基于背景荧光猝灭-免疫层析法黄曲霉毒素B_1检测卡的研制

基于背景荧光猝灭-免疫层析技术研制快速检测食用油中黄曲霉毒素B1的定量检测卡。依据黄曲霉毒素B1抗原和抗体的活性,筛选检测系统中最佳的黄曲霉毒素B1抗原浓度和抗体标记浓度,应用最佳检测系统进行食用油中黄曲霉毒素B1检测的方法学验证和样品测定。最佳检测系统中黄曲霉毒素B1抗原浓度为0.5 mg/m L,黄曲霉毒素B1抗体标记浓度为1.0μg/m L;用于测定食用油中黄曲霉毒素B1的浓度范围为1.3~50.0 ng/m L,RSD均值为0.42%,平均加标回收率为96.3%~103.2%,RSD均值为2.8%(n=9)。使用有样品采用本法与国标方法的检测结果无显著性差异(p0.05)。本方法专属性强,灵敏度高,可快速、准确的检测食用油中黄曲霉毒素B1。     

管式磁性微粒子化学发光免疫分析法测定人尿液中的雌三醇

待测尿液中的雌三醇、辣根过氧化物酶标记的雌三醇与异硫氰酸荧光素(FITC)标记的兔抗雌三醇抗体在均相体系中发生竞争性免疫反应,再加入用羊抗FITC抗体包被的磁微粒,反应生成物结合在磁微粒上,在磁场中经分离、洗涤后加发光底物,检测发光强度(RLU),测定尿液中雌三醇的含量。通过对检测条件的优化,建立了磁性微粒子化学发光免疫分析法测定人尿液中雌三醇的方法,并对正常男性、女性和孕妇的尿液中雌三醇含量进行了测定。结果表明,本方法的线性范围为1～100μg/L,检出限为0.25μg/L,具有很高的灵敏度;批内相对标准偏差<14%;批间相对标准偏差<7%,具有良好的稳定性和重现性。     

超声萃取-免疫亲和柱净化-柱后光化学衍生高效液相色谱法同时测定蜂房药材中4种黄曲霉毒素

建立超声萃取-免疫亲和柱净化-柱后光化学衍生高效液相色谱同时测定蜂房药材中黄曲霉毒素B1、黄曲霉毒素B2、黄曲霉毒素G1、黄曲霉毒素G2含量的分析方法。样品经粉碎，过孔径为120μm筛后，采用70%甲醇溶液超声处理30 min，经免疫亲和柱净化、高效液相色谱分离、光化学柱后衍生，通过荧光检测器测定4种黄曲霉毒素的含量。黄曲霉毒素B1的线性范围为0.010 4～0.052 0 ng，相关系数为0.999 9；黄曲霉毒素B2的线性范围为0.003 8～0.019 0 ng，相关系数为0.999 8；黄曲霉毒素G1的线性范围为0.010 8～0.054 0 ng，相关系数为0.999 8；黄曲霉毒素G2的线性范围为0.003 8～0.019 0 ng，相关系数为0.999 8。4种黄曲霉毒素检出限分别为0.42、0.15、0.43、0.15μg/kg，测定结果的相对标准偏差不大于2.5%(n=6)，样品加标回收率为92.9%～96.9%。该方法操作简便，灵敏度高，可用于蜂房中黄曲霉毒素含量的测定。     

高效液相色谱法对农产品中黄曲霉毒素的测定研究

采用免疫亲和方法进行样品前处理,用甲醇-乙腈-水三元流动相体系分离黄曲霉毒素,氯化汞溶液在线衍生,荧光检测器检测,建立了新型的高效液相色谱柱后衍生测定黄曲霉毒素(B1、B2、G1、G2、M1)的方法。该方法在13 min内完成测定,线性关系良好,5种黄曲霉毒素的线性相关系数r值均大于0.999。方法成功应用于花生、花生制品、大米、玉米等农产品。对样品进行不同水平的加标回收实验,回收率为83%~100%,相对标准偏差1.51%~4.98%(n=7),B1检出限(S/N=3)和定量下限(S/N=10)分别达到了0.05μg/kg和0.17μg/kg。     

板式磁颗粒化学发光免疫分析在癌胚抗原测定中的应用

开发了一种板式磁颗粒化学发光免疫分析方法并将其用于人血清中癌胚抗原(CEA)的测定,该方法利用HRP标记的CEA抗体以及FITC标记的CEA抗体与CEA抗原在微孔板中进行夹心反应,使用抗FITC抗体包被的磁性微粒子溶液作为分离固相,利用了一个特殊的适用于微孔板的磁性分离器进行分离,最后加入鲁米诺和H2O2底物进行发光反应.该方法采用微孔板代替透明管作为反应容器,磁颗粒作为分离固相在微孔里与免疫试剂反应,提前用BSA将微孔板封闭,很好地解决了管式磁颗粒方法非特异吸附高以及包被板方法线性范围小的局限性,同时避免了管间差异以及包被不均问题.该方法结合了微孔板作为反应容器以及磁颗粒分离体系的优点,使用夹心法对人血清中的CEA在0～250ng/mL浓度范围进行了测定,检测灵敏度为0.57ng/mL,批内和批间变异分别小于7%和11%.与市售CLIA试剂盒测定结果做了比对,两者显示了很好的相关性.该法经济、优越,有望实现商品化.     

农产品与饲料中T-2毒素免疫亲和柱净化-液相色谱串联质谱检测技术研究

利用T-2毒素单克隆抗体2G7和CNBr活化的Sepharose 4B研制出T-2免疫亲和柱,考察了T-2免疫亲和柱的最佳应用条件。利用免疫亲和柱,建立了农产品与饲料中T-2毒素免疫亲和柱净化/液相色谱-串联质谱(IAC/LC-MS/MS)确证性检测技术,并考察该方法的准确度和精密度。结果表明,T-2毒素在0.5~500.0 ng/g范围内线性关系良好,相关系数为0.999 7,检出限为0.05 ng/g,定量下限为0.17 ng/g。大米、玉米、饲料样品在T-2毒素10,50,100 ng/g的加标水平下,回收率为92.9%~109.7%,相对标准偏差为2.1%~8.3%。对市售36份农产品与饲料样品进行测定,检测结果的相对标准偏差均小于10.0%。     

光化学柱后衍生–高效液相色谱法测定婴幼儿营养米粉中的黄曲霉毒素B1

建立婴幼儿营养米粉中黄曲霉毒素B1的高效液相色谱荧光检测器测定方法。样品以甲醇–水(体积比70∶30)溶液匀质提取,过黄曲霉毒素B1免疫层析亲和柱净化,经CNW Athena C18色谱柱分离和光化学柱后衍生反应器衍生后,用带有荧光检测器的高效液相色谱仪测定。采用峰面积外标法定量黄曲霉毒素B1含量。黄曲霉毒素B1在0～10μg/L的浓度范围内线性关系良好,相关系数为0.999 8,检出限为0.25μg/kg。在3个添加水平下加标回收率为97.7%～106.9%,测定结果的相对标准偏差为1.7%(n=6)。该方法的灵敏度、准确度、精密度均符合黄曲霉毒素B1的检测技术要求,适用于婴幼儿营养米粉中黄曲霉毒素B1的日常检测。     

柱后光化学衍生高效液相色谱法同时测定牛奶中黄曲霉毒素

建立了高效液相色谱法同时测定牛奶中黄曲霉毒素B1,B2,G1,G2的方法。用乙腈和水的混合溶液(体积比为80∶20)提取牛奶样品中4种黄曲霉毒素,提取液经Mycosep 228 AflaPat多功能净化柱净化,浓缩后采用C18色谱柱分离,光化学衍生后进入荧光检测器测定,外标法定量。对牛奶样品进行加标回收和精密度试验,黄曲霉毒素B1,B2,G1,G2的检出限分别为0.50,0.10,0.50,0.10μg/kg,回收率均在85%以上,测定结果的相对标准偏差为1.72%～3.52%(n=6)。该方法操作简单,速度快,重现性好,满足牛奶中黄曲霉毒素检测的要求。     

直接竞争荧光免疫法测定中药材中的黄曲霉毒素B1

本文采用Mannich反应合成黄曲霉毒素B1(AFB1)人工抗原,免疫小鼠制备AFB1单克隆抗体。采用直接搅拌法将异硫氰酸荧光素(FITC)标记AFB1抗体,经Sephadex-50凝胶柱纯化,制得FITC-AFB1荧光标记抗体,分析其免疫学特性,从而建立了一种快速灵敏的直接竞争荧光免疫分析方法(FIA)以用于检测中药材中的AFB1含量。结果表明,AFB1-FITC标记抗体的结合比率为4.19。通过对检测体系多项影响因素的筛选优化,FIA检测方法的标准曲线方程为I=33.45 log C+25.55,R=0.9913,线性检测范围1~100 ng/m L,检测限0.69ng/m L,回收率90.4%~106.6%。该方法具有操作简单、快速灵敏、特异性高等特点,可用于中药材中AFB1的分析测定。     

组装型金磁微粒的制备及其在免疫学检测中的应用

以化学共沉淀和柠檬酸还原法分别合成纳米级Fe₃O₄和Au粒子, 将经3-巯丙基三乙氧基硅烷修饰形成的Fe3O4聚集体与纳米金粒子相互作用, 制备得到组装型Fe₃O₄/Au磁性复合微粒(简称金磁微粒), 并对其形成过程、形貌特征、磁学性质等进行表征. 此外, 对金磁微粒作为新型免疫学检测载体的特性包括抗体固定化、质量控制及其在免疫学检测中的应用开展研究. 结果表明: 组装型金磁微粒形状不规则、表面粗糙, 平均粒径约为2~3 μm; 具有超顺磁性, 比饱和磁化强度达41 A·m²/kg; 1 mg金磁微粒最多可固定人IgG的量为330 μg, 以含有500 ng人IgG的金磁微粒为一个检测单位, 与辣根过氧化物酶标记羊抗人IgG的每批5个重复特异性反应测定结果的相对标准偏差均小于6%, 5批特异性反应测定结果的批间相对标准偏差小于7%(以每批5次测定结果的平均值计算), 符合免疫学检测载体的质量要求; 将抗乙肝表面抗原单克隆抗体和抗白介素-8单克隆抗体分别固定于金磁微粒表面, 采用双抗体夹心法对乙肝表面抗原和白介素-8分别进行定性和定量检测, 结果表明金磁微粒是一种较好的免疫学检测载体.     

Micro-plate magnetic chemiluminescence immunoassay and its applications in carcinoembryonic antigen analysis

A micro-plate magnetic chemiluminescence immunoassay was developed for rapid and high throughput detection of carcinoembryonic antigens (CEA) in human sera. This method was based on a sandwich immunoreaction of fluorescein isothiocyanate (FITC)-labeled anti-CEA antibodies, CEA antigens, and horseradish peroxidase (HRP)-conjugated anti-CEA antibodies in mi- cro-plate. The immunomagnetic particles coated with anti-FITC antibodies were used as the solid phase for the immunoassay. The separation procedure was c...     

Electrochemical immunoassay for vitellogenin based on sequential injection using antigen-immobilized magnetic microbeads.

A rapid and sensitive immunoassay for the determination of vitellogenin (Vg) is described. The method involves a sequential injection analysis (SIA) system equipped with an amperometric detector and a neodymium magnet. Magnetic beads, onto which an antigen (Vg) was immobilized, were used as a solid support in an immunoassay. The introduction, trapping and release of magnetic beads in an immunoreaction cell were controlled by means of the neodymium magnet and by adjusting the flow of the carrier solution. The immunoassay was based on an indirect competitive immunoreaction of an alkaline phosphatase (ALP) labeled anti-Vg monoclonal antibody between the fraction of Vg immobilized on the magnetic beads and Vg in the sample solution. The immobilization of Vg on the beads involved coupling an amino group moiety of Vg with the magnetic beads after activation of a carboxylate moiety on the surface of magnetic beads that had been coated with a polylactate film. The Vg-immobilized magnetic beads were introduced and trapped in the immunoreaction cell equipped with the neodymium magnet; a Vg sample solution containing an ALP labeled anti-Vg antibody at a constant concentration and a p-aminophenyl phosphate (PAPP) solution were sequentially introduced into the immunoreaction cell. The product of the enzyme reaction of PAPP with ALP on the antibody, paminophenol, was transported to an amperometric detector, the applied voltage of which was set at +0.2 V vs. an Ag/AgCl reference electrode. A sigmoid calibration curve was obtained when the logarithm of the concentration of Vg was plotted against the peak current of the amperometric detector using various concentrations of standard Vg sample solutions (0-500 ppb). The time required for the analysis is less than 15 min.     

Resonance Light Scattering Method to Determine Binding Ratio and Functional Affinity Constant of Antigen/Antibody Immunoreaction

Abstract

Based on the immunoreaction equation and the quality function law, a method of determining the binding ratio and the affinity constant of antibody/antigen immunoreaction has been developed by measuring resonance light scattering (RLS) signals of the polystyrene latex particles. According to the method, the binding ratio and affinity constant of HIgG binding with goat anti-HIgG equal 0.71 and 47.3 mL/mg; that is, 1 mol HIgG can be bound with 1.4 mol goat anti-HigG. This new method is much simpler and easier to carry out when studying immunoreaction kinetics and determining the binding ratio and affinity constant.     

Competitive immunoassay of phenobarbital by microchip electrophoresis with laser induced fluorescence detection

A microchip electrophoresis method with laser induced fluorescence detection was developed for the immunoassay of phenobarbital. The detection was based on the competitive immunoreaction between analyte phenobarbital and fluorescein isothiocyanate (FITC) labeled phenobarbital with a limited amount of antibody. The assay was developed by varying the borate concentration, buffer pH, separation voltage, and incubation time. A running buffer system containing 35 mM borate and 15 mM sodium dodecyl sulfate (pH 9.5), and 2800 V separation voltage provided analysis conditions for a high-resolution, sensitive, and repeatable assay of phenobarbital. Free FITC-labeled phenobarbital and immunocomplex were separated within 30s. The calibration curve for phenobarbital had a detection limit of 3.4 nM and a range of 8.6-860.0 nM. The assay could be used to determine the phenobarbital plasma concentration in clinical plasma sample.     

Determination of different forms of human interferon-gamma in single natural killer cells by capillary electrophoresis with on-capillary immunoreaction and laser-induced fluorescence detection

A novel method for determining different forms of human interferon-gamma (IFN-gamma) in single natural killer cells was developed by capillary electrophoresis (CE) with on-capillary immunoreaction and laser-induced fluorescence (LIF) detection. Cells were perforated with digitonin and one single cell was electrokinatically introduced into the front end of a separation capillary. The monoclonal antibody labeled with fluorescein isothiocyanate of IFN-gamma was hydrodynamically injected into the front end of the capillary around the cell introduced. After the cell was lysed by ultrasonication, the front end of the capillary was used as a microreactor to allow different forms of IFN-gamma to process the immunoreaction with their labeled antibody. Finally, the complexes of different forms of IFN-gamma with their labeled antibody were separated and detected by CE with LIF detection with a limit of detection of zeptomoles (10(-21) mol).     

Sequential injection chemiluminescence immunoassay for nonionic surfactants by using magnetic microbeads

A rapid and sensitive immunoassay based on a sequential injection analysis (SIA) using magnetic microbeads for the determination of alkylphenol polyethoxylates (APnEOs) is described. An SIA system was constructed from a syringe pump, a switching valve, a flow-through type immunoreaction cell equipped with a photon counting unit and a neodymium magnet. Magnetic beads, to which an anti-APnEOs monoclonal antibody was immobilized, were used as a solid support in an immunoassay. The introduction, trapping and release of the magnetic beads in and from the immunoreaction cell were controlled by means of a neodymium magnet and adjusting the flow of a carrier solution. The immunoassay was based on an indirect competitive immunoreaction of an anti-APnEOs monoclonal antibody immobilized on the magnetic beads with a sample APnEOs and a horseradish peroxidase (HRP)-labeled APnEOs in the same sample solution, and was based on the subsequent chemiluminscence reaction of HRP on the magnetic microbeads with a luminol solution containing hydrogen peroxide and p-iodophenol. The anti-APnEOs antibody was immobilized on the magnetic microbeads by coupling the antibody with the magnetic beads after activation of a carboxylate moiety on the surface of the magnetic beads that had been coated with a polylactic acid film. The antibody immobilized magnetic beads were introduced in the immunoreaction cell and trapped in it by the neodymium magnet, which was equipped beneath the immunoreaction cell. An APnEOs sample solution containing the HRP-labeled APnEOs at a constant concentration, and a luminol solution containing hydrogen peroxide and p-iodophenol were sequentially introduced into the immunoreaction cell, according to an SIA programmed sequence. Chemiluminescence emission was monitored by means of a photon counting unit located at the upper side of the immunoreaction cell by collecting the emitted light with a lens. A typical sigmoidal calibration curve was obtained, when the logarithm of the concentration of APnEOs was plotted against the chemiluminescence intensity as the number of photons in 100 ms using standard APnEOs sample solutions at various concentrations (0–1000 ppb) under optimum conditions. The lower detection limit defined as IC₈₀ is ca 10 ppb. The time required for analysis is less than 15 min per a sample. The present method was successfully applied to the determination of APnEOs in river water.     

A novel piezoelectric biosensor for the detection of phytohormone beta-indole acetic acid.

A novel piezoelectric immunosensor has been developed for the determination of beta-indole acetic acid (IAA) in dilute solutions. The detection is based on competitive immunoreaction between a hapten (IAA) and an antigen (IAA-BSA, hapten-protein conjugation) bound to an anti-IAA antibody, immobilized on a quartz crystal microbalance (QCM). The frequency change (y) of the sensor caused by antigen is linearly related to the logarithm of the concentration of IAA (x) in the range of 0.5 ng/ml - 5 microg/ml with a regression equation of the form y = -23x + 151 (r = 0.9937).     

Comparative study of strategies for antibody immobilization onto the surface of magnetic particles in pseudo-homogeneous enzyme immunoassay of aflatoxin B1

Pseudo-homogeneous enzyme immunoassay (EIA) of aflatoxin B1 (AFB1) was accomplished using anti-AFM1 monoclonal antibodies conjugated with magnetic particles (MPs). The assay includes the concentration of AFB1 from the test sample on the surface of the MP-antibody conjugate, the binding of the AFB1-peroxidase conjugate to free sites of the antibodies, the separation of the complexes that formed from unreacted components by means of magnetic field, and the evaluation of the enzymatic activity of MP-bound peroxidase. A comparative study of antibody conjugates, which were prepared by three different methods, namely, by physical adsorption on native MP and covalent binding to oleic acidor polystyrene-coated MPs, was performed. For these conjugates, the detection limits of EIA for AFB1 are 2.6, 0.4, and 0.6 ng/mL, respectively. The advantages of the pseudo-homogeneous EIA format as a tool for the highly sensitive control of toxic contaminants in food are the shorter time of incubation of immunoassay reagents (5 min; the total assay time is 20 min) and the possibility of concentrating the analyte from the test samples.     

Surface plasmon resonance-based trace detection of small molecules by competitive and signal enhancement immunoreaction

A surface plasmon resonance (SPR)-immunosensor for detection of the low molecular weight compound 2,4-dinitorophenol (DNP) at ultra-low concentration has been developed. The sensor strategy is based on a competitive immunoreaction between DNP and a DNP-protein conjugate, namely DNP-bovine serum albumin conjugate (DNP-BSA). Anti-DNP monoclonal antibody was immobilized on a gold thin-film coated SPR-sensor chip by means of a chemical coupling process. DNP-BSA, on contact with the anti-DNP antibody immobilized SPR-immunosensor chip causes an increase in the resonance angle of the sensor chip. The optimum concentration of immobilized antibody on the SPR-sensor chip is 100 μg mL⁻¹. The SPR-immunosensor response for free DNP determination using the competitive immunoreaction had a response time of ca. 15 min. Using this method, DNP could be determined in the concentration range 1 ppt to 1 ppb. The SPR signal for ppt levels of DNP was enhanced by a factor of three by subsequently treating immuno-bound DNP-BSA with a secondary anti-DNP antibody.     

Electrochemical Magnetoimmunosensing Approach for the Sensitive Detection of H9N2 Avian Influenza Virus Particles

A novel electrochemical magnetoimmunosensor for fast and ultrasensitive detection of H9N2 avian influenza virus particles (H9N2 AIV) was designed based on the combination of high‐efficiency immunomagnetic separation, enzyme catalytic amplification, and the biotin–streptavidin system. The reusable, homemade magneto Au electrode (M‐AuE) was designed and used for the direct sensing. Immunocomplex‐coated magnetic beads (IMBs) were easily accumulated on the surface of the M‐AuE to obtain the catalytically reduced electrochemical signal of H₂O₂ after the immunoreaction. The transducer was regenerated through a simple washing procedure, which made it possible to detect all the samples on a single electrode with higher reproducibility. The magnetic‐bead‐based electrochemical immunosensor showed better analytical performance than the planar‐electrode‐based immunosensor with the same sandwich construction. Amounts as low as 10 pg mL^?1 H9N2 AIV could be detected even in samples of chicken dung. This electrochemical magnetoimmunosensor not only provides a simple platform for the detection of the virus with high sensitivity, selectivity, and reproducibility but also shows great potential in the early diagnosis of diseases.