基于核酸适配体的微囊藻毒素LR纳米金生物传感检测方法的建立及其识别机制研究

目的建立微囊藻毒素-LR(microcystin-LR, MC-LR)的纳米金生物传感比色检测法,并探究核酸适配体截短后对此方法检测效果的影响。方法采用柠檬酸钠还原法制备纳米金,通过优化盐浓度、适配体浓度、适配体与MC-LR的反应时间,建立了MC-LR的纳米金生物传感比色检测法。然后,采用组合型核酸适配体截短策略,探究了截短后的核酸适配体对比色法检测MC-LR的影响。结果 NaCl浓度为0.9mol/L,适配体浓度为0.4μmol/L, MC-LR与核酸适配体的反应时间为10 min时为其最适检测条件。在最适条件下,该方法的目测最低检测限为0.4μg/mL,仪器读数最低检测限为(1.05±0.002)ng/mL,线性检测范围为0～1.1μg/m L。探究得出核酸适配体截短后会影响其对MC-LR的识别活性。结论该方法简单、易行,线性检测范围宽,为小分子危害物核酸适配体的快速鉴定奠定了理论基础,同时,对截短核酸适配体与小分子危害物的识别活性研究提供了技术支撑。     

基于纳米金棒刻蚀的多色可视化传感器应用于乌头碱快速检测

目的基于纳米金棒刻蚀的多色可视化传感器快速检测乌头碱。方法采用H2O2-辣根过氧化物酶(horseradishperoxidase,HRP)-3,3’,5,5’-四甲基联苯胺(3,3’,5,5’-tetramethylbenzidine,TMB)体系的氧化产物TMB2+刻蚀纳米金棒,产生不同颜色的溶液,并将其与酶联免疫吸附测定法联用,构建一种酶联免疫多色可视化传感器应用于乌头碱快速半定量分析。结果在最优条件下,纳米金棒溶液的局域表面等离子体共振吸收峰的位移与乌头碱浓度在5~35ng/L范围内呈现较好的线性关系,检出限为1.67ng/L。结论该方法具有快速、选择性好、灵敏度高、裸眼可视化半定量等优点,对乌头碱的快速检测有一定的实际应用价值。     

基于AuPtRh纳米酶的比色适体传感器快速检测河豚毒素

目的 构建一种基于AuPtRh纳米酶和核酸适配体的比色传感器, 用于河豚毒素的可视化、快速、灵敏检测。方法 制备基于氧化石墨烯(graphene oxide, GO)修饰的金属网(stainless steel mesh, SSM)作为捕获探针, 以及AuPtRh三金属纳米酶连接核酸适配体(aptamer)作为信号探针, 通过透射电镜、原子力显微镜、X射线衍射仪、分光光度计对制备的AuPtRh纳米酶材料进行表征, 考察纳米酶的催化动力学模型, 用制备的SSM-GO/AuPtRh-aptamer传感器捕获河豚毒素。结果 最大反应速度(Vmax)为4.66×10-8 mol/(L·s), 米氏常数(Km)为0.62 mmol/L, AuPtRh作为纳米酶与H2O2的亲和力要高于单一金属和双金属与H2O2的亲和力。加入河豚毒素后, 溶液中的AuPtRh催化3,3'',5,5''-四甲基联苯胺(3,3’,5,5’-Tetramethylbenzidine, TMB)生成氧化TMB(oxTMB), 溶液由透明变为蓝色。在优化条件下, 河豚毒素在5~500 ng/L浓度范围内与652 nm处的吸光度呈良好的线性关系, 线性方程A=0.0011C+0.1523(r2=0.9901), 检测限为3 ng/L。以蛤蜊为实际样品, 测定加标样品中河豚毒素的含量, 加标样品的回收率范围为85.61%~122.66%。结论 SSM-GO/ AuPtRh-aptamer比色传感器具有操作简单、快速、灵敏度高、成本低的特点, 在现场检测领域有较大的潜力。     

锌/钴双金属无限配位聚合物纳米酶催化比色法快速检测单增李斯特菌

目的 基于锌/钴双金属无限配位聚合物(Zn/Co-bimetal infinite coordination polymers, Zn/Co-ICPs)构建快速检测单增李斯特菌的纳米酶催化比色法。方法 基于Zn/Co-ICPs过氧化物模拟酶活性、核酸适配体对类酶活性的增强作用及特异性识别能力, 以3,3’,5,5’-四甲基联苯胺(3,3’,5,5’-tetramethylbenzidine, TMB)为催化显色底物, 建立Zn/Co-ICPs纳米酶催化比色法, 对Zn/Co-ICPs的形貌和结构进行表征, 并考察适配体浓度、pH、温度和反应时间等因素对催化效果的影响, 并将该方法应用于饮用水和冷冻巴沙鱼样品中单增李斯特菌的测定。结果 在优选的条件下, 单增李斯特菌的浓度与蓝色显色产物氧化型TMB (oxidized TMB, oxTMB)在652 nm处的吸光度呈负相关关系。该方法的线性范围为3.2×102~1.0×105 CFU/mL, r2为0.9964, 检出限(limit of detection, LOD)为1.5×102 CFU/mL。加标回收率为90.7%~108.7%, 相对标准偏差为0.17%~7.20%。结论 该方法无需使用复杂昂贵的仪器即可实现可视化检测, 且检测速度快、准确度高、选择性好, 在复杂样品快速分析中具有一定潜力。     

核酸适配体功能化金纳米探针识别-共振光散射法检测腺苷

将纳米探针技术、核酸适配体识别与共振光散射检测技术有机结合,以腺苷为模式分析物,通过均相体系中腺苷与其特异结合核酸适配体识别反应,使形成网络聚集结构的金纳米结构解聚,从而引起共振光散射信号强烈变化.基于此,建立了核酸适配体识别的均相检测腺苷的新方法.该方法对腺苷检测的浓度线性范围为0.1～10 μmol/L,检测限为0.04 μmol/L(3S/N).该方法对腺苷的检测灵敏度高、选择性好,鸟苷、胸苷、胞苷、尿苷等对检测不产生干扰.     

基于适配体识别的金黄色葡萄球菌定性检测试纸条的研制及应用

本研究以金黄色葡萄球菌为检测靶标,以核酸适配体为识别分子,基于双适配体夹心和侧流层析原理,构建了定性检测金黄色葡萄球菌的适配体试纸条,并对NaCl浓度、适配体浓度、纳米金-适配体包被量及捕获探针包被量等实验条件进行优化,获得适配体试纸条最佳制备条件。在优化条件下对试纸条的灵敏度、特异性进行分析测试,最后将试纸条对116份食品进行金黄色葡萄球菌检测,并与国标法（GB 4789.10-2016）对比验证。结果显示,适配体试纸条最佳制备条件为NaCl浓度为80 mmol/L、适配体偶联浓度为1 μmol/L、结合垫上纳米金-适配体的稀释体积比为1:2、捕获探针浓度为25 μmol/L。在最佳条件下,适配体试纸条对金黄色葡萄球菌的可视化检测限为2×103 CFU/mL,检测时间为5 min,且与其他食源性致病菌如鼠伤寒沙门氏菌、单增李斯特菌、大肠杆菌、阪崎肠杆菌、痢疾志贺氏菌等无交叉反应,具有较高的特异性。将本方法应用于食品中金黄色葡萄球菌的定性检测,检测结果与国标法完全一致。该方法简便快速、准确可靠、成本低,适用于食品样品中金黄色葡萄球菌的定性检测。     

基于核酸适配体的纳米金比色法快速检测肠炎沙门氏菌

该文以肠炎沙门氏菌为研究对象,开发基于核酸适配体的纳米金可视化检测方法。通过优化体系内适配体浓度,研究纳米金-适配体体系的肠炎沙门氏菌检测限、特异性及适用温度;同时以人工污染样品为例,评价纳米金-适配体的加标回收率。结果显示：该方法可以特异性检测肠炎沙门氏菌,对其他食源性致病菌无特异反应。通过条件优化,在适配体浓度200 nmol/L 下,肠炎沙门氏菌的最低检测限为9.3×101 CFU/mL,其线性范围为103～107 CFU/mL,线性方程为y=0.187 8x-0.146（R2=0.991 3）。检测人工污染样品的加标回收率为93.68%～117.89%。利用核酸适配体纳米金比色法进行肠炎沙门氏菌的检测操作简便、结果可视;通过调整核酸适配体可进行其他致病菌的检测,具有良好的推广意义。     

羧甲基壳聚糖-分子信标-金纳米生物传感器检测鼠伤寒沙门氏菌

基于传统的沙门氏菌检测方法检测周期长、效率不高等缺陷,本研究通过合成一种羧甲基壳聚糖-分子信标-金纳米材料,采用一种新的基于分子信标共价功能化的壳聚糖技术和金纳米团聚比色的方法对含SSeC基因的鼠伤寒沙门氏菌进行检测。在羧甲基壳聚糖上交联环状结构的适配体,当加入靶标之后,由于靶标与环状结构适配体结合导致分子信标刚性结构崩解,插入茎状结构中的金纳米颗粒(GNRs)释放出来,当在溶液中加入一定量的NaCl溶液后,金纳米颗粒会发生团聚,根据聚合度的不同,产生相应颜色变化,从而实现对含SSeC基因的鼠伤寒沙门氏菌的快速检测,结果表明:通过检测金纳米颗粒发生的显色反应的吸光度可以实现对含有SSeC基因的鼠伤寒沙门氏菌进行快速检测,并且这种方法具有较高的特异性和灵敏度。在此检测体系中,靶标浓度和显色反应的吸光度值在0. 05～0. 5μmol/L内具有良好的线性关系,并且对于靶标DNA的检测下限为50nmol/L。     

基于核酸适配体结合纳米金模拟酶用于单增李斯特菌的快速检测

利用纳米金模拟酶在一定条件下能够催化过氧化氢氧化3,3',5,5'-四甲基联苯胺发生颜色反应,同时结合特异性高、亲和力强的核酸适配体建立了单增李斯特菌快速检测方法.通过对实验条件进行优化,建立了单增李斯特菌浓度与特定波长下吸光度值之间的关系式.线性回归方程为y=0.0321x+0.0248,R2=0.9963,检出限约...     

基于纳米金显色的非标记核酸适配体可视化检测重金属镉的方法研究

目的建立以特异性非标记核酸适配体为识别探针的重金属镉可视化检测方法。方法根据适配体与镉的高亲和力结合特性,利用纳米金溶液在盐诱导下凝聚后引起的颜色变化反应,通过分光光度计检测溶液的吸光度来检测镉离子浓度。通过优化适配体DNA浓度、盐离子浓度和纳米金溶液体积,确定最佳反应条件,建立样品溶液中镉离子浓度与吸光度的线性关系。结果该方法的线性范围和检测限分别是0.14~10 ng/m L和0.14 ng/m L,可以满足痕量检测要求。通过对灌溉水样的加标回收实验证明,检测体系具有很好的实用性和复杂基体适应性。结论利用核酸适配体和纳米金显色实现了镉的痕量可视化检测,该方法是一种简单、快速、灵敏的检测方法,在现场快速检测和高通量分析中都具有很好的应用前景。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the