甲氧基聚氧化乙烯丙基三甲氧基硅烷改性硅片表面的蛋白质吸附行为

以甲氧基聚氧化乙烯丙基三甲氧基硅烷对硅片表面进行改性,使其表面具有良好的亲水性能.用考马斯亮蓝法考察了硅片在不同浸泡时间和不同蛋白质初始溶液浓度下,牛血清白蛋白(BSA)在硅片表面的吸附行为.研究发现,蛋白质吸附是一个动态过程,符合Langmuir理论吸附模型,浸泡120min后,吸附和解吸附达到动态平衡.当蛋白质初始...     

Preparation of magnetic nanoparticles modified by amphiphilic copolymers

Coordination method was used to prepare magnetic nanoparticles. Magnetic hysteresis loop studies showed that the obtained nanoparticles are categorized as soft magnetic materials. Microspheres prepared by the coordination method had PBMA core and hydroxylated PGMA shell bonded with Fe ion. The magnetic content and response decreased with the adding rate of the ferrous salt, while the size and size distribution of the microspheres increased. The magnetic response increased with the concentration of the ferrous salt. Also, the influence of the polymer content was studied, which indicated the particle size decreased with the polymer concentration and its distribution increased.     

Novel drug delivery system by surface modified magnetic nanoparticles

In the recent progress of gene and cell therapy, novel drug delivery system (DDS) has been required for efficient delivery of small molecules/drugs and also the safety for clinical usage. We have already developed the unique transfection technique by preparing magnetic vector and using permanent magnet. This technique can improve the transfection efficiency. In this study, we directly associated plasmid DNA with magnetic nanoparticles, which can potentially enhance their transfection efficiency by magnetic force. Magnetic nanoparticle, such as magnetite, its average size of 18.7 nm, can be navigated by magnetic force and is basically consisted with oxidized Fe that is commonly used as the supplement drug for anemia. The magnetite particles coated with protamine sulfate, which gives a cationic surface charge onto the magnetite particle, significantly enhanced the transfection efficiency in vitro cell culture system. The magnetite particles coated with protamine sulfate also easily associated with cell surface, leading to high magnetic seeding percentage. From these results, it was found that the size and surface chemistry of magnetic particles would be tailored to meet specific demands on physical and biological characteristics accordingly. Overall, magnetic nanoparticles with different surface modification enhance the association with plasmid DNA and cell surface as well as HVJ-E, which potentially help to improve the drug delivery system.     

印迹改性磁性交联壳聚糖的表征及吸附性能

为了提高壳聚糖（CS）对Pb²⁺的去除能力,制备了印迹改性磁性交联壳聚糖（Pb-TMCS）,采用FTIR、SEM和XRD对其结构和形态进行了表征,研究了Pb-TMCS对Pb²⁺的吸附、脱附性能及选择性。结果表明：与CS相比,Pb-TMCS的表面孔隙和褶皱增多;Pb-TMCS引入了更多的-OH和-NH₂;Pb-TMCS内部包覆磁性物质Fe₃O₄,Pb-TMCS对 CS的相对选择性系数大于2;Pb-TMCS对Pb²⁺的吸附量从CS的25.57 mg/g提高到45.26 mg/g,脱附3次后仍可重复使用。Pb-TMCS回收方便,对Pb²⁺选择吸附性能好,无污染,在重金属废水处理中具有广阔的应用前景。     

pH-dependent adsorption of Au nanoparticles on chemically modified Si3N4 MEMS devices

Microelectromechanical systems (MEMS) are devices that represent the integration of mechanical and electrical components in the micrometer regime. Self-assembled monolayers (SAMs) can be used to functionalise the surface of MEMS resonators in order to fabricate chemically specific mass sensing devices. The work carried out in this article uses atomic force microscopy (AFM) and X-ray photoemission spectroscopy (XPS) data to investigate the pH-dependent adsorption of citrate-passivated Au nanoparticles to amino-terminated Si₃N₄ surfaces. AFM, XPS and mass adsorption experiments, using ‘flap’ type resonators, show that the maximum adsorption of nanoparticles takes place at pH = 5. The mass adsorption data, obtained using amino functionalised ‘flap’ type MEMS resonators, shows maximum adsorption of the Au nanoparticles at pH = 5 which is in agreement with the AFM and XPS data, which demonstrates the potential of such a device as a pH responsive nanoparticle detector.     

壳聚糖修饰氧化铁磁性纳米颗粒的制备和性能研究

通过共沉淀法制备氧化铁磁性纳米颗粒,用壳聚糖对其表面进行修饰得到样品(CS@MNPs);表征其形貌结构、尺寸、表面基团、表面电荷、磁学性质和在不同介质中的稳定性等。实验结果表明,CS@MNPs具有典型的立方反尖晶石晶体结构;粒径为16.5nm;在生理(pH值7.4)条件下拥有较高的正电荷(10mV);呈现超顺磁性,对驰豫时间T1、T2,尤其是T2*具有很强的响应;在双蒸馏水和含10%新生牛血清的RPMI 1640培养液中具有良好的稳定性,具有作为磁共振造影剂的潜力。     

Dye adsorption behavior of anatase- and rutile-type TiO2 nanoparticles modified by various heat-treatments

TiO₂ colloidal particles with a fixed crystalline phase of anatase or rutile were heat-treated under different conditions (air-heating and hydrothermal-heating) to modify their surface characters which essentially affected the adsorption behavior of a Ru-complex dye on the surfaces. Changes in the number of surface OH group (N _(OH)), apparent crystallite size, pore structure were evaluated as a function of heat-treatment conditions for various TiO₂ nanoparticles. The amount of a Ru-complex dye adsorbed (N _(dye)) was correlated to those surface properties of TiO₂ samples. N _(dye) values tended to increase with increasing crystallinity for only the anatase-type TiO₂ particles. However, there was no simple, common relationship between N _(dye) and N _(OH) for all the TiO₂ nanoparticles examined. Considerable difference in N _(dye) values obtained in different nanoparticles might be explained on the basis of the surface pore structures of those particles.     

Strong adsorption of chlorotetracycline on magnetite nanoparticles

In this work, environmentally friendly magnetite nanoparticles (Fe₃O₄ MNPs) were used to adsorb chlorotetracycline (CTC) from aqueous media. Fe₃O₄ MNPs exhibit ultrahigh adsorption ability to this widely used antibiotic. The adsorption behavior of CTC on Fe₃O₄ MNPs fitted the pseudo-second-order kinetics model, and the adsorption equilibrium was achieved within 10 h. The maximum Langmuir adsorption capacity of CTC on Fe₃O₄ (476 mg g⁻¹) was obtained at pH 6.5. Thermodynamic parameters calculated from the adsorption data at different temperature showed that the adsorption reaction was endothermic and spontaneous. Low concentration of NaCl and foreign divalent cations hardly affected the adsorption. Negative effect of coexisting humic acid (HA) on CTC adsorption was also observed when the concentration of HA was lower than 20 mg L⁻¹. But high concentration of HA (>20 mg L⁻¹) increased the CTC adsorption on Fe₃O₄ MNPs. The matrix effect of several environmental water samples on CTC adsorption was not evident. Fe₃O₄ MNPs were regenerated by treatment with H₂O₂ or calcination at 400 °C in N₂ atmosphere after separation from water solution by an external magnet. This research provided a high efficient and reusable adsorbent to remove CTC selectively from aqueous media.     

氨基化磁性纳米粒子的制备及其对Pb2+吸附性能研究

采用改进的高温分解法制备单分散Fe3O4纳米粒子,以正硅酸乙酯为硅源在其表面包覆SiO2,以N-氨乙基-γ氨丙基三甲氧基硅烷为改性剂对复合粒子进行表面氨基化修饰,制备出氨基化磁性复合纳米粒子Fe3O4@SiO2—NH2。利用红外光谱(FT-IR)、透射电镜(TEM)、X射线衍射(XRD),振动样品磁强计(VSM)等手段对复合粒子进行了表征,并研究其作为吸附剂在不同条件下对Pb2+的吸附性能。表征结果显示,所制备的复合粒子具有核壳结构,粒径均匀大约在50nm,粒子表面拥有丰富的氨基功能基团;复合粒子饱和磁化强度为69.50A.m2/kg,具有超顺磁性。吸附实验表明所制备的氨基化磁性复合纳米粒子对Pb2+具有较大的吸附容量,是一种能够有效处理含铅废水的吸附材料。     

Heavy metal ion adsorption behavior in nitrogen-doped magnetic carbon nanoparticles: isotherms and kinetic study

To clarify the heavy metal adsorption mechanism of nitrogen-doped magnetic carbon nanoparticles (N-MCNPs), adsorption capacity was investigated from the adsorption isotherms, kinetics and thermodynamics points of view. The obtained results showed that the equilibrium adsorption behavior of Cr(3+) ion onto the N-MCNPs can be applied to the Langmuir model and pseudo-second-order kinetics. It indicated that the fabricated N-MCNPs had the homogenous surface for adsorption and all adsorption sites had equal adsorption energies. Furthermore, the adsorption onto N-MCNPs taken place through a chemical process involving the valence forces. According to the thermodynamics, the adsorption process is spontaneous and endothermic in nature which means that the adsorption capacity increases with increasing temperature due to the enhanced mobility of adsorbate molecules. The effects of the solution pH and the species of heavy metal ion on the adsorption uptake were also studied. The synthesized N-MCNPs exhibited an enhanced adsorption capacity for the heavy metal ions due to the high surface area and large amount of nitrogen contents.     

Arsenic adsorption on cobalt and manganese ferrite nanoparticles

The adsorption of As(III) on cobalt and manganese ferrite nanoparticles (NPs) was studied. The ferrite NPs were synthesized using the Massart-assisted microwave hydrothermal treatment. All the NPs exhibited the spinel structure with a formula such as M _x Fe_3?x O₄, where M = Co or Mn, and x runs from 0.21 to 1.14. The changes in the stoichiometry caused different effects on the physical properties as well on the As(III) adsorption capacity of the NPs. The adsorption data were fitted in very good agreement with the Freundlich model. It was concluded that As(III) was better attracted to ferrimagnetic cobalt ferrite NPs, given that the arsenic removal was significantly higher than that exhibited by superparamagnetic manganese-substituted ferrite NPs.     

Synthesis of CoPt nanoparticles by a modified polyol method: characterization and magnetic properties

CoPt nanoparticles with an average size of 3?nm and narrow distribution were synthesized by chemical reduction of Co(CH(3)COO)(2) and Pt(acac)(2) by polyethyleneglycol-200. The as-prepared nanoparticles have a disordered fcc structure which transformed after thermal treatment to an ordered fct structure, which results in coercivity up to 6?kOe at room temperature and 9?kOe at 5?K because of the high magnetocrystalline anisotropy of the tetragonal structure [Formula: see text].     

O-羧甲基化壳聚糖修饰磁性Fe3O4纳米粒子及其生物应用

采用共沉淀法制备Fe3O4纳米粒子,用XRD测定粒子成分,用透射电镜和显微镜观测粒子形貌,用震动样品磁场计测定Fe3O4粉末饱和磁化强度,再以O-羧甲基化壳聚糖修饰后,用红外光谱检测粒子成分.粒子性能良好,能很好的应用于生物分离,连接等.     

Adverse effects of citrate/gold nanoparticles on human dermal fibroblasts

Nanoscale engineering is one of the most dynamically growing areas at the interface between electronics, physics, biology, and medicine. As there are no safety regulations yet, concerns about future health problems are rising. We investigated the effects of citrate/gold nanoparticles at different concentrations and exposure times on human dermal fibroblasts. We found that, as a result of intracellular nanoparticle presence, actin stress fibers disappeared, thereby inducing major adverse effects on cell viability. Thus, properties such as cell spreading and adhesion, cell growth, and protein synthesis to form the extracellular matrix were altered dramatically. These results suggest that the internal cell activities have been damaged.     

Surface adsorption of poisonous Pb(II) ions from water using chitosan functionalised magnetic nanoparticles

In this study, chitosan functionalised magnetic nano‐particles (CMNP) was synthesised and utilised as an effective adsorbent for the removal of Pb(II) ions from aqueous solution. The experimental studies reveal that adsorbent material has finer adsorption capacity for the removal of heavy metal ions. Parameters affecting the adsorption of Pb(II) ions on CMNP, such as initial Pb(II) ion concentration, contact time, solution pH, adsorbent dosage and temperature were studied. The adsorption equilibrium study showed that present adsorption system followed a Freundlich isotherm model. The experimental kinetic studies on the adsorption of Pb(II) ions exhibited that present adsorption process best obeyed with pseudo‐first order kinetics. The maximum monolayer adsorption capacity of CMNP for the removal of Pb(II) ions was found to be 498.6 mg g⁻¹. The characterisation of present adsorbent material was done by FTIR, energy disperse X‐ray analysis and vibrating sample magnetometer studies. Thermodynamic parameters such as Gibbs free energy (ΔG °), enthalpy (ΔH °) and entropy (ΔS °) have declared that the adsorption process was feasible, exothermic and spontaneous in nature. Sticking probability reported that adsorption of Pb(II) ions on CMNP was favourable at lower temperature and sticking capacity of Pb(II) ions was very high.Inspec keywords: adsorption, lead, wastewater treatment, monolayers, Fourier transform infrared spectra, X‐ray chemical analysis, magnetometers, pHOther keywords: poisonous Pb(II) ions surface adsorption, chitosan functionalised magnetic nanoparticle, CMNP, Pb(II) ions removal, aqueous solution, finer adsorption capacity, heavy metal ion removal, contact time, solution pH, adsorbent dosage, adsorption equilibrium, Freundlich isotherm model, pseudofirst order kinetics, monolayer adsorption capacity, FTIR, energy disperse X‐ray analysis, vibrating sample magnetometer study, thermodynamic parameter, sticking probability, Pb(II) ions sticking capacity, initial Pb(II) ion concentration     

Effect of magnetic nanoparticles on the properties of magnetic rubber

A new kind of magnetic rubber was prepared through conventional rubber mixing techniques on a two-roll mill, in which the magnetic filler was Fe₃O₄ nanoparticles and was surface modified. The effect of Fe₃O₄ nanoparticles’ content on the mechanical and magnetic properties of nature rubber was further investigated. The obtained results of six different compositions for nature rubber with 0, 5, 10, 15, 20 and 25 phr of Fe₃O₄ nanoparticles were compared. It was found that the magnetic rubber has higher magnetic properties and tensile strength, comparing with unfilled nature rubber. The result suggests that when the magnetic filler is nanoparticles and surface modified, the mechanical and magnetic properties of the rubber can be synchronously improved, which is difficult to be observed in previous work.     

Protein adsorption to titania surfaces

Titanium and its alloys are used widely in the manufacture of orthopaedic and dental implants. Their popularity is encouraged by the excellent biocompatibility of the surface oxide layer and the phenomenon of osseointegration that occurs following surgical implantation into bone. This term describes the fixation of a medical device through the formation of a direct interface with bone tissue. However, the processes that lead to osseointegration are not fully understood and, in particular, the contribution of selective protein adsorption to clinical success is the subject of debate. The aim of this study was, therefore, to investigate the adsorption of serum proteins to titanium oxide (titania) and to non-integrating surfaces as controls using a number of methods. In situ labelling of proteins with biotin and subsequent detection with avidin peroxidase on electroblots and an ELISA method gave the best results. Differences were observed between protein adsorption to the two classes of surfaces, with selective adsorption of vitronectin to the osseointegrating surfaces. It is suggested that this may influence the subsequent behaviour of cells and the process of osseointegration.     

Iron-based magnetic nanoparticles for magnetic resonance imaging

Magnetic resonance imaging (MRI) has been an extensive area of research owing to its depth of penetration for clinical diagnosis. Signal intensity under MRI is related to both T₁, spin-lattice relaxation, and T₂, spin-spin relaxation. To increase the contrast variability under MRI, several contrast agents are being used, i.e. T₁ contrast agents (e.g. gadolinium) and T₂ contrast agents (e.g. iron-based magnetic nanoparticles). These contrast agents are administered prior to scanning to increase contrast visibility. They reduce the T₁ and T₂ relaxation times to produce hyperintense and hypointense signals, respectively. Tunable properties of iron-based magnetic nanoparticles and several coating materials provide a platform to get superb MRI contrast in T₂ weighted images. It has been found that contrast enhancement by iron-based magnetic nanoparticles is dependent on the size, shape, composition, surface, and magnetic properties which can be tuned with the synthesis method and coating material. Therefore, understanding the synthesis method and properties of magnetic nanoparticles is vital to contribute to MR signal enhancement which is directing the scientist to design engineered iron-based magnetic nanoparticles. This paper introduces the concept of MRI contrast enhancement. We mainly discuss the synthesis of T₂ contrast agents, i.e. iron-based magnetic nanoparticles and the modification of these T₂ contrast agents by coating followed by their biomedical applications.     

Tryptophan complexed hydroxyapatite nanoparticles for immunoglobulin adsorption

The selective removal of immunoglobulin using different affinity–type particulate adsorbents has clinical significance in certain autoimmune diseases. This study reports the use of modified nanosized hydroxyapatite as a matrix for affinity based immunoglobulin adsorption. The adsorbent matrix consists of cyclodextrin complexed hydroxyapatite nanoparticles modified with tryptophan. It appears that presence of cyclodextrin has a synergic effect in the adsorption of immunoglobulin proteins having affinity with tryptophan complexed hydroxyapatite. The complexes were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TG) and differential scanning analysis (DSC) methods. The preferential affinity of the immunoglobulin towards tryptophan complexed particles was confirmed with polyacrylamide gel electrophoresis (PAGE) and Lowry adsorption techniques. Immunoglobulin adsorption was confirmed by quantitative turbidimetric assay using a standard immunoglobulin kit. The cytotoxicity index of the nanoparticle complexes were evaluated by MTT assay. Our proposed matrix for immunoglobulin adsorption is cost effective and adaptable for applications towards plasma perfusion.     

Influence of antibiotic adsorption on biocidal activities of silver nanoparticles

Excessive use of antibiotics has posed two major challenges in public healthcare. One of them is associated with the development of multi‐drug resistance while the other one is linked to side effects. In the present investigation, the authors report an innovative approach to tackle the challenges of multi‐drug resistance and acute toxicity of antibiotics by using antibiotics adsorbed metal nanoparticles. Monodisperse silver nanoparticles (SNPs) have been synthesised by two‐step process. In the first step, SNPs were prepared by chemical reduction of AgNO₃ with oleylamine and in the second step, oleylamine capped SNPs were phase‐transferred into an aqueous medium by ligand exchange. Antibiotics – tetracycline and kanamycin were further adsorbed on the surface of SNPs. Antibacterial activities of SNPs and antibiotic adsorbed SNPs have been investigated on gram‐positive (Staphylococcus aureus, Bacillus megaterium, Bacillus subtilis), and gram‐negative (Proteus vulgaris, Shigella sonnei, Pseudomonas fluorescens) bacterial strains. Synergistic effect of SNPs on antibacterial activities of tetracycline and kanamycin has been observed. Biocidal activity of tetracycline is improved by 0–346% when adsorbed on SNPs; while for kanamycin, the improvement is 110–289%. This synergistic effect of SNPs on biocidal activities of antibiotics may be helpful in reducing their effective dosages.Inspec keywords: silver, silver compounds, nanomedicine, nanoparticles, drug delivery systems, drugs, antibacterial activity, microorganisms, nanofabrication, materials preparation, reduction (chemical), adsorption, surface chemistry, surface treatmentOther keywords: public healthcare, multi‐drug resistance, side effect, acute antibiotic toxicity, antibiotic adsorbed metal nanoparticle, monodisperse silver nanoparticle, two‐step SNP synthesis, SNP preparation, AgNO₃ chemical reduction, oleylamine capped SNP phase‐transfer, aqueous medium, ligand exchange, tetracycline, kanamycin, antibacterial activity, antibiotic adsorbed SNP, gram‐positive bacterial strain, Staphylococcus aureus, Bacillus megaterium, Bacillus subtilis, gram‐negative bacterial strain, Proteus vulgaris, Shigella sonnei, Pseudomonas fluorescens, SNP synergistic effect, effective dosage reduction, Ag, AgNO₃