胶体金免疫层析方法快速检测腹泻性贝毒软海绵酸的初步研究

建立了赤潮毒素腹泻性贝毒软海绵酸的快速胶体金免疫层析检测方法。通过细胞融合,制备抗软海绵酸单克隆抗体,胶体金标记抗体,建立快速检测软海绵酸的免疫层析试纸条方法。检出限500 ng/mL(50 ng/条),探讨了影响测试方法的因素和提高灵敏度的可能手段。     

利用蛋白磷酸酶活力抑制法检测牡蛎体内的腹泻性贝毒

基于腹泻性贝毒(Diarrhetic Shellfish Poison,DSP)中大田软海绵酸(Okadaic acid,OA)和鳍藻毒素(Dinophysis toxins,DTXs)能够抑制蛋白磷酸酶活力的特点,人们建立了一种利用碱性蛋白磷酸酶活力变化检测贝类中大田软海绵酸毒性当量的生物化学测试方法。本实验利用该方法对威海出入境检验检疫局采集的3个牡蛎样品进行分析,结果表明:3个牡蛎样品中不含有OA和DTXs毒素,但水解后可检出OA毒性,其中两个牡蛎水解样品的毒性当量分别为1.81和1.21μg OA eq./kg贝组织(湿重)。     

酶联免疫吸附分析检测鳍藻毒素DTX1和DTX2

利用BALB/c小鼠腹水大量制备抗大田软海绵酸(Okadaic Acid,OA)的单克隆抗体,并以此抗体为探针建立了检测鳍藻毒素(Dinophysistoxins,DTXs)DTX1和DTX2的间接竞争酶联免疫吸附分析方法(Enzyme Linked Immunosorbent Assay,ELISA)。DTX1和DTX2各组分的标准曲线在一定范围内都有良好的线性范围和相关系数,最低检出浓度为0.53μg/L和0.45μg/L;批内和批间平均变异系数为6.18%、5.11%和7.28%、5.79%;加标样品平均回收率为76.4%、79.9%;OA与DTX1和DTX2的交叉反应率分别为53%和79%。结果表明,该方法可用于贝类样品中DTX1和DTX2的残留检测。     

液相色谱-串联质谱法同时测定贝类中大田软海绵酸、鳍藻毒素、蛤毒素和虾夷扇贝毒素

建立了同时测定贝类中大田软海绵酸(okadaic acid, OA)及其衍生物鳍藻毒素(dinophysistoxin-1, DTX-1)、蛤毒素(pectenotoxin-2, PTX-2)和虾夷扇贝毒素(yessotoxin, YTX)的液相色谱-串联质谱分析方法。样品经甲醇提取,固相萃取柱净化,C18色谱柱分离,经含甲酸和甲酸铵的乙腈-水溶液为流动相梯度洗脱,选择反应监测(SRM)模式检测,正、负离子切换扫描,基质标准校正,外标法定量。结果表明,OA、DTX-1和YTX的线性范围为2.0～200.0 μg/L,定量限(以信噪比(S/N)≥10计)为1.0 μg/kg; PTX-2的线性范围为1.0～100.0 μg/L,定量限为0.5 μg/kg;几种化合物的添加平均回收率为83.1%～105.7%,相对标准偏差(RSD)为3.16%～9.29%。成功应用本法对黄海灵山湾海域采集的贝类样品进行了分析,发现部分样品中含有大田软海绵酸、鳍藻毒素、蛤毒素和虾夷扇贝毒素。     

基于聚硫堇/亚甲基蓝和纳米金放大的免疫传感器检测贝类毒素大田软海绵酸

采用聚硫堇(PTH)修饰电极为传感界面提供一个生物修饰功能基质膜,借助纳米金(GNPs)的导电性、生物相容性与高比表面积特性实现抗体的有效固定,并以亚甲基蓝(MB)为电子媒介加速电极表面电化学反应的电子传递,构建了一种高灵敏的非标记电化学免疫传感器,用于贝类毒素大田软海绵酸(OA)的检测。当分子结构中含有羧基和酚基的OA与其抗体特异性结合后,生成以阴离子形式存在的抗原-抗体复合物,阻碍了传感器表面电子的传递,导致峰电流下降。利用免疫反应前后峰电流的变化,可对OA进行特异性识别和准确定量。在优化实验条件下,OA浓度的对数在0.2~100μg/L范围内与其峰电流的变化值(ΔI)呈线性相关,线性方程为ΔI=1.721 7+1.083 6lgρ,相关系数为0.992 0,检出限为0.1μg/L。该免疫传感器重现性好、特异性强,用于实际贝类样品的测定,回收率为85.3%~112%。     

基于聚硫堇/亚甲基蓝和纳米金放大的免疫传感器检测贝类毒素大田软海绵酸

采用聚硫堇(PTH)修饰电极为传感界面提供一个生物修饰功能基质膜,借助纳米金(GNPs)的导电性、生物相容性与高比表面积特性实现抗体的有效固定,并以亚甲基蓝(MB)为电子媒介加速电极表面电化学反应的电子传递,构建了一种高灵敏的非标记电化学免疫传感器,用于贝类毒素大田软海绵酸(OA)的检测。当分子结构中含有羧基和酚基的OA与其抗体特异性结合后,生成以阴离子形式存在的抗原-抗体复合物,阻碍了传感器表面电子的传递,导致峰电流下降。利用免疫反应前后峰电流的变化,可对OA进行特异性识别和准确定量。在优化实验条件下,OA浓度的对数在0.2~100 μg/L范围内与其峰电流的变化值(ΔI)呈线性相关,线性方程为ΔI=1.721 7+1.083 6lgρ,相关系数为0.992 0,检出限为0.1 μg/L。该免疫传感器重现性好、特异性强,用于实际贝类样品的测定,回收率为85.3%~112%。     

中药致肾毒性成分马兜铃酸A单抗制备及酶联免疫分析方法的建立

采用活化酯法,将马兜铃酸A分别与牛血清蛋白(BSA)和卵清蛋白(OVA)偶联,得到免疫抗原马兜铃酸A-BSA和包被抗原马兜铃酸A-OVA.利用马兜铃酸A-BSA免疫Bal b/c小鼠,制得鼠单克隆抗体1A11,单抗效价为2×104;单抗为IgG1类,轻链为κ型;与其结构类似物马兜铃酸B、C和D的交叉反应率分别为2.8%,3.5%和31.2%.基于抗马兜铃酸A单克隆抗体的间接竞争酶联免疫分析方法(icELISA)的IC50为1.9 μg/L,检测范围为0.5～7.5 μg/L.icELISA添加回收率为86%～97%,相对标准偏差在5.2%～11.1%之间.利用所建立的icELISA测定了6个中药材和5个中成药中马兜铃酸A的含量,并用高效液相色谱法(HPLC)进行了验证,其中关木通、广防己、天仙藤、马兜铃和青木香中均检测出马兜铃酸A,而川木通和5个中成药中未检测到马兜铃酸A.结果表明: 本方法可用于中药中马兜铃酸A的快速检测.     

大田软海绵酸和鳍藻毒素-1纯化样品的分析

采用高效液相色谱-荧光检测、高效液相色谱-紫外检测、流动注射进样-质谱检测和高效液相色谱-质谱联用分析等方法对从有毒利玛原甲藻(Prorocentrum lima Dodge)中分离纯化的大田软海绵酸(OA)和鳍藻毒素-1(DTX1)毒素样品进行定性鉴定和纯度分析,为毒素标准品的制备提供材料和方法依据.通过柱前衍生、H...     

液相色谱-串联质谱法检测贝类产品中腹泻性贝类毒素

建立了贝类组织中2种腹泻性贝毒(Diamletic shellfish Poisobing,DSP)聚醚类毒素-大田软海绵酸(Okadaic acid,OA)和鳍藻毒素(Dinophysistoxin-1,DTX-1)的高效液相色谱-串联质谱分析方法.贝类样品经80%甲醇溶液提取,经正己烷脱脂和HLB固相萃取柱净化,采...     

原位交联羧甲基壳聚糖/碳酸钙凝胶海绵的制备及其止血性能研究

以羧甲基壳聚糖(CMCS)、碳酸钙(CaCO₃)、葡萄糖酸内酯(GDL)和甘油(GLY)为原料，通过原位相转变制备水凝胶，经冷冻干燥工艺得到止血海绵，用于躯体非压迫性出血。通过扫描电镜、吸水率、孔隙率、溶血实验和全血凝固时间测试分别对海绵的理化性能、血液安全性、止血性能进行研究。当CaCO₃与CMCS的质量比为15%时，制得的海绵综合性能最好。该海绵呈疏松多孔片层状，止血时间较医用棉纱布材料缩短了35%,无血液毒性，是一种优良的止血海绵材料。     

A novel adenosine-based molecular beacon probe for room temperature nucleic acid rapid detection in cotton thread device

We used cotton thread as substrate to develop a novel room temperature DNA detection device for low-cost, sensitive and rapid detection of a human genetic disease, hereditary tyrosinemia type I related DNA sequences. A novel adenosine based molecular beacon (ABMB) probe modified on gold nanoparticle was used as reporter probe. In the presence of coralyne, a small molecule which can react with adenosines, the ABMB would form a hairpin structure just like traditional molecular beacon used extensively. In the presence of target DNA sequences, the hairpin structure of ABMB modified on gold nanoparticles will be opened and the biotin group modified at one end of the DNA probes will be released and react with the streptavidin immobilized on the test zone of the cotton thread. The response of the thread based DNA test device is linear over the range of 2.5–100 nM complementary DNA. The ability of our developed device for discriminating the single base mismatched DNA related to a human genetic disease, hereditary tyrosinemia type I, was improved comparing with previous report. It is worth mentioning that the whole assay procedure for DNA test is performed under room temperature which simplified the assay procedures greatly.     

Rapid pretreatment-free immunochromatographic assay of chloramphenicol in milk

A pretreatment-free immunochromatographic assay for detection of chloramphenicol (CAP) in milk was developed. The assay is based on competition between CAP molecules in the sample and immobilized CAP-protein conjugate for binding to monoclonal anti-CAP antibodies conjugated with colloidal gold particles (average diameter 30 nm). The assay is carried out in the course of sample flowing along test strip with immobilized reactants, and its results can be detected by the naked eye or by a photometric device. Effect of the concentration of immunoreactants on assay characteristics was studied. The assay protocol with maximal sensitivity and reliability was optimized using measured values of brightness of lines. Detection limit for CAP is 10 ng mL⁻¹. Assay duration is 10 min, and it can be carried out at room temperature without any additional devices and reactants. The developed test strip has been applied to CAP detection in dairy products.     

Development of a one step strip test for the detection of sulfadimidine residues.

The one step strip test described is a competitive immunoassay in which the detector reagent consists of colloidal gold particles coated with affinity purified polyclonal anti-sulfadimidine (SDD) antibodies. The capture reagent in the assay is an SDD-ovalbumin conjugate which is immobilised on the lateral flow membrane of the test device. In the test procedure, 150 microliters (four drops) of a liquid sample (buffer, urine or milk) are brought into the sample well of the test device and allowed to migrate over the membrane. The more analyte present in the sample, the more effectively it will compete with the SDD immobilised on the membrane for binding to the limited amount of antibodies of the detector reagent. A sufficient amount of SDD in the sample will therefore prevent the binding of the detector reagent to the SDD immobilised on the membrane. Therefore, a positive sample will not show a test line in the read-out zone. With spiked buffer or calf urine this was obtained at a level of > 10 ng ml-1 of SDD and with spiked (diluted) fresh cow milk at a level > 20 ng ml-1 of SDD. At these levels, the test is applicable only as a qualitative assay. The presence or absence of a test line indicates lower or higher levels of SDD, respectively. The major advantages of the one step strip test are that results can be obtained within 10 min and that all reagents are included in the test device.     

Novel gold nanoparticle trimer reporter probe combined with dry-reagent cotton thread immunoassay device for rapid human ferritin test

We reported here for the first time on the use of cotton thread combined with novel gold nanoparticle trimer reporter probe for low-cost, sensitive and rapid detection of a lung cancer related biomarker, human ferritin. A model system comprising ferritin as an analyte and a pair of monoclonal antibodies was used to demonstrate the proof-of-concept on the dry-reagent natural cotton thread immunoassay device. Results indicated that the using of novel gold nanoparticle trimer reporter probe greatly improved the sensitivity comparing with traditional gold nanoparticle reporter probe on the cotton thread immunoassay device. The assay avoids multiple incubation and washing steps performed in most conventional protein analyses. Although qualitative tests are realized by observing the color change of the test zone, quantitative data are obtained by recording the optical responses of the test zone with a commercial scanner and corresponding analysis software. Under optimal conditions, the cotton thread immunoassay device was capable of measuring 10 ng/mL human ferritin under room temperature which is sensitive enough for clinical diagnosis. Moreover, the sample solution employed in the assays is just 8 μL, which is much less than traditional lateral flow strip based biosensors.     

A simple double-bead sandwich assay for protein detection in serum using UV-vis spectroscopy

In this study a double-bead sandwich assay, employing magnetic nanoparticles and gold nanoparticles is proposed. The magnetic nanoparticles allow specific capturing of the analyte in biological samples, while the optical properties of the gold nanoparticles provide the signal transduction. We demonstrated that a major improvement in the assay sensitivity was obtained by selecting an optimal gold nanoparticle size (60 nm). A detection limit of 5-8 ng/mL, a sensitivity of 0.6-0.8 (pg/mL)⁻¹ and a dynamic range of 3 orders of magnitude were achieved without any further amplification using the detection of prostate specific antigen in serum as a model system. The proposed assay has the ability to be easily implemented within a microfluidic device for point-of-care applications whereby the readout can be executed by a fast and cheap optical measurement.     

用于乙肝表面抗原检测的压电免疫传感器的研制

研制了一种用于乙肝表面抗原（ＨＢｓＡｇ）检测的新型传感器———石英压电免疫传感器。采用聚乙烯亚胺粘附和戊二醛交联法在金电极上固定抗体蛋白，对固定化过程进行了监测。ＨＢｓＡｇ含量的检测范围为１～４０ｍｇ／Ｌ。使用过的电极用０２ｍｏｌ／Ｌ乙醇胺（ｐＨ＝８）解吸，可重复使用。将此传感器用于实际血清样品的检测，与酶联免疫吸附法所得结果吻合。     

Gold nanoparticle-based immunochromatographic assay for the detection of 7-aminoclonazepam in urine

An analytical system of immunochromatographic assay based on gold nanoparticles was developed for the detection of 7-aminoclonazepam (7-ACLZ) in human urine. The qualitative assay was based on the competitive immunoassay using anti-7-ACLZ polyclonal antibody (PcAb) and a detector reagent that contains colloidal gold particles coated with anti-7-ACLZ PcAb. Nitrocellulose membrane was separately immobilised with goat anti-rabbit IgG (control line) and 7-ACLZ-OVA conjugate (test line). The sensitivity of the strip was tested for detecting 7-ACLZ spiked in urine and each specimen was independently measured by liquid chromatography tandem mass spectrometry. Good correlation was showed by the recovery results. The limit of detection for the strip test in urine was 100 ng mL^?1. The assay can be applied to the rapid detection of 7-ACLZ with the short testing time.     

Competitive immunochromatographic assay for the detection of the organophosphorus pesticide chlorpyrifos

An immunochromatographic assay (ICA) based on competitive antigen-coated format using colloidal gold as the label was developed for the detection of the organophosphorus insecticide chlorpyrifos. The ICA test strip consisted of a membrane with a detection zone, a sample pad and an absorbent pad. The membrane was separately coated with chlorpyrifos Hapten-OVA conjugate (test line) and anti-mouse IgG (control line). Based on the fact that the competition is between the migrating analyte in the sample and the analyte hapten immobilized on the test strip for the binding sites of the antibody-colloidal gold (Ab-CG) conjugate migrating on the test strip, this study suggests that the relative migration speed between the two migrating substances is a critically important factor for the sensitive detection by competitive ICA. This criterion was utilized for the confirmation of appropriateness of a nitrocellulose (NC) membrane for chlorpyrifos ICA. The detection limit of the ICA for chlorpyrifos standard and chlorpyrifos spiked into agricultural samples were 10 and 50 ng mL(-1), respectively. The assay time for the ICA test was less than 10 min, suitable for rapid on-site testing of chlorpyrifos.     

A novel enhancement assay for immunochromatographic test strips using gold nanoparticles

The immunochromatographic assay is a well-known and convenient diagnostic system. In this report, the development of a novel enhancement assay for the test strips is described. Additionally, this highly sensitive immunochromatographic assay was applied to detect human chorionic gonadotropin hormone (HCG) as the model case. The primary antibody-conjugated gold nanoparticles were used as the enhancer of the standard method. The primary antibodies were immobilized within a defined detection zone (test line) on the diagnostic nitrocellulose membrane. The secondary antibodies were conjugated with colloidal gold nanoparticles. In combination with an effective sample pretreatment, the gold-conjugated antibodies and the primary antibodies formed a sandwich complex with the target protein. Within the test line, the sandwich complex was immobilized, and furthermore, concentrated by the enhancer resulting in a localized surface plasmon resonance (LSPR) phenomenon and a distinct red color on the test line. The intensity of color of the red test line (signal intensity), which correlated directly with the concentration of the target protein in the standard or spiked samples, was assessed visually and by computer image analysis using a three-determination analysis. Under optimum conditions, the limit of detection (LOD) for HCG assay was 1 pg/mL. When using human serum, 10 pg/mL of HCG could be detected. We have also spiked total prostate-specific antigen (TPSA) in female serum. The LOD for TPSA was determined as 0.2 ng/mL. With this method, the quantitative determination of the target protein could be completed in less than 15 min. Our novel immunochromatographic strips using the enhancing method based on LSPR of gold nanoparticles are useful as a rapid and simple screening method for the detection of important analytes for medical applications, environmental monitoring, food control, and biosecurity.