Gold nanoparticle-based paper sensor for ultrasensitive and multiple detection of 32 (fluoro)quinolones by one monoclonal antibody

For rapid and simultaneous detection of (fluoro)quinolones, a broadly specific monoclonal antibody (mAb) that recognizes 32 (fluoro)quinolone antibiotics was prepared using a mixture of a norfloxacin derivative and a sarfloxacin derivative as the hapten. An immunochromatographic strip based on gold nanoparticles (AuNPs) was then assembled with goat anti-mouse antibody and antigen (sarfloxacin coupled to ovalbumin), used to form the C line and T line, respectively. This antigen competes with the (fluoro)quinolones in a sample incubated with mAbs labeled with AuNPs. The strip can detect 32 (fluoro)quinolones including oxolinic acid, nalidixic acid, miloxacin, pipemidic acid, piromidic acid, rosoxacin, cinoxacin, norfloxacin, pefloxacin, lomfloxacin, enofloxacin, fleroxacin, ciprofloxacin, enrofloxacin, dafloxacin, orbifloxacin, sparfloxacin, gemifloxacin, besifloxacin, balofloxacin, gatifloxacin, moxifloxacin, nadifloxacin, ofloxacin, marbofloxacin, flumequine, pazufloxacin, prulifloxacin, sarafloxacin, difloxacin, trovafloxacin, and tosufloxacin in milk within 10 min with the naked eye. The cut-off values of the strip range from 1 to 100 ng/mL and the limits of detection are 0.1–10 ng/mL. The strip does not cross-react with antibiotics including tetracycline, sulfamethazine, ampicillin, erythromycin, aflatoxin B1, or gentamicin. In short, this immunochromatographic strip is a very useful tool for the primary screening of (fluoro)quinolones in milk.

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大菱鲆疾病早期快速检测方法——胶体金免疫层析试纸的研制与建立

使用成分单一的牛血清白蛋白(BSA)为模拟病原,以胶体金标记兔抗血清(即大菱鲆免疫球蛋白多抗)作为检测示踪物,并分别将BSA和葡萄球菌A蛋白印记到硝酸纤维素膜上制成检测线和对照线,通过一系列工艺创制与组装配套,首次成功制备了一套完整的大菱鲆抗体快速检测试纸。采用大菱鲆抗BSA血清作为阳性样本,以健康大菱鲆血清作为阴性样本,用以检验试纸的性能,并与酶联免疫吸附实验(ELISA)法检测结果相比较。结果表明:本试纸检测抗体的特异性与敏感性均很高,与ELISA方法相当,而且使用方便,不需专业技能和额外的试剂与辅助仪器设备,5 min内即可用裸眼获得观察结果,很适合于基层生产操作及户外调研使用。以该实验为基础建立起来的抗体检测试纸,亦可推广应用于其他病害抗体的检测,可为鱼类疾病早期发生提供简易、快捷和操作性强的诊断方法。     

Gold Nanoparticle‐Based Paper Sensor for Simultaneous Detection of 11 Benzimidazoles by One Monoclonal Antibody

A colloidal gold immunochromatographic assay based on a generic monoclonal antibody is developed for the simultaneous detection of benzimidazoles and metabolite residues in milk samples. The monoclonal antibody is prepared using 2‐(methoxycarbonylamino)‐3H‐benzimidazole‐5‐carboxylic acid as the hapten, and it can recognize 11 types of benzimidazoles simultaneously. The immunochromatographic strip is assembled and labeled using gold nanoparticles. This strip can detect 11 benzimidazoles including albendazole, albendazole s‐oxide, albendazole sulfone, fenbendazole, fenbendazole sulfone, flubendazole, mebendazole, parbendazole, oxfendazole, oxibendazole, and carbendazim within 15 min in milk samples. Results are obtained visually with the naked eye, and the cutoff values and the visual limit of detection values for these benzimidazoles are 25, 6.25, 12.5, 12.5, 50, 25, 50, 50, 50, 6.25, and 25 ng mL^?1, and 6.25, 3.125, 3.125, 1.56, 12.5, 6.25, 12.5, 12.5, 6.25, 0.78, and 12.5 ng mL^?1, respectively. Results are also obtained using a hand‐held strip scan reader, with calculated limit of detection values for these benzimidazoles of 0.83, 0.77, 1.83, 0.98, 7.67, 3.50, 3.96, 5.71, 0.92, 0.59, and 1.69 ng mL^?1, respectively. In short, the developed paper sensor is a useful tool for rapid and simple screening of residues of benzimidazoles in milk samples.     

Graphene/Gold nanoparticle composite-based paper sensor for electrochemical detection of hydrogen peroxide

In this article, we report the convenient preparation of graphene/gold nanoparticle-decorating filter membrane, which could be directly used as electrode for H₂O₂ sensing. The graphene oxide and chloroauric acid are reduced by l-ascorbic acid before covering the paper substrate. The reduced graphene oxide/gold nanoparticle-paper material is characterized by scanning electron microscopy, X-ray diffraction and Raman spectroscopy. The paper composite could be cut into piece and directly used as electrochemical sensor. The electrochemical experimental results show that the paper sensor has satisfying performances in sensing H₂O₂ with the detection limit of 15?μM and the linear range is 8.53–17.35?mM. This work would propose a novel strategy for the applications of graphene in the fields of electroanalysis and sensing.     

胶体金免疫层析分析方法用于同时检出减肥茶和咖啡中西布曲明和西地那非（英文）

本文建立了一种方便、快速、高特异性的胶体金免疫层析检测方法,用于同时检测减肥茶和咖啡中的西布曲明(SB)和西地那非(SID).我们首先制备了胶体金纳米粒子(CG),然后使之与单抗结合形成CG-mAb,将CG-mAb与抗原分别喷涂到基板上形成结合垫和检测条带,其中所需的抗原和抗体均由本实验室制备.经过条件优化,该方法在PBS缓冲溶液(0.01 mol L^-1,pH7.4),以及三种减肥茶和三种咖啡样本中,对SB和SID的消线值均为500 ng mL^-1;检测时间仅需5 min.该方法对减肥茶和咖啡样本中SB和SID的快速检出具有实际应用价值.     

Development of nanostructured ZnO thin film sensor for NO2 detection

In this work, we report on the performance of a NO₂ sensor based on nanocrystalline zinc oxide (ZnO) operating at 200°C. The sensor was fabricated using spin coating technique on glass substrates. ZnO film was characterised for their structural as well as surface morphologies and NO₂ response was studied. The XRD analysis showed formation of nanocrystalline ZnO. Morphological analysis using SEM revealed formation of a diffusion free surface. The ZnO film showed selectivity for NO₂ over methanol compared to ethanol, H₂S, Cl₂ and NH₃ (S_NO2 /S_CH3OH?=?18.6, S_NO2 /S_C2H5OH?=?12.4, S_NO2 /S_Cl2 ?=?9.3, S_NO2 /S_H2S?=?3.32 and S_NO2 /S_NH3 ?=?5.32). The maximum NO₂ response of 37.2% with 78% stability for the film annealed at 700°C at gas concentration of 100?ppm at 200°C operating temperature was achieved.     

Fabrication and characterization of Ga-doped ZnO nanowire gas sensor for the detection of CO

We demonstrate an efficient CO sensor using Ga-doped ZnO (GZO) nanowires (NWs). Various GZO NWs are synthesized with Au catalysts on sapphire substrates by hot-walled pulse laser deposition. The deposition temperature of ZnO NWs was in the range of 800-900 °C. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL) characterizations indicate that the obtained NWs have the well-crystallized hexagonal structure with customized Ga-doping concentration of 0-5 wt.%. The NWs have the diameter of about 50 nm and the length of about 8 µm. After depositing the Ag electrodes on both sides of the NW cluster, the resistance change is checked with the exposure to CO gas in the self-designed gas chamber that can facilitate the detection of the resistance change and the control of gas flow as well as temperature. The detected resistance modulations are 1.0 kΩ and 83.2 kΩ in the cases of 3 wt.% GZO and pure ZnO NW clusters, respectively, indication that we successfully customize the sensitivity of the gas sensors by controlled doping.     

Nanomechanical sensor for rapid and ultrasensitive detection of tumor markers in serum using nanobody

Early cancer diagnosis requires ultrasensitive detection of tumor markers in blood.To this end,we develop a novel microcantilever immunosensor using nanobodies(Nbs)as receptors.As the smallest antibody(Ab)entity comprising an intact antigen-binding site,Nbs achieve dense receptor layers and short distances between antigen-binding regions and sensor surfaces,which significantly elevate the generation and transmission of surface stress.Owing to the inherent thiol group at the C-terminus,Nbs are covalently immobilized on microcantilever surfaces in directed orientation via one-step reaction,which further enhances the stress generation.For microcantilever-based nanomechanical sensor,these advantages dramatically increase the sensor sensitivity.Thus,Nb-functionalized microcantilevers can detect picomolar concentrations of tumor markers with three orders of magnitude higher sensitivity,when compared with conventional Ab-functionalized microcantilevers.This proof-of-concept study demonstrates an ultrasensitive,label-free,rapid,and low-cost method for tumor marker detection.Moreover,interestingly,we find Nb inactivation on sensor interfaces when using macromolecule blocking reagents.The adsorption-induced inactivation is presumably caused by the change of interfacial properties,due to binding site occlusion upon complex coimmobilization formations.Our findings are generalized to any coimmobilization methodology for Nbs and,thus,for the construction of high-performance immuno-surfaces.     

Application of Small Punch Techniques for the Determination of Gold Mechanical Properties

Abstract: Gold has been one of the most valuable materials since ancient times. These days it is mainly used as a business commodity or as an engineering material in jewellery, medical prostheses (mainly dental) or electronics. For these engineering purposes, knowledge of its mechanical properties is a key factor in order to improve design and performance. The properties of pure gold have already been reported, although the information on them is scarce and indeed no information on properties such as fracture resistance has been found by the authors of this work. Gold alloys, especially those used for dental implants, are better characterised, but the development of new alloys requires a new characterisation of their properties. At the same time, there have been important advances in recent years in the development of non‐destructive or quasi‐non‐destructive techniques for the mechanical characterisation of materials. Among these, the small punch technique has proven to be one of the most reliable and efficient (in terms of material consumption). This technique is here applied for the determination of 24 (pure gold) and 18 (75% gold) carat gold properties, as an example of how this experimental tool is capable and suitable for the characterisation of gold, gold alloys and any other scarce, valuable material. The estimated tensile properties of 24 carat gold correlate well with the values observed in the literature, obtained through traditional test techniques.     

光纤非本征法布里-玻罗传感器兰姆波检测灵敏度分析

基于兰姆波的结构工况检测技术在评估复合材料和金属结构的安全性和耐久性方面发挥着重要的作用。作为对传统的压电换能器（PZT）的一种很好的替代,光纤传感器在传感方面的应用正被广泛地挖掘出来,包括兰姆波检测。本文从理论上建立了超声兰姆波作用下光纤非本征法布里．玻罗（EFPI）传感器参数与其输出性能之间的关系。数值结果显示了传感器的性能与其相对于声源的方向角以及传感器的计量长度与超声波长的比值相关。所得出的结论对于EFPI传感器精确地探测兰姆波提供了理论依据。     

乙内酰脲无氰电镀金工艺

为消除氰化物镀金的危害,提出并研究了以乙内酰脲为配位剂的无氰电镀金工艺。采用扫描电子显微镜（SEM）、原子力显微镜（AFM）对金镀层表面形貌进行观察,采用热震试验测试金镀层结合力,采用硝酸试验测试金镀层的耐蚀性。结果表明：控制金盐10g／L与乙内酰脲100g／L左右,并加入复配添加剂（0．05g／LC＋0．1mL／LD...     

光面式高压氢气泄漏快速可视化检测方法及数值仿真研究

针对高压氢泄漏扩散的检测问题,国内外学者利用实验和数值模拟等方法进行了相关研究,提出了一些检测方法,这些检测方法结果可靠,但是普遍存在反映速度慢的不足。本文提出了一种光面式高压氢气泄漏快速可视化检测方法,利用半导体激光器发射激光,通过柱面透镜组及反射镜后形成光面（laser sheet）照射储氢罐,利用安装在储氢罐上方特定位置的CCD相机拍照采集图像并传输至计算机,经数字图像处理后对高压氢气泄漏情况进行鉴别。基于该方法开展仿真实验,建立高压氢气射流的分层流动模型,实验结果与前人研究的实验公式吻合,证明了该方法的可行性;开展了泄漏口直径为1 mm 时3,5,7 MPa压强的仿真实验,以及压强为5 MPa时泄漏口直径为0.5,1,1.5 mm的仿真实验,获得了高压氢气泄漏口直径与特定高度、气射流边界层直径的解析关系,以及高压氢气压力与射流边界层直径的解析关系,为实现高压氢气泄漏快速准确检测提供了有力支撑。     

Characterisation of a monolithic active pixel sensor for electron detection in the energy range 10–20 keV

As part of a feasibility study into the use of novel electron detectors for X-ray photoelectron emission microscopes (XPEEM), we have characterised the imaging performance of a back-illuminated monolithic active pixel sensor (MAPS) operating under both integrating and counting modes for electrons in the energy range 10–20 keV. For integrating mode, we present the detective quantum efficiency (DQE), which shows marked improvements over conventional indirect detectors based on microchannel plates. We also present the modulation transfer function (MTF) and noise power spectrum (NPS), again demonstrating significantly improved performance. For counting mode, we present the quantum efficiency (QE) as a function of incident electron energy. We have evaluated the charge collection efficiency (CCE) and we thereby demonstrate the presence of a ~200 nm thick dead layer that is linked with reduced CCE at low electron energies. Based on our findings, we believe that the MAPS technology is well matched to future XPEEM instruments using aberration correction.     

Highly sensitive optical waveguide sensor for SO2 and H2S detection in the parts-per-trillion regime using tetraaminophenyl porphyrin

ABSTRACT

Optical waveguide (OWG) sensors present great potential for detecting trace levels of harmful gases because of their high sensitivity and anti-electromagnetic interference. However, OWG-based SO2 and H2S-detecting sensors in the parts-per-trillion (ppt) range are still lacking. We fabricated 5,10,15,20-(tetra-4-aminophenyl) porphyrin (TAPP) thin film-based OWG sensor devices (TAPP-OWG) to detect SO2 and H2S gases, in which TAPP thin film was immobilized over the surface of a potassium ion exchange glass OWG. These sensors successfully measure extremely low concentrations of SO2 and H2S (detection limit?=?1 ppt), providing good repeatability for SO2 (10 ppt) and H2S (10 ppt) gases, with relative standard deviations of 1.67% and 3.68%, respectively. With fast response (t1) and recovery (t2) times for SO2 (t1=4 s, t2=157 s) and H2S (t1=2 s, t2=117 s) at room temperature, TAPP thin film enhances the potential of OWGs for use in high-sensitivity trace-level gas detection.     

An electrochemical sensor based on Pt/g-C3N4/polyaniline nanocomposite for detection of Hg2+

The synthesis of Pt/g-C₃N₄/polyaniline nanocomposites (Pt/g-C₃N₄/PAn NCs) via the direct reduction of Pt (II) in the presence of L-cysteine as the reducing agent is presented in this study. X-ray diffraction analysis showed that the Pt cations were reduced to metallic Pt in the presence of L-cysteine. Field emission scanning electron microscope images confirmed a low agglomeration of metallic Pt when synthesized in the presence of g-C₃N₄. Electrochemical impedance spectroscopy results showed that the low conductivity of g-C₃N₄ is compensated with the presence of polyaniline (PAn). A glassy carbon electrode modified with the Pt/g-C₃N₄/PAn NCs showed high selectivity and sensitivity for the detection of Hg²⁺. The presence of active sites in the g-C₃N₄ and PAn enhanced the adsorption of Hg²⁺. The voltammetric response was linear in the concentration range of 1–500 nM Hg²⁺, with the detection limit of 0.014 nM (at S/N = 3).     

论朱金漆木雕祥瑞题材中的设计伦理实践

通过祥瑞这一特定的装饰题材分析朱金漆木雕中隐含的伦理现象,并结合几个典型案例分别从祥瑞题材的内容、祥瑞母体的事理、祥瑞装饰的结构论述伦理对设计的介入。在此基础上,梳理了朱金漆木雕在关注功能与美化之上体现出的伦理教化作用及意义,并借此为关注人文关怀的当下设计提供借鉴。     

纳米钯模拟酶用于甲醇含量的快速检测

以纳米钯作为辣根过氧化物酶的替代物,用于催化过氧化氢(H2O2)氧化3,3’,5,5’-四甲基联苯胺(TMB)的反应体系。其催化反应生成一种最大吸收波长为653 nm的蓝色产物。通过分光光度法即可实现微量H2O2的检测。在此基础上,研究甲醇在醇类氧化酶的催化下产生过氧化氢的能力,采用纳米钯模拟酶法测定甲醇产生过氧化氢的量,从而实现甲醇的快速检测。     

A digital optical sensor for the remote monitoring of temperature

A method for the continuous monitoring of the change in temperature of remote physical objects based on waveguide ring microwave resonators, and also its diagramatic representation, is proposed. The results of calculations, which enable the range of accuracy of temperature measurements to be optimized using a digital optical sensor, are presented. The short response time and the small dimensions and mass of the proposed sensor enable continuous remote monitoring of the temperature to be achieved in locations that are difficult to access. __________ Translated from Izmeritel’naya Tekhnika, No. 3, pp. 54–57, March, 2007.     

Ultrasensitive electrocatalytic detection of COX-2 rs20417: relying on 3D interconnected architecture of Pt-LSSUs@PAA nanostructures for sensor interface modification

Mutated COX-2 has become the new molecular marker of aspirin resistance. However, there is still a technical ‘bottleneck’ for direct and sensitive detection of circulating COX-2 mutant gene. In this work, we reported a simple and ultrasensitive electrochemical method for COX-2–765G/C (rs20417) detection for the first time. Polyallylamine (PAA) functionalised Pt nanostructures with long-spined sea urchin-like morphology (Pt-LSSUs@PAA) was synthesised by a simple chemical method for the construction of nano-sensing interface. Ru(NH₃)₆³⁺ is used as a primary electron acceptor that is electrostatically attracted to peptide nucleic acid modified electrodes and Fe(CN)₆^3? is introduced into the redox system as secondary electron acceptor to regenerate Ru³⁺ after electrochemical reduction for multiple redox cycles. Different pulse voltammetry was applied to record the electrochemical signals. Under optimal conditions, the DNA sensors showed a wide linear relationship, from 10?fM to 1?nM, with detection limits of 3.3?fM (S/N?=?3). This study will provide the basis for the precise use of aspirin, and it has important guiding value for individual drug testing of cardiovascular disease.