3O4@AA had an outstanding selectivity toward the template protein (BHb) with an imprinting factor of 4.43. The MIP-Fe3O4@AA was also used to capture BHb from the protein mixture and real sample with satisfactory results, which demonstrated its potential practical analytical performance.

Facile Synthesis of Bimodal Mesoporous Fe3O4@SiO2 Composite for Efficient Removal of Methylene Blue

Xianjun Tan,Liujia Lu,Lingzhi Wang,Jinlong Zhang

Graphical A bimodal mesoporous Fe 3 O 4 @SiO 2 composite was fabricated through a facile self-assembly route. Unprecedentedly good tunability of the core size (180–1700 nm) and the shell thickness (20–75 nm) has been achieved. The composite exhibits excellent performance in organic pollutant removal through adsorption and photo-Fenton degradation. A facile self-assembly synthetic procedure was exploited to fabricate mesoporous-silica-capped Fe 3 O 4 mesoporous clusters, so-called bimodal mesoporous Fe 3 O 4 @SiO 2 composites. Structural characterization demonstrated that the core of the Fe 3 O 4 clusters is coated with a mesoporous silica shell of uniform size distribution. Moreover, unprecedentedly good tunability of the core size (180–1700 nm) and the shell thickness (20–75 nm) is achievable by changing the synthetic parameters. Application of the composite in the removal of the organic dye methylene blue (MB) from aqueous solution was examined. The composite exhibits excellent adsorption of methylene blue from aqueous solution (33.12 mg g –1 ) within 5 min and is easily regenerated by the photo-Fenton degradation reaction as a result of its high specific surface area, accessible pore channels, and good magnetic separation properties. This novel adsorbent promises extensive application in the practical removal of organic dyes.

Calcein-functionalized Fe3O4@SiO2 nanoparticles as a reusable fluorescent nanoprobe for copper(II) ion

Liu Jinshui,Liu Guoning,Zang Lingjie,Liu Wenxiu

Calcein was first covalently grafted onto the surface of magnetic silica nanoparticles to obtain a novel fluorescent nanoprobe for sensitive and selective determination of Cu(II) ion. The nanoparticles were synthesized in a two-step reaction under mild conditions and characterized using small-angle X-ray scattering, Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis. The nanoprobe also displays good selectivity over other metal ions and is highly stable under conditions of high ionic strength. The response to Cu(II) ranges from 80 nM to 1.25 μM. The detection limit (LOD) is 43 nM which is lower than previously reported LODs. The probe can be regenerated by adding the complexing agent EDTA and also can be separated from a sample mixture by applying a magnetic field. We conclude that this method represents a new and convenient approach to the development of magnetic and reusable optical probes. Calcein was first covalently grafted onto the surface of magnetic silica nanoparticles to obtain a novel fluorescent nanoprobe for sensitive and selective determination of Cu(II) ion. The nanoprobe displays good selectivity over other metal ions and is highly stable under conditions of high ionic strength.

The Effectof Film Microtexture and Magnetic Field on Transparency of Fe3O4-PDMS Nanocomposite Films

Qiushu Zhang,Bei Peng,Di Li,Yang Yang,Yaling Liu

Bifunctional Superparticles Achieved by Assembling Fluorescent CuInS2@ZnS Quantum Dots and Amphibious Fe3O4 Nanocrystals

Xiaoyu Sun,Ke Ding,Yi Hou,Zhenyu Gao,Wensheng Yang,Lihong Jing,Mingyuan Gao

Monodispersed superparticles (SPs) consisting of hydrophobic CuInS2@ZnS quantum dots (QDs) were prepared through a self-assembling process induced by introducing ethanol into the cyclohexane solution of the QDs stabilized by 1-dodecanethiol. The solvent polarity-dependent size and size distribution of the resultant SPs were carefully characterized by using scanning electron microscopy, transmission electron microscopy, and dynamic light scattering. The formation and the growth mechanism of the SPs were investigated. By manipulating the nucleation and the growth kinetics through the addition rate of ethanol, the size was effectively tuned without broadening the size distribution of the SPs. By overcoating the SPs with amphibious Fe3O4 nanocrystals (NCs) stabilized by poly(4-vinylpyrollidone), aqueous dispersible SPs were obtained. Inheriting the fluorescent and magnetic properties from the corresponding mother particles, the resultant SPs presented excellent fluorescent and magnetic properties and, thus, may potentially be useful for bioseparation, detection, etc.

A versatile Fe3O4 based platform via iron-catalyzed AGET ATRP: towards various multifunctional nanomaterials

Weiwei He,Liang Cheng,Lifen Zhang,Zhuang Liu,Zhenping Cheng,Xiulin Zhu

In this work, iron-catalyzed atom transfer radical polymerization with activators generated by electron transfer (AGET ATRP) of poly(ethylene glycol) monomethyl ether methacrylate (PEGMA) and 2-((ethoxycarbonothioyl)thio)ethyl methacrylate (ETCEMA) followed by reduction were performed to modify Fe3O4@SiO2 nanoparticles (NPs) for introducing thiol groups on the surface of the NPs. Gold NPs and two near infra-red (NIR) organic dyes with different quantum yields were covalently fixed into the polymer shells independently to afford magnetic NPs with surface-enhanced Raman spectroscopy (SERS), NIR fluorescence imaging and photo-thermal therapy (PTT) functionalities, respectively. In addition, all of these NPs are able to display as contrast agents for magnetic resonance imaging (MRI) because of the existence of the paramagnetic Fe3O4 cores.

Spray-dried magnetic chitosan/Fe3O4/halloysite nanotubes/ofloxacin microspheres for sustained release of ofloxacin

Qin Wang,Junping Zhang,Aiqin Wang

A series of magnetic chitosan/Fe3O4/halloysite nanotubes/ofloxacin (CTS/Fe3O4/HNTs/OFL) microspheres was prepared by spray-drying for the sustained release of OFL. CTS was in situ crosslinked by glutaraldehyde in the spray-drying process. The magnetic microspheres were characterized by FT-IR, scanning electron microscopy and thermogravimetric analysis. The magnetic properties, encapsulation efficiency, drug loading and in vitro sustained release properties of the magnetic microspheres for OFL were also evaluated. The CTS/Fe3O4/HNTs/OFL microspheres show superparamagnetic properties and fast magnetic response. The Fe3O4 nanoparticles have a remarkable effect on the surface morphology of the microspheres compared with HNTs. The encapsulation efficiency and the cumulative release are closely related to HNTs and Fe3O4 contents, crosslinking density and CTS concentration. OFL is released from the magnetic CTS/Fe3O4/HNTs/OFL microspheres via anomalous transport.

Fe3O4@C@polyaniline trilaminar core–shell composite microspheres as separable adsorbent for organic dye

Wei Yao,Chen Shen,Yun Lu

Uniform core–shell Fe 3 O 4 @C@polyaniline (PANi) composite microspheres have been prepared via simple in situ polymerization in the absence of surfactants . In this case, the carbon intermediate layer plays an important role in the formation of trilaminar core–shell structure. By simply adjusting the molar ratio of aniline to Fe 3 O 4 , the thickness of the polymer shell can be tuned from about 27 to 62   nm. The obtained Fe 3 O 4 @C@PANi trilaminar core–shell composite microspheres are used as magnetic adsorbent for the removal of methyl orange (MO) dye from aqueous solution, exhibiting an excellent adsorption capability of 120.2   mg   g −1 for MO and retaining about 81% of the removal efficiency after five adsorption–desorption cycles. The adsorption isotherms and kinetics are well described by the Langmuir and pseudo-second-order models respectively. The Fe 3 O 4 @C@PANi composite microspheres could be a good candidate in the waste water treatment for the removal of organic dyes.

Functionalized magnetic core–shell Fe3O4@SiO2 nanoparticles for sensitive detection and removal of Hg2+

Xu Yaohui,Zhou Yang,Ma Wenhui,Wang Shixing,Li Shaoyuan

Abstract The Fe 3 O 4 nanoparticles [NPs] coated with silica nanoparticles were designed and prepared, the obtained Fe 3 O 4 @SiO 2 NPs have uniform spherical morphology with a mean diameter of about 22 nm. The inert silica coating on the surface of Fe 3 O 4 NPs not only significantly prevented their aggregation in solution but also improved their chemical stability and provided wider sites for surface modification with organic chemosensors. Subsequently an attempt had been made that the as-synthesized Fe 3 O 4 @SiO 2 NPs were modified by N -(rhodamine-6G) lactam–ethylenediamine, the functionalized magnetic Fe 3 O 4 @SiO 2 NPs (Fe 3 O 4 @SiO 2 -Rho) served as a “naked eye” fluorescent sensor to detect Hg 2+ . The Fe 3 O 4 @SiO 2 -Rho NPs exhibited selective “turn-on” type fluorescent change from colorless to orange when adding to Hg 2+ . In addition, the adsorption experiments revealed that the Fe 3 O 4 @SiO 2 -Rho NPs had effective removal toward Hg 2+ . Moreover, the functionalized Fe 3 O 4 @SiO 2 microspheres displayed superparamagnetic properties, which made it easier to separate the nanocomposites from the liquid phase by adding an external magnetic field. Our efforts provided a potential magnetic nanomaterial for sensitive detection and removal toward Hg 2+ simultaneously. Graphical Abstract A rhodamine 6G derivative functionalized Fe 3 O 4 @SiO 2 nanoparticles were designed and synthesized (as Fe 3 O 4 @SiO 2 -Rho). The Fe 3 O 4 @SiO 2 -Rho exhibited selective “turn-on” type fluorescent change from colorless to orange with Hg 2+ , which constituted an Hg 2+ -selective fluorescent colorimetric nanosensor.

Multifunctional hollow polydopamine-based composites (Fe3O4/PDA@Ag) for efficient degradation of organic dyes

Bingqi Mao,Qingda An,Bin Zhai,Zuoyi Xiao,Shangru Zhai

As a newly appeared biomimetic platform and universal surface modification agent, polydopamine (PDA) has been paid great attention recently. However, the fabrication of multifunctional hollow PDA-based nanostructures remains a challenge and has been rarely reported. Herein, a facile method to prepare multifunctional hollow Fe3O4/PDA@Ag spherical composites is reported. The in situ embedding of Fe3O4 nanoparticles and the formation of a PDA shell have been achieved in a single system employing carboxylic-capped polystyrene (PS-COOH) spheres as a hard template, which can be selectively dissolved by tetrahydrofuran. Subsequently, silver nanoparticles were anchored on the PDA surface via in situ reduction by the PDA layers, leading to a multifunctional hollow PDA-based composite, i.e., Fe3O4/PDA@Ag. This newly prepared composite could efficiently catalyze the degradation of 4-nitrophenol and rhodamine B with NaBH4 as a reducing agent, and the reaction rate constants were calculated using the pseudo-first-order reaction equation. Compared to non-hollow PS@Fe3O4/PDA@Ag, the hollow composite exhibited an enhanced performance toward both reactions without a significant loss in activity even after ten cycles. This multifunctional hollow PDA-based composite may find potential applications in other domains like heavy metal removal or antibacterial applications.