基于HGB/PTh/AuNCs无标记癌胚抗原免疫传感器的研究

本文研制了一种基于中空石墨烯球(HGB)/聚硫堇/金纳米笼的无标记型癌胚抗原传感器。将合成的中空石墨烯球修饰于玻碳电极(GCE)表面,在其上电聚合硫堇形成多孔聚硫堇(PTh)复合膜后吸附固定金纳米笼,然后将癌胚抗体(anti-CEA)固定到电极表面,制得无标记型癌胚抗原(CEA)免疫传感器。当抗体与抗原发生免疫反应时,形成的复合物阻碍了电子传递,从而降低聚硫堇的电催化活性。通过示差脉冲伏安法(DPV)检测聚硫堇的响应电流信号的降低,实现对CEA的无标记检测。在最优的实验条件下,检测癌胚抗原的线性范围为0.5~80 ng·mL-1,线性相关系数为0.9932,检测限为0.17 ng·mL-1。该免疫传感器可用于临床上CEA的检测。在血清样品中进行了CEA的检测,结果令人满意。     

基于丝网印刷电极的甲胎蛋白电化学免疫传感器

报道了一种基于金纳米粒子(AuNPs)双重信号放大的高灵敏电化学免疫传感器,并应用于肝癌标志物甲胎蛋白(AFP)的检测。通过在丝网印刷电极(SPE)表面电沉积AuNPs提高电极的重现性,利用AuNPs的吸附作用固定AFP抗体,用于捕获样品中的待测AFP抗原,并进一步与固定了辣根过氧化物酶(HRP)标记检测抗体的纳米金免疫探针发生特异性结合,所形成的夹心免疫复合物可以催化底物得到响应电流。用扫描电镜(SEM)和微分脉冲伏安法(DPV)等技术研究电极组装过程以及电极的化学性质,讨论了影响免疫传感器性能的因素。在最优实验条件下,传感器的峰电流信号与AFP浓度在2.5~30ng/mL范围内呈良好的线性关系,检出限为0.16ng/mL。该传感器具有灵敏度高、成本低、仪器体积小的优点,具有较好的应用前景。     

石墨烯-壳聚糖-纳米金修饰的免疫传感器应用于1-芘丁酸的检测研究

本文采用石墨烯(GS)-壳聚糖(CS)-纳米金(Nano-Au)复合材料修饰玻碳电极,构建性能良好的生物识别界面,制备一种无标记的电流型免疫传感器,并应用于1-芘丁酸(PBA)的高灵敏检测。研究结果表明,GS、CS和Nano-Au的协同作用,极大地提高了anti-PAHs抗体在电极表面的覆盖量,从而提高了免疫传感器的灵敏度和检测性能。采用示差脉冲伏安法(DPV)对PBA进行检测,PBA在0.001~10ng/mL和10~200ng/mL浓度范围内与峰电流值呈良好的线性关系,检出限为0.001ng/mL。该传感器应用于实际水样中痕量PBA的检测,加标回收率为90%~105%。     

基于聚2,6-二氨基吡啶膜及纳米金修饰的癌胚抗原免疫传感器研究

在玻碳电极表面电聚合2,6-二氨基吡啶(pPA), 利用硫堇(Thi)、纳米金(nano-Au)固载癌胚抗体, 制得稳定性好、灵敏度较高、线性范围宽的电流型免疫传感器. 通过循环伏安法考察了该免疫传感器的电化学特性, 在优化的实验条件下, 该免疫传感器的峰电流随着检测溶液中癌胚抗原(CEA)浓度的增大而减小, 并在0.5～20和20～160 ng/mL CEA范围内呈现出良好的线性关系, 检测下限为0.2 ng/mL. 该免疫传感器具有制作简单、重现性好、线性范围宽等优点, 可用于临床上对CEA的检测.     

基于纳米金/壳聚糖/石墨烯的癌胚抗原阻抗型免疫传感器

研究了在PBS缓冲介质中,一种检测癌胚抗原的新型免标记阻抗型免疫传感器的制备及应用,基于石墨烯、纳米金在玻碳电极表面组装制备传感器,通过循环伏安法、交流阻抗法对制备的传感器进行表征。在优化的实验条件下,该免疫传感器的阻抗值随着检测溶液中癌胚抗原(CEA)浓度的增大而增大,并在0.1～85 ng/mL CEA范围内呈线性关系,回归方程为△Ret=1605.55+39.26ρ;检测限为0.04 ng/mL(R=0.9992)。该免疫传感器可用于临床上对CEA的检测。     

苝二酰亚胺衍生物-聚苯胺-氮化碳非标记型C-反应蛋白免疫传感器的研制

本文以苝二酰亚胺衍生物(PDI)-聚苯胺(PANI)-氮化碳(C_3N_4)复合材料为电化学活性物质和基底材料构建了一种非标记型免疫传感器用于C反应蛋白(CRP)的定量检测。首先,将带有氨基的PDI与PANI结合,然后,加入羧基化的C_3N_4形成复合材料PDI-PANI-C_3N_4,提高了材料的导电性。本文所构建的免疫传感器采用差分脉冲伏安法(DPV)于PBS(pH 7.4)中定量检测CRP,无需在溶液中加入其他电活性物质。当CRP抗体和抗原在电极表面特异性结合后,能够阻碍电流的传导,其响应电流会随着结合的CRP抗原的量增多而降低,由此实现CRP实时快速的检测。本实验对CRP抗体浓度、培育时间对免疫传感器的影响进行探究,在最优检测条件下,CRP抗原浓度与响应电流呈线性关系,线性范围为5～200 ng·mL~(-1),检测下限为1.66 ng·mL~(-1)。同时,该免疫传感器在面对多种干扰物时,具有良好的抗干扰能力。     

基于Pd/COF-LZU1非标记型C-反应蛋白免疫传感器的研制

采用溶剂热法, 通过有机单体合成了一种亚胺键连接的共价有机框架材料(COF-LZU1); 在常温常压条件下, 通过后合成的方法将贵金属钯(Ⅱ)引入到COF材料中, 合成了复合材料Pd/COF-LZU1, 该材料具有优良的催化性能. 利用Pd/COF-LZU1多孔复合材料将C-反应蛋白(CRP)抗体(anti-CRP)固定在玻碳电极表面, 构建了一种非标记型CRP免疫传感器. 当抗体与抗原发生免疫反应时, 形成的免疫复合物会阻碍电化学探针[Fe(CN)₆]^4-/3-的电子传递, 降低其响应电流, 从而实现CRP的快速检测. 采用交流阻抗和差示脉冲伏安法(DPV)考察了免疫传感器的电化学特性, 同时考察了测试底液的pH值、 抗原培育时间和抗体固定浓度等实验条件对传感器性能的影响. 在最优的实验条件下, 采用DPV法对CRP进行检测的线性范围为5~180 ng/mL, 检出限为1.66 ng/mL, 线性相关系数为0.992.     

基于PoPD-MWCNTs-离子液体/纳米金的髓过氧化物酶免疫传感器

在离子液体([EMIM]Br)中, 将聚邻苯二胺(PoPD)-多壁碳纳米管(MWCNTs)复合物原位电聚合到金电极(Au)表面, 利用纳米金固载髓过氧化物酶(MPO)抗体, 构建了一种用于MPO检测的无需标记的电流型免疫传感器. 采用循环伏安法(CV)和扫描电子显微镜(SEM)对修饰过程进行表征. 探讨了邻苯二胺单体浓度、pH、孵育时间和孵育温度对该免疫传感器性能的影响. 实验结果表明, 该传感器在最适条件下对MPO响应良好, 其线性范围为0.25～350 ng/mL, 线性相关系数为0.9985, 检出限为0.07 ng/mL. 该电流型免疫传感器具有稳定性好、灵敏度较高、特异性好、结果准确可靠和可再生等优点, 可应用于临床检测.     

基于纳米金／壳聚糖掺杂碳纳米管修饰金电极非标记免疫传感器的研究

应用吸附法将羊抗人IgG抗体直接固定于纳米金(GNPs)/壳聚糖(Chit)掺杂碳纳米管(CNTs)修饰的金电极表面,制备了用于人IgG抗原检测的非标记电化学免疫传感器.利用循环伏安法和交流阻抗研究了修饰电极表面的电化学特性,用差分脉冲伏安法研究了测试底液的pH值对免疫传感器性能的影响.实验表明,在含不同浓度人IgG的...     

基于氧化石墨烯增敏的聚邻苯二胺分子印迹电化学传感器测定多巴胺

本工作结合分子印迹技术和电化学检测方法对多巴胺(DA)进行了快速测定。以DA为模板分子,邻苯二胺(o-phenylenediamine,oPD)为功能单体,在氧化石墨烯(GO)修饰电极表面通过一步电聚合法制备分子印迹电化学传感器。采用透射电镜(TEM)和扫描电镜(SEM)对GO的形貌进行了表征,通过循环伏安法(CV)和差分脉冲伏安法(DPV)对传感器的电化学性能进行了分析。当DA的浓度在0.4～2000μmol·L^-1范围内时,DA在印迹电极上的DPV峰电流值与其浓度呈线性关系,检出限为8.0×10^-8 mol·L^-1;采用该方法对实际样品中的DA进行测定,回收率在92～108%之间。     

Magnetic Properties of Ni‐Co‐B Coated Carbon Nanofibers

Continuous and uniform Ni‐Co‐B coatings were successfully deposited onto carbon nanofibers via electroless plating. SEM images of the prepared Ni‐Co‐B coated carbon nanofibers were presented. The magnetic properties of the coated carbon nanofibers were investigated. The CoSO₄/(CoSO₄+NiSO₄) ratio in the electroless bath has obvious influence on the coercivity and residual magnetic flux density of the Ni‐Co‐B coated carbon nanofibers.     

Extraction of ochratoxin A in red wine with dopamine‐coated magnetic multi‐walled carbon nanotubes

A new, rapid, green, and cost‐effective magnetic solid‐phase extraction of ochratoxin A from red wine samples was developed using polydopamine‐coated magnetic multi‐walled carbon nanotubes as the absorbent. The polydopamine‐coated magnetic multi‐walled carbon nanotubes were fabricated with magnetic multi‐walled carbon nanotubes and dopamine by an in situ oxidative self‐polymerization approach. Transmission electron microscopy, dynamic light scattering, X‐ray photoelectron spectroscopy and vibrating sample magnetometry were used to characterize the absorbents. Ochratoxin A was quantified with high‐performance liquid chromatography coupled with fluorescence detection, with excitation and emission wavelengths of 338 and 455 nm, respectively. The conditions affecting the magnetic solid‐phase extraction procedure, such as pH, extraction solution, extraction time, absorbent amount, desorption solution and desorption time were investigated to obtain the optimal extraction conditions. Under the optimized conditions, the extraction recovery was 91.8–104.5% for ochratoxin A. A linear calibration curve was obtained in the range of 0.1–2.0 ng/mL. The limit of detection was 0.07 ng/mL, and the limit of quantitation was 0.21 ng/mL. The recoveries of ochratoxin A for spiked red wine sample ranged from 95.65 to 100.65% with relative standard deviation less than 8%. The polydopamine‐coated magnetic multi‐walled carbon nanotubes showed a high affinity toward ochratoxin A, allowing selective extraction and quantification of ochratoxin A from complex sample matrixes.     

Pd@tetrahedral hollow magnetic nanoparticles coated with N‐doped porous carbon as an efficient catalyst for hydrogenation of nitroarenes

Hollow magnetic nanoparticles (MNPs) with tetrahedral morphology were synthesized and then covered by a shell prepared by coating with melamine–formaldehyde followed by the introduction of glucose‐derived carbon. Subsequently, Pd nanoparticles were immobilized and the core–shell nanocomposite was carbonized. The obtained magnetic catalyst was successfully applied for the hydrogenation of nitroarenes in aqueous media. To investigate the effects of the morphology of MNPs, the nature of carbon shell, and the order of incorporation of Pd nanoparticles, several control catalysts, including the MNPs with different morphologies (disc‐like and cylinder); MNPs coated with different shells (sole glucose‐derived carbon or melamine–formaldehyde carbon shell); and a nanocomposite, in which Pd was immobilized after carbonization, were prepared and examined as catalyst for the model reaction. To justify the observed different catalytic activities of the catalysts, their Pd loadings, leaching, and specific surface areas were compared. The results confirmed that tetrahedral MNPs coated with porous N‐rich carbon shell exhibited the best catalytic activity. The high catalytic activity of this catalyst was attributed to its high surface area and the interaction of N‐rich shell with Pd nanoparticles that led to the higher Pd loading and suppressed Pd leaching.     

Electro-less plating nickel-phosphorus of low carbon steel using various pretreatments and an external magnetic field

Electro-less plating nickel-phosphorus (EPNP) subject to various pretreatments and an external magnetic field, are prepared onto low carbon steel (LCS). The surface hardness (SH), fatigue life (FL) and corrosion behavior (CB) of Ni-P coated are respectively obtained using a nano-indenter and a high strain low cycle fatigue life (HSLCFL) and polarization test. The experimental outcome reveals that LCS substrates that are pretreated using the proposed acid mixture (25% H₂SO₄ + 5% HCl) roughening and activation allow good Ni-P films to be deposited. In terms of EPNP, as the P content decreases, the SH and FL increase. Specimens that a coated in a Ni–P film using an external magnetic field have better mechanical performance than those that are not produced in an external magnetic field. As the external magnetic field intensity is increased, the film thickness, SH and FL increase, the concentration of P decreases and thin grains are formed on the film surface. The specimens without using an external magnetic field that are coated with a Ni–P film exhibit better resistance to corrosion than the uncoated sample of LCS. However, the Ni–P film that is coated using an external magnetic field has higher SH, so it exhibits increased resistance to corrosion.     

Cobalt(II)/manganese(II)-based molecular metamagnets

This mini-review covers recent progress in the field of cobalt(Ⅱ)/manganese(Ⅱ)-based molecular metamagnets, which can undergo magnetic phase transitions to a state with a net magnetic moment under the stimulation of external field. We simply discuss mean field theory describing these compounds and the important role of the magnetic anisotropy. The experimental properties of the known Co(Ⅱ)/Mn(Ⅱ) metamagnets are discussed, with emphasis on the variety of means by which the metamagnetic transitions have been observed and studied.     

磁性碳纳米管表面新型壬基酚印迹纳米复合材料制备及吸附性能

采用聚苯胺包覆的磁性多壁碳纳米管为载体,以壬基酚(NP)为模板分子,甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂制备新型磁性壬基酚印迹复合萃取材料。 采用扫描电子显微镜(SEM)、红外光谱(FT-IR)和样品振动磁强计(VSM)等技术手段对该磁性印迹复合材料进行表征和分析,结果表明,在磁性碳纳米管表面成功接枝厚度为60~70 nm的印迹聚合层。 采用高效液相色谱(HPLC)技术对该印迹复合材料的吸附性能进行探讨,结果表明,该磁性印迹复合材料对壬基酚具有特异性吸附性能,最大吸附量为38.46 mg/g。 结合HPLC检测技术,该磁性印迹复合材料成功用于分离富集饮用水中的壬基酚。     

Floating Diamonds with Nanomagnetic Particles

In the diamond industry, ferrofluids are used in ferrohydrostatic separators for the density separation of diamonds from gangue material. The size of the magnetic core of the coated particles forming the ferrofluid suspension is vital in ensuring the stability of the fluid. The particle size must be small enough such that sedimentation does not occur in a magnetic field gradient and under the influence of a gravitational field and such that magnetic agglomeration can be overcome. This paper discusses the particle size requirements for fluid stability under the influence of these effects.     

Separation of nitrogen and oxygen gases by polymeric membrane embedded with magnetic nano‐particle

Asymmetric polyethersulfone (PES) micro‐porous flat sheet membranes were prepared by the phase inversion method (PIM) and used as the support. PES‐PDMS composite membranes were fabricated with coating polydimethylsiloxane on the surface of PES membrane. The FluidMAG‐PAD was coated on PES and PES‐PDMS membrane to prepare super‐paramagnetic membranes for separation of oxygen from nitrogen. Permeance and O₂/N₂ selectivity were evaluated in the absence or presence of external magnetic field. In the absence of external magnetic field, the super‐paramagnetic polymer provides larger surface area leading to extended sites for oxygen adsorption. In the presence of magnetic field, the super‐paramagnetic particles obtained magnetic property leading to a pronounced interaction with oxygen resulting in elevated selectivity and permeability. Copyright © 2011 John Wiley & Sons, Ltd.     

强磁场辅助TFA-MOD法制备YBCO厚膜的理论分析

为了实现YBa2Cu3O7-x(YBCO)涂层导体在电力工业中的实际应用，必须有效增加YBCO超导层的厚度。提出一个强磁场辅助TFAMOD法制备YBCO厚膜的新工艺，并从磁热力学和磁性物理出发理论分析其可行性。沿垂直基底平面方向施加强磁场时，磁场将促进c轴取向YBCO晶核的形成，诱导厚膜中非c轴取向晶核转动到c轴平行磁场取向的位置。另外，取向晶粒间磁性相互作用力使晶粒沿磁场方向定向聚合，有利于获得致密的厚膜。因此，强磁场辅助TFA—MOD法有望制备高临界电流密度的YBCO织构厚膜。     

Core‐shell structured magnetic mesoporous carbon nanospheres derived from metal‐polyphenol coordination polymer‐coated Fe3O4 and its application in the enrichment of phthalates from water samples

In this work, core‐shell structured magnetic mesoporous carbon nanospheres were fabricated from the carbonization of metal‐polyphenol coordination polymer‐coated Fe₃O₄ nanoparticles. The preparation method is simple, fast, versatile, and easy to scale up. Magnetic mesoporous carbon nanospheres exhibit a high specific surface area, high superparamagnetism, and high adsorption efficiencies for phthalates. Four phthalates were extracted from aqueous solutions by using magnetic mesoporous carbon nanospheres via magnetic solid phase extraction. Subsequent analysis was performed by using high‐performance liquid chromatography with ultraviolet detection. The analytical method has good linearity in the concentration range of 1–200 ng/mL for diethyl phthalate, diisobutyl phthalate, and dicyclohexyl phthalate, and 3–200 ng/mL for dipropyl phthalate. The limits of detection were in the range of 0.10–0.62 ng/mL. Compared with previous methods, this method has a lower detection limit, wider linearity range, and faster adsorption and desorption rates. The results indicate that magnetic mesoporous carbon nanospheres are suitable for the enrichment of hydrophobic substances from aqueous solutions.