Designing a reliable leak bio-detection system for natural gas pipelines

Monitoring of natural gas (NG) pipelines is an important task for economical/safety operation, loss prevention and environmental protection. Timely and reliable leak detection of gas pipeline, therefore, plays a key role in the overall integrity management for the pipeline system. Owing to the various limitations of the currently available techniques and the surveillance area that needs to be covered, the research on new detector systems is still thriving. Biosensors are worldwide considered as a niche technology in the environmental market, since they afford the desired detector capabilities at low cost, provided they have been properly designed/developed and rationally placed/networked/maintained by the aid of operational research techniques. This paper addresses NG leakage surveillance through a robust cooperative/synergistic scheme between biosensors and conventional detector systems; the network is validated in situ and optimized in order to provide reliable information at the required granularity level. The proposed scheme is substantiated through a knowledge based approach and relies on Fuzzy Multicriteria Analysis (FMCA), for selecting the best biosensor design that suits both, the target analyte and the operational micro-environment. This approach is illustrated in the design of leak surveying over a pipeline network in Greece.     

Detection of alpha-fetoprotein through biological signal amplification by biosensor based on imaging ellipsometry

High sensitive and quantitative detection of alpha-fetoprotein (AFP) by biosensor based on imaging ellipsometry (BIE) through biological amplification was investigated. AFP firstly reacted with the rat monoclonal antibody (rat-mAb) initially immobilized on glutaraldehyde modified silicon surface, then rabbit anti-human AFP polyclonal antibodies (Rabbit-pAb) and goat anti-rabbit IgG (goat-IgG) were sequentially applied to amplify signal. Results revealed that signal was enhanced approximately six fold. The linear range of AFP detection was 20.0-200.0 ng/ml with a low limit of 5.0 ng/ml (S/N = 3). The cross-reaction rate was less than 5.2% evaluated by biomarker (carcinoembryonic antigen, carbohydrate 19-9 and carbohydrate antigen 242) and two common proteins (human serum albumin, fibrinogen) and their mixture. Coefficient variation (CV) for intra-slide and inter-slide reproducibility were 10.3%, 6.6%, 6.3% and 10.7%, 7.9%, 6.4% for 41.6 ng/ml, 83.2 ng/ml and 128.4 ng/ml AFP. In clinic application, cut-off value at 28.6 ng/ml was also determined with sensitivity 0.72 and specificity 0.94. Results of 47 clinic patient samples detected by BIE were in good agreement with those of electrochemiluminescence immunoassay (ECLIA) (R2 = 0.9949).The area under receiver operating characteristic curve (ROC) curve is 0.89. Statistical analysis showed that BIE is high agreement with ECLIA (Kappa = 0.733, U = 3.21>U0.01). It shows a potential for hepatocellular carcinoma (HCC) diagnosis.     

Effect of plasma treatment on surface chemical-bonding states and electrical properties of polyacrylonitrile nanofibers

Electrospun polyacrylonitrile (PAN) nanofibers were subjected to surface modification by atmospheric pressure (AP) plasma treatment with reactive gases. There was no damage to the surfaces after this plasma treatment, and no significant changes were observed in the morphologies of the nanofibers. The surface energies of O₂- and N₂-plasma-treated PAN (abbreviated as OPP and NPP, respectively) nanofibers increased by almost 138.7% and 190.6%, respectively, in comparison with that of an untreated nanofiber (256.6 mJ/m²). The binding energies of both OPP and NPP samples increased through the formation of many hydrophilic bonds involving oxygen. The current-voltage (I-V) characteristics of the nanofibers were determined for the different reactive gases, and the plasma-treated nanofibers showed higher protein immobilization compared to the untreated ones. This result indicates that electrospun PAN nanofibers have the potential to be used in protein biosensor systems.     

应用于食品工业中的生物传感器

对食品及其生产加工过程中的生物传感器进行综述。主要包括食品鲜度测定；蛋白及氨基酸的测定；糖、醇、酸的分析及菌数的测定。     

Electrochemical sensors based on conducting polymer—polypyrrole

Conducting polymers can be exploited as an excellent tool for the preparation of nanocomposites with nano-scaled biomolecules. Polypyrrole (Ppy) is one of the most extensively used conducting polymers in design of bioanalytical sensors. In this review article significant attention is paid to immobilization of biologically active molecules within Ppy during electrochemical deposition of this polymer. Such unique properties of this polymer as prevention of some undesirable electrochemical interactions and facilitation of electron transfer from some redox enzymes are discussed. Recent advances in application of polypyrrole in immunosensors and DNA sensors are presented. Some new electrochemical target DNA and target protein detection methods based on changes of semiconducting properties of electrochemically generated Ppy doped by affinity agents are introduced. Recent progress and problems in development of molecularly imprinted polypyrrole are considered.     

光纤免疫传感器在环境检测中的应用

综合介绍了光纤免疫传感器的基本原理、种类、结构及其发展现状，文章着重指出，该传感器适用于毒素及其它有毒有害物质的分析检测，在环境保护等领域有着广泛的应用前景。     

淀粉双酶传感器的研制

报导了一种测定淀粉的酶生物传感器法，它具有检测速度快、灵敏度高、操作简便、且样品需要量少等优点。酶生物传感器是由固定化的ＧＯＤ、ＧＡ酶膜和氧电极组成，测试的最佳条件为温度３０℃，ｐＨ＝４．４，０．２ｍｏｌ／Ｌ醋酸缓冲液，响应时间２ｍｉｎ。该法的精密度、准确度均良好，线性范围０．０５％～０．８％。     

基于核壳型量子点的生物传感器在真菌毒素检测中的应用进展

真菌毒素是真菌产生的有毒次生代谢物,其广泛存在于被污染的食物中,其中黄曲霉毒素已被认定为天然存在的剧毒致癌物。鉴于真菌毒素污染给人类健康与安全带来的风险与危害,发展低成本、快速、高效的检测方法以确保食品安全,具有重要的现实意义。已有大量研究者构建了基于单一量子点或其他荧光材料为荧光探针的生物传感器用于检测真菌毒素,并且从材料、检测方法和生物传感器等角度进行了详细的检测。然而,这些传感器在应用于真菌毒素检测时仍存在荧光探针易团聚、荧光性能不稳定、耐光漂白性能差等一种或多种局限,而基于核壳型量子点的新型生物传感器具有信号增敏、性能稳定、选择性好等优点,已成为构建真菌毒素检测新方法的热点研究内容。然而,目前并没有系统的去阐述核壳量子点构建的生物传感器在真菌毒素中的应用,因此,为了弥补该领域综述的空缺,本文主要从基于核壳量子点构建的免疫电化学发光传感器、适配体ECL传感器、免疫荧光传感器、适配体荧光传感器和试纸条传感器在真菌毒素中的应用进展进行阐述,本文首次系统地阐述了核壳型量子点生物传感器在粮油食品真菌毒素分析检测中的研究进展,以期为同类研究提供一定的理论依据。     

Electrochemical study of rat brain acetylcholinesterase inhibition by chlorofos: Kinetic aspects and analytical applications

An electrochemical sensor was applied for investigating the immobilized rat brain acetylcholinesterase inhibition by chlorofos. Two alternative routes were explored as response-generating reactions: (i) direct electrochemical oxidation of thiocholine produced upon acetylthiocholine enzymatic hydrolysis and (ii) reduction of the produced thiocholine with hexacyanoferrate (III), followed by hexacyanoferrate (II) electrochemical detection. The advantages of the direct way are simplicity and higher sensitivity compared to the indirect one, which however avoids the interferences because of the lower potential applied.Enzyme inhibition was identified as competitive, the increasing from 1.31 to 1.43 mmol L⁻¹ with chlorofos concentration in the range 0.2-1.0 mmol L⁻¹ and the maximal rate of the enzyme reaction remaining constant (I_max = 579.30 ± 5.71 μA) in the presence of chlorofos. The inhibition constant was calculated using the Dixon method (K_I = 10.07 mmol L⁻¹).The suppression of the acetylcholinesterase activity by the inhibitor, expressed as current decrease at a constant substrate concentration, was exploited for chlorofos quantification optimized by the design of experiments methodology. Optimal response was obtained for an acetylthiocholine concentration of 0.2 mmol L⁻¹, at 26 °C and pH 7.     

自组装单分子膜在生物传感器中的应用

论述了单分子膜及其在生物传感器中的应用。构成单分子膜组分化学参数的简单、连续可调决定了生物传感器的性质完全可控,取向有序、稳定可靠的单分子膜是生物传感器理想的基底材料。