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Sample records for field-portable immunoassay instruments

  1. Field-Portable Immunoassay Instruments and Reagents to Measure Chelators and Mobile Forms of Uranium

    International Nuclear Information System (INIS)

    Blake, Diane A.

    2006-01-01

    Progress Report Date: 01/23/06 (report delayed due to Hurricane Katrina) Report of results to date: The goals of this 3-year project are to: (1) update and successfully deploy our present immunosensors at DOE sites; (2) devise immunosensor-based assays for Pb(II), Hg(II), chelators, and/or Cr(III) in surface and groundwater; and (3) develop new technologies in antibody engineering that will enhance this immunosensor program. Note: Work on this project was temporarily disrupted when Hurricane Katrina shut down the University on August 29, 2005. While most of the reagents stored in our refrigerators and freezers were destroyed, all of our hybridoma cell lines were saved because they had been stored in liquid nitrogen. We set up new tissue culture reactors with the hybridomas that synthesize the anti-uranium antibodies, and are purifying new monoclonal antibodies from these culture supernatants. Both the in-line and the field-portable sensor were rescued from our labs in New Orleans in early October, and we continued experiments with these sensors in the temporary laboratory we set up in Hammond, LA at Southeastern Louisiana University

  2. A Field-Portable X-Ray Fluorescence Instrument: Design and Applications

    International Nuclear Information System (INIS)

    Civici, Nikolla

    2007-01-01

    The field portable XRF (FPXRF) spectrometer is composed of a measuring head that holds the detector (Si-PIN) and the excitation sources (Cd-109 and Am-241) and the spectrum acquisition system. The application of this system for the analysis of cultural heritage artifacts will be presented and discussed

  3. Field-portable high-resolution EDXRF analysis with HgI2-detector-based instrumentation

    International Nuclear Information System (INIS)

    Berry, P.F.; Little, S.R.; Voots, G.R.

    1992-01-01

    Energy dispersive x-ray fluorescence (EDXRF) analysis is well known for its efficient use of x-ray detector technology for simultaneous multielement determination. Low-intensity excitation, such as from a radioisotope source, can thus be employed and has enabled the design of many types of truly portable EDXRF instrumentation. Portable design, however, has not been without significant compromise in analytical performance because of the limited x-ray resolving power of prior detection methods, except by the use of a cryogenically operated detector. The developments we refer to stem from the use of a comparatively new x-ray detection device fabricated from mercuric iodide (HgI 2 ). For this detector, only a modest degree of cooling is required to achieve an energy resolution of > 300 eV. Two field-portable instrument designs of different hand-held measurement probe configurations are available that have applications for industrial quality assurance and environmental screening

  4. Field portable low temperature porous layer open tubular cryoadsorption headspace sampling and analysis part I: Instrumentation.

    Science.gov (United States)

    Bruno, Thomas J

    2016-01-15

    Building on the successful application in the laboratory of PLOT-cryoadsorption as a means of collecting vapor (or headspace) samples for chromatographic analysis, in this paper a field portable apparatus is introduced. This device fits inside of a briefcase (aluminum tool carrier), and can be easily transported by vehicle or by air. The portable apparatus functions entirely on compressed air, making it suitable for use in locations lacking electrical power, and for use in flammable and explosive environments. The apparatus consists of four aspects: a field capable PLOT-capillary platform, the supporting equipment platform, the service interface between the PLOT-capillary and the supporting equipment, and the necessary peripherals. Vapor sampling can be done with either a hand piece (containing the PLOT capillary) or with a custom fabricated standoff module. Both the hand piece and the standoff module can be heated and cooled to facilitate vapor collection and subsequent vapor sample removal. The service interface between the support platform and the sampling units makes use of a unique counter current approach that minimizes loss of cooling and heating due to heat transfer with the surroundings (recuperative thermostatting). Several types of PLOT-capillary elements and sampling probes are described in this report. Applications to a variety of samples relevant to forensic and environmental analysis are discussed in a companion paper. Published by Elsevier B.V.

  5. Moving your laboratories to the field – Advantages and limitations of the use of field portable instruments in environmental sample analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gałuszka, Agnieszka, E-mail: Agnieszka.Galuszka@ujk.edu.pl [Geochemistry and the Environment Division, Institute of Chemistry, Jan Kochanowski University, 15G Świętokrzyska St., 25-406 Kielce (Poland); Migaszewski, Zdzisław M. [Geochemistry and the Environment Division, Institute of Chemistry, Jan Kochanowski University, 15G Świętokrzyska St., 25-406 Kielce (Poland); Namieśnik, Jacek [Department of Analytical Chemistry, Chemical Faculty, Gdańsk University of Technology (GUT), 11/12 G. Narutowicz St., 80-233 Gdańsk (Poland)

    2015-07-15

    The recent rapid progress in technology of field portable instruments has increased their applications in environmental sample analysis. These instruments offer a possibility of cost-effective, non-destructive, real-time, direct, on-site measurements of a wide range of both inorganic and organic analytes in gaseous, liquid and solid samples. Some of them do not require the use of reagents and do not produce any analytical waste. All these features contribute to the greenness of field portable techniques. Several stationary analytical instruments have their portable versions. The most popular ones include: gas chromatographs with different detectors (mass spectrometer (MS), flame ionization detector, photoionization detector), ultraviolet–visible and near-infrared spectrophotometers, X-ray fluorescence spectrometers, ion mobility spectrometers, electronic noses and electronic tongues. The use of portable instruments in environmental sample analysis gives a possibility of on-site screening and a subsequent selection of samples for routine laboratory analyses. They are also very useful in situations that require an emergency response and for process monitoring applications. However, quantification of results is still problematic in many cases. The other disadvantages include: higher detection limits and lower sensitivity than these obtained in laboratory conditions, a strong influence of environmental factors on the instrument performance and a high possibility of sample contamination in the field. This paper reviews recent applications of field portable instruments in environmental sample analysis and discusses their analytical capabilities. - Highlights: • Field portable instruments are widely used in environmental sample analysis. • Field portable instruments are indispensable for analysis in emergency response. • Miniaturization of field portable instruments reduces resource consumption. • In situ analysis is in agreement with green analytical chemistry

  6. Moving your laboratories to the field – Advantages and limitations of the use of field portable instruments in environmental sample analysis

    International Nuclear Information System (INIS)

    Gałuszka, Agnieszka; Migaszewski, Zdzisław M.; Namieśnik, Jacek

    2015-01-01

    The recent rapid progress in technology of field portable instruments has increased their applications in environmental sample analysis. These instruments offer a possibility of cost-effective, non-destructive, real-time, direct, on-site measurements of a wide range of both inorganic and organic analytes in gaseous, liquid and solid samples. Some of them do not require the use of reagents and do not produce any analytical waste. All these features contribute to the greenness of field portable techniques. Several stationary analytical instruments have their portable versions. The most popular ones include: gas chromatographs with different detectors (mass spectrometer (MS), flame ionization detector, photoionization detector), ultraviolet–visible and near-infrared spectrophotometers, X-ray fluorescence spectrometers, ion mobility spectrometers, electronic noses and electronic tongues. The use of portable instruments in environmental sample analysis gives a possibility of on-site screening and a subsequent selection of samples for routine laboratory analyses. They are also very useful in situations that require an emergency response and for process monitoring applications. However, quantification of results is still problematic in many cases. The other disadvantages include: higher detection limits and lower sensitivity than these obtained in laboratory conditions, a strong influence of environmental factors on the instrument performance and a high possibility of sample contamination in the field. This paper reviews recent applications of field portable instruments in environmental sample analysis and discusses their analytical capabilities. - Highlights: • Field portable instruments are widely used in environmental sample analysis. • Field portable instruments are indispensable for analysis in emergency response. • Miniaturization of field portable instruments reduces resource consumption. • In situ analysis is in agreement with green analytical chemistry

  7. Field-Portable Immunoassay Instruments and Reagents to Measure Chelators and Mobile Forms of Uranium

    International Nuclear Information System (INIS)

    Blake, Diane A.

    2003-01-01

    The goals for the 3-year project period are (1) to test and validate the present uranium sensor and develop protocols for its use at the NABIR Field Research Center; (2) to develop new reagents that will provide superior performance for the present hand-held immunosensor; and (3) to develop new antibodies that will permit this sensor to also measure other environmental contaminants (chromium, mercury, and/or DTPA). Sensor design modifications are underway via international collaborations. New reagents that will provide superior performance for the present hand-held immunosensor are being prepared and tested. New methods have been developed, to produce recombinant forms of metal-specific monoclonal antibodies for use with the sensor. Site-directed mutagenesis experiments are underway to determine the mechanisms of binding. Immunization experiments with sheep and rabbits to develop new recombinant forms of antibodies to metal-chelate complexes (chromium, mercury, and/or DTPA) have been initiated

  8. Design and development of a highly sensitive, field portable plasma source instrument for on-line liquid stream monitoring and real-time sample analysis

    International Nuclear Information System (INIS)

    Duan, Yixiang; Su, Yongxuan; Jin, Zhe; Abeln, Stephen P.

    2000-01-01

    The development of a highly sensitive, field portable, low-powered instrument for on-site, real-time liquid waste stream monitoring is described in this article. A series of factors such as system sensitivity and portability, plasma source, sample introduction, desolvation system, power supply, and the instrument configuration, were carefully considered in the design of the portable instrument. A newly designed, miniature, modified microwave plasma source was selected as the emission source for spectroscopy measurement, and an integrated small spectrometer with a charge-coupled device detector was installed for signal processing and detection. An innovative beam collection system with optical fibers was designed and used for emission signal collection. Microwave plasma can be sustained with various gases at relatively low power, and it possesses high detection capabilities for both metal and nonmetal pollutants, making it desirable to use for on-site, real-time, liquid waste stream monitoring. An effective in situ sampling system was coupled with a high efficiency desolvation device for direct-sampling liquid samples into the plasma. A portable computer control system is used for data processing. The new, integrated instrument can be easily used for on-site, real-time monitoring in the field. The system possesses a series of advantages, including high sensitivity for metal and nonmetal elements; in situ sampling; compact structure; low cost; and ease of operation and handling. These advantages will significantly overcome the limitations of previous monitoring techniques and make great contributions to environmental restoration and monitoring. (c)

  9. Identification of V-type nerve agents in vapor samples using a field-portable capillary gas chromatography/membrane-interfaced electron ionization quadrupole mass spectrometry instrument with Tri-Bed concentrator and fluoridating conversion tube.

    Science.gov (United States)

    Ohrui, Y; Nagoya, T; Kurimata, N; Sodeyama, M; Seto, Y

    2017-07-01

    A field-portable gas chromatography-mass spectrometry (GC-MS) system (Hapsite ER) was evaluated for the detection of nonvolatile V-type nerve agents (VX and Russian VX (RVX)) in the vapor phase. The Hapsite ER system consists of a Tri-Bed concentrator gas sampler, a nonpolar low thermal-mass capillary GC column and a hydrophobic membrane-interfaced electron ionization quadrupole mass spectrometer evacuated by a non-evaporative getter pump. The GC-MS system was attached to a VX-G fluoridating conversion tube containing silver nitrate and potassium fluoride. Sample vapors of VX and RVX were converted into O-ethyl methylphosphonofluoridate (EtGB) and O-isobutyl methylphosphonofluoridate (iBuGB), respectively. These fluoridated derivatives were detected within 10 min. No compounds were detected when the VX and RVX samples were analyzed without the conversion tube. A vapor sample of tabun (GA) was analyzed, in which GA and O-ethyl N,N-dimethylphosphoramidofluoridate were detected. The molar recovery percentages of EtGB and iBuGB from VX and RVX vapors varied from 0.3 to 17%, which was attributed to variations in the vaporization efficiency of the glass vapor container. The conversion efficiencies of the VX-G conversion tube for VX and RVX to their phosphonate derivatives were estimated to be 40%. VX and RVX vapors were detected at concentrations as low as 0.3 mg m -3 . Gasoline vapor was found to interfere with the analyses of VX and RVX. In the presence of 160 mg m -3 gasoline, the detection limits of VX and RVX vapor were increased to 20 mg m -3 . Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  10. Identification of chemical warfare agents from vapor samples using a field-portable capillary gas chromatography/membrane-interfaced electron ionization quadrupole mass spectrometry instrument with Tri-Bed concentrator.

    Science.gov (United States)

    Nagashima, Hisayuki; Kondo, Tomohide; Nagoya, Tomoki; Ikeda, Toru; Kurimata, Naoko; Unoke, Shohei; Seto, Yasuo

    2015-08-07

    A field-portable gas chromatograph-mass spectrometer (Hapsite ER system) was evaluated for the detection of chemical warfare agents (CWAs) in the vapor phase. The system consisted of Tri-Bed concentrator gas sampler (trapping time: 3s(-1)min), a nonpolar low thermal-mass capillary gas chromatography column capable of raising temperatures up to 200°C, a hydrophobic membrane-interfaced electron ionization quadrupole mass spectrometer evacuated by a non-evaporative getter pump for data acquisition, and a personal computer for data analysis. Sample vapors containing as little as 22μg sarin (GB), 100μg soman (GD), 210μg tabun (GA), 55μg cyclohexylsarin (GF), 4.8μg sulfur mustard, 390μg nitrogen mustard 1, 140μg of nitrogen mustard 2, 130μg nitrogen mustard 3, 120μg of 2-chloroacetophenone and 990μg of chloropicrin per cubic meter could be confirmed after Tri-Bed micro-concentration (for 1min) and automated AMDIS search within 12min. Using manual deconvolution by background subtraction of neighboring regions on the extracted ion chromatograms, the above-mentioned CWAs could be confirmed at lower concentration levels. The memory effects were also examined and we found that blister agents showed significantly more carry-over than nerve agents. Gasoline vapor was found to interfere with the detection of GB and GD, raising the concentration limits for confirmation in the presence of gasoline by both AMDIS search and manual deconvolution; however, GA and GF were not subject to interference by gasoline. Lewisite 1, and o-chlorobenzylidene malononitrile could also be confirmed by gas chromatography, but it was hard to quantify them. Vapors of phosgene, chlorine, and cyanogen chloride could be confirmed by direct mass spectrometric detection at concentration levels higher than 2, 140, and 10mg/m(3) respectively, by bypassing the micro-concentration trap and gas chromatographic separation. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Analytical evaluation of the automated galectin-3 assay on the Abbott ARCHITECT immunoassay instruments.

    Science.gov (United States)

    Gaze, David C; Prante, Christian; Dreier, Jens; Knabbe, Cornelius; Collet, Corinne; Launay, Jean-Marie; Franekova, Janka; Jabor, Antonin; Lennartz, Lieselotte; Shih, Jessie; del Rey, Jose Manuel; Zaninotto, Martina; Plebani, Mario; Collinson, Paul O

    2014-06-01

    Galectin-3 is secreted from macrophages and binds and activates fibroblasts forming collagen. Tissue fibrosis is central to the progression of chronic heart failure (CHF). We performed a European multicentered evaluation of the analytical performance of the two-step routine and Short Turn-Around-Time (STAT) galectin-3 immunoassay on the ARCHITECT i1000SR, i2000SR, and i4000SR (Abbott Laboratories). We evaluated the assay precision and dilution linearity for both routine and STAT assays and compared serum and plasma, and fresh vs. frozen samples. The reference interval and biological variability were also assessed. Measurable samples were compared between ARCHITECT instruments and between the routine and STAT assays and also to a galectin-3 ELISA (BG Medicine). The total assay coefficient of variation (CV%) was 2.3%-6.2% and 1.7%-7.4% for the routine and STAT assays, respectively. Both assays demonstrated linearity up to 120 ng/mL. Galectin-3 concentrations were higher in plasma samples than in serum samples and correlated well between fresh and frozen samples (R=0.997), between the routine and STAT assays, between the ARCHITECT i1000 and i2000 instruments and with the galectin-3 ELISA. The reference interval on 627 apparently healthy individuals (53% male) yielded upper 95th and 97.5th percentiles of 25.2 and 28.4 ng/mL, respectively. Values were significantly lower in subjects younger than 50 years. The galectin-3 routine and STAT assays on the Abbott ARCHITECT instruments demonstrated good analytical performance. Further clinical studies are required to demonstrate the diagnostic and prognostic potential of this novel marker in patients with CHF.

  12. A next generation field-portable goniometer system

    Science.gov (United States)

    Harms, Justin D.; Bachmann, Charles M.; Faulring, Jason W.; Ruiz Torres, Andres J.

    2016-05-01

    Various field portable goniometers have been designed to capture in-situ measurements of a materials bi-directional reflectance distribution function (BRDF), each with a specific scientific purpose in mind.1-4 The Rochester Institute of Technology's (RIT) Chester F. Carlson Center for Imaging Science recently created a novel instrument incorporating a wide variety of features into one compact apparatus in order to obtain very high accuracy BRDFs of short vegetation and sediments, even in undesirable conditions and austere environments. This next generation system integrates a dual-view design using two VNIR/SWIR pectroradiometers to capture target reflected radiance, as well as incoming radiance, to provide for better optical accuracy when measuring in non-ideal atmospheric conditions or when background illumination effects are non-negligible. The new, fully automated device also features a laser range finder to construct a surface roughness model of the target being measured, which enables the user to include inclination information into BRDF post-processing and further allows for roughness effects to be better studied for radiative transfer modeling. The highly portable design features automatic leveling, a precision engineered frame, and a variable measurement plane that allow for BRDF measurements on rugged, un-even terrain while still maintaining true angular measurements with respect to the target, all without sacrificing measurement speed. Despite the expanded capabilities and dual sensor suite, the system weighs less than 75 kg, which allows for excellent mobility and data collection on soft, silty clay or fine sand.

  13. Field-portable Capillary Electrophoresis Instrument with Conductivity Detection

    International Nuclear Information System (INIS)

    Zhang, H F; Liu, X W; Wang, W; Wang, X L; Tian, L

    2006-01-01

    In this paper a novel capillary electrophoresis chip (CEC) is presented with integrated platinum electrodes and simplified conductivity detector. CEC is fabricated by the method of mechanical modification with probe on organic glass. Capillary electrophoresis chip can rapidly completed ion separation by simulation of concentration distribution and zone-broadening. Detection circuit is simple which can detect pA order current. This system has those advantages such as small volume, low power consumption and linearity, and well suit for field analysis

  14. Field-portable pixel super-resolution colour microscope.

    Directory of Open Access Journals (Sweden)

    Alon Greenbaum

    Full Text Available Based on partially-coherent digital in-line holography, we report a field-portable microscope that can render lensfree colour images over a wide field-of-view of e.g., >20 mm(2. This computational holographic microscope weighs less than 145 grams with dimensions smaller than 17×6×5 cm, making it especially suitable for field settings and point-of-care use. In this lensfree imaging design, we merged a colorization algorithm with a source shifting based multi-height pixel super-resolution technique to mitigate 'rainbow' like colour artefacts that are typical in holographic imaging. This image processing scheme is based on transforming the colour components of an RGB image into YUV colour space, which separates colour information from brightness component of an image. The resolution of our super-resolution colour microscope was characterized using a USAF test chart to confirm sub-micron spatial resolution, even for reconstructions that employ multi-height phase recovery to handle dense and connected objects. To further demonstrate the performance of this colour microscope Papanicolaou (Pap smears were also successfully imaged. This field-portable and wide-field computational colour microscope could be useful for tele-medicine applications in resource poor settings.

  15. Fully automated laboratory and field-portable goniometer used for performing accurate and precise multiangular reflectance measurements

    Science.gov (United States)

    Harms, Justin D.; Bachmann, Charles M.; Ambeau, Brittany L.; Faulring, Jason W.; Ruiz Torres, Andres J.; Badura, Gregory; Myers, Emily

    2017-10-01

    Field-portable goniometers are created for a wide variety of applications. Many of these applications require specific types of instruments and measurement schemes and must operate in challenging environments. Therefore, designs are based on the requirements that are specific to the application. We present a field-portable goniometer that was designed for measuring the hemispherical-conical reflectance factor (HCRF) of various soils and low-growing vegetation in austere coastal and desert environments and biconical reflectance factors in laboratory settings. Unlike some goniometers, this system features a requirement for "target-plane tracking" to ensure that measurements can be collected on sloped surfaces, without compromising angular accuracy. The system also features a second upward-looking spectrometer to measure the spatially dependent incoming illumination, an integrated software package to provide full automation, an automated leveling system to ensure a standard frame of reference, a design that minimizes the obscuration due to self-shading to measure the opposition effect, and the ability to record a digital elevation model of the target region. This fully automated and highly mobile system obtains accurate and precise measurements of HCRF in a wide variety of terrain and in less time than most other systems while not sacrificing consistency or repeatability in laboratory environments.

  16. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT - FIELD PORTABLE GAS CHROMATOGRAPH/MASS SPECTROMETER - VIKING INSTRUMENTS CORPORATION

    Science.gov (United States)

    The performance evaluation of innovative and alternative environmental technologies is an integral part of the U.S. Environmental Protection Agency's (EPA) mission. Early efforts focused on evaluation technologies that supported the implementation of the Clean Air and Clean Wate...

  17. Laser-induced breakdown spectroscopy - An emerging chemical sensor technology for real-time field-portable, geochemical, mineralogical, and environmental applications

    International Nuclear Information System (INIS)

    Harmon, Russell S.; DeLucia, Frank C.; McManus, Catherine E.; McMillan, Nancy J.; Jenkins, Thomas F.; Walsh, Marianne E.; Miziolek, Andrzej

    2006-01-01

    Laser induced breakdown spectroscopy (LIBS) is a simple spark spectrochemical sensor technology in which a laser beam is directed at a sample surface to create a high-temperature microplasma and a detector used to collect the spectrum of light emission and record its intensity at specific wavelengths. LIBS is an emerging chemical sensor technology undergoing rapid advancement in instrumentation capability and in areas of application. Attributes of a LIBS sensor system include: (i) small size and weight; (ii) technologically mature, inherently rugged, and affordable components; (iii) real-time response; (iv) in situ analysis with no sample preparation required; (v) a high sensitivity to low atomic weight elements which are difficult to determine by other field-portable sensor techniques, and (vi) point sensing or standoff detection. Recent developments in broadband LIBS provide the capability for detection at very high resolution (0.1 nm) of all elements in any unknown target material because all chemical elements emit in the 200-980 nm spectral region. This progress portends a unique potential for the development of a rugged and reliable field-portable chemical sensor that has the potential to be utilized in variety of geochemical, mineralogical, and environmental applications

  18. Field Portable Low Temperature Porous Layer Open Tubular Cryoadsorption Headspace Sampling and Analysis Part II: Applications*

    Science.gov (United States)

    Harries, Megan; Bukovsky-Reyes, Santiago; Bruno, Thomas J.

    2016-01-01

    This paper details the sampling methods used with the field portable porous layer open tubular cryoadsorption (PLOT-cryo) approach, described in Part I of this two-part series, applied to several analytes of interest. We conducted tests with coumarin and 2,4,6-trinitrotoluene (two solutes that were used in initial development of PLOT-cryo technology), naphthalene, aviation turbine kerosene, and diesel fuel, on a variety of matrices and test beds. We demonstrated that these analytes can be easily detected and reliably identified using the portable unit for analyte collection. By leveraging efficiency-boosting temperature control and the high flow rate multiple capillary wafer, very short collection times (as low as 3 s) yielded accurate detection. For diesel fuel spiked on glass beads, we determined a method detection limit below 1 ppm. We observed greater variability among separate samples analyzed with the portable unit than previously documented in work using the laboratory-based PLOT-cryo technology. We identify three likely sources that may help explain the additional variation: the use of a compressed air source to generate suction, matrix geometry, and variability in the local vapor concentration around the sampling probe as solute depletion occurs both locally around the probe and in the test bed as a whole. This field-portable adaptation of the PLOT-cryo approach has numerous and diverse potential applications. PMID:26726934

  19. Field portable low temperature porous layer open tubular cryoadsorption headspace sampling and analysis part II: Applications.

    Science.gov (United States)

    Harries, Megan; Bukovsky-Reyes, Santiago; Bruno, Thomas J

    2016-01-15

    This paper details the sampling methods used with the field portable porous layer open tubular cryoadsorption (PLOT-cryo) approach, described in Part I of this two-part series, applied to several analytes of interest. We conducted tests with coumarin and 2,4,6-trinitrotoluene (two solutes that were used in initial development of PLOT-cryo technology), naphthalene, aviation turbine kerosene, and diesel fuel, on a variety of matrices and test beds. We demonstrated that these analytes can be easily detected and reliably identified using the portable unit for analyte collection. By leveraging efficiency-boosting temperature control and the high flow rate multiple capillary wafer, very short collection times (as low as 3s) yielded accurate detection. For diesel fuel spiked on glass beads, we determined a method detection limit below 1 ppm. We observed greater variability among separate samples analyzed with the portable unit than previously documented in work using the laboratory-based PLOT-cryo technology. We identify three likely sources that may help explain the additional variation: the use of a compressed air source to generate suction, matrix geometry, and variability in the local vapor concentration around the sampling probe as solute depletion occurs both locally around the probe and in the test bed as a whole. This field-portable adaptation of the PLOT-cryo approach has numerous and diverse potential applications. Published by Elsevier B.V.

  20. Report on a field-portable VME-based distributed data acquisition system

    International Nuclear Information System (INIS)

    Drigert, M.W.; Cole, J.D.; Reber, E.L.; Young, J.M.

    1996-01-01

    A development effort was started two years ago to develop a portable data acquisition system which could be used for performing arms control verification and environmental monitoring measurements with complex multi-detector systems in the field. A field portable data acquisition system has been developed around a VMEbus based micro-processor and standard TCP/IP network protocols. The hardware consists of a compact VME crate and a single CAMAC crate containing the signal processing electronics. The component processes of the data acquisition system transfer control and event data over a set of TCP/IP socket connections. The use of network sockets for the interprocess communications allows the data acquisition system to be operated transparently on one workstation or on a number of workstations distributed around a local network

  1. Applications of field portable computers to NDE of nuclear power plant steam turbine/generator rotors, discs, and retaining rings

    International Nuclear Information System (INIS)

    Reinhart, E.R.; Leon-Salamanca, T.

    2004-01-01

    The new generation of compact, powerful portable computers have been incorporated into a number of nondestructive evaluation (NDE) systems used to inspect critical areas of the steam turbine and generator units of nuclear power plants. Due to the complex geometry of turbine rotors, generator rotors, retaining rings, and shrunk-on turbine discs, the computers are needed to rapidly calculate the optimum position of an ultrasonic transducer or eddy current probe in order to detect defects at several critical areas. Examples where computers have been used to overcome problems in nondestructive evaluation include; analysis of large numbers of closely spaced near-bore ultrasonic reflectors to determine their potential for link-up in turbine and generator rotor bores, distinguishing ultrasonic crack signals from other reflectors such as the shrink-fit form reflector detected during ultrasonic scanning of shrunk-on generator retaining rings, and detection and recording of eddy current and ultrasonic signals from defects that could be missed by data acquisition systems with inadequate response. The computers are also used to control scanners to insure total inspection coverage. To facilitate the use of data from detected discontinuities in conjunction with stress and fracture mechanics analysis programs, the computers provide presentations of flaws in color and in three dimensions. The field computers have been instrumental in allowing the inspectors to develop on-site reports that enable the owner/operator to rapidly make run/repair/replace decisions. Examples of recent experiences using field portable computers in NDE systems will be presented along with anticipated future developments. (author)

  2. A Field-Portable Cell Analyzer without a Microscope and Reagents.

    Science.gov (United States)

    Seo, Dongmin; Oh, Sangwoo; Lee, Moonjin; Hwang, Yongha; Seo, Sungkyu

    2017-12-29

    This paper demonstrates a commercial-level field-portable lens-free cell analyzer called the NaviCell (No-stain and Automated Versatile Innovative cell analyzer) capable of automatically analyzing cell count and viability without employing an optical microscope and reagents. Based on the lens-free shadow imaging technique, the NaviCell (162 × 135 × 138 mm³ and 1.02 kg) has the advantage of providing analysis results with improved standard deviation between measurement results, owing to its large field of view. Importantly, the cell counting and viability testing can be analyzed without the use of any reagent, thereby simplifying the measurement procedure and reducing potential errors during sample preparation. In this study, the performance of the NaviCell for cell counting and viability testing was demonstrated using 13 and six cell lines, respectively. Based on the results of the hemocytometer ( de facto standard), the error rate (ER) and coefficient of variation (CV) of the NaviCell are approximately 3.27 and 2.16 times better than the commercial cell counter, respectively. The cell viability testing of the NaviCell also showed an ER and CV performance improvement of 5.09 and 1.8 times, respectively, demonstrating sufficient potential in the field of cell analysis.

  3. Feasibility of field portable near infrared (NIR) spectroscopy to determine cyanide concentrations in soil

    Science.gov (United States)

    Sut, Magdalena; Fischer, Thomas; Repmann, Frank; Raab, Thomas

    2013-04-01

    In Germany, at more than 1000 sites, soil is polluted with an anthropogenic contaminant in form of iron-cyanide complexes. These contaminations are caused by former Manufactured Gas Plants (MGPs), where electricity for lighting was produced in the process of coal gasification. The production of manufactured gas was restrained in 1950, which caused cessation of MGPs. Our study describes the application of Polychromix Handheld Field Portable Near-Infrared (NIR) Analyzer to predict the cyanide concentrations in soil. In recent times, when the soil remediation is of major importance, there is a need to develop rapid and non-destructive methods for contaminant determination in the field. In situ analysis enables determination of 'hot spots', is cheap and time saving in comparison to laboratory methods. This paper presents a novel usage of NIR spectroscopy, where a calibration model was developed, using multivariate calibration algorithms, in order to determine NIR spectral response to the cyanide concentration in soil samples. As a control, the contaminant concentration was determined using conventional Flow Injection Analysis (FIA). The experiments revealed that portable near-infrared spectrometers could be a reliable device for identification of contamination 'hot spots', where cyanide concentration are higher than 2400 mg kg-1 in the field and >1750 mg kg-1 after sample preparation in the laboratory, but cannot replace traditional laboratory analyses due to high limits of detection.

  4. Immunoassays in Biotechnology

    Science.gov (United States)

    Immunoassays have broad applications for a wide variety of important biological compounds and environmental contaminants. Immunoassays can detect the presence of an antigen in the human body, a pollutant in the environment, or a critical antibody in a patient’s serum to develop a...

  5. Advanced techniques in immunoassay

    International Nuclear Information System (INIS)

    Toth, G.

    1982-01-01

    A brief overview of the development history of radioimmunoassay and related techniques with their theory and practice are given. A comparison of radioimmunoassay (RIA), enzyme immunoassay (EIA), spin immunoassay (SIA), sequential saturation analysis (SSA) etc., based on their main parameters, and their fields of application and recent trends are presented. (Sz.J.)

  6. Field-portable-XRF reveals the ubiquity of antimony in plastic consumer products.

    Science.gov (United States)

    Turner, Andrew; Filella, Montserrat

    2017-04-15

    Very little systematic information exists on the occurrence and concentrations of antimony (Sb) in consumer products. In this study, a Niton XL3t field-portable-X-ray fluorescence (FP-XRF) spectrometer was deployed in situ and in the laboratory to provide quantitative information on Sb dissipated in plastic items and fixtures (including rubber, textile and foamed materials) from the domestic, school, vehicular and office settings. The metalloid was detected in 18% of over 800 measurements performed, with concentrations ranging from about 60 to 60,000μgg -1 . The highest concentrations were encountered in white, electronic casings and in association with similar concentrations of Br, consistent with the use of antimony oxides (e.g. Sb 2 O 3 ) as synergistic flame retardants. Concentrations above 1000μgg -1 , and with or without Br, were also encountered in paints, piping and hosing, adhesives, whiteboards, Christmas decorations, Lego blocks, document carriers, garden furniture, upholstered products and interior panels of private motor vehicles. Lower concentrations of Sb were encountered in a wide variety of items but its presence (without Br) in food tray packaging, single-use drinks bottles, straws and small toys were of greatest concern from a human health perspective. While the latter observations are consistent with the use of antimony compounds as catalysts in the production of polyethylene terephthalate, co-association of Sb and Br in many products not requiring flame retardancy suggests that electronic casings are widely recycled. Further research is required into the mobility of Sb when dissipated in new, recycled and aged polymeric materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Radiolabelling for immunoassay

    International Nuclear Information System (INIS)

    Chapman, R.S.

    1998-01-01

    Since the early 1960s labelled compounds employed in immunoassay techniques, both radioimmunoassay and immunoradiometric assay, have involved radioisotopes typically 3 H (tritium) and 125 Iodine. With the advent of increasingly stringent governmental regulations regarding usage and disposal of radioisotopes and the impetus of research towards improved immunoassay sensitivity following the discovery of monoclonal antibodies and their application to excess reagent immunometric assay methodology, radioisotopic labels are gradually being replaced by non-isotopic labels: enzyme, fluorescence and chemiluminescence

  8. Quantification of trace arsenic in soils by field-portable X-ray fluorescence spectrometry: considerations for sample preparation and measurement conditions.

    Science.gov (United States)

    Parsons, Chris; Margui Grabulosa, Eva; Pili, Eric; Floor, Geerke H; Roman-Ross, Gabriela; Charlet, Laurent

    2013-11-15

    Recent technological improvements have led to the widespread adoption of field portable energy dispersive X-ray fluorescence (FP-XRF) by governmental agencies, environmental consultancies and research institutions. FP-XRF units often include analysis modes specifically designed for the quantification of trace elements in soils. Using these modes, X-ray tube based FP-XRF units can offer almost "point and shoot" ease of use and results comparable to those of laboratory based instruments. Nevertheless, FP-XRF analysis is sensitive to spectral interferences as well as physical and chemical matrix effects which can result in decreased precision and accuracy. In this study, an X-ray tube-based FP-XRF analyser was used to determine trace (low ppm) concentrations of As in a floodplain soil. The effect of different sample preparation and analysis conditions on precision and accuracy were systematically evaluated. We propose strategies to minimise sources of error and maximise data precision and accuracy, achieving in situ limits of detection and precision of 6.8 ppm and 14.4%RSD, respectively for arsenic. We demonstrate that soil moisture, even in relatively dry soils, dramatically affects analytical performance with a signal loss of 37% recorded for arsenic at 20 wt% soil moisture relative to dry soil. We also highlight the importance of the use of certified reference materials and independent measurement methods to ensure accurate correction of field values. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Environmental Technology Verification Report. Field Portable Gas Chromatograph/Mass Spectrometer. Viking Instruments Corporation SpectraTrak (Trademark) 672

    National Research Council Canada - National Science Library

    Enfield, Wayne

    1997-01-01

    .... This self-contained, field transportable system, whose design has been adapted from laboratory technology, uses a contained, chromatographic column and accompanying mass spectrometer to provide...

  10. Hydrogel nanoparticle based immunoassay

    Science.gov (United States)

    Liotta, Lance A; Luchini, Alessandra; Petricoin, Emanuel F; Espina, Virginia

    2015-04-21

    An immunoassay device incorporating porous polymeric capture nanoparticles within either the sample collection vessel or pre-impregnated into a porous substratum within fluid flow path of the analytical device is presented. This incorporation of capture particles within the immunoassay device improves sensitivity while removing the requirement for pre-processing of samples prior to loading the immunoassay device. A preferred embodiment is coreshell bait containing capture nanoparticles which perform three functions in one step, in solution: a) molecular size sieving, b) target analyte sequestration and concentration, and c) protection from degradation. The polymeric matrix of the capture particles may be made of co-polymeric materials having a structural monomer and an affinity monomer, the affinity monomer having properties that attract the analyte to the capture particle. This device is useful for point of care diagnostic assays for biomedical applications and as field deployable assays for environmental, pathogen and chemical or biological threat identification.

  11. Technical design issues for a field-portable supercritical fluid extractor

    Energy Technology Data Exchange (ETDEWEB)

    Wright, B.W.; Zemanian, T.S.; Robins, W.H.; Wright, C.W.

    1995-01-01

    Supercritical fluid extraction is gaining acceptance as an alternative sample preparation method for trace organic analysis. The development of SFE instrumentation optimized for field use requires taking several technical design issues including size and weight requirements, user-friendly operation, and technical performance capabilities into consideration. Parameters associated with a prototype SFE instrument under development for potential use in conducting on-site inspections of the Chemical Weapons Convention and its preliminary technical and operational performance are described.

  12. Bead-based immunoassays

    NARCIS (Netherlands)

    Wal, van der F.J.; Bergervoet, J.H.W.; Achterberg, R.P.; Haasnoot, W.

    2014-01-01

    Since the first immunoassay with (radioactive) labeled antibodies in the middle of the 20th century [1], many different formats on various platforms have been developed, using antibodies for capture and/or detection. If antibodies are used to capture compounds, a support, such as the wall of a

  13. The immunoassay handbook

    National Research Council Canada - National Science Library

    Wild, David (David G.)

    2001-01-01

    ... importantly, enabling them to keep current on the basic theory behind immunoassay. Since the publication of the previous edition in 1994, the field has continued to evolve rapidly, and the need for a fully updated version of this book is now paramount. The second edition has been comprehensively updated and new chapters have been added to each section" [publisher's web site].

  14. Field Portable GC-MS Unit for Semi-Volatile Compound Analysis in Groundwater

    Science.gov (United States)

    2011-06-01

    the size and power consumption compared to standard GC systems. These modifications to the instrument design all serve to decrease the size and...Environment Mass Spectrometry (HEMS) Conference, September 2007, Cocoa Beach, FL. USEPA. 1998. USEPA Superfund Record of Decision, Milan Army

  15. Instrumentation

    International Nuclear Information System (INIS)

    Prieur, G.; Nadi, M.; Hedjiedj, A.; Weber, S.

    1995-01-01

    This second chapter on instrumentation gives little general consideration on history and classification of instrumentation, and two specific states of the art. The first one concerns NMR (block diagram of instrumentation chain with details on the magnets, gradients, probes, reception unit). The first one concerns precision instrumentation (optical fiber gyro-meter and scanning electron microscope), and its data processing tools (programmability, VXI standard and its history). The chapter ends with future trends on smart sensors and Field Emission Displays. (D.L.). Refs., figs

  16. Novel immunoassay formats for integrated microfluidic circuits: diffusion immunoassays (DIA)

    Science.gov (United States)

    Weigl, Bernhard H.; Hatch, Anson; Kamholz, Andrew E.; Yager, Paul

    2000-03-01

    Novel designs of integrated fluidic microchips allow separations, chemical reactions, and calibration-free analytical measurements to be performed directly in very small quantities of complex samples such as whole blood and contaminated environmental samples. This technology lends itself to applications such as clinical diagnostics, including tumor marker screening, and environmental sensing in remote locations. Lab-on-a-Chip based systems offer many *advantages over traditional analytical devices: They consume extremely low volumes of both samples and reagents. Each chip is inexpensive and small. The sampling-to-result time is extremely short. They perform all analytical functions, including sampling, sample pretreatment, separation, dilution, and mixing steps, chemical reactions, and detection in an integrated microfluidic circuit. Lab-on-a-Chip systems enable the design of small, portable, rugged, low-cost, easy to use, yet extremely versatile and capable diagnostic instruments. In addition, fluids flowing in microchannels exhibit unique characteristics ('microfluidics'), which allow the design of analytical devices and assay formats that would not function on a macroscale. Existing Lab-on-a-chip technologies work very well for highly predictable and homogeneous samples common in genetic testing and drug discovery processes. One of the biggest challenges for current Labs-on-a-chip, however, is to perform analysis in the presence of the complexity and heterogeneity of actual samples such as whole blood or contaminated environmental samples. Micronics has developed a variety of Lab-on-a-Chip assays that can overcome those shortcomings. We will now present various types of novel Lab- on-a-Chip-based immunoassays, including the so-called Diffusion Immunoassays (DIA) that are based on the competitive laminar diffusion of analyte molecules and tracer molecules into a region of the chip containing antibodies that target the analyte molecules. Advantages of this

  17. Chemiluminescence immunoassay for chloramphenicol

    International Nuclear Information System (INIS)

    Lin Si; Xu Wenge; Liu Yibing

    2007-06-01

    A simple, solid-phase chemiluminescence immunoassay (CLIA) for the measurement of Chloramphenicol(CAP) in foodstuffs is described. A rabbit anti-CAP IgG is passively adsorbed onto the walls of polypropylene plates. The labeled conjugant is horseradish peroxidase(HRP) conjugate of CAP. Luminol solution is used as the substrate of HRP. The light yield is inversely proportional to the concentration of CAP. The method has a similar sensitivity (0.05 ng/mL), specificity, precision, and accuracy to a conventional enzyme immunoassay (EIA). The intra-assay and inter-assay CVs of ten samples were <8 and <20%, respectively, and the analytical recovery of the method was 87% 100%. The experimental correlation coefficient of dilution was found to be 0.999 using milk supernatant as buffer. The assay range for the method was 0.1-10 ng/mL, and it displayed good linearity. (authors)

  18. Instrumentation

    International Nuclear Information System (INIS)

    Decreton, M.

    2000-01-01

    SCK-CEN's research and development programme on instrumentation aims at evaluating the potentials of new instrumentation technologies under the severe constraints of a nuclear application. It focuses on the tolerance of sensors to high radiation doses, including optical fibre sensors, and on the related intelligent data processing needed to cope with the nuclear constraints. Main achievements in these domains in 1999 are summarised

  19. Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Decreton, M

    2001-04-01

    SCK-CEN's research and development programme on instrumentation involves the assessment and the development of sensitive measurement systems used within a radiation environment. Particular emphasis is on the assessment of optical fibre components and their adaptability to radiation environments. The evaluation of ageing processes of instrumentation in fission plants, the development of specific data evaluation strategies to compensate for ageing induced degradation of sensors and cable performance form part of these activities. In 2000, particular emphasis was on in-core reactor instrumentation applied to fusion, accelerator driven and water-cooled fission reactors. This involved the development of high performance instrumentation for irradiation experiments in the BR2 reactor in support of new instrumentation needs for MYRRHA, and for diagnostic systems for the ITER reactor.

  20. Instrumentation

    International Nuclear Information System (INIS)

    Decreton, M.

    2001-01-01

    SCK-CEN's research and development programme on instrumentation involves the assessment and the development of sensitive measurement systems used within a radiation environment. Particular emphasis is on the assessment of optical fibre components and their adaptability to radiation environments. The evaluation of ageing processes of instrumentation in fission plants, the development of specific data evaluation strategies to compensate for ageing induced degradation of sensors and cable performance form part of these activities. In 2000, particular emphasis was on in-core reactor instrumentation applied to fusion, accelerator driven and water-cooled fission reactors. This involved the development of high performance instrumentation for irradiation experiments in the BR2 reactor in support of new instrumentation needs for MYRRHA, and for diagnostic systems for the ITER reactor

  1. FieldSpec: A field portable mass spectrometer prototype for high frequency measurements of δ (2) H and δ (18) O ratios in water

    Science.gov (United States)

    López Días, Veneranda; Quang Hoang, Hung; Martínez-Carreras, Núria; Barnich, François; Wirtz, Tom; Pfister, Laurent; McDonnell, Jeffrey

    2016-04-01

    Hydrological studies relying on stable water isotopes to better understand water sources, flowpaths and transit times are currently limited by the coarse temporal resolution of sampling and analysis protocols. At present, two kinds of lab-based instruments are used : (i) the standard isotope ratio mass spectrometers (IRMS) [1] and (ii) the laser-based instruments [2, 3]. In both cases, samples need to be collected in the field and then transferred to the laboratory for the water isotopic ratio measurements (even further complex sample preparation is required for the IRMS). Hence, past and ongoing research targets the development of field deployable instruments for measuring stable water isotopes at high temporal frequencies. While recent studies have demonstrated that laser-based instruments may be taken to the field [4, 5], their size and power consumption still restrict their use to sites equipped with mains power or generators. Here, we present progress on the development of a field portable mass spectrometer (FieldSpec) for direct high frequency measurements of δ2H and δ18O ratios in water. The FieldSpec instrument is based upon the use of a double focusing magnetic sector mass spectrometer in combination with an electron impact ion source and a membrane dual inlet system. The instrument directly collects liquid water samples in the field, which are then converted into water vapour before being injected into the mass spectrometer for the stable isotope analysis. δ2H and δ18O are derived from the measured mass spectra. All the components are arranged in a vacuum case having a suit case type dimension with portable electronics and battery. Proof-of-concept experiments have been carried out to characterize the instrument. The results show that the FieldSpec instrument has good linearity (R2 = 0.99). The reproducibility of the instrument ranges between 1 and 4 ‰ for δ2H and between 0.1 and 0.4 ‰ for δ18O isotopic ratio measurements. A measurement

  2. Instrumentation

    International Nuclear Information System (INIS)

    Decreton, M.

    2002-01-01

    SCK-CEN's R and D programme on instrumentation involves the development of advanced instrumentation systems for nuclear applications as well as the assessment of the performance of these instruments in a radiation environment. Particular emphasis is on the use of optical fibres as umbilincal links of a remote handling unit for use during maintanance of a fusion reacor, studies on the radiation hardening of plasma diagnostic systems; investigations on new instrumentation for the future MYRRHA accelerator driven system; space applications related to radiation-hardened lenses; the development of new approaches for dose, temperature and strain measurements; the assessment of radiation-hardened sensors and motors for remote handling tasks and studies of dose measurement systems including the use of optical fibres. Progress and achievements in these areas for 2001 are described

  3. Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Decreton, M

    2002-04-01

    SCK-CEN's R and D programme on instrumentation involves the development of advanced instrumentation systems for nuclear applications as well as the assessment of the performance of these instruments in a radiation environment. Particular emphasis is on the use of optical fibres as umbilincal links of a remote handling unit for use during maintanance of a fusion reacor, studies on the radiation hardening of plasma diagnostic systems; investigations on new instrumentation for the future MYRRHA accelerator driven system; space applications related to radiation-hardened lenses; the development of new approaches for dose, temperature and strain measurements; the assessment of radiation-hardened sensors and motors for remote handling tasks and studies of dose measurement systems including the use of optical fibres. Progress and achievements in these areas for 2001 are described.

  4. Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Decreton, M

    2000-07-01

    SCK-CEN's research and development programme on instrumentation aims at evaluating the potentials of new instrumentation technologies under the severe constraints of a nuclear application. It focuses on the tolerance of sensors to high radiation doses, including optical fibre sensors, and on the related intelligent data processing needed to cope with the nuclear constraints. Main achievements in these domains in 1999 are summarised.

  5. Specificity of immunoassays. Pt. 2

    International Nuclear Information System (INIS)

    Pratt, J.J.; Woldring, M.G.; Boonman, R.; Kittikool, J.

    1979-01-01

    Practical aspects of the measurement of the specificity of immunoassay are reviewed. Antibody heterogeneity in an antiserum makes a pragmatic rather than a theoretical approach necessary. A new method for the measurement of immunoassay specificity is described. This method is based on the errors caused by the cross-reacting antigens and is directly relevant to the validity of results obtained by immunoassay methods. The effect of selectively blocking the least specific antibodies in antisera raised against steroid haptens is tested. The practical consequences of these considerations are tested using steroid radioimmunoassay and enzyme-immunoassay. (orig.) [de

  6. Field-portable and automated immunosensors for hexavalent uranium, other heavy metals and chelators. Final Report

    International Nuclear Information System (INIS)

    Blake, Diane A.

    2009-01-01

    This is the final technical report for this 10-year project. A better understanding of in situ bioremediation processes and the development of strategies to enhance bacterial remediation of contaminated sites depend either directly or indirectly upon accurate detection and measurement of organics, metal and other toxic elements prior to, during and following the remediation process. Detection and measurement costs are presently high due to the complex methodologies required for analysis. Remediation costs could be significantly reduced through the use of rapid, simple on-site methods. The cost of laboratory analysis continues to climb and the outlay for the assessment of a single site can frequently reach hundreds of thousands of dollars. One estimate suggests that the use of low cost field methods (defined as less than $100/test) with 5-20% standard laboratory confirmation could reduce analytical costs by greater than 70%. Perhaps as important as the cost of analysis is ability to obtain data about the remediation process in near real-time. The instruments normally used for environmental analysis of uranium (atomic absorption spectrophotometer, inductive coupled plasma emission spectrometer, IC-MS and kinetic phosphorescence analyzer) or can be quite expensive; these instruments are thus usually located only in centralized facilities. Environmental samples must therefore be transported to these facilities and often wait in a queue before they can be analyzed. Both sample transport and time-in-queue lead to long turn-around times (days to weeks). Such long turn-around times are especially worrisome during site remediation, especially when an unexpected finding might dictate a change in the methodologies being employed at the site. The goal of this project was to develop sensors that could yield reliable data in near realtime (< 1 hour) be field-ready (ie, simple, durable and accurate) and present low costs (<< $100/assay and <$5,000 for the initial equipment

  7. Instrumentation

    International Nuclear Information System (INIS)

    Umminger, K.

    2008-01-01

    A proper measurement of the relevant single and two-phase flow parameters is the basis for the understanding of many complex thermal-hydraulic processes. Reliable instrumentation is therefore necessary for the interaction between analysis and experiment especially in the field of nuclear safety research where postulated accident scenarios have to be simulated in experimental facilities and predicted by complex computer code systems. The so-called conventional instrumentation for the measurement of e. g. pressures, temperatures, pressure differences and single phase flow velocities is still a solid basis for the investigation and interpretation of many phenomena and especially for the understanding of the overall system behavior. Measurement data from such instrumentation still serves in many cases as a database for thermal-hydraulic system codes. However some special instrumentation such as online concentration measurement for boric acid in the water phase or for non-condensibles in steam atmosphere as well as flow visualization techniques were further developed and successfully applied during the recent years. Concerning the modeling needs for advanced thermal-hydraulic codes, significant advances have been accomplished in the last few years in the local instrumentation technology for two-phase flow by the application of new sensor techniques, optical or beam methods and electronic technology. This paper will give insight into the current state of instrumentation technology for safety-related thermohydraulic experiments. Advantages and limitations of some measurement processes and systems will be indicated as well as trends and possibilities for further development. Aspects of instrumentation in operating reactors will also be mentioned.

  8. A field-portable supercritical fluid extractor for characterizing sources of waterborne organic compounds

    International Nuclear Information System (INIS)

    Fruchter, J.S.; Wright, B.W.

    1992-01-01

    Supercritical fluid extraction (SFE) is a viable alternative to current methods of liquid extraction for analyzing semivolatile organic compounds in contaminated solid matrices, such as soil and sediment. Because the SFE method is rapid (less than 30 min), large quantities of glassware and large volumes of solvent are not required, and there are fewer sample-handling and sample-preparation steps than in conventional liquid extraction methods, SFE lends itself to in-the-field extraction of solid samples. Laboratory-scale and portable SFE instruments were designed and tested both in the laboratory and in the field. The SFE method was validated through two recovery studies using individual polycyclic aromatic hydrocarbon (PAH) standards ranging from two to six rings in size and through two Soxhlet extraction comparison studies. Supercritical fluid extraction followed by gas chromatography was applied to 20 coal-tar-contaminated soil samples from three locations, 10 petroleum-oil-tar-contaminated soil samples, and 20 polychlorinated-biphenyl-contaminated soil samples. The SFE apparatus was transported and used in the field at four locations across the United States. Carbon dioxide was used as the extraction fluid

  9. Interference in immunoassay

    International Nuclear Information System (INIS)

    Chapman, R.S.

    1998-01-01

    Interfering factors are evident in both limited reagent (radioimmunoassay) and excess reagent (immunometric assay) technologies and should be suspected whenever there is a discrepancy between analytical results and clinical findings in the investigation of particular diseases. The overall effect of interference in immunoassay is analytical bias in result, either positive or negative of variable magnitude. The interference maybe caused by a wide spectrum of factors from poor sample collection and handling to physiological factors e.g. lipaemia, heparin treatment, binding protein abnormalities, autoimmunity and drug treatments. The range of interfering factors is extensive and difficult to discuss effectively in a short review

  10. Instruments

    International Nuclear Information System (INIS)

    Buehrer, W.

    1996-01-01

    The present paper mediates a basic knowledge of the most commonly used experimental techniques. We discuss the principles and concepts necessary to understand what one is doing if one performs an experiment on a certain instrument. (author) 29 figs., 1 tab., refs

  11. Procedures for Sensitive Immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Givol, D. [Department of Chemical Immunology, Weizmann Institute of Science, Rehovot (Israel)

    1970-02-15

    Sensitive immunoassay methods should be applied to small molecules of biological importance, which are non-immunogenic by themselves, such as small peptide hormones (e.g. bradykinin), plant hormones (e.g. indoleacetic acid), nucleotides and other small molecules. Methods of binding these small molecules, as haptens, to immunogenic carriers by various cross-linking agents are described (dicyclohexylcarbodiimide, tolylene-diisocyanate and glutaraldehyde), and the considerations involved in relation to the methods of binding and the specificity of the antibodies formed are discussed. Some uses of antibody bound to bromoacetyl cellulose as an immuno adsorbent convenient for assay of immunoglobulins are described. Finally, the sensitive immunoassay method of chemically modified phage is described. This includes methods of binding small molecules (such as the dinitrophenyl group, penicillin, indoleacetic acid) or proteins (such as insulin, immunoglobulins) to phages. Methods of direct chemical conjugation, or an indirect binding via anti-phage Fab, are described. The phage inactivation method by direct plating and its modifications (such as decision technique and complex inactivation) are compared with the more simple end-point titration method. The inhibition of phage inactivation has some advantages as it does not require radioactive material, or expensive radioactive counters, and avoids the need for separation between bound and unbound antigen. Hence, if developed, it could be used as an alternative to radioimmunoassay. (author)

  12. Instrumentation

    International Nuclear Information System (INIS)

    Muehllehner, G.; Colsher, J.G.

    1982-01-01

    This chapter reviews the parameters which are important to positron-imaging instruments. It summarizes the options which various groups have explored in designing tomographs and the methods which have been developed to overcome some of the limitations inherent in the technique as well as in present instruments. The chapter is not presented as a defense of positron imaging versus single-photon or other imaging modality, neither does it contain a description of various existing instruments, but rather stresses their common properties and problems. Design parameters which are considered are resolution, sampling requirements, sensitivity, methods of eliminating scattered radiation, random coincidences and attenuation. The implementation of these parameters is considered, with special reference to sampling, choice of detector material, detector ring diameter and shielding and variations in point spread function. Quantitation problems discussed are normalization, and attenuation and random corrections. Present developments mentioned are noise reduction through time-of-flight-assisted tomography and signal to noise improvements through high intrinsic resolution. Extensive bibliography. (U.K.)

  13. Low-Cost, Robust, and Field Portable Smartphone Platform Photometric Sensor for Fluoride Level Detection in Drinking Water.

    Science.gov (United States)

    Hussain, Iftak; Ahamad, Kamal Uddin; Nath, Pabitra

    2017-01-03

    Groundwater is the major source of drinking water for people living in rural areas of India. Pollutants such as fluoride in groundwater may be present in much higher concentration than the permissible limit. Fluoride does not give any visible coloration to water, and hence, no effort is made to remove or reduce the concentration of this chemical present in drinking water. This may lead to a serious health hazard for those people taking groundwater as their primary source of drinking water. Sophisticated laboratory grade tools such as ion selective electrodes (ISE) and portable spectrophotometers are commercially available for in-field detection of fluoride level in drinking water. However, such tools are generally expensive and require expertise to handle. In this paper, we demonstrate the working of a low cost, robust, and field portable smartphone platform fluoride sensor that can detect and analyze fluoride concentration level in drinking water. For development of the proposed sensor, we utilize the ambient light sensor (ALS) of the smartphone as light intensity detector and its LED flash light as an optical source. An android application "FSense" has been developed which can detect and analyze the fluoride concentration level in water samples. The custom developed application can be used for sharing of in-field sensing data from any remote location to the central water quality monitoring station. We envision that the proposed sensing technique could be useful for initiating a fluoride removal program undertaken by governmental and nongovernmental organizations here in India.

  14. Field portable petroleum analysis for validation of the site characterization and analysis penetrometer system petroleum, oil and lubricant sensor

    International Nuclear Information System (INIS)

    Davis, W.M.; Jones, P.; Porter, B.

    1995-01-01

    A petroleum, oil and lubricant (POL) sensor for the Site Characterization and Analysis Penetrometer System (SCAPS) has been developed by the Tri-Services (e.g. Army, Navy and Air Force) to characterize the distribution of POL contaminants on military sites. The sensor is based on the detection of POL contaminants using a laser induced fluorescence (LIF) spectrometer. The SCAPS POL sensor has been shown to be a valuable tool for the rapid screening of POL contamination in the subsurface. However, many factors can affect the LIF response of a particular fuel at a particular site. These include fuel type, age of spill (e.g. weathering) and soil type. The LIF sensor also detects fluorescence from any naturally occurring fluorophores, including humic substances and fluorescent minerals. These factors lead to the development of an independent procedure for the verification of the POL sensor response. This paper describes a field portable total recoverable petroleum hydrocarbon (TRPH) method based on EPA Method 418.1 and its application to on site validation of the SCAPS POL sensor response at a number of contaminated sites

  15. Immunoassay separation technique

    International Nuclear Information System (INIS)

    1977-01-01

    A method for effecting the immunoassay of a multiplicity of samples, each possibly containing an antigen or an antibody to be assayed, is discussed. Each sample is incubated with a solution containing a detectable antigen or antibody to form a multiplicity of mixtures, each mixture containing as components antigen-antibody, non-complexed antigen and non-complexed antibody. At least one of the components of the said mixture is separated by adsorption. There after, quantity of detectable antigen or antibody is detected in one of the non-adsorbed portions of the mixture. An improvement, compared to other techniques, is the continuous and sequential separation of at least one component, which is intended to be separated from each said multiplicity of mixtures

  16. Monoclonal antibody-based immunoassays.

    Science.gov (United States)

    Appleby, P; Reischl, U

    1998-01-01

    An immunoassay may be defined as an assay that employs an immunological reagent, usually an antibody, to confer specificity for the ligand being measured. As a corollary to this, the discovery, and subsequent development, of monoclonal antibodies (MAbs) has greatly expanded the application and use of immunoassays. Polyclonal reagents, with their associated problems of specificity and quality control, have now been largely replaced by readily available MAbs of potential immortality and well-defined specificity and affinity. This has resulted, in the last two decades, in a great expansion in the range of immunoassays available and also a significant improvement in their reproducibility and reliability.

  17. Use of field-portable ultrasonography reveals differences in developmental phenology and maternal egg provisioning in two sympatric viviparous snakes.

    Science.gov (United States)

    Sparkman, Amanda M; Chism, Kenneth R; Bronikowski, Anne M; Brummett, Lilly J; Combrink, Lucia L; Davis, Courtney L; Holden, Kaitlyn G; Kabey, Nicole M; Miller, David A W

    2018-03-01

    A thorough understanding of the life cycles underlying the demography of wild species is limited by the difficulty of observing hidden life-history traits, such as embryonic development. Major aspects of embryonic development, such as the rate and timing of development, and maternal-fetal interactions can be critical features of early-life fitness and may impact population trends via effects on individual survival. While information on development in wild snakes and lizards is particularly limited, the repeated evolution of viviparity and diversity of reproductive mode in this clade make it a valuable subject of study. We used field-portable ultrasonography to investigate embryonic development in two sympatric garter snake species, Thamnophis sirtalis and Thamnophis elegans in the Sierra Nevada mountains of California. This approach allowed us to examine previously hidden reproductive traits including the timing and annual variation in development and differences in parental investment in young. Both species are viviparous, occupy similar ecological niches, and experience the same annual environmental conditions. We found that T. sirtalis embryos were more developmentally advanced than T. elegans embryos during June of three consecutive years. We also found that eggs increased in volume more substantially across developmental stages in T. elegans than in T. sirtalis , indicating differences in maternal provisioning of embryos via placental transfer of water. These findings shed light on interspecific differences in parental investment and timing of development within the same environmental context and demonstrate the value of field ultrasonography for pursuing questions relating to the evolution of reproductive modes, and the ecology of development.

  18. Immunoassay for thymopoietin

    International Nuclear Information System (INIS)

    Goldstein, G.

    1979-01-01

    The patent describes the development of a radio-immunoassay for thymopoietin in biological samples. The method of raising antibodies to this polypeptide hormone is described. This is achieved by injecting a host animal with an antigen consisting of thymopoietin covalently bonded by glutaraldehyde to a carrier protein such as bovine serum albumin and equine globulin. Different methods of radiolabelling thymopoietin with 125 I for use as the tracer antigen are described. The Bolton-Hunter procedure was preferred to the chloramine-T method since direct iodination of the tyrosyl moieties of thymopoietin resulted in some loss of immunoreactivity. Systems for separating the antigen-antibody complex and unbound antigen are compared. Binding-inhibition curves for unlabelled thymopoietin in the assay employing polyethylene glycol separation showed a sensitivity of 5 ng thymopoietin/ml. However, using the double antibody or dextran coated charcoal separation techniques, the sensitivity of thymopoietin was 0.1 ng/ml. Thus these latter two procedures are thus especially suitable for measuring thymopoietin levels in serum or plasma samples. The assay was shown to be specific for thymopoietin, no significant displacement being produced by control polypeptides. (U.K.)

  19. Use of field-portable X-ray fluorescence (FPXRF) analyzer to measure airborne lead levels in Korean workplaces.

    Science.gov (United States)

    Kim, Nam-Soo; Kim, Jin-Ho; Ahn, Kyu-Dong; Lee, Byung-Kook

    2007-11-01

    We evaluated the possibility of applying field-portable x-ray fluorescence (FPXRF) analysis as a rapid, on-site and near real-time method for evaluating airborne lead contamination in Korean workplaces. A total of 287 airborne lead filter samples were measured in 12 lead-using workplaces during routine industrial hygienic monitoring procedures as required by Korean government regulations. All filter samples were collected using the standard industrial hygiene sampling protocol described in NIOSH Method 7300 using closed-face 37-mm cassettes with preloaded cellulose ester membrane filters with a pore size of 0.8 microm. The samples were first analyzed using the non-destructive, FPXRF analytical method (NIOSH method 7702), and then subsequently analyzed using inductively coupled plasma atomic emission spectrophotometry (ICP) (NIOSH method 7300) as a reference analytical method. Pair-wise comparison of filter samples using the paired t-test revealed no statistically significant differences between the two methods over a wide range of airborne lead levels (0.018-0.201 microg/m(3)) either over the industries assessed or separately in the 12 lead-using workplaces. Linear regression of the data between the ICP and FPXRF methods produced a slope of 1.03, a y-intercept of 0.13 microg/sample, and a coefficient of determinant (r(2)) of 0.975 for all the data. For samples in the range from 0 to 100 microg, the corresponding values were 1.07, -1.20 microg/sample, and 0.925, respectively. There were no significant differences in the regression analyses of the three industry types (r(2)=0.964-0.982). Our data suggest that FPXRF data are highly correlated with those from the laboratory-based ICP method in terms of accuracy, precision, and bias. Therefore, FPXRF can be used for the rapid, on-site analysis of lead air-filter samples for values up to 26 microg/sample prior to laboratory confirmation by the ICP method.

  20. Evaluation of field-portable X-ray fluorescence spectrometry for the determination of lead contamination on small-arms firing ranges

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, J.F.; Taylor, J.D.; Bass, D.A.; Zellmer, D. [Argonne National Lab., IL (United States); Rieck, M. [U.S. Army, Grafenwoehr Training Area (Germany)

    1995-02-01

    Field analytical methods for the characterization of lead contamination in soil are being developed. In this study, the usefulness of a commercially available, field-portable energy-dispersive X-ray fluorescence spectrometer (XRF) is evaluated for determining the extent of lead contamination in soils on small-arms firing ranges at a military installation. This field screening technique provides significant time and cost savings for the study of sites with lead-contaminated soil. Data obtained with the XRF unit in the field are compared with data obtained from soil samples analyzed in an analytical laboratory by inductively coupled plasma atomic emission spectroscopy. Results indicate that the field-portable XRF unit evaluated in this study provides data that are useful in determining the extent and relative magnitude of lead contamination. For the commercial unit used in this study, improvements in the spectral resolution and in the limit of detection would be required to make the unit more than just a screening tool.

  1. Evaluation and refinement of a field-portable drinking water toxicity sensor utilizing electric cell-substrate impedance sensing and a fluidic biochip.

    Science.gov (United States)

    Widder, Mark W; Brennan, Linda M; Hanft, Elizabeth A; Schrock, Mary E; James, Ryan R; van der Schalie, William H

    2015-07-01

    The US Army's need for a reliable and field-portable drinking water toxicity sensor was the catalyst for the development and evaluation of an electric cell-substrate impedance sensing (ECIS) device. Water testing technologies currently available to soldiers in the field are analyte-specific and have limited capabilities to detect broad-based water toxicity. The ECIS sensor described here uses rainbow trout gill epithelial cells seeded on fluidic biochips to measure changes in impedance for the detection of possible chemical contamination of drinking water supplies. Chemicals selected for testing were chosen as representatives of a broad spectrum of toxic industrial compounds. Results of a US Environmental Protection Agency (USEPA)-sponsored evaluation of the field portable device were similar to previously published US Army testing results of a laboratory-based version of the same technology. Twelve of the 18 chemicals tested following USEPA Technology Testing and Evaluation Program procedures were detected by the ECIS sensor within 1 h at USEPA-derived human lethal concentrations. To simplify field-testing methods further, elimination of a procedural step that acclimated cells to serum-free media streamlined the test process with only a slight loss of chemical sensitivity. For field use, the ECIS sensor will be used in conjunction with an enzyme-based sensor that is responsive to carbamate and organophosphorus pesticides. Copyright © 2014 John Wiley & Sons, Ltd.

  2. Immunoassay for determination of trilobolide

    Czech Academy of Sciences Publication Activity Database

    Huml, L.; Jurášek, M.; Mikšátková, P.; Zimmermann, T.; Tomanová, P.; Buděšínský, Miloš; Rottnerová, Z.; Šimková, M.; Harmatha, Juraj; Kmoníčková, Eva; Lapčík, O.; Drašar, P. B.

    2017-01-01

    Roč. 117, Jan (2017), s. 105-111 ISSN 0039-128X. [Conference on Isoprenoids /23./. Minsk, 04.09.2016-07.09.2016] Institutional support: RVO:61388963 ; RVO:68378041 Keywords : trilobolide * avidin-biotin * ELISA * Laser trilobum * synthesis * immunoassay Subject RIV: CE - Biochemistry; FR - Pharmacology ; Medidal Chemistry (UEM-P) OBOR OECD: Biochemical research methods; Pharmacology and pharmacy (UEM-P) Impact factor: 2.282, year: 2016

  3. Microfluidic "Pouch" Chips for Immunoassays and Nucleic Acid Amplification Tests.

    Science.gov (United States)

    Mauk, Michael G; Liu, Changchun; Qiu, Xianbo; Chen, Dafeng; Song, Jinzhao; Bau, Haim H

    2017-01-01

    Microfluidic cassettes ("chips") for processing and analysis of clinical specimens and other sample types facilitate point-of-care (POC) immunoassays and nucleic acid based amplification tests. These single-use test chips can be self-contained and made amenable to autonomous operation-reducing or eliminating supporting instrumentation-by incorporating laminated, pliable "pouch" and membrane structures for fluid storage, pumping, mixing, and flow control. Materials and methods for integrating flexible pouch compartments and diaphragm valves into hard plastic (e.g., acrylic and polycarbonate) microfluidic "chips" for reagent storage, fluid actuation, and flow control are described. We review several versions of these pouch chips for immunoassay and nucleic acid amplification tests, and describe related fabrication techniques. These protocols thus offer a "toolbox" of methods for storage, pumping, and flow control functions in microfluidic devices.

  4. [Automated analyzer of enzyme immunoassay].

    Science.gov (United States)

    Osawa, S

    1995-09-01

    Automated analyzers for enzyme immunoassay can be classified by several points of view: the kind of labeled antibodies or enzymes, detection methods, the number of tests per unit time, analytical time and speed per run. In practice, it is important for us consider the several points such as detection limits, the number of tests per unit time, analytical range, and precision. Most of the automated analyzers on the market can randomly access and measure samples. I will describe the recent advance of automated analyzers reviewing their labeling antibodies and enzymes, the detection methods, the number of test per unit time and analytical time and speed per test.

  5. Effective gasoline site assessment using the D TECH trademark BTEX immunoassay

    International Nuclear Information System (INIS)

    Hudak, R.T.; Melby, J.M.; Stave, J.W.

    1994-01-01

    The application of immunoassay to environmental testing can greatly aid in assessing sites for various contaminants including PCB, TNT, RDX, PAH and BTEX. Immunoassay offers several benefits to site assessment: it is accurate, reproducible and relatively inexpensive compared to instrumental analysis. In addition, because of its ease-of-use, this technique is ideal for the field and requires minimal user training. To demonstrate not only the effectiveness of the BTEX immunoassay, but also the reliability of the field results, a gasoline contaminated site was assessed comparing the BTEX immunoassay to gas chromatography. All sampling and site related activities were executed in accordance to the USEPA SW-846 guidelines. Three (3) analyses were performed on each sample. One immunoassay analysis was performed in the field by an individual who received two (2) hours of training prior to the start of the study. A technician familiar with the immunoassay ran the second analysis in a laboratory. Finally, an independent GC laboratory certified for BTEX method 8020 and 602 performed the GC analyses. One hundred one (101) samples were analyzed: thirty-nine (39) samples were water, the other sixty-two (62) were soils ranging from clay to silt. The results and costs of the methods are compared

  6. Survey of immunoassay techniques for biological analysis

    International Nuclear Information System (INIS)

    Burtis, C.A.

    1986-10-01

    Immunoassay is a very specific, sensitive, and widely applicable analytical technique. Recent advances in genetic engineering have led to the development of monoclonal antibodies which further improves the specificity of immunoassays. Originally, radioisotopes were used to label the antigens and antibodies used in immunoassays. However, in the last decade, numerous types of immunoassays have been developed which utilize enzymes and fluorescent dyes as labels. Given the technical, safety, health, and disposal problems associated with using radioisotopes, immunoassays that utilize the enzyme and fluorescent labels are rapidly replacing those using radioisotope labels. These newer techniques are as sensitive, are easily automated, have stable reagents, and do not have a disposal problem. 6 refs., 1 fig., 2 tabs

  7. Immunoassay of β-endorphin

    International Nuclear Information System (INIS)

    Hoellt, V.; Gramsch, C.; Herz, A.

    1979-01-01

    The present paper describes the characteristics of a series of antisera against β-endorphin (β-E) developed in our laboratory which all recognize β-lipotropin and their use in (1) the determination of β-E in tissue and in body fluids and in (2) the immunocytochemical localization of β-E containing neurons in the rat brain and in (3) the study of the conversion of the β-E/β-LPH precursor into β-LPH and β-E in the pars intermedia/nervosa of the rat pituitary. It is the purpose of the present report to critically analyze the pitfalls and drawbacks, as well as the advantage, of the use of radioimmunoassay and other immunoassays in the determination of β-E. (Auth.)

  8. A review of promising new immunoassay technology for monitoring forest herbicides

    Science.gov (United States)

    Charles K. McMahon

    1993-01-01

    Rising costs of classical instrumental methods of chemical analysis coupled with an increasing need for environmental monitoring has lead to the development of highly sensitive, low-cost immunochemical methods of analysis for the detection of environmental contaminants. These methods known simply as immunoassays are chemical assays which use antibodies as reagents. A...

  9. Materials for Microfluidic Immunoassays: A Review.

    Science.gov (United States)

    Mou, Lei; Jiang, Xingyu

    2017-08-01

    Conventional immunoassays suffer from at least one of these following limitations: long processing time, high costs, poor user-friendliness, technical complexity, poor sensitivity and specificity. Microfluidics, a technology characterized by the engineered manipulation of fluids in channels with characteristic lengthscale of tens of micrometers, has shown considerable promise for improving immunoassays that could overcome these limitations in medical diagnostics and biology research. The combination of microfluidics and immunoassay can detect biomarkers with faster assay time, reduced volumes of reagents, lower power requirements, and higher levels of integration and automation compared to traditional approaches. This review focuses on the materials-related aspects of the recent advances in microfluidics-based immunoassays for point-of-care (POC) diagnostics of biomarkers. We compare the materials for microfluidic chips fabrication in five aspects: fabrication, integration, function, modification and cost, and describe their advantages and drawbacks. In addition, we review materials for modifying antibodies to improve the performance of the reaction of immunoassay. We also review the state of the art in microfluidic immunoassays POC platforms, from the laboratory to routine clinical practice, and also commercial products in the market. Finally, we discuss the current challenges and future developments in microfluidic immunoassays. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Laboratory evaluation of a field-portable sealed source X-ray fluorescence spectrometer for determination of metals in air filter samples.

    Science.gov (United States)

    Lawryk, Nicholas J; Feng, H Amy; Chen, Bean T

    2009-07-01

    Recent advances in field-portable X-ray fluorescence (FP XRF) spectrometer technology have made it a potentially valuable screening tool for the industrial hygienist to estimate worker exposures to airborne metals. Although recent studies have shown that FP XRF technology may be better suited for qualitative or semiquantitative analysis of airborne lead in the workplace, these studies have not extensively addressed its ability to measure other elements. This study involved a laboratory-based evaluation of a representative model FP XRF spectrometer to measure elements commonly encountered in workplace settings that may be collected on air sample filter media, including chromium, copper, iron, manganese, nickel, lead, and zinc. The evaluation included assessments of (1) response intensity with respect to location on the probe window, (2) limits of detection for five different filter media, (3) limits of detection as a function of analysis time, and (4) bias, precision, and accuracy estimates. Teflon, polyvinyl chloride, polypropylene, and mixed cellulose ester filter media all had similarly low limits of detection for the set of elements examined. Limits of detection, bias, and precision generally improved with increasing analysis time. Bias, precision, and accuracy estimates generally improved with increasing element concentration. Accuracy estimates met the National Institute for Occupational Safety and Health criterion for nearly all the element and concentration combinations. Based on these results, FP XRF spectrometry shows potential to be useful in the assessment of worker inhalation exposures to other metals in addition to lead.

  11. Variance function estimation for immunoassays

    International Nuclear Information System (INIS)

    Raab, G.M.; Thompson, R.; McKenzie, I.

    1980-01-01

    A computer program is described which implements a recently described, modified likelihood method of determining an appropriate weighting function to use when fitting immunoassay dose-response curves. The relationship between the variance of the response and its mean value is assumed to have an exponential form, and the best fit to this model is determined from the within-set variability of many small sets of repeated measurements. The program estimates the parameter of the exponential function with its estimated standard error, and tests the fit of the experimental data to the proposed model. Output options include a list of the actual and fitted standard deviation of the set of responses, a plot of actual and fitted standard deviation against the mean response, and an ordered list of the 10 sets of data with the largest ratios of actual to fitted standard deviation. The program has been designed for a laboratory user without computing or statistical expertise. The test-of-fit has proved valuable for identifying outlying responses, which may be excluded from further analysis by being set to negative values in the input file. (Auth.)

  12. Recent advancements in the immunoassay domain

    International Nuclear Information System (INIS)

    Pradelles, Ph.

    1997-01-01

    The two types of immunoassay techniques, the competition analysis and the immuno-metric analysis (sandwich type), are described; the tracers used with theses methods have high specific radioactivity levels in order to be traced at extremely low content. Non radioactive tracers have been also developed, such as enzymatic, fluorescent, luminescent tracers, which are simpler and may be used at home. The Cea has recently developed some innovative immunoassay formats, such as acetylcholinesterase as a new enzymatic tracer, and immuno-metric dosage for very small molecules such as haptenes

  13. The right environment for the immunoassay

    International Nuclear Information System (INIS)

    Emon, J.M. Van; Gerlach, C.L.

    1995-01-01

    For the US Environmental Protection Agency (EPA), the first in-house research effort began in 1987, when results of an early immunoassay field study verified the technology's potential for environmental applications. Looking at the fundamental features of immunochemical reactions from the clinical laboratories, analytical chemists realized the potential value of these methods for hazardous waste site characterization and pesticide monitoring. Immunoassays rely on the interaction between an antibody and a target analyte. For environmental purposes, enzyme immunoassays are generally used. After the target analyte binds to the antibody, an enzymatic reaction yields a colorimetric change. This change, read visually or by a spectrophotometer, indicates the concentration of the target analyte. Promising results with assays for compounds (such as paraquat and pentachlorophenol) and compound groups (such as total petroleum hydrocarbons and polychlorinated biphenyls) spurred interest among various entrepreneurs. The first target market for immunoassays was environmental engineers and field crews who needed quick answers on-site to determine the direction of further remediation efforts

  14. DUVAS (derivative uv-absorption spectrometer): instrument description and operating manual

    International Nuclear Information System (INIS)

    Hawthorne, A.R.; Dougherty, J.M.; Metcalfe, C.E.

    1980-11-01

    DUVAS is a real-time, field-portable spectrometer capable of monitoring a variety of aromatic organic vapors and inorganic gases at sub-ppM concentrations. The instrument is a prototype, microcomputer-controlled, derivative ultraviolet (UV) absorption spectrometer (DUVAS) developed primarily for area monitoring at coal conversion facilities, although other important occupational and environmental monitoring applications for compounds such as SO 2 , NO/sub x/, NH 3 , and HCHO are also being pursued

  15. Development of national immunoassay reagent programmes

    International Nuclear Information System (INIS)

    Sufi, S.B.; Micallef, J.V.; Ahsan, R.; Goncharov, N.P.

    1992-01-01

    Despite the existence of networks of fully equipped laboratories with well-trained staff, the availability of immunodiagnostic services in developing countries is often limited by the high cost of imported kits. There are a number of ways of tackling this problem, ranging from bulk purchase of kits or reagents to local development and production of assay systems. Argentina/Chile, China, Cuba/Mexico, and Thailand are amongst the countries which have established local immunoassay reagent programmes to manufacture low cost, high quality immunoassay reagents. Kits from these projects are now beginning to become available, and it is hoped that they will promote national diagnostic services and research, as well as stimulating the development of reagent programmes for other analytes. (author). 4 refs, 1 tab

  16. Studies on direct and indirect electrochemical immunoassays

    OpenAIRE

    Buckley, Eileen

    1989-01-01

    Two approaches to electrochemical immunoassay are reported. The first approach was an indirect method, involving an electroactive, enzyme-catalysed, substrate to product reaction. Conditions were optimised for the amperometric detection of para-aminophenol, the electroactive product of the alkaline phosphatase catalysed hydrolysis of a new substrate, p-aminophenylphosphate, after separation by HPLC. The second approach involved the direct electrochemical detection of an immunoglo...

  17. Lateral Flow Immunoassays for Ebola Virus Disease Detection in Liberia.

    Science.gov (United States)

    Phan, Jill C; Pettitt, James; George, Josiah S; Fakoli, Lawrence S; Taweh, Fahn M; Bateman, Stacey L; Bennett, Richard S; Norris, Sarah L; Spinnler, David A; Pimentel, Guillermo; Sahr, Phillip K; Bolay, Fatorma K; Schoepp, Randal J

    2016-10-15

    Lateral flow immunoassays (LFIs) are point-of-care diagnostic assays that are designed for single use outside a formal laboratory, with in-home pregnancy tests the best-known example of these tests. Although the LFI has some limitations over more-complex immunoassay procedures, such as reduced sensitivity and the potential for false-positive results when using complex sample matrices, the assay has the benefits of a rapid time to result and ease of use. These benefits make it an attractive option for obtaining rapid results in an austere environment. In an outbreak of any magnitude, a field-based rapid diagnostic assay would allow proper patient transport and for safe burials to be conducted without the delay caused by transport of samples between remote villages and testing facilities. Use of such point-of-care instruments in the ongoing Ebola virus disease (EVD) outbreak in West Africa would have distinct advantages in control and prevention of local outbreaks, but proper understanding of the technology and interpretation of results are important. In this study, a LFI, originally developed by the Naval Medical Research Center for Ebola virus environmental testing, was evaluated for its ability to detect the virus in clinical samples in Liberia. Clinical blood and plasma samples and post mortem oral swabs submitted to the Liberian Institute for Biomedical Research, the National Public Health Reference Laboratory for EVD testing, were tested and compared to results of real-time reverse transcription-polymerase chain reaction (rRT-PCR), using assays targeting Ebola virus glycoprotein and nucleoprotein. The LFI findings correlated well with those of the real-time RT-PCR assays used as benchmarks. Rapid antigen-detection tests such as LFIs are attractive alternatives to traditional immunoassays but have reduced sensitivity and specificity, resulting in increases in false-positive and false-negative results. An understanding of the strengths, weaknesses, and

  18. Flotation Immunoassay: Masking the Signal from Free Reporters in Sandwich Immunoassays.

    Science.gov (United States)

    Chen, Hui; Hagström, Anna E V; Kim, Jinsu; Garvey, Gavin; Paterson, Andrew; Ruiz-Ruiz, Federico; Raja, Balakrishnan; Strych, Ulrich; Rito-Palomares, Marco; Kourentzi, Katerina; Conrad, Jacinta C; Atmar, Robert L; Willson, Richard C

    2016-04-14

    In this work, we demonstrate that signal-masking reagents together with appropriate capture antibody carriers can eliminate the washing steps in sandwich immunoassays. A flotation immunoassay (FI) platform was developed with horseradish peroxidase chemiluminescence as the reporter system, the dye Brilliant Blue FCF as the signal-masking reagent, and buoyant silica micro-bubbles as the capture antibody carriers. Only reporters captured on micro-bubbles float above the dye and become visible in an analyte-dependent manner. These FIs are capable of detecting proteins down to attomole levels and as few as 10(6) virus particles. This signal-masking strategy represents a novel approach to simple, sensitive and quantitative immunoassays in both laboratory and point-of-care settings.

  19. Massively multi-parametric immunoassays using ICPMS

    International Nuclear Information System (INIS)

    Tanner, S.D.; Ornatsky, O.; Bandura, D.R.; Baranov, V.I.

    2009-01-01

    The use of stable isotopes as tags in immunoassays, and their determination by ICPMS, is poised to have a huge impact on multi-parametric bioanalysis. A new technology, which we term 'mass cytometry', enables high throughput, highly multiplexed individual cell analysis. Preliminary results for T-cell immunophenotyping in peripheral blood mononuclear cells (PBMC), agonist influence on concomitant phosphorylation pathways, and sub-classification of acute myeloid leukemia patients' samples will be presented. The significance of individual cell analysis is demonstrated by the identification of populations of rogue cells in PBMC samples through the use of multidimensional neural network cluster analysis. (author)

  20. Gliadin Detection in Food by Immunoassay

    Science.gov (United States)

    Grant, Gordon; Sporns, Peter; Hsieh, Y.-H. Peggy

    Immunoassays are very sensitive and efficient tests that are commonly used to identify a specific protein. Examples of applications in the food industry include identification of proteins expressed in genetically modified foods, allergens, or proteins associated with a disease, including celiac disease. This genetic disease is associated with Europeans and affects about one in every 200 people in North America. These individuals react immunologically to wheat proteins, and consequently their own immune systems attack and damage their intestines. This disease can be managed if wheat proteins, specifically "gliadins," are avoided in foods.

  1. Fluorescence immunoassay for detecting periodontal bacterial pathogens in plaque.

    OpenAIRE

    Wolff, L F; Anderson, L; Sandberg, G P; Aeppli, D M; Shelburne, C E

    1991-01-01

    A particle concentration fluorescence immunoassay has been modified into a bacterial concentration fluorescence immunoassay (BCFIA) to rapidly detect periodontopathic bacteria in human plaque samples. The BCFIA utilizes fluorescently tagged monoclonal antibodies (MAbs) directed against the lipopolysaccharide of selected gram-negative plaque bacteria. Microorganisms closely associated with periodontal disease that can be identified in plaque with the BCFIA include Porphyromonas gingivalis, Bac...

  2. Review of the biochemical basis of enzyme immunoassays

    International Nuclear Information System (INIS)

    Klingler, W.

    1982-01-01

    The ever increasing number of radioimmunological determination poses problems allied with the handling of radioactive substances. In recent years various non-radioactive methods have been developed, among which the enzyme immunoassay is already in routine use. Homogeneous and heterogeneous enzyme immunoassays are described. Criteria for enzymes, substrates and enzyme-substrate reactions are listed. (orig.) [de

  3. Fake news? Biotin interference in thyroid immunoassays.

    Science.gov (United States)

    Koehler, Viktoria F; Mann, Ulrike; Nassour, Ayham; Alexander Mann, W

    2018-05-29

    We report on a 47 year old male patient with multiple sclerosis (MS) presenting in our outpatient neurology clinic in Frankfurt/Main for therapy evaluation. Before change of treatment laboratory investigations were performed. Thyroid function tests (TFTs) with a streptavidin/biotin based immunoassay revealed severe hyperthyroidism with positive thyroid autoantibodies suggestive for Graves' disease. Clinical presentation and thyroid sonography were unremarkable. Due to the discordance between clinical presentation and TFTs, we repeated medical history, in which the patient reported taking high-doses of biotin (300 mg/day) for MS. Recent studies with patients suffering from primary and secondary progressive MS, indicated promising effects of high-dose biotin on MS-related disability. In immunoassays relaying on streptavidin-biotin interaction, biotin intake can cause falsely high or low results. Two weeks after withdrawing biotin, biotin/streptavidin dependant assays showed no longer the biochemical picture of severe hyperthyroidism. Biotin intake should be paused for at least two to five days prior to the use of biotin/streptavidin dependant assays. Alternatively, non-biotin/streptavidin dependant assays (radioimmunoassay, gas chromatography-mass spectrometry/liquid chromatography-mass spectrometry) may be used. Copyright © 2017. Published by Elsevier B.V.

  4. A Switchable Linker-Based Immunoassay for Ultrasensitive Visible Detection of Salmonella in Tomatoes.

    Science.gov (United States)

    Hahn, Jungwoo; Kim, Eunghee; You, Young Sang; Gunasekaran, Sundaram; Lim, Seokwon; Choi, Young Jin

    2017-10-01

    On-site detection for sensitive identification of foodborne pathogens on fresh produce with minimal use of specialized instrumentation is crucial to the food industry. A switchable linker (SL)-based immunoassay was designed for ultrasensitive on-site detection of Salmonella in tomato samples. The assay is based on large-scale aggregation of gold nanoparticles (GNPs), induced by a quantitative relationship among the biotinylated Salmonella polyclonal antibody (b-Ab) used as the SL, the functionalized GNPs, and Salmonella. Important factors such as the concentration of SLs, time required for large-scale aggregation, and selectivity of b-Ab were optimized to minimize the detection time (within 45 min with gentle agitation) and achieve the lowest limit of detection (LOD; 10 CFU/g in tomato samples) possible. This SL-based immunoassay with its relatively low LOD and short detection time may meet the need for rapid, simple, on-site analysis of pathogens in fresh produce. The novel switchable linker-based immunoassay is a rapid, specific, and sensitive method that has potential applications for routine diagnostics of Salmonella in tomato products. These advantages make it a practical approach for general use in the processing industry to detect Salmonella rapidly and to implement appropriate regulatory procedures. Furthermore, it could be applied to other fresh products including cantaloupe, strawberry, and cucumbers. © 2017 Institute of Food Technologists®.

  5. The microassay on a card: A rugged, portable immunoassay

    Science.gov (United States)

    Kidwell, David

    1991-01-01

    The Microassay on a Card (MAC) is a portable, hand-held, non-instrumental immunoassay that can test for the presence of a wide variety of substances in the environment. The MAC is a simple device to use. A drop of test solution is placed on one side of the card and within five minutes a color is developed on the other side in proportion to the amount of substance in the test solution, with sensitivity approaching 10 ng/ml. The MAC is self-contained and self-timed; no reagents or timing is necessary. The MAC may be configured with multiple wells to provide simultaneous testing for multiple species. As envisioned, the MAC will be employed first as an on-site screen for drugs of abuse in urine or saliva. If the MAC can be used as a screen of saliva for drugs of abuse, it could be applied to driving while intoxicated, use of drugs on the job, or testing of the identity of seized materials. With appropriate modifications, the MAC also could be used to test for environmental toxins or pollutants.

  6. A compact HV supply for field/PC based nuclear instrumentation

    International Nuclear Information System (INIS)

    Manna, A.; Nikhare, D.M.; Madhavi, V.; Bayala, A.K.; Mukhopadhyay, P.K.; Kataria, S.K.

    2001-01-01

    In the recent years, most of the nuclear instruments that were earlier based on NIM Bin standards, are becoming available as PC Add-on cards. This trend is due to the decreasing prices of desktop personal computers and the necessity for automation in radioactivity measurements. This paper describes the design and development of a HV supply module and its PC Add-on card version for field portable/ PC based nuclear instrumentation. The HV supply though being very compact in size meets all the stringent specifications required for detector biasing applications and it has been tested for use with NaI, BF 3 . (author)

  7. Abbott’s Fluorescence Polarization Immunoassay for Cyclosporine and Metabolites Compared with the Sandoz “Sandimmune” RIA

    OpenAIRE

    Sanghvi, Ajit; Diven, Warren; Seltman, Howard; Starzl, Thomas

    1988-01-01

    A new procedure for measuring cyclosporine in plasma has been introduced by Abbott Laboratories, involving their TDx instrumentation and fluorescence polarization immunoassay. Radioimmunoassay (RIA) and high-performance liquid chromatography are currently the conventional methods for measuring cyclosporine in plasma and whole blood. In an effort to find a method that will decrease the radioactive hazard, the reagent and supply cost, and the labor requirements associated with RIA procedures, w...

  8. Chemiluminescence immunoassay for prostate-specific antigen

    International Nuclear Information System (INIS)

    Zhang Xuefeng; Liu Yibing; Jia Juanjuan; Xu Wenge; Li Ziying; Chen Yongli; Han Shiquan

    2008-01-01

    The chemiluminescence immunoassay (CLIA) for serum total prostate-specific antigen (T-PSA) was developed. The reaction of luminol with hydrogen peroxide was introduced into this chemiluminescence system. The detection limit is established as 0.12 μg/L (n=10, mean of zero standard + 2SD) and the analytical recovery of PSA is 83.8%-118.7%. The intra-assay and inter-assay CVs vary from 4.4%-5.0% and 6.2%-11.7%, respectively. The experimental correlation coefficient of dilution is found to be 0.999. Compared with immunoradiometric assay (IRMA) kits, the correlative equation is y=1.07x+0.68, and correlation coefficient r=0.97. The standard range for the method is 1.5-80 μg/L, and it presents good linearity. (authors)

  9. Development of a portable ambient temperature radiometric assaying instrument

    International Nuclear Information System (INIS)

    Lavietes, A.D.; McQuaid, J.H.; Ruhter, W.D.; Paulus, T.J.

    1995-01-01

    There is a strong need for portable radiometric instrumentation that can accurately confirm the presence of nuclear materials and allow isotopic analysis of radionuclides in the field. To fulfill this need, the authors are developing a hand-held, non-cryogenic, low-power gamma- and X-ray measurement and analysis instrument that can both search and then accurately verify the presence of nuclear materials. The authors report on the use of cadmium zinc telluride detectors, signal processing electronics, and the new field-portable instrument based on the MicroNOMAD Multichannel Analyzer from EG and G ORTEC. They will also describe the isotopic analysis that allows uranium enrichment measurements to be made accurately in the field. The benefits of this work are realized in a wide spectrum of applications that include Arms Control, Nuclear Safeguards, Environmental Management, Emergency Response, and Treaty Verification

  10. Evaluation of Beckman Coulter DxI 800 immunoassay system using clinically oriented performance goals.

    Science.gov (United States)

    Akbas, Neval; Schryver, Patricia G; Algeciras-Schimnich, Alicia; Baumann, Nikola A; Block, Darci R; Budd, Jeffrey R; Gaston, S J Stephen; Klee, George G

    2014-11-01

    We evaluated the analytical performance of 24 immunoassays using the Beckman Coulter DxI 800 immunoassay systems at Mayo Clinic, Rochester, MN for trueness, precision, detection limits, linearity, and consistency (across instruments and reagent lots). Clinically oriented performance goals were defined using the following methods: trueness-published desirable accuracy limits, precision-published desirable biologic variation; detection limits - 0.1 percentile of patient test values, linearity - 50% of total error, and consistency-percentage test values crossing key decision points. Local data were collected for precision, linearity, and consistency. Data were provided by Beckman Coulter, Inc. for trueness and detection limits. All evaluated assays except total thyroxine were within the proposed goals for trueness. Most of the assays met the proposed goals for precision (86% of intra-assay results and 75% of inter-assay results). Five assays had more than 15% of the test results below the minimum detection limits. Carcinoembryonic antigen, total thyroxine and free triiodothyronine exceeded the proposed goals of ±6.3%, ±5% and ±5.7% for dilution linearity. All evaluated assays were within the proposed goals for instrument consistency. Lot-to-lot consistency results for cortisol, ferritin and total thyroxine exceeded the proposed goals of 3.3%, 11.4% and 7% at one medical decision level, while vitamin B12 exceeded the proposed goals of 5.2% and 3.8% at two decision levels. The Beckman Coulter DxI 800 immunoassay system meets most of these proposed goals, even though these clinically focused performance goals represent relatively stringent limits. Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  11. Can LC and LC-MS ever replace immunoassays?

    Directory of Open Access Journals (Sweden)

    Timothy G. Cross

    2016-10-01

    Full Text Available Immunoassays have been the technology of choice for the analysis of biomolecules for many decades across a wide range of applications in research, diagnostics and infectious disease monitoring. There are good reasons for the wide adoption of immunoassays but even such a well established and characterised technique has limitations and as such investigators are looking at alternative technologies. One such alternative is liquid chromatography (LC and, more specifically, liquid chromatography coupled with mass spectrometry (LC-MS. This article will review both immunoassay and LC and LC-MS technologies and methodologies and discuss the advantages and limitations of both approaches. In addition, the next developments that will need to occur before there is widespread adoption of LC and LC-MS technology preferentially over immunoassays will be examined.

  12. Detection of narcotics with an immunoassay film badge

    International Nuclear Information System (INIS)

    Lukens, H.R.

    1993-01-01

    Efficient personnel performance, a major requirement for a safe nuclear industry, is jeopardized where personnel use narcotics. However, detection of narcotics at nuclear plants is a challenge. The unique specificity and sensitivity of an immunoassay has been implemented in the form of a small, dry immunoassay film badge (IFB) for the detection of vapors emitted by narcotics. The device is suitable as an area monitor, and its characteristics are suitable for use as a breath monitor for the detection of drug use

  13. Status of immunoassay as an analytical tool in environmental investigations

    International Nuclear Information System (INIS)

    Van Emon, J.M.

    2000-01-01

    Immunoassay methods were initially applied in clinical situations where their sensitivity and selectivity were utilized for diagnostic purposes. In the 1970s, pesticide chemists realized the potential benefits of immunoassay methods for compounds difficult to analyze by gas chromatography. This transition of the technology has extended to the analysis of soil, water, food and other matrices of environmental and human exposure significance particularly for compounds difficult to analyze by chromatographic methods. The utility of radioimmunoassays and enzyme immunoassays for environmental investigations was recognized in the 1980s by the U.S. Environmental Protection Agency (U.S. EPA) with the initiation of an immunoassay development programme. The U.S. Department of Agriculture (USDA) and the U.S. Food and Drug Administration (PDA) have investigated immunoassays for the detection of residues in food both from an inspection and a contamination prevention perspective. Environmental immunoassays are providing rapid screening information as well as quantitative information to fulfill rigorous data quality objectives for monitoring programmes

  14. Potential applications of immunoassays in studies of flatfish recruitment

    Science.gov (United States)

    Feller, Robert J.

    The fisheries recruitment-stock problem, a lack of correlation between measures of reproductive output of the parent stock and recruitment to the fishery, has several potential biotic and abiotic causes. Immunoassays may be useful in examining several aspects of this and several other problems in flatfish ecology: stock identification, parasitism and disease, and trophic interactions. Given stage-specific antisera capable of recognozing antigenic moieties of, for instance, eggs, larvae, or newly-settled juveniles, it is possible to screen stomach contents of many putative predators ( e.g., shrimp or crabs) rapidly for the presence and amounts of platfish prey. This trophic application of immunological methods has great promise for measuring loss of potential recruits to predation. All immunoassays are limited by the quality of antisera used and the researcher's ability to interpret quantitative data in an ecologically meaningful way. Key references for applications of immunoassays in fish-related questions are provided with recommendations for their utilization.

  15. [Membrane-filtration immunoassay: reagents, methods and the diagnostic and technical means for detection].

    Science.gov (United States)

    Khramov, E N; Osin, N S; Pomelova, V G; Vikha, I V; Bychenkova, T A; Smirnova, V G; Grakina, G I; Kas'ianova, T A

    1999-01-01

    The comprehensive development of dot-EIA made at the State Research Institute of Biological Instrument-Making Industry has provided devices KIMF-02 and KIMF-03), a base of chemical reagents, immunoassays, test systems for detection of a wide range of causative agents of viral and bacterial infections, that of serodiagnosis of their related diseases. The KIMF-02 kit has undergone engineering and medical tests and recommended for the Ministry of Health of the Russian Federation to produce them in stock. The kit includes all required for analysis even in an ill-equipped laboratory, a set of attached agents ensures a valid visual recording of results. The developed procedures and test systems allow the immunoassay to be as sensitive as TIFA; however, they are laborious and much simpler in design. The simple and rapid procedures of dot-EIA are recommended for incorporation into the a package of laboratory methods for verification of the accumulation of virus-specific antigens in various biological substrata, environmental samples, for control of the activity of antigens and antibodies used in serological tests, for detection of specific antigens in the clinical samples, and for serodiagnosis of infections.

  16. Rapid detection of fungal alpha-amylase in the work environment with a lateral flow immunoassay

    NARCIS (Netherlands)

    Bogdanovic, J.; Koets, M.; Sander, I.; Wouters, I.; Meijster, T.; Heederik, D.J.J.; Amerongen, van A.; Doekes, G.

    2006-01-01

    Background Occupational allergen exposure assessment usually requires airborne dust sampling at the worksite followed by dust extraction and enzyme immunoassay (EIA) analysis at the laboratory. Use of semiquantitative lateral flow immunoassays (LFIAs) may allow a more rapid detection procedure with

  17. Preparation by irradiation of a solid support for enzyme immunoassay

    International Nuclear Information System (INIS)

    Kumakura, M.; Kaetsu, I.

    1984-01-01

    Reagents (immobilized anti-α-fetoprotein discs) having a porous structure were prepared for enzyme immunoassay of α-fetoprotein by radiation polymerization at low temperatures. Discs were attached to sticks for easy handling. The activity (determined by absorbance at 492 nm) of the discs varied with the hydrophilic properties and size of the discs. The discs are sufficiently sensitive and precise for enzyme immunoassay of α-fetoprotein. Anti-AFP dissolved in PBS solution was mixed with a monomer solution of hydroxyethyl methacrylate and hydroxypropyl methacrylate. The mixture was frozen to -78 0 C and gamma irradiated. (Auth.)

  18. Multiplex Immunoassay Profiling of Hormones Involved in Metabolic Regulation.

    Science.gov (United States)

    Stephen, Laurie; Guest, Paul C

    2018-01-01

    Multiplex immunoassays are used for rapid profiling of biomarker proteins and small molecules in biological fluids. The advantages over single immunoassays include lower sample consumption, cost, and labor. This chapter details a protocol to develop a 5-plex assay for glucagon-like peptide 1, growth hormone, insulin, leptin, and thyroid-stimulating hormone on the Luminex ® platform. The results of the analysis of insulin in normal control subjects are given due to the important role of this hormone in nutritional programming diseases.

  19. Advanced sampling techniques for hand-held FT-IR instrumentation

    Science.gov (United States)

    Arnó, Josep; Frunzi, Michael; Weber, Chris; Levy, Dustin

    2013-05-01

    FT-IR spectroscopy is the technology of choice to identify solid and liquid phase unknown samples. The challenging ConOps in emergency response and military field applications require a significant redesign of the stationary FT-IR bench-top instruments typically used in laboratories. Specifically, field portable units require high levels of resistance against mechanical shock and chemical attack, ease of use in restrictive gear, extreme reliability, quick and easy interpretation of results, and reduced size. In the last 20 years, FT-IR instruments have been re-engineered to fit in small suitcases for field portable use and recently further miniaturized for handheld operation. This article introduces the HazMatID™ Elite, a FT-IR instrument designed to balance the portability advantages of a handheld device with the performance challenges associated with miniaturization. In this paper, special focus will be given to the HazMatID Elite's sampling interfaces optimized to collect and interrogate different types of samples: accumulated material using the on-board ATR press, dispersed powders using the ClearSampler™ tool, and the touch-to-sample sensor for direct liquid sampling. The application of the novel sample swipe accessory (ClearSampler) to collect material from surfaces will be discussed in some detail. The accessory was tested and evaluated for the detection of explosive residues before and after detonation. Experimental results derived from these investigations will be described in an effort to outline the advantages of this technology over existing sampling methods.

  20. Targeted deposition of antibodies on a multiplex CMOS microarray and optimization of a sensitive immunoassay using electrochemical detection.

    Directory of Open Access Journals (Sweden)

    John Cooper

    2010-03-01

    Full Text Available The CombiMatrix ElectraSense microarray is a highly multiplex, complementary metal oxide semiconductor with 12,544 electrodes that are individually addressable. This platform is commercially available as a custom DNA microarray; and, in this configuration, it has also been used to tether antibodies (Abs specifically on electrodes using complementary DNA sequences conjugated to the Abs.An empirical method is described for developing and optimizing immunoassays on the CombiMatrix ElectraSense microarray based upon targeted deposition of polypyrrole (Ppy and capture Ab. This process was automated using instrumentation that can selectively apply a potential or current to individual electrodes and also measure current generated at the electrodes by an enzyme-enhanced electrochemical (ECD reaction. By designating groups of electrodes on the array for different Ppy deposition conditions, we determined that the sensitivity and specificity of a sandwich immunoassay for staphylococcal enterotoxin B (SEB is influenced by the application of different voltages or currents and the application time. The sandwich immunoassay used a capture Ab adsorbed to the Ppy and a reporter Ab labeled for fluorescence detection or ECD, and results from these methods of detection were different.Using Ppy deposition conditions for optimum results, the lower limit of detection for SEB using the ECD assay was between 0.003 and 0.01 pg/ml, which represents an order of magnitude improvement over a conventional enzyme-linked immunosorbant assay. In the absence of understanding the variables and complexities that affect assay performance, this highly multiplexed electrode array provided a rapid, high throughput, and empirical approach for developing a sensitive immunoassay.

  1. Biosensor immunoassay for flumequine in broiler serum and muscle

    NARCIS (Netherlands)

    Haasnoot, W.; Gercek, H.; Cazemier, G.; Nielen, M.W.F.

    2007-01-01

    Flumequine (Flu) is one of the fluoroquinolones most frequently applied for the treatment of broilers in The Netherlands. For the detection of residues of Flu in blood serum of broilers, a biosensor immunoassay (BIA) was developed which was fast (7.5 min per sample) and specific (no cross-reactivity

  2. Feasibility of a simple microsieve-based immunoassay platform

    NARCIS (Netherlands)

    Zweitzig, D.R.; Tibbe, Arjan G.J.; Nguyen, A.T.; van Rijn, C.J.M.; Kopnitsky, M.J.; Cichonski, K.; Terstappen, Leonardus Wendelinus Mathias Marie

    2016-01-01

    The intrinsic properties of silicon microsieves, such as an optically flat surface, high overall porosity, and low flow resistance have led to an increasing number of biotechnology applications. In this report, the feasibility of creating a microsieve-based immunoassay platform was explored.

  3. Feasibility of a simple microsieve-based immunoassay platform

    NARCIS (Netherlands)

    Zweitzig, Daniel R.; Tibbe, Arjan G.; Nguyen, Ai T.; Rijn, van Cees J.M.; Kopnitsky, Mark J.; Cichonski, Kathleen; Terstappen, Leon W.M.M.

    2016-01-01

    The intrinsic properties of silicon microsieves, such as an optically flat surface, high overall porosity, and low flow resistance have led to an increasing number of biotechnology applications. In this report, the feasibility of creating a microsieve-based immunoassay platform was explored.

  4. Kinase Activity Studied in Living Cells Using an Immunoassay

    Science.gov (United States)

    Bavec, Aljos?a

    2014-01-01

    This laboratory exercise demonstrates the use of an immunoassay for studying kinase enzyme activity in living cells. The advantage over the classical method, in which students have to isolate the enzyme from cell material and measure its activity in vitro, is that enzyme activity is modulated and measured in living cells, providing a more…

  5. IMMUNOASSAYS FOR THE DETECTION OF UROKINASE RECEPTOR FORMS

    DEFF Research Database (Denmark)

    2004-01-01

    amounts of uPAR forms in a sample with data indicative of the presence of the cancer disease. The method can be used for staging, prognosis or diagnosis of prostate cancer. Two novel monoclonal antibodies and a kit and immunoassays for detecting at least one uPAR form(s) are also described in the present...

  6. Rapid micromotor-based naked-eye immunoassay.

    Science.gov (United States)

    de Ávila, Berta Esteban-Fernández; Zhao, Mingjiao; Campuzano, Susana; Ricci, Francesco; Pingarrón, José M; Mascini, Marcello; Wang, Joseph

    2017-05-15

    A dynamic micromotor-based immunoassay, exemplified by cortisol detection, based on the use of tubular micromotors functionalized with a specific antibody is described. The use of antibody-functionalized micromotors offers huge acceleration of both direct and competitive cortisol immunoassays, along with greatly enhanced sensitivity of direct and competitive immunoassays. The dramatically improved speed and sensitivity reflect the greatly increased likelihood of antibody-cortisol contacts and fluid mixing associated with the dynamic movement of these microtube motors and corresponding bubble generation that lead to a highly efficient and rapid recognition process. Rapid naked-eye detection of cortisol in the sample is achieved in connection to use of horseradish peroxidase (HRP) tag and TMB/H 2 O 2 system. Key parameters of the competitive immunoassay (e.g., incubation time and reaction volume) were optimized. This fast visual micromotor-based sensing approach enables "on the move" specific detection of the target cortisol down to 0.1μgmL -1 in just 2min, using ultrasmall (50µL) sample volumes. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Direct salivary cortisol radio-immunoassay determination. Clinical applications

    International Nuclear Information System (INIS)

    Simon, C.; Cherfan, J.; Kurtz, F.; Vignon, F.; Schlienger, J.L.; Chabrier, G.

    1987-01-01

    Salivary cortisol levels reflect the biologically active free fraction of blood cortisol. The authors describe the results obtained with the aim of a radio-immunoassay commercial serum cortisol kit, without prealable extraction in different physiological and pathological situations. Salivary cortisol determination appears performant both in nycthemeral studies and in stimulation or freination tests [fr

  8. Evaluation of Six Different Immunoassays for Serum Thyrotropin

    International Nuclear Information System (INIS)

    Ma Donghong; Lu Hankui; Gao Yunchao; Ge Wenli; Xiong Jiang; Liu Qiaoping; Gu Qing

    2010-01-01

    To analyzes the discrepancy and association among six different thyrotropin (TSH) immunoassay methods and to study their impact on the clinical diagnoses of thyroid diseases, the 150 serum samples from three groups consisting of hyperthyroidism, hypothyroidism and healthy subjects, 50 samples in each group were included in this study. The serum TSH levels were measured simultaneously by radioimmunoassay (RIA), immunoradiometric assay (IRMA), three-type chemilumiminescence immunoassay (CLIA) and electrochemiluminescence immunoassay (ECLIA). The results showed that individual serum TSH level varied significantly from one assay to another. There was no correlation between TSH RIA and other five assays in groups of hyperthyroidism and healthy subjects(P>0.05). The correlations between TSH IRMA and four automatic assays in hyperthyroidism group were relatively low (r= 0.38∼0.41). However, among the four automatic assays, TSH levels were well correlated (r= 0.92∼0.99). For clinical diagnoses, TSH RIA alone was not useful in the differentiation of hyperthyroidism and normal subjects, and TSH IRMA was misleading in some hyperthyroidism. There were no significant differences for four TSH automatic immunoassays in differential diagnoses of thyroid diseases. (authors)

  9. Organic geochemistry and environmental instrumentation programs

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    The areas of research of the Organic Geochemistry Group include (1) computer-assisted gas chromatrographic, qualitative, and quantitative analyses of coal-derived complex mixtures; (2) chemodynamic measurements in complex organic mixtures to study the transport and transformation processes of chemicals in the environment; (3) bioassay-directed characterization of mutagenic polycyclic aromatic hydrocarbons in coal-derived materials; (4) chemical and toxicological evaluation of condensates from mild coal gasification processes; (5) development of rapid (high-pressure liquid chromatography) characterization techniques for primary aromatic amines in coal-derived liquids; (6) study of flame ionization detector response factors and chemical structure in gas chromatography; (7) development of a simple, portable device for preconcentrating airborne aromatic amines to be analyzed by portable liquid chromatography; (8) initial uptake and release studies of perchloroethylene and trichloroethylene in pine needles; (9) application of stable carbon isotope techniques in tracing environmental pollutants; (10) development of control technology for hydrazine fuels by neutralization with hypochlorite II. The Environmental Instrumentation group is engaged in research to develop and build prototype field-portable devices and instruments for the detection, identification, and quantification of volatile hazardous gases in a variety of environmental and workplace settings

  10. Comparison of capillary electrophoresis-based immunoassay with fluorescence polarization immunoassay for the immunodetermination of methamphetamine using various methamphetamine antibodies.

    Science.gov (United States)

    Choi, J; Kim, C; Choi, M J

    1998-11-01

    An accurate and simple immunoassay using capillary electrophoresis (CE) with laser-induced fluorescence (LIF) was performed for the detection of methamphetamine (MA) in urine. The CE-LIF was conducted with an untreated fused-silica column using antiserum and a tracer of fluorescein isothiocyanate (FITC)-labeled MA. This CE-LIF system was compared with fluorescence polarization immunoassay (FPIA) in a TDx analyzer in the photo-check mode using the same FITC-labeled tracer and the same antiserum. Various antibodies, not only those prepared by our own immunogens but also those from commercial sources, were screened and characterized in both assay systems with regard to sensitivity, precision, and cross-reactivity. Both systems satisfied analytical precision and gave similar cross-reactivity patterns. However, the CE-LIF-based immunoassay was approximately one order superior to FPIA in sensitivity, requiring less volume of sample, antiserum, and tracer for the assay. Considering that the FPIA system is well known to be a useful tool for screening antibodies and detecting drugs, the CE-LIF-based immunoassay system, which is seemingly more advantageous than the FPIA system, appears to have great power for the characterization of antibodies and for the detection of MA in urine.

  11. Development of Indirect Competitive Immuno-Assay Method Using SPR Detection for Rapid and Highly Sensitive Measurement of Salivary Cortisol Levels

    International Nuclear Information System (INIS)

    Tahara, Yusuke; Huang, Zhe; Kiritoshi, Tetsuro; Onodera, Takeshi; Toko, Kiyoshi

    2014-01-01

    The monitoring of salivary cortisol as a key biomarker of an individual’s stress response has been increasingly focused on. This paper describes the development of a novel cortisol immuno-assay method based on an indirect competitive method using a commercially available surface plasmon resonance instrument. The surface of an Au chip was modified with PEG6-COOH aromatic dialkanethiol self-assembled monolayers and hydrocortisone 3-(O-carboxymethyl) oxime (hydrocortisone 3-CMO) as a cortisol analog. A detection limit of 38 ppt range with a measurement range of 10 ppt–100 ppb was accomplished without the incubation of a mixing solution consisting of standard cortisol and an anti-cortisol antibody, and the time for quantification of cortisol concentration was 8 min from the sample injection. We experimentally compared our immuno-assay with a commercialized salivary cortisol enzyme-linked immunosorbent assay (ELISA) kit using human saliva samples. It was found that the results obtained by the cortisol immuno-assay had a good correlation with those obtained by ELISA assay (R = 0.96). Our findings indicate the potential utility of the cortisol immuno-assay for measurements of human salivary cortisol levels.

  12. Development of Indirect Competitive Immuno-Assay Method Using SPR Detection for Rapid and Highly Sensitive Measurement of Salivary Cortisol Levels

    Energy Technology Data Exchange (ETDEWEB)

    Tahara, Yusuke; Huang, Zhe; Kiritoshi, Tetsuro [Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka (Japan); Onodera, Takeshi [Research and Development Center for Taste and Odor Sensing, Kyushu University, Fukuoka (Japan); Toko, Kiyoshi, E-mail: toko@ed.kyushu-u.ac.jp [Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka (Japan); Research and Development Center for Taste and Odor Sensing, Kyushu University, Fukuoka (Japan)

    2014-05-30

    The monitoring of salivary cortisol as a key biomarker of an individual’s stress response has been increasingly focused on. This paper describes the development of a novel cortisol immuno-assay method based on an indirect competitive method using a commercially available surface plasmon resonance instrument. The surface of an Au chip was modified with PEG6-COOH aromatic dialkanethiol self-assembled monolayers and hydrocortisone 3-(O-carboxymethyl) oxime (hydrocortisone 3-CMO) as a cortisol analog. A detection limit of 38 ppt range with a measurement range of 10 ppt–100 ppb was accomplished without the incubation of a mixing solution consisting of standard cortisol and an anti-cortisol antibody, and the time for quantification of cortisol concentration was 8 min from the sample injection. We experimentally compared our immuno-assay with a commercialized salivary cortisol enzyme-linked immunosorbent assay (ELISA) kit using human saliva samples. It was found that the results obtained by the cortisol immuno-assay had a good correlation with those obtained by ELISA assay (R = 0.96). Our findings indicate the potential utility of the cortisol immuno-assay for measurements of human salivary cortisol levels.

  13. Radioisotope instruments

    CERN Document Server

    Cameron, J F; Silverleaf, D J

    1971-01-01

    International Series of Monographs in Nuclear Energy, Volume 107: Radioisotope Instruments, Part 1 focuses on the design and applications of instruments based on the radiation released by radioactive substances. The book first offers information on the physical basis of radioisotope instruments; technical and economic advantages of radioisotope instruments; and radiation hazard. The manuscript then discusses commercial radioisotope instruments, including radiation sources and detectors, computing and control units, and measuring heads. The text describes the applications of radioisotop

  14. Design and Fabrication of a PDMS Microchip Based Immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Guocheng; Wang, Wanjun; Wang, Jun; Lin, Yuehe

    2010-07-01

    In this paper, we describe the design and fabrication process of a polydimethylsiloxane (PDMS) microchip for on-chip multiplex immunoassay application. The microchip consists of a PDMS microfluidic channel layer and a micro pneumatic valve control layer. By selectively pressurizing the pneumatic microvalves, immuno reagents were controlled to flow and react in certain fluidic channel sites. Cross contamination was prevented by tightly closed valves. Our design was proposed to utilize PDMS micro channel surface as the solid phase immunoassay substrate and simultaneously detect four targets antigens on chip. Experiment result shows that 20psi valve pressure is sufficient to tightly close a 200µm wide micro channel with flow rate up to 20µl/min.

  15. Evaluation of four immunoassays for diagnosis of brucellosis in Cuba

    International Nuclear Information System (INIS)

    Peraza, C.; Valdes, O.; Fonseca, N.; Garcia, M.; Alvarez, M.; Izquierdo, D.L.

    1998-01-01

    Four immunoassays (two indirect and two competitive ones) were evaluated by samples from areas free of disease, free by vaccination and affected areas using as reference techniques the Bengal Rose Tests, the Antigen in Buffered Plate Tests and the Complement Fixation Reaction Test. The evaluated samples demonstrated that the competitive assays (ELISAC-1 and ELISAC-2) detected less false positives than the indirect ones (ELISAI-1 and ELISAI-2). Of the competitive ELISAS, version 2 presented better sensitivity and specificity results in affected areas for 95% confidence: 80.9 - 96.9% and 97.5 - 99.4% respectively with positive predictive value in the range of 76 to 94% and negative predictive one between 98.1 and 99.7%. It was concluded that this assay can be used for brucellosis control because it gives higher assurance than the other evaluated immunoassays and it can discriminate infected from vaccinated animals. (author)

  16. Evaluation of the on-site immunoassay drug-screening device Triage-TOX in routine forensic autopsy.

    Science.gov (United States)

    Tominaga, Mariko; Michiue, Tomomi; Maeda, Hitoshi

    2015-11-01

    Instrumental identification of drugs with quantification is essential in forensic toxicology, while on-site immunoassay urinalysis drug-screening devices conveniently provide preliminary information when adequately used. However, suitable or sufficient urine specimens are not always available. The present study evaluated the efficacy of a new on-site immunoassay drug-screening device Triage-TOX (Alere Inc., San Diego, CA, USA), which has recently been developed to provide objective data on the one-step automated processor, using 51 urine and 19 pericardial fluid samples from 66 forensic autopsy cases, compared with Triage-Drug of Abuse (DOA) and Monitect-9. For benzodiazepines, the positive predictive value and specificity of Triage-TOX were higher than those of Triage-DOA; however, sensitivity was higher with Monitect-9, despite frequent false-positives. The results for the other drugs with the three devices also included a few false-negatives and false-positives. These observations indicate the applicability of Triage-TOX in preliminary drug screening using urine or alternative materials in routine forensic autopsy, when a possible false-negative is considered, especially for benzodiazepines, providing objective information; however, the combined use of another device such as Monitect-9 can help minimize misinterpretation prior to instrumental analysis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  17. Label-Free Electrochemical Immunoassay for C-Reactive Protein

    Directory of Open Access Journals (Sweden)

    Madasamy Thangamuthu

    2018-03-01

    Full Text Available C-reactive protein (CRP is one of the most expressed proteins in blood during acute phase inflammation, and its minute level increase has also been recognized for the clinical diagnosis of cardio vascular diseases. Unfortunately, the available commercial immunoassays are labour intensive, require large sample volumes, and have practical limitations, such as low stability and high production costs. Hence, we have developed a simple, cost effective, and label-free electrochemical immunoassay for the measurement of CRP in a drop of serum sample using an immunosensor strip made up of a screen printed carbon electrode (SPE modified with anti-CRP functionalized gold nanoparticles (AuNPs. The measurement relies on the decrease of the oxidation current of the redox indicator Fe3+/Fe2+, resulting from the immunoreaction between CRP and anti-CRP. Under optimal conditions, the present immunoassay measures CRP in a linear range from 0.4–200 nM (0.047–23.6 µg mL−1, with a detection limit of 0.15 nM (17 ng mL−1, S/N = 3 and sensitivity of 90.7 nA nM−1, in addition to a good reproducibility and storage stability. The analytical applicability of the presented immunoassay is verified by CRP measurements in human blood serum samples. This work provides the basis for a low-priced, safe, and easy-to-use point-of-care immunosensor assay to measure CRP at clinically relevant concentrations.

  18. Determination of digoxin by enzyme immunoassay and radioimmunoassay

    International Nuclear Information System (INIS)

    Mueller, H.; Braeuer, H.; Foerster, G.; Reinhardt, M.

    1978-01-01

    The results of parallel determinations of digoxin in the sera of non selected patients (n=104) by enzyme immunoassay (EMIT.EIA) and radioimmunoassay (J-125 labeled RIA) were compared with each other. The determinations revealed considerably different concentrations; the values determined by EIA were statistical lower (for EIA 1,09+'0,99ng/ml, for RIA 1,34+'1,01ng/ml, p [de

  19. Towards the development of a radioenzyme-immunoassay

    International Nuclear Information System (INIS)

    Schuurs, A.H.W.M.; Waart, M. v. d.

    1976-01-01

    We have tried to develop a very sensitive enzyme-immunoassay. For this purpose, a very sensitive radiochemical enzyme assay was used. HCG was chosen as test model and AChE as labelling enzyme. The test appeared to be much more sensitive than the normal enzymeimmunoassay. And, in comparison with RIA, it was about as sensitive but less time-consuming, and it makes use, in principle, of stable reagents. (orig./GSE) [de

  20. History of inductively coupled plasma mass spectrometry-based immunoassays

    International Nuclear Information System (INIS)

    Giesen, Charlotte; Waentig, Larissa; Panne, Ulrich; Jakubowski, Norbert

    2012-01-01

    The analysis of biomolecules requires highly sensitive and selective detection methods capable of tolerating a complex, biological matrix. First applications of biomolecule detection by ICP-MS relied on the use of heteroelements as a label for quantification. However, the combination of immunoassays and ICP-MS facilitates multiparametric analyses through elemental tagging, and provides a powerful alternative to common bioanalytical methods. This approach extends the detection of biomarkers in clinical diagnosis, and has the potential to provide a deeper understanding of the investigated biological system. The results might lead to the detection of diseases at an early stage, or guide treatment plans. Immunoassays are well accepted and established for diagnostic purposes, albeit ICP-MS is scarcely applied for the detection of immune-based assays. However, the screening of biomarkers demands high throughput and multiplex/multiparametric techniques, considering the variety of analytes to be queried. Finally, quantitative information on the expression level of biomarkers is highly desirable to identify abnormalities in a given organism. Thus, it is the aim of this review to introduce the fundamentals, and to discuss the enormous strength of ICP-MS for the detection of different immunoassays on the basis of selected applications, with a special focus on LA‐ICP‐MS. - Highlights: ► We discuss the fundamentals of elemental tagging for ICP‐MS applications. ► We propose a definition for the expressions “label” and “tag”. ► We highlight LA‐ICP‐MS‐based heteroelement detection. ► We give an historic overview on ICP-MS and LA‐ICP‐MS-based immunoassays. ► In a personal outlook, we discuss future improvements realistically attainable.

  1. Abbott prism: a multichannel heterogeneous chemiluminescence immunoassay analyzer.

    Science.gov (United States)

    Khalil, O S; Zurek, T F; Tryba, J; Hanna, C F; Hollar, R; Pepe, C; Genger, K; Brentz, C; Murphy, B; Abunimeh, N

    1991-09-01

    We describe a multichannel heterogeneous immunoassay analyzer in which a sample is split between disposable reaction trays in a group of linear tracks. The system's pipettor uses noninvasive sensing of the sample volume and disposable pipet tips. Each assay track has (a) a conveyor belt for moving reaction trays to predetermined functional stations, (b) temperature-controlled tunnels, (c) noncontact transfer of the reaction mixture between incubation and detection wells, and (d) single-photon counting to detect a chemiluminescence (CL) signal from the captured immunochemical product. A novel disposable reaction tray, with separate reaction and detection wells and self-contained fluid removal, is used in conjunction with the transfer device on the track to produce a carryover-free system. The linear immunoassay track has nine predetermined positions for performing individual assay steps. Assay step sequence and timing is selected by changing the location of the assay modules between these predetermined positions. The assay methodology, a combination of microparticle capture and direct detection of a CL signal on a porous matrix, offers excellent sensitivity, specificity, and ease of automation. Immunoassay configurations have been tested for hepatitis B surface antigen and for antibodies to hepatitis B core antigen, hepatitis C virus, human immunodeficiency virus I and II, and human T-cell leukemia virus I and II.

  2. Development of immunoassays for detecting clothianidin residue in agricultural products.

    Science.gov (United States)

    Li, Ming; Sheng, Enze; Cong, Lujing; Wang, Minghua

    2013-04-17

    Two enzyme-linked immunosorbent assays (ELISAs) based on polyclonal antibodies (PcAbs) for clothianidin are described: colorimetric detection format (ELISA) and pattern of chemiluminescent assay (CLEIA). Clothianidin hapten was synthesized and conjugated to bovine serum albumin (BSA) and ovalbumin (OVA) to produce immunogen and coating antigen. Anticlothianidin PcAbs were obtained from immunized New Zealand white rabbits. Under optimal conditions, the half-maximal inhibition concentration (IC₅₀) and the limit of detection (LOD, IC₂₀) of clothianidin were 0.046 and 0.0028 mg/L for the ELISA and 0.015 and 0.0014 mg/L for the CLEIA, respectively. There were no obvious cross-reactivities of the antibodies with its analogues except for dinotefuran. Recoveries of 76.4-116.4% for the immunoassays were achieved from spiked samples. The results of immunoassays for the spiked and authentic samples were largely consistent with gas chromatography. Therefore, the proposed immunoassays would be convenient and satisfactory analytical methods for the monitoring of clothianidin in agricultural products.

  3. Current status and future developments in radiolabelled immunoassays

    International Nuclear Information System (INIS)

    Edwards, R.

    1998-01-01

    Radioisotopes are used extensively in medical practice and their use in RIA or IRMA usually represent a small proportion of the total. Radiolabelled immunoassays based on 125 I constitute a simple didactic, cost effective and robust technology which is still regarded as the reference method in many clinical applications. The IAEA has implemented many successful programmes using the ''bulk reagent'' approach, involving 68 countries in all the different regions. The main achievements have been in technology transfer with self sufficiency in production for some countries; training of large numbers of staff; quality control and quality assurance schemes; devolution of screening programmes for neonatal congenital hypothryoidism. Alternatives to the use of radioisotopic tracers are constrained by many factors and are often only available in restricted commercial packages. They are often not suitable for technology transfer programmes and often lack any didactic component in addition to a relative high cost. The production of radiolabels using 125 I is both simple and adaptable. In addition expertise in their preparation and purification is widespread even in developing countries. Together with the ease of producing antibodies, the facts have made 125 I-radiolabelled immunoassays ideal for investigative procedures for many research activities (30,31) particularly in the medical context where radioisotopes are commonly used. In conclusion, even a superficial examination of public health statistics for various countries throughout the continents indicates a need for a simple, inexpensive and robust analytical tool. In this light, there is a predicted continuing role for radiolabelled immunoassays. (author)

  4. Simple patterned nanofiber scaffolds and its enhanced performance in immunoassay.

    Directory of Open Access Journals (Sweden)

    Jing Wang

    Full Text Available Cancer has become the leading cause of death worldwide; early diagnosis and treatment of cancers is critical for the survival of the patients. The concentration of cancer markers in easy-to-access biological fluids can provide great assistance in screening for occult primary cancers, distinguishing malignant from benign findings, determining prognosis and prediction for cancer patients. The multiplex detection technology of a panel of cancer markers can greatly increase the accuracy of disease diagnosis. Herein, we briefly fabricate a high-throughput micro-immunoassay based on the electrospun polystyrene (PS substrates to improve detection sensitivity. The immunoassay was evaluated by analyzing three different cancer biomarkers (AFP, CEA, VEGF. For AFP, CEA, VEGF immunofluorescence assay, the LOD of assay conducted on electrospun PS substrates before or after plasma and the conventional PS substrates were 0.42, 0.10, 1.12 ng/mL, 0.57, 0.09, 1.24 ng/mL, and 159.75, 26.19, 385.59 pg/mL, respectively (P < 0.05. Due to the high porosity and large surface area-to-volume ratio which is the foremost merit of nanostructures, and the plasma treatment which make the hydrophobic PS nanofibers hydropholic, the nanofibers substrates showed sufficient retention of immunoassay functionality and high potential for capture molecules immobilization. Consequently, the immunofluorescence assay conducted on electrospun PS substrates could significantly enhance the sensitivity and limits of detection.

  5. Instrumental interaction

    OpenAIRE

    Luciani , Annie

    2007-01-01

    International audience; The expression instrumental interaction as been introduced by Claude Cadoz to identify a human-object interaction during which a human manipulates a physical object - an instrument - in order to perform a manual task. Classical examples of instrumental interaction are all the professional manual tasks: playing violin, cutting fabrics by hand, moulding a paste, etc.... Instrumental interaction differs from other types of interaction (called symbolic or iconic interactio...

  6. Floating Chip Mounting System Driven by Repulsive Force of Permanent Magnets for Multiple On-Site SPR Immunoassay Measurements

    Science.gov (United States)

    Horiuchi, Tsutomu; Tobita, Tatsuya; Miura, Toru; Iwasaki, Yuzuru; Seyama, Michiko; Inoue, Suzuyo; Takahashi, Jun-ichi; Haga, Tsuneyuki; Tamechika, Emi

    2012-01-01

    We have developed a measurement chip installation/removal mechanism for a surface plasmon resonance (SPR) immunoassay analysis instrument designed for frequent testing, which requires a rapid and easy technique for changing chips. The key components of the mechanism are refractive index matching gel coated on the rear of the SPR chip and a float that presses the chip down. The refractive index matching gel made it possible to optically couple the chip and the prism of the SPR instrument easily via elastic deformation with no air bubbles. The float has an autonomous attitude control function that keeps the chip parallel in relation to the SPR instrument by employing the repulsive force of permanent magnets between the float and a float guide located in the SPR instrument. This function is realized by balancing the upward elastic force of the gel and the downward force of the float, which experiences a leveling force from the float guide. This system makes it possible to start an SPR measurement immediately after chip installation and to remove the chip immediately after the measurement with a simple and easy method that does not require any fine adjustment. Our sensor chip, which we installed using this mounting system, successfully performed an immunoassay measurement on a model antigen (spiked human-IgG) in a model real sample (non-homogenized milk) that included many kinds of interfering foreign substances without any sample pre-treatment. The ease of the chip installation/removal operation and simple measurement procedure are suitable for frequent on-site agricultural, environmental and medical testing. PMID:23202030

  7. Instrumentation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Provides instrumentation support for flight tests of prototype weapons systems using a vast array of airborne sensors, transducers, signal conditioning and encoding...

  8. Micromotor-based lab-on-chip immunoassays

    Science.gov (United States)

    García, Miguel; Orozco, Jahir; Guix, Maria; Gao, Wei; Sattayasamitsathit, Sirilak; Escarpa, Alberto; Merkoçi, Arben; Wang, Joseph

    2013-01-01

    Here we describe the first example of using self-propelled antibody-functionalized synthetic catalytic microengines for capturing and transporting target proteins between the different reservoirs of a lab-on-a-chip (LOC) device. A new catalytic polymer/Ni/Pt microtube engine, containing carboxy moieties on its mixed poly(3,4-ethylenedioxythiophene) (PEDOT)/COOH-PEDOT polymeric outermost layer, is further functionalized with the antibody receptor to selectively recognize and capture the target protein. The new motor-based microchip immunoassay operations are carried out without any bulk fluid flow, replacing the common washing steps in antibody-based protein bioassays with the active transport of the captured protein throughout the different reservoirs, where each step of the immunoassay takes place. A first microchip format involving an `on-the-fly' double-antibody sandwich assay (DASA) is used for demonstrating the selective capture of the target protein, in the presence of excess of non-target proteins. A secondary antibody tagged with a polymeric-sphere tracer allows the direct visualization of the binding events. In a second approach the immuno-nanomotor captures and transports the microsphere-tagged antigen through a microchannel network. An anti-protein-A modified microengine is finally used to demonstrate the selective capture, transport and convenient label-free optical detection of a Staphylococcus aureus target bacteria (containing proteinA in its cell wall) in the presence of a large excess of non-target (Saccharomyces cerevisiae) cells. The resulting nanomotor-based microchip immunoassay offers considerable potential for diverse applications in clinical diagnostics, environmental and security monitoring fields.Here we describe the first example of using self-propelled antibody-functionalized synthetic catalytic microengines for capturing and transporting target proteins between the different reservoirs of a lab-on-a-chip (LOC) device. A new catalytic

  9. Chimeric recombinant antibody fragments in cardiac troponin I immunoassay.

    Science.gov (United States)

    Hyytiä, Heidi; Heikkilä, Taina; Brockmann, Eeva-Christine; Kekki, Henna; Hedberg, Pirjo; Puolakanaho, Tarja; Lövgren, Timo; Pettersson, Kim

    2015-03-01

    To introduce a novel nanoparticle-based immunoassay for cardiac troponin I (cTnI) utilizing chimeric antibody fragments and to demonstrate that removal of antibody Fc-part and antibody chimerization decrease matrix related interferences. A sandwich-type immunoassay for cTnI based on recombinant chimeric (mouse variable/human constant) antigen binding (cFab) antibodies and intrinsically fluorescent nanoparticles was developed. To test whether using chimeric antibody fragments helps to avoid matrix related interferences, samples (n=39) with known amounts of triglycerides, bilirubin, rheumatoid factor (RF) or human anti-mouse antibodies (HAMAs) were measured with the novel assay, along with a previously published nanoparticle-based research assay with the same antibody epitopes. The limit of detection (LoD) was 3.30ng/L. Within-laboratory precision for 29ng/L and 2819ng/L cTnI were 13.7% and 15.9%, respectively. Regression analysis with Siemens ADVIA Centaur® yielded a slope (95% confidence intervals) of 0.18 (0.17-1.19) and a y-intercept of 1.94 (-1.28-3.91) ng/L. When compared to a previously published nanoparticle-based assay, the novel assay showed substantially reduced interference in the tested interference prone samples, 15.4 vs. 51.3%. A rheumatoid factor containing sample was decreased from 241ng/L to immunoassay for the detection of cTnI and decreased matrix related interferences, thus resulting in a lower number of falsely elevated cTnI-values. Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  10. Fast and sensitive detection of enteropathogenic Yersinia by immunoassays.

    Science.gov (United States)

    Laporte, Jérôme; Savin, Cyril; Lamourette, Patricia; Devilliers, Karine; Volland, Hervé; Carniel, Elisabeth; Créminon, Christophe; Simon, Stéphanie

    2015-01-01

    Yersinia enterocolitica and Yersinia pseudotuberculosis, the two Yersinia species that are enteropathogenic for humans, are distributed worldwide and frequently cause diarrhea in inhabitants of temperate and cold countries. Y. enterocolitica is a major cause of foodborne disease resulting from consumption of contaminated pork meat and is further associated with substantial economic cost. However, investigation of enteropathogenic Yersinia species is infrequently performed routinely in clinical laboratories because of their specific growth characteristics, which make difficult their isolation from stool samples. Moreover, current isolation procedures are time-consuming and expensive, thus leading to underestimates of the incidence of enteric yersiniosis, inappropriate prescriptions of antibiotic treatments, and unnecessary appendectomies. The main objective of the study was to develop fast, sensitive, specific, and easy-to-use immunoassays, useful for both human and veterinary diagnosis. Monoclonal antibodies (MAbs) directed against Y. enterocolitica bioserotypes 2/O:9 and 4/O:3 and Y. pseudotuberculosis serotypes I and III were produced. Pairs of MAbs were selected by testing their specificity and affinity for enteropathogenic Yersinia and other commonly found enterobacteria. Pairs of MAbs were selected to develop highly sensitive enzyme immunoassays (EIAs) and lateral flow immunoassays (LFIs or dipsticks) convenient for the purpose of rapid diagnosis. The limit of detection of the EIAs ranged from 3.2 × 10(3) CFU/ml to 8.8 × 10(4) CFU/ml for pathogenic serotypes I and III of Y. pseudotuberculosis and pathogenic bioserotypes 2/O:9 and 4/O:3 of Y. enterocolitica and for the LFIs ranged from 10(5) CFU/ml to 10(6) CFU/ml. A similar limit of detection was observed for artificially contaminated human feces. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  11. Tumor specific lung cancer diagnostics with multiplexed FRET immunoassays

    Science.gov (United States)

    Geißler, D.; Hill, D.; Löhmannsröben, H.-G.; Thomas, E.; Lavigne, A.; Darbouret, B.; Bois, E.; Charbonnière, L. J.; Ziessel, R. F.; Hildebrandt, N.

    2010-02-01

    An optical multiplexed homogeneous (liquid phase) immunoassay based on FRET from a terbium complex to eight different fluorescent dyes is presented. We achieved highly sensitive parallel detection of four different lung cancer specific tumor markers (CEA, NSE, SCC and CYFRA21-1) within a single assay and show a proof-of-principle for 5- fold multiplexing. The method is well suited for fast and low-cost miniaturized point-of-care testing as well as for highthroughput screening in a broad range of in-vitro diagnostic applications.

  12. Linkage of biomolecules to solid phases for immunoassay

    International Nuclear Information System (INIS)

    Chapman, R.S.

    1998-01-01

    Topics covered by this lecture include a brief review of the principal methods of linkage of biomolecules to solid phase matrices. Copies of the key self explanatory slides are presented as figures together with reprints of two publications by the author dealing with a preferred chemistry for the covalent linkage of antibodies to hydroxyl and amino functional groups and the effects of changes in solid phase matrix and antibody coupling chemistry on the performance of a typical excess reagent immunoassay for thyroid stimulating hormone

  13. On-Chip Immunoassay for Determination of Urinary Albumin

    OpenAIRE

    Laiwattanapaisal, Wanida; Songjaroen, Temsiri; Maturos, Thitima; Lomas, Tanom; Sappat, Assawapong; Tuantranont, Adisorn

    2009-01-01

    An immunoassay performed on a portable microfluidic device was evaluated for the determination of urinary albumin. An increase in absorbance at 500 nm resulting from immunoagglutination was monitored directly on the poly(dimethylsiloxane) (PDMS) microchip using a portable miniature fibre-optic spectrometer. A calibration curve was linear up to 10 mg L–1 (r2 = 0.993), with a detection limit of 0.81 mg L–1 (S/N = 3). The proposed system showed good precision, with relative standard deviations (...

  14. Analytical evaluation of the novel Lumipulse G BRAHMS procalcitonin immunoassay

    OpenAIRE

    Ruzzenente, Orazio; Salvagno, Gian Luca; Gelati, Matteo; Lippi, Giuseppe

    2016-01-01

    Objectives: This study was designed to evaluate the analytical performance of the novel Lumipulse G1200 BRAHMS procalcitonin (PCT) immunoassay. Design and methods: This analytical evaluation encompassed the calculation of the limit of blank (LOB), limit of detection (LOD), functional sensitivity, intra- and inter-assay imprecision, confirmation of linearity and a comparison with the Vidas BRAHMS PCT assay. Results: The LOB, LOD and functional sensitivity were 0.0010 ng/mL, 0.0016 ng/mL and ...

  15. Photonic ring resonance is a versatile platform for performing multiplex immunoassays in real time.

    Science.gov (United States)

    Mudumba, Sasi; de Alba, Sophia; Romero, Randy; Cherwien, Carli; Wu, Alice; Wang, Jue; Gleeson, Martin A; Iqbal, Muzammil; Burlingame, Rufus W

    2017-09-01

    Photonic ring resonance is a property of light where in certain circumstances specific wavelengths are trapped in a ring resonator. Sensors based on silicon photonic ring resonators function by detecting the interaction between light circulating inside the sensor and matter deposited on the sensor surface. Binding of biological material results in a localized change in refractive index on the sensor surface, which affects the circulating optical field extending beyond the sensor boundary. That is, the resonant wavelength will change when the refractive index of the medium around the ring resonator changes. Ring resonators can be fabricated onto small silicon chips, allowing development of a miniature multiplex array of ring based biosensors. This paper describes the properties of such a system when responding to the refractive index changed in a simple and precise way by changing the ionic strength of the surrounding media, and in a more useful way by the binding of macromolecules to the surface above the resonators. Specifically, a capture immunoassay is described that measures the change of resonant wavelength as a patient serum sample with anti-SS-A autoantibodies is flowed over a chip spotted with SS-A antigen and amplified with anti-IgG. The technology has been miniaturized and etched into a 4×6mm silicon chip that can measure 32 different reactions in quadruplicate simultaneously. The variability between 128 rings on a chip as measured by 2M salt assays averaged 0.6% CV. The output of the assays is the average shift per cluster of 4 rings, and the assays averaged 0.5% CV between clusters. The variability between chips averaged 1.8%. Running the same array on multiple instruments showed that after some improvements to the wavelength referencing system, the upper boundary of variation was 3% between 13 different instruments. The immunoassay displayed about 2% higher variability than the salt assays. There are several outstanding features of this system. The

  16. 340nm UV LED excitation in time-resolved fluorescence system for europium-based immunoassays detection

    Science.gov (United States)

    Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter; Pedersen, Christian

    2017-02-01

    In immunoassay analyzers for in-vitro diagnostics, Xenon flash lamps have been widely used as excitation light sources. Recent advancements in UV LED technology and its advantages over the flash lamps such as smaller footprint, better wall-plug efficiency, narrow emission spectrum, and no significant afterglow, have made them attractive light sources for gated detection systems. In this paper, we report on the implementation of a 340 nm UV LED based time-resolved fluorescence system based on europium chelate as a fluorescent marker. The system performance was tested with the immunoassay based on the cardiac marker, TnI. The same signal-to-noise ratio as for the flash lamp based system was obtained, operating the LED below specified maximum current. The background counts of the system and its main contributors were measured and analyzed. The background of the system of the LED based unit was improved by 39% compared to that of the Xenon flash lamp based unit, due to the LEDs narrower emission spectrum and longer pulse width. Key parameters of the LED system are discussed to further optimize the signal-to-noise ratio and signal-to-background, and hence the sensitivity of the instrument.

  17. Comparative determination of phenytoin by spectrophotometry, gas chromatography, liquid chromatography, enzyme immunoassay, and radioimmunoassay

    International Nuclear Information System (INIS)

    Castro, A.; Ibanez, J.; DiCesare, J.L.; Adams, R.F.; Malkus, H.

    1978-01-01

    Sera from patients being treated with phenytoin were analyzed for the drug by spectrophotometry, gas chromatography, radioimmunoasay, enzyme immunoassay, and liquid chromatography. The assay values obtained were intercompared statistically. Enzyme immunoassay and liquid chromatography appear to be attractive alternatives to the more traditional methods of spectrophotometry and gas chromatography. Our radioimmunoassay data correlated poorly with results by the four other methods

  18. Determining total thyroxine with the aid of the homogeneous enzyme immunoassay

    International Nuclear Information System (INIS)

    Vogt, W.

    1978-01-01

    Total thyrozine values obtained with the aid of the homogeneous enzyme immunoassay are compared with those delivered by the RIA and the efficiency of the EMIT technique is evaluated. Some results obtained via Enzymun-T4, a heterologous enzyme immunoassay, are also given. (VJ) 891 VJ [de

  19. Evaluation of six immunoassays for detection of dengue virus-specific immunoglobulin M and G antibodies

    NARCIS (Netherlands)

    J. Groen (Jan); P. Koraka (Penelope); J. Velzing (Jans); C. Copra (Cederick); A.D.M.E. Osterhaus (Albert)

    2000-01-01

    textabstractThe performance of six commercially available immunoassay systems for the detection of dengue virus-specific immunoglobulin M (IgM) and IgG antibodies in serum was evaluated. These included two IgM and IgG enzyme immunoassays (EIA) from MRL Laboratories and PanBio, a rapid

  20. Instrumentation development

    International Nuclear Information System (INIS)

    Ubbes, W.F.; Yow, J.L. Jr.

    1988-01-01

    Instrumentation is developed for the Civilian Radioactive Waste Management Program to meet several different (and sometimes conflicting) objectives. This paper addresses instrumentation development for data needs that are related either directly or indirectly to a repository site, but does not touch on instrumentation for work with waste forms or other materials. Consequently, this implies a relatively large scale for the measurements, and an in situ setting for instrument performance. In this context, instruments are needed for site characterization to define phenomena, develop models, and obtain parameter values, and for later design and performance confirmation testing in the constructed repository. The former set of applications is more immediate, and is driven by the needs of program design and performance assessment activities. A host of general technical and nontechnical issues have arisen to challenge instrumentation development. Instruments can be classed into geomechanical, geohydrologic, or other specialty categories, but these issues cut across artificial classifications. These issues are outlined. Despite this imposing list of issues, several case histories are cited to evaluate progress in the area

  1. Trends in interfacial design for surface plasmon resonance based immunoassays

    International Nuclear Information System (INIS)

    Shankaran, Dhesingh Ravi; Miura, Norio

    2007-01-01

    Immunosensors based on surface plasmon resonance (SPR) have become a promising tool in sensor technology for biomedical, food, environmental, industrial and homeland security applications. SPR is a surface sensitive optical technique, suitable for real-time and label-free analysis of biorecognition events at functional transducer surfaces. Fabrication of highly active and robust sensing surfaces is an important part in immunoassays because the quality, quantity, chemistry and topography of the interfacial biomembranes play a major role in immunosensor performance. Eventually, a variety of immobilization methods such as physical adsorption, covalent coupling, Langmuir-Blodgett film, polymer thin film, self-assembly, sol-gel, etc, have been introduced over the years for the immobilization of biomolecules (antibody or antigen) on the transducer surfaces. The selection of an immobilization method for an immunoassay is governed by several factors such as nature and stability of the biomolecules, target analyte, application, detection principle, mode of signal transduction, matrix complexity, etc. This paper provides an overview of the various surface modification methods for SPR based immunosensor fabrication. The preparation, structure and application of different functional interfacial surfaces have been discussed along with a brief introduction to the SPR technology, biomolecules and detection principles. (review article)

  2. Aequorin fusion proteins as bioluminescent tracers for competitive immunoassays

    Science.gov (United States)

    Mirasoli, Mara; Michelini, Elisa; Deo, Sapna K.; Dikici, Emre; Roda, Aldo; Daunert, Sylvia

    2004-06-01

    The use of bio- and chemiluminescence for the development of quantitative binding assays offers undoubted advantages over other detection systems, such as spectrophotometry, fluorescence, or radioactivity. Indeed, bio- and chemiluminescence detection provides similar, or even better, sensitivity and detectability than radioisotopes, while avoiding the problems of health hazards, waste disposal, and instability associated with the use of radioisotopes. Among bioluminescent labels, the calcium-activated photoprotein aequorin, originally isolated from Aequorea victoria and today available as a recombinant product, is characterized by very high detectability, down to attomole levels. It has been used as a bioluminescent label for developing a variety of highly sensitive immunoassays, using various analyte-aequorin conjugation strategies. When the analyte is a protein or a peptide, genetic engineering techniques can be used to produce protein fusions where the analyte is in-frame fused with aequorin, thus producing homogeneous one-to-one conjugation products, available in virtually unlimited amount. Various assays were developed using this strategy: a short review of the most interesting applications is presented, as well as the cloning, purification and initial characterization of an endothelin-1-aequorin conjugate suitable for developing a competitive immunoassay for endothelin-1, a potent vasoconstrictor peptide, involved in hypertension.

  3. Determination of phospholipid transfer proteins in rat tissues by immunoassays

    International Nuclear Information System (INIS)

    Teerlink, T.

    1983-01-01

    Several quantitative immunoassays have been developed for two phospholipid transfer proteins from rat liver, i.e. the phosphatidylcholine transfer protein and the non-specific lipid transfer protein. The development of a double-antibody radioimmunoassay for the phosphatidylcholine transfer protein is described. The transfer protein was labelled with iodine-125 by the mild glucose oxidase-lactoperoxidase method. Although less than one tyrosine residue per molecule of transfer protein was labelled, only 20% of the labelled transfer protein was immunoprecipitable. This value could be increased to 80% by purifying the labelled protein by affinity chromatography on a column of anti-phosphatidylcholine transfer protein-IgG coupled to Sepharose 4B. The radioimmunoassay was used to determine the levels of phosphatidylcholine transfer protein in homogenates and 105 000 xg supernatants from various rat tissues as well as several Morris hepatomas. An enzyme immunoassay for the non-specific lipid transfer protein is also described. The antiserum that was raised especially by the author was cross-reactive with the non-specific lipid transfer protein present in 105 000 xg supernatants from human, mouse and bovine liver. The non-specific lipid transfer protein lost its immunoreactivity upon labelling with iodine-125 using different labelling techniques. Therefore, a regular radioimmunoassay could not be developed. The results of these different assays were compared. (Auth.)

  4. Trends in interfacial design for surface plasmon resonance based immunoassays

    Energy Technology Data Exchange (ETDEWEB)

    Shankaran, Dhesingh Ravi [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga-shi, Fukuoka, 816-8580 (Japan); Miura, Norio [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga-shi, Fukuoka, 816-8580 (Japan)

    2007-12-07

    Immunosensors based on surface plasmon resonance (SPR) have become a promising tool in sensor technology for biomedical, food, environmental, industrial and homeland security applications. SPR is a surface sensitive optical technique, suitable for real-time and label-free analysis of biorecognition events at functional transducer surfaces. Fabrication of highly active and robust sensing surfaces is an important part in immunoassays because the quality, quantity, chemistry and topography of the interfacial biomembranes play a major role in immunosensor performance. Eventually, a variety of immobilization methods such as physical adsorption, covalent coupling, Langmuir-Blodgett film, polymer thin film, self-assembly, sol-gel, etc, have been introduced over the years for the immobilization of biomolecules (antibody or antigen) on the transducer surfaces. The selection of an immobilization method for an immunoassay is governed by several factors such as nature and stability of the biomolecules, target analyte, application, detection principle, mode of signal transduction, matrix complexity, etc. This paper provides an overview of the various surface modification methods for SPR based immunosensor fabrication. The preparation, structure and application of different functional interfacial surfaces have been discussed along with a brief introduction to the SPR technology, biomolecules and detection principles. (review article)

  5. Multiplex detection of plant pathogens using a microsphere immunoassay technology.

    Directory of Open Access Journals (Sweden)

    Ratthaphol Charlermroj

    Full Text Available Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac, chilli vein-banding mottle virus (CVbMV, potyvirus, watermelon silver mottle virus (WSMoV, tospovirus serogroup IV and melon yellow spot virus (MYSV, tospovirus. An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour was much shorter than that of ELISA (4 hours. This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection.

  6. Multiplex detection of plant pathogens using a microsphere immunoassay technology.

    Science.gov (United States)

    Charlermroj, Ratthaphol; Himananto, Orawan; Seepiban, Channarong; Kumpoosiri, Mallika; Warin, Nuchnard; Oplatowska, Michalina; Gajanandana, Oraprapai; Grant, Irene R; Karoonuthaisiri, Nitsara; Elliott, Christopher T

    2013-01-01

    Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac), chilli vein-banding mottle virus (CVbMV, potyvirus), watermelon silver mottle virus (WSMoV, tospovirus serogroup IV) and melon yellow spot virus (MYSV, tospovirus). An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE)-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA) when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour) was much shorter than that of ELISA (4 hours). This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection.

  7. Development of a novel ultrasensitive enzyme immunoassay for human glutamic acid decarboxylase 65 antibody.

    Science.gov (United States)

    Numata, Satoshi; Katakami, Hideki; Inoue, Shinobu; Sawada, Hirotake; Hashida, Seiichi

    2016-07-01

    We developed a novel, ultrasensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) for determination of glutamic acid decarboxylase autoantibody concentrations in serum samples from patients with type 2 diabetes. We developed an immune complex transfer enzyme immunoassay for glutamic acid decarboxylase autoantibody and measured glutamic acid decarboxylase autoantibody from 22 patients with type 1 diabetes, 29 patients with type 2 diabetes, and 32 healthy controls. A conventional ELISA kit identified 10 patients with type 1 diabetes and one patient with type 2 diabetes as glutamic acid decarboxylase autoantibody positive, whereas 15 patients with type 1 diabetes and six patients with type 2 diabetes were identified as glutamic acid decarboxylase autoantibody positive using immune complex transfer enzyme immunoassay. Immune complex transfer enzyme immunoassay is a highly sensitive and specific assay for glutamic acid decarboxylase autoantibody and might be clinically useful for diabetic onset prediction and early diagnosis. © The Author(s) 2016.

  8. Development of a portable X-ray and gamma-ray detector instrument and imaging camera for use in radioactive and hazardous materials management

    International Nuclear Information System (INIS)

    Scyoc, J.M. van; James, R.B.; Anderson, R.J.

    1997-08-01

    The overall goal of this LDRD project was to develop instruments for use in the management of radioactive and hazardous wastes. Devices for identifying and imaging such wastes are critical to developing environmental remediation strategies. Field portable units are required to enable the on-site analysis of solids, liquids, and gas effluents. Red mercuric iodide (α-HgI 2 ) is a semiconductor material that can be operated as a high-energy-resolution radiation detector at ambient temperatures. This property provides the needed performance of conventional germanium- and silicon-based devices, while eliminating the need for the cryogenic cooling of such instruments. The first year of this project focused on improving the materials properties of the mercuric iodide to enable the new sensor technology; in particular the charge carrier traps limiting device performance were determined and eliminated. The second year involved the development of a field portable x-ray fluorescence analyzer for compositional analyses. The third and final year of the project focused on the development of imaging sensors to provide the capability for mapping the composition of waste masses. This project resulted in instruments useful not only for managing hazardous and radioactive wastes, but also in a variety of industrial and national security applications

  9. AN ENVIRONMENTAL TECHNOLOGY VERIFICATION (ETV) TESTING OF THREE IMMUNOASSAY TEST KITS FOR ANTHRAX, BOTULINUM TOXIN AND RICIN

    Science.gov (United States)

    Immunoassay test kits are based on immunoassay methods, where specific antibodies are used to detect and measure the contaminants of interest. Immunoassay test kits rely on the reaction of a contaminant or antigen with a selective antibody to give a product that can be measures....

  10. Instrumental analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Jae; Seo, Seong Gyu

    1995-03-15

    This textbook deals with instrumental analysis, which consists of nine chapters. It has Introduction of analysis chemistry, the process of analysis and types and form of the analysis, Electrochemistry on basic theory, potentiometry and conductometry, electromagnetic radiant rays and optical components on introduction and application, Ultraviolet rays and Visible spectrophotometry, Atomic absorption spectrophotometry on introduction, flame emission spectrometry and plasma emission spectrometry. The others like infrared spectrophotometry, X-rays spectrophotometry and mass spectrometry, chromatography and the other instrumental analysis like radiochemistry.

  11. Instrumental analysis

    International Nuclear Information System (INIS)

    Kim, Seung Jae; Seo, Seong Gyu

    1995-03-01

    This textbook deals with instrumental analysis, which consists of nine chapters. It has Introduction of analysis chemistry, the process of analysis and types and form of the analysis, Electrochemistry on basic theory, potentiometry and conductometry, electromagnetic radiant rays and optical components on introduction and application, Ultraviolet rays and Visible spectrophotometry, Atomic absorption spectrophotometry on introduction, flame emission spectrometry and plasma emission spectrometry. The others like infrared spectrophotometry, X-rays spectrophotometry and mass spectrometry, chromatography and the other instrumental analysis like radiochemistry.

  12. LOFT instrumentation

    International Nuclear Information System (INIS)

    Bixby, W.W.

    1979-01-01

    A description of instrumentation used in the Loss-of-Fluid Test (LOFT) large break Loss-of-Coolant Experiments is presented. Emphasis is placed on hydraulic and thermal measurements in the primary system piping and components, reactor vessel, and pressure suppression system. In addition, instrumentation which is being considered for measurement of phenomena during future small break testing is discussed. (orig.) 891 HP/orig. 892 BRE [de

  13. Multiplexed capillary microfluidic immunoassay with smartphone data acquisition for parallel mycotoxin detection.

    Science.gov (United States)

    Machado, Jessica M D; Soares, Ruben R G; Chu, Virginia; Conde, João P

    2018-01-15

    The field of microfluidics holds great promise for the development of simple and portable lab-on-a-chip systems. The use of capillarity as a means of fluidic manipulation in lab-on-a-chip systems can potentially reduce the complexity of the instrumentation and allow the development of user-friendly devices for point-of-need analyses. In this work, a PDMS microchannel-based, colorimetric, autonomous capillary chip provides a multiplexed and semi-quantitative immunodetection assay. Results are acquired using a standard smartphone camera and analyzed with a simple gray scale quantification procedure. The performance of this device was tested for the simultaneous detection of the mycotoxins ochratoxin A (OTA), aflatoxin B1 (AFB1) and deoxynivalenol (DON) which are strictly regulated food contaminants with severe detrimental effects on human and animal health. The multiplexed assay was performed approximately within 10min and the achieved sensitivities of<40, 0.1-0.2 and<10ng/mL for OTA, AFB1 and DON, respectively, fall within the majority of currently enforced regulatory and/or recommended limits. Furthermore, to assess the potential of the device to analyze real samples, the immunoassay was successfully validated for these 3 mycotoxins in a corn-based feed sample after a simple sample preparation procedure. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Clinical development of placental malaria vaccines and immunoassays harmonization

    DEFF Research Database (Denmark)

    Chêne, Arnaud; Houard, Sophie; Nielsen, Morten A

    2016-01-01

    Placental malaria caused by Plasmodium falciparum infection constitutes a major health problem manifesting as severe disease and anaemia in the mother, impaired fetal development, low birth weight or spontaneous abortion. Prevention of placental malaria currently relies on two key strategies...... that are losing efficacy due to spread of resistance: long-lasting insecticide-treated nets and intermittent preventive treatment during pregnancy. A placental malaria vaccine would be an attractive, cost-effective complement to the existing control tools. Two placental malaria vaccine candidates are currently...... in Phase Ia/b clinical trials. During two workshops hosted by the European Vaccine Initiative, one in Paris in April 2014 and the other in Brussels in November 2014, the main actors in placental malaria vaccine research discussed the harmonization of clinical development plans and of the immunoassays...

  15. Development of an Ultrasensitive Immunoassay for Detecting Tartrazine

    Directory of Open Access Journals (Sweden)

    Chuanlai Xu

    2013-06-01

    Full Text Available We have developed an ultrasensitive indirect competitive enzyme-linked immunosorbent assay for the determination of tartrazine. Two carboxylated analogues of tartrazine with different spacer lengths, and one derivative from commercial tartrazine after a little chemical modification, were synthesized as haptens in order to produce antibodies specific to tartrazine. The effect of sulfonic acid groups on the hapten structure of tartrazine was also studied carefully for the first time. A most specific monoclonal antibody against tartrazine was created and exhibited an IC50 value of 0.105 ng/mL and a limit of detection of 0.014 ng/mL, with no cross-reactivity to other structurally-related pigments. The established immunoassay was applied to the determination of tartrazine in fortified samples of orange juice and in real positive samples of carbonated beverages.

  16. Integrated immunoassay using tuneable surface acoustic waves and lensfree detection.

    Science.gov (United States)

    Bourquin, Yannyk; Reboud, Julien; Wilson, Rab; Zhang, Yi; Cooper, Jonathan M

    2011-08-21

    The diagnosis of infectious diseases in the Developing World is technologically challenging requiring complex biological assays with a high analytical performance, at minimal cost. By using an opto-acoustic immunoassay technology, integrating components commonly used in mobile phone technologies, including surface acoustic wave (SAW) transducers to provide pressure driven flow and a CMOS camera to enable lensfree detection technique, we demonstrate the potential to produce such an assay. To achieve this, antibody functionalised microparticles were manipulated on a low-cost disposable cartridge using the surface acoustic waves and were then detected optically. Our results show that the biomarker, interferon-γ, used for the diagnosis of diseases such as latent tuberculosis, can be detected at pM concentrations, within a few minutes (giving high sensitivity at a minimal cost). This journal is © The Royal Society of Chemistry 2011

  17. Plasma myelin basic protein assay using Gilford enzyme immunoassay cuvettes.

    Science.gov (United States)

    Groome, N P

    1981-10-01

    The assay of myelin basic protein in body fluids has potential clinical importance as a routine indicator of demyelination. Preliminary details of a competitive enzyme immunoassay for this protein have previously been published by the author (Groome, N. P. (1980) J. Neurochem. 35, 1409-1417). The present paper now describes the adaptation of this assay for use on human plasma and various aspects of routine data processing. A commercially available cuvette system was found to have advantages over microtitre plates but required a permuted arrangement of sample replicates for consistent results. For dose interpolation, the standard curve could be fitted to a three parameter non-linear equation by regression analysis or linearised by the logit/log transformation.

  18. A redox-mediated chromogenic reaction and application in immunoassay.

    Science.gov (United States)

    Yu, Ru-Jia; Ma, Wei; Peng, Mao-Pan; Bai, Zhi-Shan; Long, Yi-Tao

    2016-08-31

    A novel redox-mediated chromogenic reaction was demonstrated based on the reaction between HAuCl4 and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), which generate various color responses from red to green in the resulting solutions. Various redox substance could be used to mediate the reaction and trigger a distinct color response. We established a sensitive hydrogen peroxide colorimetric sensor based on the redox-mediated chromogenic reaction and depicted the application both in detection of enzyme and in an immunoassay. Combining the traditional chromogenic reagent with gold nanoparticles, our assay has the advantage in short response time (within three minutes), high sensitivity (10(-12) g mL(-1) for HBsAg) and stability. Copyright © 2016. Published by Elsevier B.V.

  19. Development of an ultrasensitive immunoassay for detecting tartrazine.

    Science.gov (United States)

    Li, Zhuokun; Song, Shanshan; Xu, Liguang; Kuang, Hua; Guo, Shidong; Xu, Chuanlai

    2013-06-25

    We have developed an ultrasensitive indirect competitive enzyme-linked immunosorbent assay for the determination of tartrazine. Two carboxylated analogues of tartrazine with different spacer lengths, and one derivative from commercial tartrazine after a little chemical modification, were synthesized as haptens in order to produce antibodies specific to tartrazine. The effect of sulfonic acid groups on the hapten structure of tartrazine was also studied carefully for the first time. A most specific monoclonal antibody against tartrazine was created and exhibited an IC50 value of 0.105 ng/mL and a limit of detection of 0.014 ng/mL, with no cross-reactivity to other structurally-related pigments. The established immunoassay was applied to the determination of tartrazine in fortified samples of orange juice and in real positive samples of carbonated beverages.

  20. On-Chip Immunoassay for Determination of Urinary Albumin

    Directory of Open Access Journals (Sweden)

    Adisorn Tuantranont

    2009-12-01

    Full Text Available An immunoassay performed on a portable microfluidic device was evaluated for the determination of urinary albumin. An increase in absorbance at 500 nm resulting from immunoagglutination was monitored directly on the poly(dimethylsiloxane (PDMS microchip using a portable miniature fibre-optic spectrometer. A calibration curve was linear up to 10 mg L–1 (r2 = 0.993, with a detection limit of 0.81 mg L–1 (S/N = 3. The proposed system showed good precision, with relative standard deviations (RSDs of 5.1%, when evaluated with 10 mg L–1 albumin (n = 10. Determination of urinary albumin with the proposed system gave results highly similar to those determined by the conventional spectrophotometric method using immunoturbidimetric detection (r2 = 0.995; n = 15.

  1. Performance of immunoassay kits for site characterization and remediation

    International Nuclear Information System (INIS)

    Waters, L.C.; Palausky, A.; Counts, R.W.; Jenkins, R.A.

    1995-01-01

    The US Department of Energy (DOE) is supporting efforts to identify, validate and implement the use of effective, low-cost alternatives to currently used analytical methods for environmental management. As part of that program, we have evaluated the performances of a number of immunoassay (IA) kits with specificities for environmental contaminants of concern to the DOE. The studies were done in the laboratory using both spiked and field test samples. The analyte specificity and manufacturers of the kits evaluated were the following: mercury, BioNebraska; polychlorinated biphenyls (PCBs), EnSys and Millipore; petroleum fuel hydrocarbons, Millipore and Ohmicron; and polyaromatic hydrocarbons (PAHs), Ohmicron and Millipore. The kits were used in either a semiquantitative or quantitative format according to the preference of the manufacturers

  2. Instrumental Capital

    Directory of Open Access Journals (Sweden)

    Gabriel Valerio

    2007-07-01

    Full Text Available During the history of human kind, since our first ancestors, tools have represented a mean to reach objectives which might otherwise seemed impossibles. In the called New Economy, where tangibles assets appear to be losing the role as the core element to produce value versus knowledge, tools have kept aside man in his dairy work. In this article, the author's objective is to describe, in a simple manner, the importance of managing the organization's group of tools or instruments (Instrumental Capital. The characteristic conditions of this New Economy, the way Knowledge Management deals with these new conditions and the sub-processes that provide support to the management of Instrumental Capital are described.

  3. Streptavidin-functionalized capillary immune microreactor for highly efficient chemiluminescent immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Yang Zhanjun [State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093 (China); College of Chemistry and Engineering, Yangzhou University, 88 South University Avenue, Yangzhou 225002 (China); Zong Chen [State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093 (China); Ju Huangxian, E-mail: hxju@nju.edu.cn [State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093 (China); Yan Feng, E-mail: yanfeng2007@sohu.com [Jiangsu Institute of Cancer Prevention and Cure, Nanjing 210009 (China)

    2011-11-07

    Highlights: {yields} A novel capillary immune microreactor was proposed for highly efficient flow-through chemiluminescent immunoassay. {yields} The microreactor was prepared by functionalizing capillary inner wall with streptavidin for capture of biotinylated antibody. {yields} The proposed immunoassay method showed wide dynamic range, good reproducibility, stability and practicality. {yields} The microreactor was low-cost and disposable, and possessed several advantages over the conventional immunoreactors. - Abstract: A streptavidin functionalized capillary immune microreactor was designed for highly efficient flow-through chemiluminescent (CL) immunoassay. The functionalized capillary could be used as both a support for highly efficient immobilization of antibody and a flow cell for flow-through immunoassay. The functionalized inner wall and the capture process were characterized using scanning electron microscopy. Compared to conventional packed tube or thin-layer cell immunoreactor, the proposed microreactor showed remarkable properties such as lower cost, simpler fabrication, better practicality and wider dynamic range for fast CL immunoassay with good reproducibility and stability. Using {alpha}-fetoprotein as model analyte, the highly efficient CL flow-through immunoassay system showed a linear range of 3 orders of magnitude from 0.5 to 200 ng mL{sup -1} and a low detection limit of 0.1 ng mL{sup -1}. The capillary immune microreactor could make up the shortcoming of conventional CL immunoreactors and provided a promising alternative for highly efficient flow-injection immunoassay.

  4. Nanobody medicated immunoassay for ultrasensitive detection of cancer biomarker alpha-fetoprotein.

    Science.gov (United States)

    Chen, Jing; He, Qing-hua; Xu, Yang; Fu, Jin-heng; Li, Yan-ping; Tu, Zhui; Wang, Dan; Shu, Mei; Qiu, Yu-lou; Yang, Hong-wei; Liu, Yuan-yuan

    2016-01-15

    Immunoassay for cancer biomarkers plays an important role in cancer prevention and early diagnosis. To the development of immunoassay, the quality and stability of applied antibody is one of the key points to obtain reliability and high sensitivity for immunoassay. The main purpose of this study was to develop a novel immunoassay for ultrasensitive detection of cancer biomarker alpha-fetoprotein (AFP) based on nanobody against AFP. Two nanobodies which bind to AFP were selected from a phage display nanobody library by biopanning strategy. The prepared nanobodies are clonable, thermally stable and applied in both sandwich enzyme linked immunoassay (ELISA) and immuno-PCR assay for ultrasensitive detection of AFP. The limit detection of sandwich ELISA setup with optimized nanobodies was 0.48ng mL(-1), and the half of saturation concentration (SC50) value was 6.68±0.56ng mL(-1). These nanobodies were also used to develop an immuno-PCR assay for ultrasensitive detection of AFP, its limit detection values was 0.005ng mL(-1), and the linear range was 0.01-10,000ng mL(-1). These established immunoassays based on nanobodies were highly specific to AFP and with negligible cross reactivity with other tested caner biomarkers. Furthermore, this novel concept of nanobodies mediated immunoassay may provide potential applications in a general method for the ultrasensitive detection of various cancer biomarkers. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Innovative instrumentation

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    At this year's particle physics conference at Brighton, a parallel session was given over to instrumentation and detector development. While this work is vital to the health of research and its continued progress, its share of prime international conference time is limited. Instrumentation can be innovative three times — first when a new idea is outlined, secondly when it is shown to be feasible, and finally when it becomes productive in a real experiment, amassing useful data rather than operational experience. Hyams' examples showed that it can take a long time for a new idea to filter through these successive stages, if it ever makes it at all

  6. Innovative instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1983-11-15

    At this year's particle physics conference at Brighton, a parallel session was given over to instrumentation and detector development. While this work is vital to the health of research and its continued progress, its share of prime international conference time is limited. Instrumentation can be innovative three times — first when a new idea is outlined, secondly when it is shown to be feasible, and finally when it becomes productive in a real experiment, amassing useful data rather than operational experience. Hyams' examples showed that it can take a long time for a new idea to filter through these successive stages, if it ever makes it at all.

  7. Instrumental aspects

    Directory of Open Access Journals (Sweden)

    Qureshi Navid

    2017-01-01

    Full Text Available Every neutron scattering experiment requires the choice of a suited neutron diffractometer (or spectrometer in the case of inelastic scattering with its optimal configuration in order to accomplish the experimental tasks in the most successful way. Most generally, the compromise between the incident neutron flux and the instrumental resolution has to be considered, which is depending on a number of optical devices which are positioned in the neutron beam path. In this chapter the basic instrumental principles of neutron diffraction will be explained. Examples of different types of experiments and their respective expectable results will be shown. Furthermore, the production and use of polarized neutrons will be stressed.

  8. Algorithms for a hand-held miniature x-ray fluorescence analytical instrument

    International Nuclear Information System (INIS)

    Elam, W.T.; Newman, D.; Ziemba, F.

    1998-01-01

    The purpose of this joint program was to provide technical assistance with the development of a Miniature X-ray Fluorescence (XRF) Analytical Instrument. This new XRF instrument is designed to overcome the weaknesses of spectrometers commercially available at the present time. Currently available XRF spectrometers (for a complete list see reference 1) convert spectral information to sample composition using the influence coefficients technique or the fundamental parameters method. They require either a standard sample with composition relatively close to the unknown or a detailed knowledge of the sample matrix. They also require a highly-trained operator and the results often depend on the capabilities of the operator. In addition, almost all existing field-portable, hand-held instruments use radioactive sources for excitation. Regulatory limits on such sources restrict them such that they can only provide relatively weak excitation. This limits all current hand-held XRF instruments to poor detection limits and/or long data collection times, in addition to the licensing requirements and disposal problems for radioactive sources. The new XRF instrument was developed jointly by Quantrad Sensor, Inc., the Naval Research Laboratory (NRL), and the Department of Energy (DOE). This report describes the analysis algorithms developed by NRL for the new instrument and the software which embodies them

  9. Surgical Instrument

    NARCIS (Netherlands)

    Dankelman, J.; Horeman, T.

    2009-01-01

    The present invention relates to a surgical instrument for minimall-invasive surgery, comprising a handle, a shaft and an actuating part, characterised by a gastight cover surrounding the shaft, wherein the cover is provided with a coupler that has a feed- through opening with a loskable seal,

  10. Weather Instruments.

    Science.gov (United States)

    Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

    This booklet presents some activities to measure various weather phenomena. Directions for constructing a weather station are included. Instruments including rain gauges, thermometers, wind vanes, wind speed devices, humidity devices, barometers, atmospheric observations, a dustfall jar, sticky-tape can, detection of gases in the air, and pH of…

  11. Nuclear instrumentation

    International Nuclear Information System (INIS)

    Weill, Jacky; Fabre, Rene.

    1981-01-01

    This article sums up the Research and Development effort at present being carried out in the five following fields of applications: Health physics and Radioprospection, Control of nuclear reactors, Plant control (preparation and reprocessing of the fuel, testing of nuclear substances, etc.), Research laboratory instrumentation, Detectors. It also sets the place of French industrial activities by means of an estimate of the French market, production and flow of trading with other countries [fr

  12. Divided Instruments

    Science.gov (United States)

    Chapman, A.; Murdin, P.

    2000-11-01

    Although the division of the zodiac into 360° probably derives from Egypt or Assyria around 2000 BC, there is no surviving evidence of Mesopotamian cultures embodying this division into a mathematical instrument. Almost certainly, however, it was from Babylonia that the Greek geometers learned of the 360° circle, and by c. 80 BC they had incorporated it into that remarkably elaborate device gener...

  13. Instrumentation development

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Areas being investigated for instrumentation improvement during low-level pollution monitoring include laser opto-acoustic spectroscopy, x-ray fluorescence spectroscopy, optical fluorescence spectroscopy, liquid crystal gas detectors, advanced forms of atomic absorption spectroscopy, electro-analytical chemistry, and mass spectroscopy. Emphasis is also directed toward development of physical methods, as opposed to conventional chemical analysis techniques for monitoring these trace amounts of pollution related to energy development and utilization

  14. Instrumentation maintenance

    International Nuclear Information System (INIS)

    Mack, D.A.

    1976-09-01

    It is essential to any research activity that accurate and efficient measurements be made for the experimental parameters under consideration for each individual experiment or test. Satisfactory measurements in turn depend upon having the necessary instruments and the capability of ensuring that they are performing within their intended specifications. This latter requirement can only be achieved by providing an adequate maintenance facility, staffed with personnel competent to understand the problems associated with instrument adjustment and repair. The Instrument Repair Shop at the Lawrence Berkeley Laboratory is designed to achieve this end. The organization, staffing and operation of this system is discussed. Maintenance policy should be based on studies of (1) preventive vs. catastrophic maintenance, (2) records indicating when equipment should be replaced rather than repaired and (3) priorities established to indicate the order in which equipment should be repaired. Upon establishing a workable maintenance policy, the staff should be instructed so that they may provide appropriate scheduled preventive maintenance, calibration and corrective procedures, and emergency repairs. The education, training and experience of the maintenance staff is discussed along with the organization for an efficient operation. The layout of the various repair shops is described in the light of laboratory space and financial constraints

  15. Correlations between calcineurin phosphatase inhibition and cyclosporine metabolites concentrations in kidney transplant recipients: Implications for immunoassays

    DEFF Research Database (Denmark)

    Jørgensen, Kaj Anker; Karamperis, Nikolaos; Koefoed-Nielsen, Pernille Bundgaard

    2006-01-01

    by inhibiting the enzyme calcineurin phosphatase. Determination of the enzyme's activity is one of the most promising pharmacodynamic markers. It is unknown how calcineurin phosphatase inhibition correlates with various cyclosporine monitoring assays and what is the potential impact of metabolites...... by the enzyme multiplied immunoassay technique (EMIT) and by the polyclonal fluorescence polarization immunoassay (pFPIA). Calcineurin phosphatase activity was measured by its ability to dephosphorylate a previously phosphorylated 19-amino acid peptide. We found that calcineurin phosphatase inhibition...

  16. Correlations between calcineurin phosphatase inhibition and cyclosporine metabolites concentrations in kidney transplant recipients: implications for immunoassays

    DEFF Research Database (Denmark)

    Karamperis, N; Koefoed-Nielsen, PB; Brahe, P

    2006-01-01

    by inhibiting the enzyme calcineurin phosphatase. Determination of the enzyme's activity is one of the most promising pharmacodynamic markers. It is unknown how calcineurin phosphatase inhibition correlates with various cyclosporine monitoring assays and what is the potential impact of metabolites...... by the enzyme multiplied immunoassay technique (EMIT) and by the polyclonal fluorescence polarization immunoassay (pFPIA). Calcineurin phosphatase activity was measured by its ability to dephosphorylate a previously phosphorylated 19-amino acid peptide. We found that calcineurin phosphatase inhibition...

  17. Control of (pre-analytical aspects in immunoassay measurements of metabolic hormones in rodents

    Directory of Open Access Journals (Sweden)

    Maximilian Bielohuby

    2018-04-01

    Full Text Available The measurement of circulating hormones by immunoassay remains a cornerstone in preclinical endocrine research. For scientists conducting and interpreting immunoassay measurements of rodent samples, the paramount aim usually is to obtain reliable and meaningful measurement data in order to draw conclusions on biological processes. However, the biological variability between samples is not the only variable affecting the readout of an immunoassay measurement and a considerable amount of unwanted or unintended variability can be quickly introduced during the pre-analytical and analytical phase. This review aims to increase the awareness for the factors ‘pre-analytical’ and ‘analytical’ variability particularly in the context of immunoassay measurement of circulating metabolic hormones in rodent samples. In addition, guidance is provided how to gain control over these variables and how to avoid common pitfalls associated with sample collection, processing, storage and measurement. Furthermore, recommendations are given on how to perform a basic validation of novel single and multiplex immunoassays for the measurement of metabolic hormones in rodents. Finally, practical examples from immunoassay measurements of plasma insulin in mice address the factors ‘sampling site and inhalation anesthesia’ as frequent sources of introducing an unwanted variability during the pre-analytical phase. The knowledge about the influence of both types of variability on the immunoassay measurement of circulating hormones as well as strategies to control these variables are crucial, on the one hand, for planning and realization of metabolic rodent studies and, on the other hand, for the generation and interpretation of meaningful immunoassay data from rodent samples.

  18. A study using an isotope probe comparing immunoassay with serology in detection of Brucella Abortus antibody

    International Nuclear Information System (INIS)

    Devlin, J.G.; Redington, F.; Stephenson, M.

    1986-01-01

    We report a comparison of radio-immunoassay with conventional serology in the detection of brucella abortus antibody from three laboratories. Overall agreement by Chi squared analysis is 5%. There are significant differences between laboratories and a significant number of sero negative suspect sera (from 20% - 60%) were positive by ratio-immunoassay test. We suspect that conventional serology under-reports the incidence of antibody to brucella abortus. (author)

  19. Analytical evaluation of the novel Lumipulse G BRAHMS procalcitonin immunoassay

    Directory of Open Access Journals (Sweden)

    Orazio Ruzzenente

    2016-12-01

    Full Text Available Objectives: This study was designed to evaluate the analytical performance of the novel Lumipulse G1200 BRAHMS procalcitonin (PCT immunoassay. Design and methods: This analytical evaluation encompassed the calculation of the limit of blank (LOB, limit of detection (LOD, functional sensitivity, intra- and inter-assay imprecision, confirmation of linearity and a comparison with the Vidas BRAHMS PCT assay. Results: The LOB, LOD and functional sensitivity were 0.0010 ng/mL, 0.0016 ng/mL and 0.008 ng/mL, respectively. The total analytical imprecision was found to be 2.1% and the linearity was excellent (r=1.00 in the range of concentrations between 0.006–75.5 ng/mL. The correlation coefficient with Vidas BRAHMS PCT was 0.995 and the equation of the Passing and Bablok regression analysis was [Lumipulse G BRAHMS PCT]=0.76×[Vidas BRAHMS PCT]+0.04. The mean overall bias of Lumipulse G BRAHMS PCT versus Vidas BRAHMS PCT was −3.03 ng/mL (95% confidence interval [CI]: −4.32 to −1.74 ng/mL, whereas the mean bias in samples with PCT concentration between 0–10 ng/mL was −0.49 ng/mL (95% CI: −0.77 to −0.24 ng/mL. The diagnostic agreement was 100% at 0.5 ng/mL, 97% at 2.0 ng/mL and 95% at 10 ng/mL, respectively. Conclusions: These results attest that Lumipulse G BRAHMS PCT exhibits excellent analytical performance, among the best of the methods currently available on the diagnostic market. However, the significant bias compared to the Vidas BRAHMS PCT suggests that the methods cannot be used interchangeably. Keywords: Sepsis, Infection, Procalcitonin, Immunoassay

  20. Catch and measure-mass spectrometry-based immunoassays in biomarker research.

    Science.gov (United States)

    Weiß, Frederik; van den Berg, Bart H J; Planatscher, Hannes; Pynn, Christopher J; Joos, Thomas O; Poetz, Oliver

    2014-05-01

    Mass spectrometry-based (MS) methods are effective tools for discovering protein biomarker candidates that can differentiate between physiological and pathophysiological states. Promising candidates are validated in studies comprising large patient cohorts. Here, targeted protein analytics are used to increase sample throughput. Methods involving antibodies, such as sandwich immunoassays or Western blots, are commonly applied at this stage. Highly-specific and sensitive mass spectrometry-based immunoassays that have been established in recent years offer a suitable alternative to sandwich immunoassays for quantifying proteins. Mass Spectrometric ImmunoAssays (MSIA) and Stable Isotope Standards and Capture by Anti-Peptide Antibodies (SISCAPA/iMALDI) are two prominent types of MS-based immunoassays in which the capture is done either at the protein or the peptide level. We present an overview of these emerging types of immunoassays and discuss their suitability for the discovery and validation of protein biomarkers. This article is part of a Special Issue entitled: Biomarkers: A Proteomic Challenge. © 2013.

  1. Determination of five abused drugs in nitrite-adulterated urine by immunoassays and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Tsai, S C; ElSohly, M A; Dubrovsky, T; Twarowska, B; Towt, J; Salamone, S J

    1998-10-01

    The adulteration of urine specimens with nitrite ion hasseen shown to mask the gas chromatography-mass spectrometry (GC-MS) confirmation testing of marijuana use. This study was designed to further investigate the effect of nitrite adulteration on the detection of five commonly abused drugs by immunoassay screening and GC-MS analysis. The drugs tested are cocaine metabolite (benzoylecgonine), morphine, 11-nor-delta-tetrahydrocannabinol-9-carboxylic acid (THCCOOH), amphetamine, and phencyclidine. The immunoassays evaluated included the instrument-based Abuscreen ONLINE assays, the on-site Abuscreen ONTRAK assays, and the one-step ONTRAK TESTCUP-5 assay. Multianalyte standards containing various levels of drugs were used to test the influence of both potassium and sodium nitrite. In the ONLINE immunoassays, the presence of up to 1.0M nitrite in the multianalyte standards had no significant effect for benzoylecgonine, morphine, and phencyclidine assays. With a high concentration of nitrite, ONLINE became more sensitive for amphetamine (detected more drug than what was expected) and less sensitive for THCCOOH (detected less drug than what was expected). No effects of nitrite were observed on the results of the Abuscreen ONTRAK assays. Similarly, no effects were observed on the absolute qualitative results of the TESTCUP-5 when testing the nitrite-adulterated standards. However, the produced intensities of the signals that indicate the negative test results were slightly lowered in the THC and phencyclidine assays. The presence of 1.0M of nitrite did not show dramatic interference with the GC-MS analysis of benzoylecgonine, morphine, amphetamine, and phencyclidine. In contrast, nitrite ion significantly interfered with the detection of THCCOOH by GC-MS. The presence of 0.03M of nitrite ion resulted in significant loss in the recovery of THCCOOH and its internal standard by GC-MS. The problem of nitrite adulteration could be alleviated by sodium bisulfite treatment even

  2. Novel enzyme immunoassay system for simultaneous detection of six subclasses of antiphospholipid antibodies for differential diagnosis of antiphospholipid syndrome.

    Science.gov (United States)

    Nojima, Junzo; Motoki, Yukari; Hara, Kazusa; Sakata, Toshiyuki; Ichihara, Kiyoshi

    2017-06-01

    : Antiphospholipid syndrome, which often complicates systemic lupus erythematosus (SLE), features high occurrence of arterial and/or venous thrombosis and recurrent fetal loss. However, which antibody subclass contributes to which clinical event remains uncertain. We newly developed an up-to-date enzyme immunoassay system using the AcuStar automated analyzer (Instrumentation Laboratory, Bedford, Massachusetts, USA) for parallel detection of six subclasses of antiphospholipid antibodies (aPLs): anticardiolipin antibodies (aCL) of IgG, IgM, and IgA and anti-β2-glycoprotein I antibodies (aβ2GPI) of IgG, IgM, and IgA. They were measured in 276 healthy volunteers and 138 patients with SLE: 45 with thromboembolic complications (29 arterial; 16 venous) and 93 without. Lupus anticoagulant activity in their plasma was measured according to the guidelines recommended by the Subcommittee on Lupus Anticoagulant/Phospholipid-Dependent Antibodies. aCL/β2GPI was measured with a standard ELISA kit commonly used in Japan. The positive results of IgG aCL, IgA aCL, and IgG aβ2GPI were closely associated with thromboembolic complications, whereas IgM aCL and IgM aβ2GPI were not. receiver operating characteristic analysis revealed that the accuracy of predicting thromboembolic complications based on the composite test results of the former three antibodies were obviously higher than by each alone. Regarding agreement with the test results of lupus anticoagulant activity, IgG aβ2GPI showed the closest match. Patients with SLE frequently possess various combinations of the six aPL subclasses, and this antibody spectrum is closely associated with thromboembolic events in these patients. This new automated enzyme immunoassay system allows simultaneous analysis of the profile of aPL subclasses for the differential diagnosis of antiphospholipid antibody syndrome in its early stage.

  3. Nanoparticle-based immunosensors and immunoassays for aflatoxins

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xu; Niessner, Reinhard [Institute of Hydrochemistry and Chair of Analytical Chemistry, Technische Universität München, Marchioninistrasse 17, D-81377 München (Germany); Tang, Dianping [Key Laboratory of Analysis and Detection for Food Safety, MOE & Fujian Province, Department of Chemistry, Fuzhou University, Fuzhou 350108 (China); Knopp, Dietmar, E-mail: dietmar.knopp@ch.tum.de [Institute of Hydrochemistry and Chair of Analytical Chemistry, Technische Universität München, Marchioninistrasse 17, D-81377 München (Germany)

    2016-03-17

    Aflatoxins are naturally existing mycotoxins produced mainly by Aspergillus flavus and Aspergillus parasiticus, present in a wide range of food and feed products. Because of their extremely high toxicity and carcinogenicity, strict control of maximum residue levels of aflatoxins in foodstuff is set by many countries. In daily routine, different chromatographic methods are used almost exclusively. As supplement, in several companies enzyme immunoassay-based sample testing as primary screening is performed. Recently, nanomaterials such as noble metal nanoparticles, magnetic particles, carbon nanomaterials, quantum dots, and silica nanomaterials are increasingly utilized for aflatoxin determination to improve the sensitivity and simplify the detection. They are employed either as supports for the immobilization of biomolecules or as electroactive or optical labels for signal transduction and amplification. Several nanoparticle-based electrochemical, piezoelectric, optical, and immunodipstick assays for aflatoxins have been developed. In this review, we summarize these recent advances and illustrate novel concepts and promising applications in the field of food safety. - Highlights: • Novel concepts and promising applications of nanoparticle-based immunological methods for the determination of aflatoxins. • Inclusion of most important nanomaterials and hybrid nanostructures. • Inclusion of electrochemical, optical and mass-sensitive biosensors as well as optical and immunochromatographic assays.

  4. Basic and clinical investigation of T3 immunoassay kit

    International Nuclear Information System (INIS)

    Konishi, Junji; Nakajima, Akiko; Morita, Rikushi; Endo, Keigo; Ikekubo, Katsuji

    1976-01-01

    T 3 immunoassay kit was investigated basically and clinically. A good result was obtained at the prescribed incubation temperature and for 16 hours of incubation time. Moreover, it was thought to be possible that incubation time could be shortened to 1 - 4 hours at 37 0 C. Specificity of antibody was good. Recovery of added T 3 was 100+-5 (S.D.) % on an average and parallel of dilution curve of high T 3 serum was also good. Variation coefficient of accuracy of this kit was 1.5 - 2.1 % and that of reproducibility was 1.3 - 6.6 %. Mild hemolysis did not affect measurement value. Serum T 3 level in normals, untreated patients with Basedow's disease and patients with primary hypothyroidism was 142+-21 ng/100 ml, 452+-156 ng/100 ml and 67+-17 ng/100 ml, respectively. Serum T 3 level in patients with Hashimoto's disease was distributed to a wide extent, but that of patients with goiter and simple goiter ranged within normal range. On the other side, serum T 3 level of normal pregnant woman was high and that of patients with anorexia nervosa showed low level. From the above mentioned results, it was concluded that this kit was simple in method and good in sensitivity, specificity and reproducibility and it was also useful for clinical applications. (M. Tsunoda)

  5. Detection of Aspergillus fumigatus mycotoxins: immunogen synthesis and immunoassay development.

    Science.gov (United States)

    Fox, M; Gray, G; Kavanagh, K; Lewis, C; Doyle, S

    2004-02-01

    Immunological detection of secreted low molecular weight toxins represents a potentially novel means of diagnosing infection by the fungus Aspergillus fumigatus. Two such metabolites, gliotoxin and helvolic acid, were selected and conjugated to thyroglobulin for antisera generation in rabbits. Gliotoxin was initially activated using N-[p-maleimidophenyl] isocyanate (PMPI) and subsequently conjugated to S-acetyl thioglycolic acid N-hydroxysuccinimide-activated thyroglobulin, whereas helvolic acid was activated with N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) in the presence of thyroglobulin prior to immunisation. To facilitate subsequent antisera evaluation, both toxins were similarly conjugated to bovine serum albumin (BSA). Matrix-Assisted Laser Desorption Ionisation-Time Of Flight (MALDI-TOF) mass spectrometry and SDS-PAGE analysis confirmed covalent attachment of toxins to BSA in the ratios of 15 and 2.4 mol per mol BSA for gliotoxin and helvolic acid, respectively. Resultant high titer antisera were capable of detecting both BSA-conjugated toxins (inhibitory concentration (IC)(50): 4-5 microg/ml). Free toxins were also detectable by competitive immunoassay, whereby 10 microg/ml free gliotoxin (30 microM) and helvolic acid (17 microM), respectively, inhibited antibody binding to cognate toxin-BSA previously immobilised on microwells. This work confirms that sensitive and specific antisera can be raised against fungal toxins and may have an application in diagnosing fungal infection.

  6. Enzyme immunoassay for DDT analysis in Lebanese soils

    International Nuclear Information System (INIS)

    Bashour, I.; Dagher, S.; Shammas, G.; Sukkariyah, B.; Kawar, N.

    2000-01-01

    Full text: The use of enzyme-linked immunosorbent assay (ELISA) technique in estimating pesticide residue in soils is a faster, less expensive and easier method to use than the gas chromatography (GC) analysis technique..In the test, DDT pesticide residues in the simple compete with enzyme (horseradish peroxidase)-labeled DDT for a limited number of antibody binding sites on the inside surfaces of the test wells; the envirologix plate kit was tested for the measurement of total DDT in virgin and fortified (0-1000 ng g exp-1) soil samples of different properties from Lebanon. Extraction of DDT from soil was done by shaking the samples for 16 hours on a mechanical shaker with 90% methanol without any clean-up steps. Then the samples were allowed to stand for 30 minutes and an aliquot was taken from the clear supernatant. The DDT in the extract was measured in triplicate by GC and ELISA. The results indicated that the two techniques were highly correlated (r2 =0.9671-0.9973). Differences in soils physical and chemical properties did not accuracy of the detection limits of ELISA when compared to GC-ECD results. Immunoassay technique is a suitable method for rapid and accurate measurement of DDT residue in mineral Lebanese soils

  7. Sensitive, Fast, and Specific Immunoassays for Methyltestosterone Detection

    Directory of Open Access Journals (Sweden)

    Na Kong

    2015-04-01

    Full Text Available An indirect competitive enzyme-linked immunosorbent assay (icELISA and an immunochromatographic strip assay using a highly specific monoclonal antibody, were developed to detect methyltestosterone (MT residues in animal feed. The optimized icELISA had a half-inhibition concentration value of 0.26 ng/mL and a limit of detection value of 0.045 ng/mL. There was no cross-reactivity with eight analogues, revealing high specificity for MT. Based on icELISA results, the recovery rate of MT in animal feed was 82.4%–100.6%. The results were in accordance with those obtained by gas chromatography-mass spectrometry. The developed immunochromatographic strip assay, as the first report for MT detection, had a visual cut-off value of 1 ng/mL in PBS, 2.5 ng/g in fish feed, and 2.5 ng/g in pig feed. Therefore, these immunoassays are useful and fast tools for MT residue detection in animal feed.

  8. Evidence for carcinoembryonic antigen using radioimmunoassay and enzyme immunoassay

    International Nuclear Information System (INIS)

    Kungda Gao, L.

    1980-01-01

    A commercially available radioimmunoassay for the determination of carcinoembryonic antigen (CEA) was initially compared with an enzyme immunoassay (EIA). Considerable differences were found between the individual value. For three patients suffering from carcinomas of the digestive tract a better indication of the disease was given in the RIA than in the EIA. A further 110 patients with various illnesses were examined for serum CEA-levels using RIA. A method for measuring CEA in feces by RIA was developed. The normal range lies below 300 ng/ml. This assay could be of significance for the early recognition of colo-rectal carcinoma. In part II of this dissertation CEA was isolated from colo-rectal carcinomas using three different gel filtration media. It was only possible to obtain almost pure CEA (24 μg CEA per μg protein) by one of the methods. Six guinea pigs were immunized with the isolated CEA and all developed antibodies. The isolated CEA was labelled with 125 I and an own RIA saturation sequence and double antibody separation was developed. One of the antisera was able to distinguish without overlap 7 healthy patients from 7 suffering from colo-rectal carcinomas in non-extracted serum. (orig./MG) [de

  9. Graphene-based chemiluminescence resonance energy transfer for homogeneous immunoassay.

    Science.gov (United States)

    Lee, Joon Seok; Joung, Hyou-Arm; Kim, Min-Gon; Park, Chan Beum

    2012-04-24

    We report on chemiluminescence resonance energy transfer (CRET) between graphene nanosheets and chemiluminescent donors. In contrast to fluorescence resonance energy transfer, CRET occurs via nonradiative dipole-dipole transfer of energy from a chemiluminescent donor to a suitable acceptor molecule without an external excitation source. We designed a graphene-based CRET platform for homogeneous immunoassay of C-reactive protein (CRP), a key marker for human inflammation and cardiovascular diseases, using a luminol/hydrogen peroxide chemiluminescence (CL) reaction catalyzed by horseradish peroxidase. According to our results, anti-CRP antibody conjugated to graphene nanosheets enabled the capture of CRP at the concentration above 1.6 ng mL(-1). In the CRET platform, graphene played a key role as an energy acceptor, which was more efficient than graphene oxide, while luminol served as a donor to graphene, triggering the CRET phenomenon between luminol and graphene. The graphene-based CRET platform was successfully applied to the detection of CRP in human serum samples in the range observed during acute inflammatory stress.

  10. Significance of isolated reactive treponemal chemiluminescence immunoassay results.

    Science.gov (United States)

    Hunter, Michael G; Robertson, Peter W; Post, Jeffrey J

    2013-05-01

    Isolated reactive serum treponemal chemiluminescence immunoassay (CIA) specimens cause clinical uncertainty. Sera were screened by CIA, and reactive samples underwent reflex testing with rapid plasma reagin (RPR), Treponema pallidum particle agglutination (TPPA), and fluorescent treponemal antibody absorption (FTA Abs) assays. Samples reactive only on the CIA were deemed "isolated" reactive CIA samples. We undertook detailed review of a subset of subjects with isolated reactive CIA specimens. Of 28 261 specimens, 1171 (4.1%) were reactive on CIA, of which 133 (11.3%) had isolated CIA reactivity. Most subjects (66 of 82 [80.5%]) with isolated reactive CIA specimens were from high-prevalence populations. We found evidence of CIA, TPPA, and FTA Abs seroreversion. The median chemiluminescent signal-to-cutoff ratio was similar for isolated reactive CIA sera and sera that were reactive on either FTA Abs or TPPA assays (2.19 vs 2.32; P = .15) but lower than for sera reactive on both FTA Abs and TPPA assays (12.37; P < .001) or for sera reactive on RPR assays (25.53; P < .001). A total of 11 of 20 patients (55%) with an isolated reactive CIA specimen who underwent medical record review had previous or subsequent evidence of syphilis infection. Isolated reactive CIA specimens may represent true T. pallidum infection and may be found after seroreversion of traditional treponemal assays.

  11. Serum gastrin: interests and limitations of radio-immunoassay

    International Nuclear Information System (INIS)

    Rougier, P.; Linhart, N.; Bok, B.

    1980-01-01

    Radio-immunoassay of serum gastrin may now be carried out in all laboratories of radio-immunology. Comparison of two commercial kits A: Schwartz-Mann and B: CEA-SORIN according to criteria of specificity, sensitivity and reproducibility within and between systems, shows that they both permit the detection of pathological hypergastrinemias (Zollinger Ellison and atropic gastritis). Both kits have an identical intrasystem coefficient of variation (10 p. cent and 7 p. cent fort A, 5 p. cent and 8 p. cent for B) on the other hand, the inter-system coefficient of variation is better for kit B (22.4 p. cent and 37 p. cent for kit A, and 11.5 p. cent and 14.2 p. cent for kit B). The normal values for each kit are quite different: 97 . 64 pg.ml -1 for A and 51 . 23 pg.ml -1 for B preventing one from comparing estimations carried out with two different kits [fr

  12. Establishment of carcinoembryonic antigen working standard for immunoassay

    International Nuclear Information System (INIS)

    Xu Ligen; Sun Youxiang; Jiao Yan

    2001-01-01

    The author is to prepare the working standard of carcinoembryonic antigen (CEA) for immunoassay and determine its potency. CEA solution of 320 μg/L was prepared from purified CEA solution of 4.6 mg/L and 1% human albumin solution buffered with 50 mmol/L sodium phosphate, pH7.4. This solution was distributed in an aliquot of 0.5 mL (160 ng per ampoule) and lyophilized. The potency of CEA working standard, in terms of present standard of CEA RIA and IRMA kits made by Chinese manufacturers and in terms of 1st IRP CEA HUMAN 73/601 supplied by WHO, has been determined. Mean immunological potency of the working standard is 163 ng per ampoule with confident limit of 159-168 ng per ampoule at 95% probability level. Test of parallelism of dose-response curve for the working standard to that for 1st IRP CEA HUMAN 73/601 has been passed. CEA working standard is suitable to the kits standard for CEA radioimmunoassay and immunoradiometric assay

  13. Designing novel nano-immunoassays: antibody orientation versus sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Puertas, S; Moros, M; Fernandez-Pacheco, R; Ibarra, M R; Grazu, V; De la Fuente, J M, E-mail: vgrazu@unizar.e, E-mail: jmfuente@unizar.e [Instituto de Nanociencia de Aragon (INA), Universidad de Zaragoza, Campus RIo Ebro, EdifIcio I-D, Mariano Esquillor, s/n, 50018 Zaragoza (Spain)

    2010-12-01

    There is a growing interest in the use of magnetic nanoparticles (MNPs) for their application in quantitative and highly sensitive biosensors. Their use as labels of biological recognition events and their detection by means of some magnetic method constitute a very promising strategy for quantitative high-sensitive lateral-flow assays. In this paper, we report the importance of nanoparticle functionalization for the improvement of sensitivity for a lateral-flow immunoassay. More precisely, we have found that immobilization of IgG anti-hCG through its polysaccharide moieties on MNPs allows more successful recognition of the hCG hormone. Although we have used the detection of hCG as a model in this work, the strategy of binding antibodies to MNPs through its sugar chains reported here is applicable to other antibodies. It has huge potential as it will be very useful for the development of quantitative and high-sensitive lateral-flow assays for its use on human and veterinary, medicine, food and beverage manufacturing, pharmaceutical, medical biologics and personal care product production, environmental remediation, etc.

  14. Molecularly Imprinted Polymer as an Antibody Substitution in Pseudo-immunoassays for Chemical Contaminants in Food and Environmental Samples.

    Science.gov (United States)

    Chen, Chaochao; Luo, Jiaxun; Li, Chenglong; Ma, Mingfang; Yu, Wenbo; Shen, Jianzhong; Wang, Zhanhui

    2018-03-21

    The chemical contaminants in food and the environment are quite harmful to food safety and human health. Rapid, accurate, and cheap detection can effectively control the potential risks derived from these chemical contaminants. Among all detection methods, the immunoassay based on the specific interaction of antibody-analyte is one of the most widely used techniques in the field. However, biological antibodies employed in the immunoassay usually cannot tolerate extreme conditions, resulting in an unstable state in both physical and chemical profiles. Molecularly imprinted polymers (MIPs) are a class of polymers with specific molecular recognition abilities, which are highly robust, showing excellent operational stability under a wide variety of conditions. Recently, MIPs have been used in biomimetic immunoassays for chemical contaminants as an antibody substitute in food and the environment. Here, we reviewed these applications of MIPs incorporated in different analytical platforms, such as enzyme-linked immunosorbent assay, fluorescent immunoassay, chemiluminescent immunoassay, electrochemical immunoassay, microfluidic paper-based immunoassay, and homogeneous immunoassay, and discussed current challenges and future trends in the use of MIPs in biomimetic immunoassays.

  15. Analytical evaluation of the novel Lumipulse G BRAHMS procalcitonin immunoassay.

    Science.gov (United States)

    Ruzzenente, Orazio; Salvagno, Gian Luca; Gelati, Matteo; Lippi, Giuseppe

    2016-12-01

    This study was designed to evaluate the analytical performance of the novel Lumipulse G1200 BRAHMS procalcitonin (PCT) immunoassay. This analytical evaluation encompassed the calculation of the limit of blank (LOB), limit of detection (LOD), functional sensitivity, intra- and inter-assay imprecision, confirmation of linearity and a comparison with the Vidas BRAHMS PCT assay. The LOB, LOD and functional sensitivity were 0.0010 ng/mL, 0.0016 ng/mL and 0.008 ng/mL, respectively. The total analytical imprecision was found to be 2.1% and the linearity was excellent (r=1.00) in the range of concentrations between 0.006-75.5 ng/mL. The correlation coefficient with Vidas BRAHMS PCT was 0.995 and the equation of the Passing and Bablok regression analysis was [Lumipulse G BRAHMS PCT]=0.76×[Vidas BRAHMS PCT]+0.04. The mean overall bias of Lumipulse G BRAHMS PCT versus Vidas BRAHMS PCT was -3.03 ng/mL (95% confidence interval [CI]: -4.32 to -1.74 ng/mL), whereas the mean bias in samples with PCT concentration between 0-10 ng/mL was -0.49 ng/mL (95% CI: -0.77 to -0.24 ng/mL). The diagnostic agreement was 100% at 0.5 ng/mL, 97% at 2.0 ng/mL and 95% at 10 ng/mL, respectively. These results attest that Lumipulse G BRAHMS PCT exhibits excellent analytical performance, among the best of the methods currently available on the diagnostic market. However, the significant bias compared to the Vidas BRAHMS PCT suggests that the methods cannot be used interchangeably.

  16. Highly sensitive immunoassay based on E. coli with autodisplayed Z-domain

    International Nuclear Information System (INIS)

    Jose, Joachim; Park, Min; Pyun, Jae-Chul

    2010-01-01

    The Z-domain of protein A has been known to bind specifically to the F c region of antibodies (IgGs). In this work, the Z-domain of protein A was expressed on the outer membrane of Escherichia coli by using 'Autodisplay' technology as a fusion protein of autotransport domain. The E. coli with autodisplayed Z-domain was applied to the sandwich-type immunoassay as a solid-support of detection-antibodies against a target analyte. For the feasibility demonstration of the E. coli based immunoassay, C-reactive protein (CRP) assay was carried out by using E. coli with autodisplayed Z-domain. The limit of detection (LOD) and binding capacity of the E. coli based immunoassay were estimated to be far more sensitive than the conventional ELISA. Such a far higher sensitivity of E. coli based immunoassay than conventional ELISA was explained by the orientation control of immobilized antibodies and the mobility of E. coli in assay matrix. From the test results of 45 rheumatoid arthritis (RA) patients' serum and 15 healthy samples, a cut-off value was established to have optimal sensitivity and selectivity values for RA. The CRP test result of each individual sample was compared with ELISA which is the reference method for RA diagnosis. From this work, the E. coli with Z-domain was proved to be feasible for the medical diagnosis based on sandwich-type immunoassay.

  17. Sensitivity-Enhancement of FRET Immunoassays by Multiple-Antibody Conjugation on Quantum Dots.

    Science.gov (United States)

    Annio, Giacomo; Jennings, Travis; Tagit, Oya; Hildebrandt, Niko

    2018-05-23

    Quantum dots (QDs) are not only advantageous for color-tuning, improved brightness, and high stability, but their nanoparticle surfaces also allow for the attachment of many biomolecules. Because IgG antibodies (ABs) are in the same size range of biocompatible QDs and the AB orientation after conjugation to the QD is often random, it is difficult to predict if few or many ABs per QD will lead to an efficient AB-QD conjugate. This is particularly true for homogeneous Förster resonance energy transfer (FRET) sandwich immunoassays, for which the ABs on the QD must bind a biomarker that needs to bind a second AB-FRET-conjugate. Here, we investigate the performance of Tb-to-QD FRET immunoassays against total prostate specific antigen (TPSA) by changing the number of ABs per QD while leaving all the other assay components unchanged. We first characterize the AB-QD conjugation by various spectroscopic, microscopic, and chromatographic techniques and then quantify the TPSA immunoassay performance regarding sensitivity, limit of detection, and dynamic range. Our results show that an increasing conjugation ratio leads to significantly enhanced FRET immunoassays. These findings will be highly important for developing QD-based immunoassays in which the concentrations of both ABs and QDs can significantly influence the assay performance.

  18. Seismic instrumentation

    International Nuclear Information System (INIS)

    1984-06-01

    RFS or Regles Fondamentales de Surete (Basic Safety Rules) applicable to certain types of nuclear facilities lay down requirements with which compliance, for the type of facilities and within the scope of application covered by the RFS, is considered to be equivalent to compliance with technical French regulatory practice. The object of the RFS is to take advantage of standardization in the field of safety, while allowing for technical progress in that field. They are designed to enable the operating utility and contractors to know the rules pertaining to various subjects which are considered to be acceptable by the Service Central de Surete des Installations Nucleaires, or the SCSIN (Central Department for the Safety of Nuclear Facilities). These RFS should make safety analysis easier and lead to better understanding between experts and individuals concerned with the problems of nuclear safety. The SCSIN reserves the right to modify, when considered necessary, any RFS and specify, if need be, the terms under which a modification is deemed retroactive. The aim of this RFS is to define the type, location and operating conditions for seismic instrumentation needed to determine promptly the seismic response of nuclear power plants features important to safety to permit comparison of such response with that used as the design basis

  19. Meteorological instrumentation

    International Nuclear Information System (INIS)

    1982-06-01

    RFS or ''Regles Fondamentales de Surete'' (Basic Safety Rules) applicable to certain types of nuclear facilities lay down requirements with which compliance, for the type of facilities and within the scope of application covered by the RFS, is considered to be equivalent to compliance with technical French regulatory practice. The object of the RFS is to take advantage of standardization in the field of safety , while allowing for technical progress in that field. They are designed to enable the operating utility and contractors to know the rules pertaining to various subjects which are considered to be acceptable by the ''Service Central de Surete des Installations Nucleaires'' or the SCSIN (Central Department for the Safety of Nuclear Facilities). These RFS should make safety analysis easier and lead to better understanding between experts and individuals concerned with the problems of nuclear safety. The SCSIN reserves the right to modify, when considered necessary any RFS and specify, if need be, the terms under which a modification is deemed retroactive. The purpose of this RFS is to specify the meteorological instrumentation required at the site of each nuclear power plant equipped with at least one pressurized water reactor

  20. Advanced instrumentation for nuclear monitoring

    International Nuclear Information System (INIS)

    Armantrout, G.; McGibbon, A.; Swierkowski, S.; Sherohman, J.; Yee, J.

    1975-01-01

    Research on semiconductor radiation detectors is described. Computational models to calculate the energy band structure, carrier mobility, and carrier lifetime of proposed detector materials are presented; and a computer spectrum simulation that accurately predicts the potential performance of the materials as detectors is given. Also, a self contained, field-portable spectrometer for laboratory-grade pulse-height analysis of gamma-ray spectra suitable for use under extreme environmental conditions and isolated locations by personnel not trained in electronics is reported. (auth)

  1. Radiological instrument

    International Nuclear Information System (INIS)

    Kronenberg, S.; McLaughlin, W.L.; Seibentritt, C.R. Jr.

    1986-01-01

    An instrument is described for measuring radiation, particularly nuclear radiation, comprising: a radiation sensitive structure pivoted toward one end and including a pair of elongated solid members contiguously joined together along their length dimensions and having a common planar interface therebetween. One of the pairs of members is comprised of radiochromic material whose index of refraction changes due to anomolous dispersion as a result of being exposed to nuclear radiation. The pair of members further has mutually different indices of refraction with the member having the larger index of refraction further being transparent for the passage of light and of energy therethrough; means located toward the other end of the structure for varying the angle of longitudinal elevation of the pair of members; means for generating and projecting a beam of light into one end of the member having the larger index of refraction. The beam of light is projected toward the planar interface where it is reflected out of the other end of the same member as a first output beam; means projecting a portion of the beam of light into one end of the member having the larger index of refraction where it traverses therethrough without reflection and out of the other end of the same member as a second output beam; and means adjacent the structure for receiving the first and second output beams, whereby a calibrated change in the angle of elevation of the structure between positions of equal intensity of the first and second output beams prior to and following exposure provides a measure of the radiation sensed due to a change of refraction of the radiochromic material

  2. Nitrocellulose membrane-based enzyme-linked immunoassay for dengue serotype-1 IgM detection

    International Nuclear Information System (INIS)

    Leon, S.; Guevara, C.; Chunga, A.

    1999-01-01

    To evaluate the sensitivity and specifity of a nitrocellulose membrane-based immunoassay for dengue IgM, with respect to capture enzyme immunoassay, for the diagnosis of dengue virus infection. 101 serum samples were processed and divided into 2 groups: 53 from dengue serotype 1 (DEN1) infected patients, and 48 from healthy subjects. Both groups were tested with a nitrocellulose membrane-based IgM capture enzyme immunoassay (NMB-EIA) and also with an ELISA as referential pattern. NMB-EIA testing detected IgM anti-DEN1 in 94,34% of samples from infected patients, and in 14,58% of control samples, whereas ELISA fails to report false positive or false negative results: NMB-EIA appears to be a good alternative for dengue infection diagnosis. (authors)

  3. Distribution of Phytophthora spp. in Field Soils Determined by Immunoassay.

    Science.gov (United States)

    Miller, S A; Madden, L V; Schmitthenner, A F

    1997-01-01

    ABSTRACT Populations of Phytophthora spp. were determined by enzyme-linked immunosorbent assay (ELISA) in field soils used for pepper and soybean production in Ohio. Soybean fields were sampled extensively (64 fields, n = 6 samples per field over 2 years) and intensively (4 fields, n = 64 samples per field in 1 year) to assess heterogeneity of P. sojae populations. Four pepper fields (n = 64), three of which had a history of Phytophthora blight (caused by P. capsici), also were sampled intensively during a 6-month period. Mean (m), variance (v), and measures of aggregation (e.g., variance-to-mean ratio [v/m]) of immunoassay values, translated to Phytophthora antigen units (PAU), were related to the disease history in each of the pepper and soybean fields. Mean PAU values for fields in which Phytophthora root rot (soybean) or blight (pepper) had been moderate to severe were higher than in fields in which disease incidence had been low or not observed. A detection threshold value of 11.3 PAU was calculated with values for 64 samples from one pepper field, all of which tested negative for Phytophthora by bioassay and ELISA. Seven of the eight intensively sampled fields contained at least some detectable Phytophthora propagules, with the percentage of positive samples ranging from 1.6 to 73.4. Mean PAU values ranged from 1 to 84 (extensive soybean field sampling), 6 to 24 (intensive soybean field sampling), and 4 to 30 (intensive pepper field sampling); however, variances ranged from 0 to 7,774 (extensive sampling), 30 to 848 (intensive soybean field sampling), and 5 to 2,401 (intensive pepper field sampling). Heterogeneity of PAU was high in most individual soybean and pepper fields, with values of v/m greater than 1, and log(v) increasing with log(m), with a slope of about 2.0. Spatial autocorrelation coefficients were not significant, indicating there was no relationship of PAU values in neighboring sampling units (i.e., field locations) of the intensively sampled

  4. Negative interference by rheumatoid factor in alpha-fetoprotein chemiluminescent microparticle immunoassay.

    Science.gov (United States)

    Wang, Hui; Bi, Xiaohui; Xu, Lei; Li, Yirong

    2017-01-01

    Background Rheumatoid factor causes positive interference in multiple immunoassays. Recently, negative interference has also been found in immunoassays in the presence of rheumatoid factor. The chemiluminescent microparticle immunoassay is widely used to determine serum alpha-fetoprotein. However, it is not clear whether the presence of rheumatoid factor in the serum causes interference in the chemiluminescent microparticle immunoassay of alpha-fetoprotein. Methods Serum alpha-fetoprotein was determined using the ARCHITECT alpha-fetoprotein assay. The estimation of alpha-fetoprotein recovery was carried out in samples prepared by diluting high-concentration alpha-fetoprotein serum with rheumatoid factor-positive or rheumatoid factor-negative serum. Paramagnetic microparticles coated with hepatitis B surface antigen-anti-HBs complexes were used to remove rheumatoid factor from the serum. Results The average recovery of alpha-fetoprotein was 88.4% and 93.8% in the rheumatoid factor-positive and rheumatoid factor-negative serum samples, respectively. The recovery of alpha-fetoprotein was significantly lower in the rheumatoid factor-positive serum samples than in the rheumatoid factor-negative serum samples. In two of five rheumatoid factor-positive samples, a large difference was found (9.8%) between the average alpha-fetoprotein recoveries in the serially diluted and initial recoveries. Fourteen rheumatoid factor-positive serum samples were pretreated with hepatitis B surface antigen-anti-HBs complex-coated paramagnetic microparticles. The alpha-fetoprotein concentrations measured in the pretreated samples increased significantly. Conclusions It was concluded that the alpha-fetoprotein chemiluminescent microparticle immunoassay is susceptible to interference by rheumatoid factor, leading to significantly lower results. Eliminating the incidence of negative interference from rheumatoid factor should be an important goal for immunoassay providers. In the meantime

  5. Alkaline phosphatase-fused repebody as a new format of immuno-reagent for an immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Hyo-Deok; Lee, Joong-jae [Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Kim, Yu Jung [Industrial Biotechnology and Bioenergy Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon (Korea, Republic of); Hantschel, Oliver [School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne (Switzerland); Lee, Seung-Goo [Industrial Biotechnology and Bioenergy Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon (Korea, Republic of); Kim, Hak-Sung, E-mail: hskim76@kaist.ac.kr [Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of)

    2017-01-15

    Enzyme-linked immunoassays based on an antibody-antigen interaction are widely used in biological and medical sciences. However, the conjugation of an enzyme to antibodies needs an additional chemical process, usually resulting in randomly cross-linked molecules and a loss of the binding affinity and enzyme activity. Herein, we present the development of an alkaline phosphatase-fused repebody as a new format of immuno-reagent for immunoassays. A repebody specifically binding to human TNF-α (hTNF-α) was selected through a phage display, and its binding affinity was increased up to 49 nM using a modular engineering approach. A monomeric alkaline phosphatase (mAP), which was previously isolated from a metagenome library, was genetically fused to the repebody as a signal generator, and the resulting repebody-mAP fusion protein was used for direct and sandwich immunoassays of hTNF-α. We demonstrate the utility and potential of the repebody-mAP fusion protein as an immuno-reagent by showing the sensitivity of 216 pg mL{sup −1} for hTNF-α in a sandwich immunoassay. Furthermore, this repebody-mAP fusion protein enabled the detection of hTNF-α spiked in a serum-supplemented medium with high accuracy and reproducibility. It is thus expected that a mAP-fused repebody can be broadly used as an immuno-reagent in immunoassays. - Highlights: • A human TNF-α (hTNF-α)-specific repebody was selected using a phage display. • A monomeric alkaline phosphatase (mAP) was genetically fused to the repebody. • mAP-fused repebody enabled detection of hTNF-α with high sensitivity and accuracy. • mAP-fused repebody can be widely used as a new immuno-reagent in immunoassays.

  6. BIOTIN INTERFERENCE WITH ROUTINE CLINICAL IMMUNOASSAYS: UNDERSTAND THE CAUSES AND MITIGATE THE RISKS.

    Science.gov (United States)

    Samarasinghe, Shanika; Meah, Farah; Singh, Vinita; Basit, Arshi; Emanuele, Nicholas; Emanuele, Mary Ann; Mazhari, Alaleh; Holmes, Earle W

    2017-08-01

    The objectives of this report are to review the mechanisms of biotin interference with streptavidin/biotin-based immunoassays, identify automated immunoassay systems vulnerable to biotin interference, describe how to estimate and minimize the risk of biotin interference in vulnerable assays, and review the literature pertaining to biotin interference in endocrine function tests. The data in the manufacturer's "Instructions for Use" for each of the methods utilized by seven immunoassay system were evaluated. We also conducted a systematic search of PubMed/MEDLINE for articles containing terms associated with biotin interference. Available original reports and case series were reviewed. Abstracts from recent scientific meetings were also identified and reviewed. The recent, marked, increase in the use of over-the-counter, high-dose biotin supplements has been accompanied by a steady increase in the number of reports of analytical interference by exogenous biotin in the immunoassays used to evaluate endocrine function. Since immunoassay methods of similar design are also used for the diagnosis and management of anemia, malignancies, autoimmune and infectious diseases, cardiac damage, etc., biotin-related analytical interference is a problem that touches every area of internal medicine. It is important for healthcare personnel to become more aware of immunoassay methods that are vulnerable to biotin interference and to consider biotin supplements as potential sources of falsely increased or decreased test results, especially in cases where a lab result does not correlate with the clinical scenario. FDA = U.S. Food & Drug Administration FT3 = free tri-iodothyronine FT4 = free thyroxine IFUs = instructions for use LH = luteinizing hormone PTH = parathyroid hormone SA/B = streptavidin/biotin TFT = thyroid function test TSH = thyroid-stimulating hormone.

  7. Activity assays and immunoassays for plasma Renin and prorenin: information provided and precautions necessary for accurate measurement

    DEFF Research Database (Denmark)

    Campbell, Duncan J; Nussberger, Juerg; Stowasser, Michael

    2009-01-01

    into focus the differences in information provided by activity assays and immunoassays for renin and prorenin measurement and has drawn attention to the need for precautions to ensure their accurate measurement. CONTENT: Renin activity assays and immunoassays provide related but different information...... provided by these assays and of the precautions necessary to ensure their accuracy....

  8. Field Portable Methods for Rapid Water Quality Analysis

    Science.gov (United States)

    1996-10-01

    a pie-shaped segment of the rolled cylinder, also stored in a sterile flask. Several membrane layers were pulled away, and a scraping was removed for...For example, the H. pylori urease A gene can be used, and thefla A gene can be used for the campylobacter species. 12 2. Implement microwave technology

  9. A field portable mass spectrometer for monitoring organic vapors.

    Science.gov (United States)

    Meier, R W

    1978-03-01

    A portable mass spectrometer has been designed and built under the sponsorship of the US Army for the purpose of monitoring low concentrations of specified organics in the ambient atmosphere. The goals of the development were discrimination, sensitivity, portability, simplicity of operation, economy and convenience. These objectives were met in a system consisting of a computer operated mass spectrometer with a Llewellyn membrane separator inlet system housed in two 26 x 18 x 9 inch aluminum cases with a total weight less than 150 pounds. This system has shown the capability for field detection of hundreds of specific organic vapors at the parts per billion level in the ambient and workplace environments.

  10. Tackling field-portable Raman spectroscopy of real world samples

    Science.gov (United States)

    Shand, Neil C.

    2008-10-01

    A major challenge confronting first responders, customs authorities and other security-related organisations is the accurate, rapid, and safe identification of potentially hazardous chemicals outside a laboratory environment. Currently, a range of hand portable Raman equipment is commercially available that is low cost and increasingly more sophisticated. These systems are generally based on the 785nm Stokes shifted Raman technique with many using dispersive grating spectrometers. This technique offers a broad range of capabilities including the ability to analyse illicit drugs, explosives, chemical weapons and pre-cursors but still has some fundamental constraints. 'Real world' samples, such as those found at a crime scene, will often not be presented in the most accessible manner. Simple issues such as glass fluorescence can make an otherwise tractable sample impossible to analyse in-situ. A new generation of portable Raman equipment is currently being developed to address these issues. Consideration is given to the use of longer wavelength for fluorescence reduction. Alternative optical designs are being tested to compensate for the signal reduction incurred by moving to longer wavelengths. Furthermore, the use of anti-Stokes spectroscopy is being considered as well as investigating the robustness and portability of traditional Fourier Transform interferometer designs along with future advances in detector technology and ultra small spectrometers.

  11. Study on the determination of human placental lactogen (HPL) using an enzyme-immunoassay. Comparison with a commercial radio-immunoassay in the course of normal pregnancies

    International Nuclear Information System (INIS)

    Schneider, B.

    1982-01-01

    A novel enzyme-immunoassay (EIA) for determining human placental lactogen (HPL) was studied for its practicability and quality. The precision of the system in series was tested by using a serum taken each in the 19th, 29th and 40th pregnancy week. A normal range graph between the 10th and the 40th pregnancy week (10 sera per pregnancy week) was established from 310 sera of normal-course pregnancies. The graph practically agreed with the known RIA-established graphs. When comparing with a radio-immunoassay for HPL of routine application and known quality criteria, r=0.93 indicated a close correlation of the values found. (orig./MG) [de

  12. Electrochemical immunoassay using magnetic beads for the determination of zearalenone in baby food: an anticipated analytical tool for food safety.

    Science.gov (United States)

    Hervás, Miriam; López, Miguel Angel; Escarpa, Alberto

    2009-10-27

    In this work, electrochemical immunoassay involving magnetic beads to determine zearalenone in selected food samples has been developed. The immunoassay scheme has been based on a direct competitive immunoassay method in which antibody-coated magnetic beads were employed as the immobilisation support and horseradish peroxidase (HRP) was used as enzymatic label. Amperometric detection has been achieved through the addition of hydrogen peroxide substrate and hydroquinone as mediator. Analytical performance of the electrochemical immunoassay has been evaluated by analysis of maize certified reference material (CRM) and selected baby food samples. A detection limit (LOD) of 0.011 microg L(-1) and EC(50) 0.079 microg L(-1) were obtained allowing the assessment of the detection of zearalenone mycotoxin. In addition, an excellent accuracy with a high recovery yield ranging between 95 and 108% has been obtained. The analytical features have shown the proposed electrochemical immunoassay to be a very powerful and timely screening tool for the food safety scene.

  13. Comparison of enzyme immunoassays for the diagnosis of bovine brucellosis

    International Nuclear Information System (INIS)

    Nielsen, K.; Kelly, L.; Gall, D.; Balsevicius, S.; Bosse, J.; Kelly, W.; Nicoletti, P.

    1998-01-01

    The indirect enzyme immunoassay for measurement of bovine antibody to Brucella abortus was tested on 15,716 Canadian sera to assess the specificity. These sera were also tested by the buffered plate antigen test. Two ELISA formats were used for assessment of data: the targeting procedure using a positive control serum allowed to develop to an optical density of 1.0 and the use of a positive control serum to determine relative positivity at a set time. Two different cut-off values were also assessed for each assay. A total of 763 sera gave reactions above established cut-off values in the ELISA while 216 were positive in the buffered plate antigen test (BPAT). A modification of the indirect ELISA employed divalent cation chelating agents (EDTA/EGTA) incorporated into the serum incubation stage to eliminate some non-specific reactions. This method was applied only to the 763 indirect ELISA reactor sera and it eliminated all but 93 or 37, depending on the cut-off selected, of the reactions. Sensitivity was assessed by testing 424 sera from Brucella abortus culture positive cattle. The indirect ELISA classified all 424 sera as positive by either method of data handling and with or without addition of EDTA/EGTA for a specificity estimate of 100%. In the BPAT, 412 sera gave a positive agglutination reaction. Ten percent of the 15,716 sera were randomly selected and tested by two different competitive ELISAs and by the complement fixation test (CFT). One competitive ELISA used Brucella abortus O-polysaccharide as the antigen and an enzyme conjugated monoclonal antibody to the O-polysaccharide for competition and detection. Of the sera tested, 34 gave false positive reactions. On a retest, the false positive reactions were reduced to 2. The second competitive ELISA used lipopolysaccharide as the antigen, a different monoclonal antibody but also specific for the O-polysaccharide for competition and commercially available goat anti-mouse IgG enzyme conjugate for detection

  14. Radio-immunoassays for glucagon-like peptides 1 and 2 (GLP-1 and GLP-2)

    DEFF Research Database (Denmark)

    Orskov, C; Holst, J J

    1987-01-01

    Gene-sequencing studies have shown that the glucagon precursor contains two additional glucagon-like sequences, the so-called glucagon-like peptides 1 and 2 (GLP-1 and GLP-2). We developed radio-immunoassays against synthetic peptides corresponding to these sequences. Antisera were raised in rabb...

  15. Direct biosensor immunoassays for the detection of nonmilk proteins in milk powder

    NARCIS (Netherlands)

    Haasnoot, W.; Olieman, K.; Cazemier, G.; Verheijen, R.

    2001-01-01

    The low prices of some nonmilk proteins make them attractive as potential adulterants in dairy products. An optical biosensor (BIACORE 3000) was used to develop a direct and combined biosensor immunoassay (BIA) for the simultaneous detection of soy, pea, and soluble wheat proteins in milk powders.

  16. Single biosensor immunoassay for the detection of five aminoglycosides in reconstituted skimmed milk

    NARCIS (Netherlands)

    Haasnoot, W.; Cazemier, G.; Koets, M.; Amerongen, van A.

    2003-01-01

    The application of an optical biosensor (Biacore 3000), with four flow channels (Fcs), in combination with a mixture of four specific antibodies resulted in a competitive inhibition biosensor immunoassay (BIA) for the simultaneous detection of the five relevant aminoglycosides in reconstituted

  17. Multiplex immunoassays for quantification of cytokines, growth factors, and other proteins in stem cell communication

    Czech Academy of Sciences Publication Activity Database

    Valeková, Ivona; Kupcová Skalníková, Helena; Jarkovská, Karla; Motlík, Jan; Kovářová, Hana

    -, č. 1212 (2015), s. 39-63 ISSN 1940 -6029 R&D Projects: GA MŠk ED2.1.00/03.0124; GA TA ČR(CZ) TA01011466 Institutional support: RVO:67985904 Keywords : multiplex immunoassays * antibody microarray * luminex xMAP Subject RIV: EB - Genetics ; Molecular Biology

  18. Serum sample containing endogenous antibodies interfering with multiple hormone immunoassays. Laboratory strategies to detect interference

    Directory of Open Access Journals (Sweden)

    Elena García-González

    2016-04-01

    Full Text Available Objectives: Endogenous antibodies (EA may interfere with immunoassays, causing erroneous results for hormone analyses. As (in most cases this interference arises from the assay format and most immunoassays, even from different manufacturers, are constructed in a similar way, it is possible for a single type of EA to interfere with different immunoassays. Here we describe the case of a patient whose serum sample contains EA that interfere several hormones tests. We also discuss the strategies deployed to detect interference. Subjects and methods: Over a period of four years, a 30-year-old man was subjected to a plethora of laboratory and imaging diagnostic procedures as a consequence of elevated hormone results, mainly of pituitary origin, which did not correlate with the overall clinical picture. Results: Once analytical interference was suspected, the best laboratory approaches to investigate it were sample reanalysis on an alternative platform and sample incubation with antibody blocking tubes. Construction of an in-house ‘nonsense’ sandwich assay was also a valuable strategy to confirm interference. In contrast, serial sample dilutions were of no value in our case, while polyethylene glycol (PEG precipitation gave inconclusive results, probably due to the use of inappropriate PEG concentrations for several of the tests assayed. Conclusions: Clinicians and laboratorians must be aware of the drawbacks of immunometric assays, and alert to the possibility of EA interference when results do not fit the clinical pattern. Keywords: Endogenous antibodies, Immunoassay, Interference, Pituitary hormones, Case report

  19. An enzyme immunoassay to quantify neurofilament light chain in cerebrospinal fluid.

    NARCIS (Netherlands)

    Geel, W.J.A. van; Rosengren, L.E.; Verbeek, M.M.

    2005-01-01

    Neurofilament light chain is a component of the axonal cytoskeleton. The concentration of the neurofilament light chain in cerebrospinal fluid may reflect axonal damage or the extent of white matter damage. In this study we describe a sensitive immunoassay for the detection of neurofilament light

  20. Automation on an Open-Access Platform of Alzheimer's Disease Biomarker Immunoassays.

    Science.gov (United States)

    Gille, Benjamin; Dedeene, Lieselot; Stoops, Erik; Demeyer, Leentje; Francois, Cindy; Lefever, Stefanie; De Schaepdryver, Maxim; Brix, Britta; Vandenberghe, Rik; Tournoy, Jos; Vanderstichele, Hugo; Poesen, Koen

    2018-04-01

    The lack of (inter-)laboratory standardization has hampered the application of universal cutoff values for Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers and their transfer to general clinical practice. The automation of the AD biomarker immunoassays is suggested to generate more robust results than using manual testing. Open-access platforms will facilitate the integration of automation for novel biomarkers, allowing the introduction of the protein profiling concept. A feasibility study was performed on an automated open-access platform of the commercial immunoassays for the 42-amino-acid isoform of amyloid-β (Aβ 1-42 ), Aβ 1-40 , and total tau in CSF. Automated Aβ 1-42 , Aβ 1-40 , and tau immunoassays were performed within predefined acceptance criteria for bias and imprecision. Similar accuracy was obtained for ready-to-use calibrators as for reconstituted lyophilized kit calibrators. When compared with the addition of a standard curve in each test run, the use of a master calibrator curve, determined before and applied to each batch analysis as the standard curve, yielded an acceptable overall bias of -2.6% and -0.9% for Aβ 1-42 and Aβ 1-40 , respectively, with an imprecision profile of 6.2% and 8.4%, respectively. Our findings show that transfer of commercial manual immunoassays to fully automated open-access platforms is feasible, as it performs according to universal acceptance criteria.

  1. IMMUNOASSAY METHOD FOR THE DETERMINATION OF PENTACHLOROPHENOL IN SOIL AND SEDIMENT

    Science.gov (United States)

    The journal article describes the use of a prototype immunoassay method for the determination of pentacholorphenol (PCP) in soil and sediment. PCP was used as a pesticide and wood preservative and is not currently available to the general public. The paper stresses the importan...

  2. Monoclonal antibody-based broad-specificity immunoassay for monitoring organophosphorus pesticides in environmental water samples

    Science.gov (United States)

    The extensive use of organophosphorus pesticides (OPs) in agriculture and domestic settings can result in widespread water contamination. The development of easy-to-use and rapid-screening immunoassay methods in a class-selective manner is a topic of considerable environmental interest. In this wo...

  3. Heparin interferes with the radioenzymatic and homogeneous enzyme immunoassays for aminoglycosides

    International Nuclear Information System (INIS)

    Krogstad, D.J.; Granich, G.G.; Murray, P.R.; Pfaller, M.A.; Valdes, R.

    1981-01-01

    Heparin interferes with measurement of aminoglycosides in serum by biological, radioenzymatic, and homogeneous enzyme immunoassay techniques, but not with radioimmunoassay. At concentrations greater than or equal to 10 5 and greater than or equal to 3 X 10 6 USP units/L, respectively, it interferes with the radioenzymatic assay by inhibiting the gentamicin 3-acetyltransferase and kanamycin 6'-acetyltransferase enzymes used in the assay. It interferes with the homogeneous enzyme immunoassays for gentamicin and tobramycin (at concentrations greater than or equal to 10 5 and greater than or equal to10 4 USP units/L, respectively), but not with the commercially available homogeneous enzyme immunoassays for other drugs. Heparin interference with the homogeneous enzyme immunoassay for aminoglycosides requires both the heparin polyanion and glucose-6-phosphate dehydrogenase bound to a cationic aminoglycoside. This interference can be reproduced with dextran sulfate (but not dextran), and does not occur with free enzyme (glucose-6-phosphate dehydrogenase) alone. Heparin interference with these two assays and at concentrations that may be present in intravenous infusions or in seriously underfilled blood-collection tubes is described

  4. An ultrasensitive chemiluminescence immunoassay of chloramphenicol based on gold nanoparticles and magnetic beads.

    Science.gov (United States)

    Tao, Xiaoqi; Jiang, Haiyang; Yu, Xuezhi; Zhu, Jinghui; Wang, Xia; Wang, Zhanhui; Niu, Lanlan; Wu, Xiaoping; Shen, Jianzhong

    2013-05-01

    A competitive, direct, chemiluminescent immunoassay based on a magnetic beads (MBs) separation and gold nanoparticles (AuNPs) labelling technique to detect chloramphenicol (CAP) has been developed. Horseradish peroxidase (HRP)-labelled anti-CAP monoclonal antibody conjugated with AuNPs and antigen-immobilized MBs were prepared. After optimization parameters of immunocomplex MBs, the IC50 values of chemiluminescence magnetic nanoparticles immunoassay (CL-MBs-nano-immunoassay) were 0.017 µg L(-1) for extract method I and 0.17 µg L(-1) for extract method II. The immunoassay with two extract methods was applied to detect CAP in milk. Comparison of these two extract methods showed that extract method I was advantageous in better sensitivity, in which the sensitivity was 10 times compared to that of extract method II, while extract method II was superior in simple operation, suitable for high throughout screen. The recoveries were 86.7-98.0% (extract method I) and 80.0-103.0% (extract method II), and the coefficients of variation (CVs) were all recovery with both extract methods and high correlation with traditional ELISA kit in milk system confirmed that the immunomagnetic assay based on AuNPs exhibited promising potential in rapid field screening for trace CAP analysis. Copyright © 2013 John Wiley & Sons, Ltd.

  5. An Inexpensive, Fast and Sensitive Quantitative Lateral Flow Magneto-Immunoassay for Total Prostate Specific Antigen

    Directory of Open Access Journals (Sweden)

    Jacqueline M. Barnett

    2014-07-01

    Full Text Available We describe the detection characteristics of a device the Resonant Coil Magnetometer (RCM to quantify paramagnetic particles (PMPs in immunochromatographic (lateral flow assays. Lateral flow assays were developed using PMPs for the measurement of total prostate specific antigen (PSA in serum samples. A detection limit of 0.8 ng/mL was achieved for total PSA using the RCM and is at clinically significant concentrations. Comparison of data obtained in a pilot study from the analysis of serum samples with commercially available immunoassays shows good agreement. The development of a quantitative magneto-immunoassay in lateral flow format for total PSA suggests the potential of the RCM to operate with many immunoassay formats. The RCM has the potential to be modified to quantify multiple analytes in this format. This research shows promise for the development of an inexpensive device capable of quantifying multiple analytes at the point-of-care using a magneto-immunoassay in lateral flow format.

  6. Immunoassay: Principles, development and potential applications in the applied plant sciences

    Energy Technology Data Exchange (ETDEWEB)

    Hofman, P J

    1986-02-01

    The article briefly discusses the general principles of, and the methods involved in, immunoassay, and their development. Emplasis is placed on radioimmunoassay (RIA) and to a lesser extent, enzyme-linked immunosorbent assay (ELISA). The practical applications, with special reference to the citrus and subtropical fruit industries are discussed.

  7. Thermophilic Campylobacter spp. in turkey samples: evaluation of two automated enzyme immunoassays and conventional microbiological techniques

    DEFF Research Database (Denmark)

    Borck, Birgitte; Stryhn, H.; Ersboll, A.K.

    2002-01-01

    Aims: To determine the sensitivity and specificity of two automated enzyme immunoassays (EIA), EiaFoss and Minividas, and a conventional microbiological culture technique for detecting thermophilic Campylobacter spp. in turkey samples. Methods and Results: A total of 286 samples (faecal, meat...

  8. Ervaringen met een solid phase enzyme immunoassay voor het aantonen van gonorroe bij promiscue vrouwen

    NARCIS (Netherlands)

    Ulsen; J.van*; Michel; M.F.*; Strik; R.van*; Joost; T.H.van*; Stolz; E.*; Eijk; R.V.W.van

    1985-01-01

    De Gonozyme test (Abbott Laboratories), een nieuwe enzyme immunoassay (EIA) voor het aantonen van Neisseria gonorrhoeae werd geevalueerd in een grote groep promiscue vrouwen. Als de EIA werd uitgevoerd met materiaal afkomstig van de cervix, bedroeg de prevalentie van gonorroe 8,2%. Vergeleken

  9. Sensitive and rapid immunoassay for parathyroid hormone using magnetic particle labels and magnetic actuation

    NARCIS (Netherlands)

    Dittmer, W.U.; Kievit, de P.; Prins, M.W.J.; Vissers, J.L.M.; Mersch, M.E.C.; Martens, M.F.W.C.

    2008-01-01

    A rapid method for the sensitive detection of proteins using actuated magnetic particle labels, which are measured with a giant magneto-resistive (GMR) biosensor, is described. The technique involves a 1-step sandwich immunoassay with no fluid replacement steps. The various assay binding reactions

  10. False-negative syphilis treponemal enzyme immunoassay results in an HIV-infected case-patient.

    Science.gov (United States)

    Katz, Alan R; Komeya, Alan Y; Tomas, Juval E

    2017-06-01

    We present a case report of a false-negative syphilis treponemal enzyme immunoassay test result in an HIV-infected male. While treponemal tests are widely considered to be more sensitive and specific than non-treponemal tests, our findings point to potential challenges using the reverse sequence syphilis screening algorithm.

  11. Optimized Lateral Flow Immunoassay Reader for the Detection of Infectious Diseases in Developing Countries.

    Science.gov (United States)

    Pilavaki, Evdokia; Demosthenous, Andreas

    2017-11-20

    Detection and control of infectious diseases is a major problem, especially in developing countries. Lateral flow immunoassays can be used with great success for the detection of infectious diseases. However, for the quantification of their results an electronic reader is required. This paper presents an optimized handheld electronic reader for developing countries. It features a potentially low-cost, low-power, battery-operated device with no added optical accessories. The operation of this proof of concept device is based on measuring the reflected light from the lateral flow immunoassay and translating it into the concentration of the specific analyte of interest. Characterization of the surface of the lateral flow immunoassay has been performed in order to accurately model its response to the incident light. Ray trace simulations have been performed to optimize the system and achieve maximum sensitivity by placing all the components in optimum positions. A microcontroller enables all the signal processing to be performed on the device and a Bluetooth module allows transmission of the results wirelessly to a mobile phone app. Its performance has been validated using lateral flow immunoassays with influenza A nucleoprotein in the concentration range of 0.5 ng/mL to 200 ng/mL.

  12. Optimized Lateral Flow Immunoassay Reader for the Detection of Infectious Diseases in Developing Countries

    Directory of Open Access Journals (Sweden)

    Evdokia Pilavaki

    2017-11-01

    Full Text Available Detection and control of infectious diseases is a major problem, especially in developing countries. Lateral flow immunoassays can be used with great success for the detection of infectious diseases. However, for the quantification of their results an electronic reader is required. This paper presents an optimized handheld electronic reader for developing countries. It features a potentially low-cost, low-power, battery-operated device with no added optical accessories. The operation of this proof of concept device is based on measuring the reflected light from the lateral flow immunoassay and translating it into the concentration of the specific analyte of interest. Characterization of the surface of the lateral flow immunoassay has been performed in order to accurately model its response to the incident light. Ray trace simulations have been performed to optimize the system and achieve maximum sensitivity by placing all the components in optimum positions. A microcontroller enables all the signal processing to be performed on the device and a Bluetooth module allows transmission of the results wirelessly to a mobile phone app. Its performance has been validated using lateral flow immunoassays with influenza A nucleoprotein in the concentration range of 0.5 ng/mL to 200 ng/mL.

  13. Surface-Enhanced Raman Scattering (SERS) for Detection in Immunoassays: applications, fundamentals, and optimization

    International Nuclear Information System (INIS)

    Jeremy Daniel Driskell

    2006-01-01

    Immunoassays have been utilized for the detection of biological analytes for several decades. Many formats and detection strategies have been explored, each having unique advantages and disadvantages. More recently, surface-enhanced Raman scattering (SERS) has been introduced as a readout method for immunoassays, and has shown great potential to meet many key analytical figures of merit. This technology is in its infancy and this dissertation explores the diversity of this method as well as the mechanism responsible for surface enhancement. Approaches to reduce assay times are also investigated. Implementing the knowledge gained from these studies will lead to a more sensitive immunoassay requiring less time than its predecessors. This dissertation is organized into six sections. The first section includes a literature review of the previous work that led to this dissertation. A general overview of the different approaches to immunoassays is given, outlining the strengths and weaknesses of each. Included is a detailed review of binding kinetics, which is central for decreasing assay times. Next, the theoretical underpinnings of SERS is reviewed at its current level of understanding. Past work has argued that surface plasmon resonance (SPR) of the enhancing substrate influences the SERS signal; therefore, the SPR of the extrinsic Raman labels (ERLs) utilized in our SERS-based immunoassay is discussed. Four original research chapters follow the Introduction, each presented as separate manuscripts. Chapter 2 modifies a SERS-based immunoassay previously developed in our group, extending it to the low-level detection of viral pathogens and demonstrating its versatility in terms of analyte type, Chapter 3 investigates the influence of ERL size, material composition, and separation distance between the ERLs and capture substrate on the SERS signal. This chapter links SPR with SERS enhancement factors and is consistent with many of the results from theoretical treatments

  14. Surface-Enhanced Raman Scattering (SERS) for Detection in Immunoassays. Applications, fundamentals, and optimization

    Energy Technology Data Exchange (ETDEWEB)

    Driskell, Jeremy Daniel [Iowa State Univ., Ames, IA (United States)

    2006-08-09

    Immunoassays have been utilized for the detection of biological analytes for several decades. Many formats and detection strategies have been explored, each having unique advantages and disadvantages. More recently, surface-enhanced Raman scattering (SERS) has been introduced as a readout method for immunoassays, and has shown great potential to meet many key analytical figures of merit. This technology is in its infancy and this dissertation explores the diversity of this method as well as the mechanism responsible for surface enhancement. Approaches to reduce assay times are also investigated. Implementing the knowledge gained from these studies will lead to a more sensitive immunoassay requiring less time than its predecessors. This dissertation is organized into six sections. The first section includes a literature review of the previous work that led to this dissertation. A general overview of the different approaches to immunoassays is given, outlining the strengths and weaknesses of each. Included is a detailed review of binding kinetics, which is central for decreasing assay times. Next, the theoretical underpinnings of SERS is reviewed at its current level of understanding. Past work has argued that surface plasmon resonance (SPR) of the enhancing substrate influences the SERS signal; therefore, the SPR of the extrinsic Raman labels (ERLs) utilized in our SERS-based immunoassay is discussed. Four original research chapters follow the Introduction, each presented as separate manuscripts. Chapter 2 modifies a SERS-based immunoassay previously developed in our group, extending it to the low-level detection of viral pathogens and demonstrating its versatility in terms of analyte type, Chapter 3 investigates the influence of ERL size, material composition, and separation distance between the ERLs and capture substrate on the SERS signal. This chapter links SPR with SERS enhancement factors and is consistent with many of the results from theoretical treatments

  15. Automated water analyser computer supported system (AWACSS) Part I: Project objectives, basic technology, immunoassay development, software design and networking.

    Science.gov (United States)

    Tschmelak, Jens; Proll, Guenther; Riedt, Johannes; Kaiser, Joachim; Kraemmer, Peter; Bárzaga, Luis; Wilkinson, James S; Hua, Ping; Hole, J Patrick; Nudd, Richard; Jackson, Michael; Abuknesha, Ram; Barceló, Damià; Rodriguez-Mozaz, Sara; de Alda, Maria J López; Sacher, Frank; Stien, Jan; Slobodník, Jaroslav; Oswald, Peter; Kozmenko, Helena; Korenková, Eva; Tóthová, Lívia; Krascsenits, Zoltan; Gauglitz, Guenter

    2005-02-15

    A novel analytical system AWACSS (automated water analyser computer-supported system) based on immunochemical technology has been developed that can measure several organic pollutants at low nanogram per litre level in a single few-minutes analysis without any prior sample pre-concentration nor pre-treatment steps. Having in mind actual needs of water-sector managers related to the implementation of the Drinking Water Directive (DWD) (98/83/EC, 1998) and Water Framework Directive WFD (2000/60/EC, 2000), drinking, ground, surface, and waste waters were major media used for the evaluation of the system performance. The instrument was equipped with remote control and surveillance facilities. The system's software allows for the internet-based networking between the measurement and control stations, global management, trend analysis, and early-warning applications. The experience of water laboratories has been utilised at the design of the instrument's hardware and software in order to make the system rugged and user-friendly. Several market surveys were conducted during the project to assess the applicability of the final system. A web-based AWACSS database was created for automated evaluation and storage of the obtained data in a format compatible with major databases of environmental organic pollutants in Europe. This first part article gives the reader an overview of the aims and scope of the AWACSS project as well as details about basic technology, immunoassays, software, and networking developed and utilised within the research project. The second part article reports on the system performance, first real sample measurements, and an international collaborative trial (inter-laboratory tests) to compare the biosensor with conventional anayltical methods.

  16. Exploiting fluorescence for multiplex immunoassays on protein microarrays

    International Nuclear Information System (INIS)

    Herbáth, Melinda; Balogh, Andrea; Matkó, János; Papp, Krisztián; Prechl, József

    2014-01-01

    Protein microarray technology is becoming the method of choice for identifying protein interaction partners, detecting specific proteins, carbohydrates and lipids, or for characterizing protein interactions and serum antibodies in a massively parallel manner. Availability of the well-established instrumentation of DNA arrays and development of new fluorescent detection instruments promoted the spread of this technique. Fluorescent detection has the advantage of high sensitivity, specificity, simplicity and wide dynamic range required by most measurements. Fluorescence through specifically designed probes and an increasing variety of detection modes offers an excellent tool for such microarray platforms. Measuring for example the level of antibodies, their isotypes and/or antigen specificity simultaneously can offer more complex and comprehensive information about the investigated biological phenomenon, especially if we take into consideration that hundreds of samples can be measured in a single assay. Not only body fluids, but also cell lysates, extracted cellular components, and intact living cells can be analyzed on protein arrays for monitoring functional responses to printed samples on the surface. As a rapidly evolving area, protein microarray technology offers a great bulk of information and new depth of knowledge. These are the features that endow protein arrays with wide applicability and robust sample analyzing capability. On the whole, protein arrays are emerging new tools not just in proteomics, but glycomics, lipidomics, and are also important for immunological research. In this review we attempt to summarize the technical aspects of planar fluorescent microarray technology along with the description of its main immunological applications. (topical review)

  17. Evaluating musical instruments

    International Nuclear Information System (INIS)

    Campbell, D. Murray

    2014-01-01

    Scientific measurements of sound generation and radiation by musical instruments are surprisingly hard to correlate with the subtle and complex judgments of instrumental quality made by expert musicians

  18. False biochemical diagnosis of hyperthyroidism in streptavidin-biotin-based immunoassays: the problem of biotin intake and related interferences.

    Science.gov (United States)

    Piketty, Marie-Liesse; Polak, Michel; Flechtner, Isabelle; Gonzales-Briceño, Laura; Souberbielle, Jean-Claude

    2017-05-01

    Immunoassays are now commonly used for hormone measurement, in high throughput analytical platforms. Immunoassays are generally robust to interference. However, endogenous analytical error may occur in some patients; this may be encountered in biotin supplementation or in the presence of anti-streptavidin antibody, in immunoassays involving streptavidin-biotin interaction. In these cases, the interference may induce both false positive and false negative results, and simulate a seemingly coherent hormonal profile. It is to be feared that this type of errors will be more frequently observed. This review underlines the importance of keeping close interactions between biologists and clinicians to be able to correlate the hormonal assay results with the clinical picture.

  19. IOT Overview: IR Instruments

    Science.gov (United States)

    Mason, E.

    In this instrument review chapter the calibration plans of ESO IR instruments are presented and briefly reviewed focusing, in particular, on the case of ISAAC, which has been the first IR instrument at VLT and whose calibration plan served as prototype for the coming instruments.

  20. Health physics instrument manual

    International Nuclear Information System (INIS)

    Gupton, E.D.

    1978-08-01

    The purpose of this manual is to provide apprentice health physics surveyors and other operating groups not directly concerned with radiation detection instruments a working knowledge of the radiation detection and measuring instruments in use at the Laboratory. The characteristics and applications of the instruments are given. Portable instruments, stationary instruments, personnel monitoring instruments, sample counters, and miscellaneous instruments are described. Also, information sheets on calibration sources, procedures, and devices are included. Gamma sources, beta sources, alpha sources, neutron sources, special sources, a gamma calibration device for badge dosimeters, and a calibration device for ionization chambers are described

  1. Astronomical Instruments in India

    Science.gov (United States)

    Sarma, Sreeramula Rajeswara

    The earliest astronomical instruments used in India were the gnomon and the water clock. In the early seventh century, Brahmagupta described ten types of instruments, which were adopted by all subsequent writers with minor modifications. Contact with Islamic astronomy in the second millennium AD led to a radical change. Sanskrit texts began to lay emphasis on the importance of observational instruments. Exclusive texts on instruments were composed. Islamic instruments like the astrolabe were adopted and some new types of instruments were developed. Production and use of these traditional instruments continued, along with the cultivation of traditional astronomy, up to the end of the nineteenth century.

  2. In vitro conditions modify immunoassayability of bovine pituitary prolactin and growth hormone: insights into their secretory granule storage forms

    International Nuclear Information System (INIS)

    Lorenson, M.Y.

    1985-01-01

    The amount of immunoassayable intracellular bovine (b) PRL and GH varies depending on treatment conditions. The present studies were designed to characterize the mechanisms involved and to compare immunoassayability of both hormones under similar conditions. Pituitary homogenate and secretory granule hormones displayed both time- and temperature-dependent increases when incubated at pH 10.5 with reduced glutathione. Changes in immunoassayability seem to reflect conversion from poorly immunoactive tissue hormone oligomers to monomeric hormone. The data indicate that oligomeric bPRL is stabilized primarily by intermolecular disulfide bonds, although it is also susceptible to urea, SDS, and EDTA; granule thiols may also influence the conversion to monomer. The storage form of bGH appears to be stabilized differently. Maneuvers demonstrated in these studies to influence immunoassayability correlate very well with their previously established effects on hormone release and secretion, strengthening the likelihood that a functional link exists between assayability and secretion

  3. DEMONSTRATION BULLETIN: PCP IMMUNOASSAY TECHNOLOGIES - PENTA RISC BY ENSYS INC., PENTA RAPID BY OHMICRON CORP., ENVIROGARD BY MILLIPORE

    Science.gov (United States)

    The objectives of this demonstration were to test these field screening technologies for accuracy and precision in detecting Pentachlorophenol (PCP) levels in soil and water by comparing their results with those of a confirmatory laboratory. The three immunoassay technologies ...

  4. Troubleshooting in nuclear instruments

    International Nuclear Information System (INIS)

    1987-06-01

    This report on troubleshooting of nuclear instruments is the product of several scientists and engineers, who are closely associated with nuclear instrumentation and with the IAEA activities in the field. The text covers the following topics: Preamplifiers, amplifiers, scalers, timers, ratemeters, multichannel analyzers, dedicated instruments, tools, instruments, accessories, components, skills, interfaces, power supplies, preventive maintenance, troubleshooting in systems, radiation detectors. The troubleshooting and repair of instruments is illustrated by some real examples

  5. IFSA: a microfluidic chip-platform for frit-based immunoassay protocols

    Science.gov (United States)

    Hlawatsch, Nadine; Bangert, Michael; Miethe, Peter; Becker, Holger; Gärtner, Claudia

    2013-03-01

    Point-of-care diagnostics (POC) is one of the key application fields for lab-on-a-chip devices. While in recent years much of the work has concentrated on integrating complex molecular diagnostic assays onto a microfluidic device, there is a need to also put comparatively simple immunoassay-type protocols on a microfluidic platform. In this paper, we present the development of a microfluidic cartridge using an immunofiltration approach. In this method, the sandwich immunoassay takes place in a porous frit on which the antibodies have immobilized. The device is designed to be able to handle three samples in parallel and up to four analytical targets per sample. In order to meet the critical cost targets for the diagnostic market, the microfluidic chip has been designed and manufactured using high-volume manufacturing technologies in mind. Validation experiments show comparable sensitivities in comparison with conventional immunofiltration kits.

  6. A competitive chemiluminescence enzyme immunoassay for rapid and sensitive determination of enrofloxacin

    Science.gov (United States)

    Yu, Fei; Wu, Yongjun; Yu, Songcheng; Zhang, Huili; Zhang, Hongquan; Qu, Lingbo; Harrington, Peter de B.

    With alkaline phosphatase (ALP)-adamantane (AMPPD) system as the chemiluminescence (CL) detection system, a highly sensitive, specific and simple competitive chemiluminescence enzyme immunoassay (CLEIA) was developed for the measurement of enrofloxacin (ENR). The physicochemical parameters, such as the chemiluminescent assay mediums, the dilution buffer of ENR-McAb, the volume of dilution buffer, the monoclonal antibody concentration, the incubation time, and other relevant variables of the immunoassay have been optimized. Under the optimal conditions, the detection linear range of 350-1000 pg/mL and the detection limit of 0.24 ng/mL were provided by the proposed method. The relative standard deviations were less than 15% for both intra and inter-assay precision. This method has been successfully applied to determine ENR in spiked samples with the recovery of 103%-96%. It showed that CLEIA was a good potential method in the analysis of residues of veterinary drugs after treatment of related diseases.

  7. Microfluidic Platform for Enzyme-Linked and Magnetic Particle-Based Immunoassay

    Directory of Open Access Journals (Sweden)

    Dorota G. Pijanowska

    2013-06-01

    Full Text Available This article presents design and testing of a microfluidic platform for immunoassay. The method is based on sandwiched ELISA, whereby the primary antibody is immobilized on nitrocelluose and, subsequently, magnetic beads are used as a label to detect the analyte. The chip takes approximately 2 h and 15 min to complete the assay. A Hall Effect sensor using 0.35-μm BioMEMS TSMC technology (Taiwan Semiconductor Manufacturing Company Bio-Micro-Electro-Mechanical Systems was fabricated to sense the magnetic field from the beads. Furthermore, florescence detection and absorbance measurements from the chip demonstrate successful immunoassay on the chip. In addition, investigation also covers the Hall Effect simulations, mechanical modeling of the bead–protein complex, testing of the microfluidic platform with magnetic beads averaging 10 nm, and measurements with an inductor-based system.

  8. A sandwich immunoassay for human prolyl 4-hydroxylase using monoclonal antibody

    International Nuclear Information System (INIS)

    Yoshida, Shinichi

    1986-01-01

    Monoclonal antibody was used in a sandwich enzyme immunoassay and in a radioimmunoassay for human serum immunoreactive prolyl 4-hydroxylase. The enzyme immunoassay utilized a monoclonal antibody as a solid phase and horseradish peroxidase-labeled rabbit antibody to human prolyl 4-hydroxylase as a conjugate. Sensitivity was 0.1 ng of enzyme per tube. With a conjugate purified by an enzyme-bound affinity column, sensitivity was increased to 0.01 ng per tube, and linearity was obtained between 0.01 to 30 ng per tube. The radioimmunoassay used a 125 I-labeled rabbit antibody (IgG) as the conjugate. Sensitivity of this technique was 0.4 ng of enzyme per tube. (Auth.)

  9. On-chip signal amplification of magnetic bead-based immunoassay by aviating magnetic bead chains.

    Science.gov (United States)

    Jalal, Uddin M; Jin, Gyeong Jun; Eom, Kyu Shik; Kim, Min Ho; Shim, Joon S

    2017-11-06

    In this work, a Lab-on-a-Chip (LOC) platform is used to electromagnetically actuate magnetic bead chains for an enhanced immunoassay. Custom-made electromagnets generate a magnetic field to form, rotate, lift and lower the magnetic bead chains (MBCs). The cost-effective, disposable LOC platform was made with a polymer substrate and an on-chip electrochemical sensor patterned via the screen-printing process. The movement of the MBCs is controlled to improve the electrochemical signal up to 230% when detecting beta-type human chorionic gonadotropin (β-hCG). Thus, the proposed on-chip MBC-based immunoassay is applicable for rapid, qualitative electrochemical point-of-care (POC) analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Comparative studies on the determination of alphafetoprotein by enzyme immunoassay and by radioimmunoassay

    International Nuclear Information System (INIS)

    Haller, G.; Linneke, P.; Voss, P.; Jeske, W.

    1987-01-01

    Alphafetoprotein (AFP) was determined in serum of pregnant women in the tenth till sixteenth week of pregnancy by means of two enzyme immunoassays (Enzymun-Test AFP, Boehringer Mannheim, FRG and AFP EIA 'Dessau' 1000, Research Institute for Vaccine Dessau, GDR) and a radioimmunoassay (Radioimmunoassay Kit, AFP-PR, CIS, France). Parallel determinations in sera of 438 patients, who had come to surveillance for the first consultation were estimated. A comparison between the methods showed a good correlation. (author)

  11. Multiplex dipstick immunoassay for semi-quantitative determination of Fusarium mycotoxins in cereals

    International Nuclear Information System (INIS)

    Lattanzio, Veronica M.T.; Nivarlet, Noan; Lippolis, Vincenzo; Gatta, Stefania Della; Huet, Anne-Catherine; Delahaut, Philippe; Granier, Benoit; Visconti, Angelo

    2012-01-01

    Highlights: ► We developed a rapid method based on a multiplex dipstick immunoassay. ► The assay allowed the determination of major Fusarium toxins in wheat, oats, maize. ► We obtained cut off levels close to EU regulatory levels. - Abstract: A multiplex dipstick immunoassay based method for the simultaneous determination of major Fusarium toxins, namely zearalenone, T-2 and HT-2 toxins, deoxynivalenol and fumonisins in wheat, oats and maize has been developed. The dipstick format was based on an indirect competitive approach. Four test lines (mycotoxin–BSA conjugates) and one control line were located on the strip membrane. Labelled antibodies were freeze-dried within the microwell. Two matrix-related sample preparation protocols have been developed for wheat/oats (not containing fumonisins) and maize (containing fumonisins) respectively. The use of a methanol/water mixture for sample preparation allowed recoveries in the range 73–109% for all mycotoxins in all tested cereals, with relative standard deviation less than 10%. The optimized immunoassay was able to detect target mycotoxins at cut off levels equal to 80% of EU maximum permitted levels, i.e. 280, 400, 1400 and 3200 μg kg −1 , respectively, for zearalenone, T-2/HT-2 toxins, deoxynivalenol and fumonisins in maize, and 80, 400 and 1400 μg kg −1 , respectively, for zearalenone, T-2/HT-2 toxins and deoxynivalenol in wheat and oats. Analysis of naturally contaminated samples resulted in a good agreement between multiplex dipstick and validated confirmatory LC–MS/MS. The percentage of false positive results was less than or equal to 13%, whereas no false negative results were obtained. Data on the presence/absence of 6 mycotoxins at levels close to EU regulatory levels were obtained within 30 min. The proposed immunoassay protocol is rapid, inexpensive, easy-to-use and fit for purpose of rapid screening of mycotoxins in cereals.

  12. Development of a prototype lateral flow immunoassay (LFI for the rapid diagnosis of melioidosis.

    Directory of Open Access Journals (Sweden)

    Raymond L Houghton

    2014-03-01

    Full Text Available Burkholderia pseudomallei is a soil-dwelling bacterium and the causative agent of melioidosis. Isolation of B. pseudomallei from clinical samples is the "gold standard" for the diagnosis of melioidosis; results can take 3-7 days to produce. Alternatively, antibody-based tests have low specificity due to a high percentage of seropositive individuals in endemic areas. There is a clear need to develop a rapid point-of-care antigen detection assay for the diagnosis of melioidosis. Previously, we employed In vivo Microbial Antigen Discovery (InMAD to identify potential B. pseudomallei diagnostic biomarkers. The B. pseudomallei capsular polysaccharide (CPS and numerous protein antigens were identified as potential candidates. Here, we describe the development of a diagnostic immunoassay based on the detection of CPS. Following production of a CPS-specific monoclonal antibody (mAb, an antigen-capture immunoassay was developed to determine the concentration of CPS within a panel of melioidosis patient serum and urine samples. The same mAb was used to produce a prototype Active Melioidosis Detect Lateral Flow Immunoassay (AMD LFI; the limit of detection of the LFI for CPS is comparable to the antigen-capture immunoassay (∼0.2 ng/ml. The analytical reactivity (inclusivity of the AMD LFI was 98.7% (76/77 when tested against a large panel of B. pseudomallei isolates. Analytical specificity (cross-reactivity testing determined that 97.2% of B. pseudomallei near neighbor species (35/36 were not reactive. The non-reactive B. pseudomallei strain and the reactive near neighbor strain can be explained through genetic sequence analysis. Importantly, we show the AMD LFI is capable of detecting CPS in a variety of patient samples. The LFI is currently being evaluated in Thailand and Australia; the focus is to optimize and validate testing procedures on melioidosis patient samples prior to initiation of a large, multisite pre-clinical evaluation.

  13. Multiplex dipstick immunoassay for semi-quantitative determination of Fusarium mycotoxins in cereals

    Energy Technology Data Exchange (ETDEWEB)

    Lattanzio, Veronica M.T., E-mail: veronica.lattanzio@ispa.cnr.it [National Research Council of Italy, Institute of Sciences of Food Production (ISPA-CNR), Via Amendola 122/O, 70126 Bari (Italy); Nivarlet, Noan [UNISENSOR S.A., Zoning industriel du Dossay, Rue du Dossay no 3, B-4020 Liege (Belgium); Lippolis, Vincenzo; Gatta, Stefania Della [National Research Council of Italy, Institute of Sciences of Food Production (ISPA-CNR), Via Amendola 122/O, 70126 Bari (Italy); Huet, Anne-Catherine; Delahaut, Philippe [Centre d' Economie Rurale (CER Groupe), Rue du Point du Jour no 8, B-6900 Marloie (Belgium); Granier, Benoit [UNISENSOR S.A., Zoning industriel du Dossay, Rue du Dossay no 3, B-4020 Liege (Belgium); Visconti, Angelo [National Research Council of Italy, Institute of Sciences of Food Production (ISPA-CNR), Via Amendola 122/O, 70126 Bari (Italy)

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer We developed a rapid method based on a multiplex dipstick immunoassay. Black-Right-Pointing-Pointer The assay allowed the determination of major Fusarium toxins in wheat, oats, maize. Black-Right-Pointing-Pointer We obtained cut off levels close to EU regulatory levels. - Abstract: A multiplex dipstick immunoassay based method for the simultaneous determination of major Fusarium toxins, namely zearalenone, T-2 and HT-2 toxins, deoxynivalenol and fumonisins in wheat, oats and maize has been developed. The dipstick format was based on an indirect competitive approach. Four test lines (mycotoxin-BSA conjugates) and one control line were located on the strip membrane. Labelled antibodies were freeze-dried within the microwell. Two matrix-related sample preparation protocols have been developed for wheat/oats (not containing fumonisins) and maize (containing fumonisins) respectively. The use of a methanol/water mixture for sample preparation allowed recoveries in the range 73-109% for all mycotoxins in all tested cereals, with relative standard deviation less than 10%. The optimized immunoassay was able to detect target mycotoxins at cut off levels equal to 80% of EU maximum permitted levels, i.e. 280, 400, 1400 and 3200 {mu}g kg{sup -1}, respectively, for zearalenone, T-2/HT-2 toxins, deoxynivalenol and fumonisins in maize, and 80, 400 and 1400 {mu}g kg{sup -1}, respectively, for zearalenone, T-2/HT-2 toxins and deoxynivalenol in wheat and oats. Analysis of naturally contaminated samples resulted in a good agreement between multiplex dipstick and validated confirmatory LC-MS/MS. The percentage of false positive results was less than or equal to 13%, whereas no false negative results were obtained. Data on the presence/absence of 6 mycotoxins at levels close to EU regulatory levels were obtained within 30 min. The proposed immunoassay protocol is rapid, inexpensive, easy-to-use and fit for purpose of rapid screening of mycotoxins

  14. In-electrode vs. on-electrode: ultrasensitive Faraday cage-type electrochemiluminescence immunoassay.

    Science.gov (United States)

    Guo, Zhiyong; Sha, Yuhong; Hu, Yufang; Wang, Sui

    2016-03-28

    A new-concept of an "in-electrode" Faraday cage-type electrochemiluminescence immunoassay (ECLIA) method for the ultrasensitive detection of neurotensin (NT) was reported with capture antibody (Ab1)-nanoFe3O4@graphene (GO) and detector antibody (Ab2)&N-(4-aminobutyl)-N-ethylisoluminol (ABEI)@GO, which led to about 1000-fold improvement in sensitivity by extending the Helmholtz plane (OHP) of the proposed electrode assembly effectively.

  15. Competitive enzyme immunoassay for human chorionic somatomammotropin using the avidin-biotin system

    International Nuclear Information System (INIS)

    Rappuoli, R.; Leoncini, P.; Tarli, P.; Neri, P.

    1981-01-01

    Human chorionic somatomammotropin (HCS) is determined by an enzyme immunoassay where HCS competes with biotin-labeled HCS for insolubilized anti-HCS antibodies. Enzyme-labeled avidin is then used to reveal the amount of bound HCS. The system proves to be sensitive (1 ng/ml of HCS can be detected) and results agree with radioimmunoassay determinations (correlation coefficient = 0.979). Kinetics of the avidin-biotin reaction and coating of polystyrene wells are also investigated

  16. Evaluation of automated enzyme immunoassays for five anticonvulsants and theophylline adapted to a centrifugal analyzer.

    Science.gov (United States)

    Urquhart, N; Godolphin, W; Campbell, D J

    1979-05-01

    We report a clinical evaluation of the enzyme immunoassay (EMIT) performed with the GEMSAEC centrifugal analyzer as compared to gas-liquid and liquid chromatography for anticonvulsant drugs and theophylline, respectively. A good correlation was obtained for all drugs, although some difficulties were experienced with one lot of reagent for ethosuximide. The analyzer has an economic advantage if many samples are being analyzed for few drugs in each sample.

  17. Deoxynivalenol-mimic nanobody isolated from a naïve phage display nanobody library and its application in immunoassay.

    Science.gov (United States)

    Qiu, Yu-Lou; He, Qing-Hua; Xu, Yang; Bhunia, Arun K; Tu, Zhui; Chen, Bo; Liu, Yuan-Yuan

    2015-08-05

    In this study, using mycotoxin deoxynivalenol (DON) as a model hapten, we developed a nanobody-based environmental friendly immunoassay for sensitive detection of DON. Two nanobodies (N-28 and N-31) which bind to anti-DON monoclonal antibody (MAb) were isolated from a naive phage display library. These nanobodies are clonable, thermally stable and mycotoxin-free products and can be served as coating antigen mimetics in heterologous immunoassay. The half inhibition concentration (IC50) of the immunoassay developed with N-28 and N-31 was 8.77 ± 0.41 ng mL(-1) and 19.97 ± 0.84 ng mL(-1), respectively, which were 18- and 8-fold more sensitive than the conventional coating antigen (DON-BSA) based immunoassay. In order to better understand the molecular mechanism of antigen mimicry by nanobody, the 3D structure of "nanobody (N-28) - anti-DON MAb" complex was presented and verified by molecular modeling and alanine-scanning mutagenesis. The results showed that hydrogen bond and hydrophobic interaction formed between Thr 102 - Ser 106 of N-28 and CDR H3 residues of anti-DON antibody may contribute to their binding. This novel concept of enhancing sensitivity of immunoassay for DON based on nanobody may provide potential applications in a general method for immunoassay of various food chemical contaminants. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. A fast universal immobilization of immunoglobulin G at 4 °C for the development of array-based immunoassays.

    Directory of Open Access Journals (Sweden)

    Shu-Lin Guo

    Full Text Available To maintain the antibody activity and enhance performance of array-based immunoassays, protein G was used to allow a shorter duration of immunoglobulin G immobilization at 4 °C, with the antibody placed in the appropriate orientation. The multiplexed detection of six pain-related message molecules (PRMMs was used as examples for the development of array-based immunoassays: substance P, calcitonin gene-related peptide, nerve growth factor, brain-derived neurotrophic factor, tumor necrosis factor-α, and β-endorphin. Protein G- and non-protein G-coated slides were tested. Compared to non-protein G immunoassays, protein G shortened the antibody immobilization time at 4 °C from overnight to 2 hours. Only protein G-facilitated immunoassays succeeded in simultaneously detecting all six PRMMs with high specificity. Dose-response curves showed that the limits of detection of the protein G-multiplexed immunoassays for the PRMMs was approximately 164, 167, 120, 60, 80, and 92 pg/ml, respectively. Thus, protein G effectively shortens the duration of antibody immobilization at 4 °C, allowing the use of sensitive array-based immunoassays for the simultaneous detection of PRMMs.

  19. Diagnostic effectiveness of immunoassays systems for hepatitis C virus in samples from multi-transfusion patients

    International Nuclear Information System (INIS)

    Rivero Jimenez, Rene A; Merlin Linares, Julio C; Blanco de Armas, Madelin; Navea Leyva, Leonor M

    2009-01-01

    Hepatitis C virus (CHV) blood-transmission is a health problem in Cuba and in the world. Some types of diagnostic immunoassays have been developed for the blood certification and in general have a high diagnostic sensitivity and specificity in healthy donors. However, its behavior in samples from multi-transfusion patients could by less effective. To assess the diagnostic effectiveness of the UMELISA HCV third generation Cuban immunoassay (TecnoSUMA, S.A. La Habana), Cuba) in samples from multi-transfusion patients, in parallel, 335 sera from patients were processed by UBI HCV EIA 4.0 (United Biomedical, EE.UU) and UMELISA HCV third generation, and the samples with incongruous results were verified by PCR COBAS AmpliScreen HCV Test, v2 system (Roche, EE.UU.) Comparing the UMELISA HCV third generation system with the UBI HCV EIA 4.0 it was achieved a Sd of 95,8% CI(95%): 92,5-99,15 and a Ed of 100% CI (95%): 99,7-100, with IY: 0,96 (0,93-0,99) with k: 0,0582 ID (95%): 0,9276-0,9888, p = 0,000. Both immunoassay systems were satisfactory for immunodiagnosis of multi-transfusion patients

  20. Detection of alpha-fetoprotein in magnetic immunoassay of thin channels using biofunctional nanoparticles

    Science.gov (United States)

    Tsai, H. Y.; Gao, B. Z.; Yang, S. F.; Li, C. S.; Fuh, C. Bor

    2014-01-01

    This paper presents the use of fluorescent biofunctional nanoparticles (10-30 nm) to detect alpha-fetoprotein (AFP) in a thin-channel magnetic immunoassay. We used an AFP model biomarker and s-shaped deposition zones to test the proposed detection method. The results show that the detection using fluorescent biofunctional nanoparticle has a higher throughput than that of functional microparticle used in previous experiments on affinity reactions. The proposed method takes about 3 min (versus 150 min of previous method) to detect 100 samples. The proposed method is useful for screening biomarkers in clinical applications, and can reduce the run time for sandwich immunoassays to less than 20 min. The detection limits (0.06 pg/ml) and linear ranges (0.068 pg/ml-0.68 ng/ml) of AFP using fluorescent biofunctional nanoparticles are the same as those of using functional microparticles within experimental errors. This detection limit is substantially lower and the linear range is considerably wider than those of enzyme-linked immunosorbent assay (ELISA) and other methods in sandwich immunoassay methods. The differences between this method and an ELISA in AFP measurements of serum samples were less than 12 %. The proposed method provides simple, fast, and sensitive detection with a high throughput for biomarkers.

  1. Targeted selected reaction monitoring mass spectrometric immunoassay for insulin-like growth factor 1.

    Directory of Open Access Journals (Sweden)

    Eric E Niederkofler

    Full Text Available Insulin-like growth factor 1 (IGF1 is an important biomarker of human growth disorders that is routinely analyzed in clinical laboratories. Mass spectrometry-based workflows offer a viable alternative to standard IGF1 immunoassays, which utilize various pre-analytical preparation strategies. In this work we developed an assay that incorporates a novel sample preparation method for dissociating IGF1 from its binding proteins. The workflow also includes an immunoaffinity step using antibody-derivatized pipette tips, followed by elution, trypsin digestion, and LC-MS/MS separation and detection of the signature peptides in a selected reaction monitoring (SRM mode. The resulting quantitative mass spectrometric immunoassay (MSIA exhibited good linearity in the range of 1 to 1,500 ng/mL IGF1, intra- and inter-assay precision with CVs of less than 10%, and lowest limits of detection of 1 ng/mL. The linearity and recovery characteristics of the assay were also established, and the new method compared to a commercially available immunoassay using a large cohort of human serum samples. The IGF1 SRM MSIA is well suited for use in clinical laboratories.

  2. Magnetofluorescent nanocomposites and quantum dots used for optimal application in magnetic fluorescence-linked immunoassay.

    Science.gov (United States)

    Tsai, H Y; Li, S Y; Fuh, C Bor

    2018-03-01

    Magnetofluorescent nanocomposites with optimal magnetic and fluorescent properties were prepared and characterized by combining magnetic nanoparticles (iron oxide@polymethyl methacrylate) with fluorescent nanoparticles (rhodamine 6G@mSiO 2 ). Experimental parameters were optimized to produce nanocomposites with high magnetic susceptibility and fluorescence intensity. The detection of a model biomarker (alpha-fetoprotein) was used to demonstrate the feasibility of applying the magnetofluorescent nanocomposites combined with quantum dots and using magnetic fluorescence-linked immunoassay. The magnetofluorescent nanocomposites enable efficient mixing, fast re-concentration, and nanoparticle quantization for optimal reactions. Biofunctional quantum dots were used to confirm the alpha-fetoprotein (AFP) content in sandwich immunoassay after mixing and washing. The analysis time was only one third that required in ELISA. The detection limit was 0.2 pg mL -1 , and the linear range was 0.68 pg mL -1 -6.8 ng mL -1 . This detection limit is lower, and the linear range is wider than those of ELISA and other methods. The measurements made using the proposed method differed by less than 13% from those obtained using ELISA for four AFP concentrations (0.03, 0.15, 0.75, and 3.75 ng mL -1 ). The proposed method has a considerable potential for biomarker detection in various analytical and biomedical applications. Graphical abstract Magnetofluorescent nanocomposites combined with fluorescent quantum dots were used in magnetic fluorescence-linked immunoassay.

  3. Evaluation of field test kits including immunoassays for the detection of contaminants in soil and water

    International Nuclear Information System (INIS)

    Waters, L.C.; Smith, R.R.; Counts, R.W.; Stewart, J.H.; Jenkins, R.A.

    1993-01-01

    Effective field test methods are needed for hazardous waste site characterization and remediation. Useful field methods should be rapid, analyte-specific, cost-effective and accurate in the concentration range at which the analyte is regulated. In this study, field test kits for polychlorinated biphenyls (PCBs), mercury, lead and nitrate were evaluated with reference to these criteria. PCBs and mercury, in soils, were analyzed by immunoassay. Ionic lead and nitrate, in water, were measured chemically using test strips. Except for lead, each analyte was measured in both spiked and actual field samples. Twenty to 40 samples per day can be analyzed with the immunoassays and even more with the strip tests. The sensitivity of the immunoassays is in the 1-3 ppM range. Nitrate was consistently detected at ≥5 ppM; lead ions at ≥20 ppM. Results obtained using these methods compared favorably with those obtained by standard laboratory methods. In addition to being useful field screening methods, these kits can be used in the laboratory to sort out negative samples and/or to define proper dilutions for positive samples requiring further analysis

  4. Comparison of pre-processing methods for multiplex bead-based immunoassays.

    Science.gov (United States)

    Rausch, Tanja K; Schillert, Arne; Ziegler, Andreas; Lüking, Angelika; Zucht, Hans-Dieter; Schulz-Knappe, Peter

    2016-08-11

    High throughput protein expression studies can be performed using bead-based protein immunoassays, such as the Luminex® xMAP® technology. Technical variability is inherent to these experiments and may lead to systematic bias and reduced power. To reduce technical variability, data pre-processing is performed. However, no recommendations exist for the pre-processing of Luminex® xMAP® data. We compared 37 different data pre-processing combinations of transformation and normalization methods in 42 samples on 384 analytes obtained from a multiplex immunoassay based on the Luminex® xMAP® technology. We evaluated the performance of each pre-processing approach with 6 different performance criteria. Three performance criteria were plots. All plots were evaluated by 15 independent and blinded readers. Four different combinations of transformation and normalization methods performed well as pre-processing procedure for this bead-based protein immunoassay. The following combinations of transformation and normalization were suitable for pre-processing Luminex® xMAP® data in this study: weighted Box-Cox followed by quantile or robust spline normalization (rsn), asinh transformation followed by loess normalization and Box-Cox followed by rsn.

  5. Development and analytical performance of a new ARCHITECT automated dipeptidyl peptidase-4 immunoassay

    Directory of Open Access Journals (Sweden)

    Philip M. Hemken

    2017-12-01

    Full Text Available Background: Dipeptidyl peptidase-4 (DPP-4 may be a suitable biomarker to identify people with severe asthma who have greater activation of the interleukin-13 (IL-13 pathway and may therefore benefit from IL-13-targeted treatments. We report the analytical performance of an Investigational Use Only immunoassay and provide data on the biological range of DPP-4 concentrations. Methods: We assessed assay performance, utilising analyses of precision, linearity and sensitivity; interference from common endogenous assay interferents, and from asthma and anti-diabetic medications, were also assessed. The assay was used to measure the range of serum DPP-4 concentrations in healthy volunteers and subjects with diabetes and severe, uncontrolled asthma. Results: The total precision of DPP-4 concentration measurement (determined using percentage coefficient of variation was ≤5% over 20 days. Dilution analysis yielded linear results from 30 to 1305 ng/mL; the limit of quantitation was 19.2 ng/mL. No notable endogenous or drug interferences were observed at the expected therapeutic concentration. Median DPP-4 concentrations in healthy volunteers and subjects with asthma or Type 1 diabetes were assessed, with concentrations remaining similar in subjects with diabetes and asthma across different demographics. Conclusion: These analyses indicate that the ARCHITECT DPP-4 Immunoassay is a reliable and robust method for measuring serum DPP-4 concentration. Keywords: Asthma, Automated immunoassay, Biomarker, Dipeptidyl peptidase-4, IL-13

  6. Which amphetamine-type stimulants can be detected by oral fluid immunoassays?

    Science.gov (United States)

    Souza, Daniele Z; Boehl, Paula O; Comiran, Eloisa; Prusch, Débora S; Zancanaro, Ivomar; Fuentefria, Alexandre M; Pechansky, Flavio; Duarte, Paulina C A V; De Boni, Raquel B; Fröehlich, Pedro E; Limberger, Renata P

    2012-02-01

    The use of oral fluid for monitoring drug consumption on roads has many advantages over conventional biological fluids; therefore, several immunoassays have been developed for this purpose. In this work, the ability of 3 commercial immunoassays to detect amphetamine-type stimulants (ATSs) in oral fluid was assessed. In addition, it was reviewed the main controlled ATSs available worldwide, as well as the oral fluid immunological screening tests that have been used for identifying ATSs in drivers. The analytical specificity of amphetamine direct enzyme-linked immunosorbent assay (ELISA), methamphetamine direct ELISA (Immunalysis Corporation), and Oral-View saliva multidrug of abuse test (Alfa Scientific Designs) was evaluated using ATS-spiked oral fluid. Legislation and published articles that report the use of immunological screening tests to detect ATS consumption in conductors were reviewed, including the kit's technical information, project reports, police and drug databases. Even at high concentrations, the tested assays were not able to detect methylphenidate, fenproporex, or diethylpropion, controlled ATSs legally marketed in many countries. This evidences the need to develop new kits that enable one to control the misuse of prescription ATSs on roads through oral fluid immunoassays.

  7. Factitious Graves' Disease Due to Biotin Immunoassay Interference-A Case and Review of the Literature.

    Science.gov (United States)

    Elston, Marianne S; Sehgal, Shekhar; Du Toit, Stephen; Yarndley, Tania; Conaglen, John V

    2016-09-01

    Biotin (vitamin B7) is an essential co-factor for four carboxylases involved in fatty acid metabolism, leucine degradation, and gluconeogenesis. The recommended daily intake (RDI) of biotin is approximately 30 μg per day. Low-moderate dose biotin is a common component of multivitamin preparations, and high-dose biotin (10 000 times RDI) has been reported to improve clinical outcomes and quality of life in patients with progressive multiple sclerosis. Biotin is also a component of immunoassays, and supplementation may cause interference in both thyroid and non-thyroid immunoassays. To assess whether biotin ingestion caused abnormal thyroid function tests (TFTs) in a patient through assay interference. We report a patient with biotin-associated abnormal TFTs and a systematic review of the literature. A tertiary endocrine service in Hamilton, New Zealand. The patient had markedly abnormal TFTs that did not match the clinical context. After biotin cessation, TFTs normalized far more rapidly than possible given the half-life of T4, consistent with assay interference by biotin. Multiple other analytes also tested abnormal in the presence of biotin. Biotin ingested in moderate to high doses can cause immunoassay interference. Depending on the assay format, biotin interference can result in either falsely high or low values. Interference is not limited to thyroid tests and has the potential to affect a wide range of analytes. It is important for clinicians to be aware of this interaction to prevent misdiagnosis and inappropriate treatment.

  8. Discordant Analytical Results Caused by Biotin Interference on Diagnostic Immunoassays in a Pediatric Hospital.

    Science.gov (United States)

    Ali, Mahesheema; Rajapakshe, Deepthi; Cao, Liyun; Devaraj, Sridevi

    2017-09-01

    Recent studies have reported that biotin interferes with certain immunoassays. In this study, we evaluated the analytical interference of biotin on immunoassays that use streptavidin-biotin in our pediatric hospital. We tested the effect of different concentrations of biotin (1.5-200 ng/ml) on TSH, Prolactin, Ferritin, CK-MB, β-hCG, Troponin I, LH, FSH, Cortisol, Anti-HAV antibody (IgG and IgM), assays on Ortho Clinical Diagnostic Vitros 5600 Analyzer. Biotin (up to 200 ng/mL) did not significantly affect Troponin I and HAV assays. Biotin (up to 12.5 ng/ml) resulted in biotin >6.25 ng/mL significantly affected TSH (>20% bias) assay. Prolactin was significantly affected even at low levels (Biotin 1.5 ng/mL). Thus, we recommend educating physicians about biotin interference in common immunoassays and adding an electronic disclaimer. © 2017 by the Association of Clinical Scientists, Inc.

  9. Chemiluminescence enzyme immunoassay based on magnetic nanoparticles for detection of hepatocellular carcinoma marker glypican-3

    Directory of Open Access Journals (Sweden)

    Qian-Yun Zhang

    2011-08-01

    Full Text Available Glypican-3 (GPC3 is reported as a great promising tumor marker for hepatocellular carcinoma (HCC diagnosis. Highly sensitive and accurate analysis of serum GPC3 (sGPC3, in combination with or instead of traditional HCC marker alpha-fetoprotein (AFP, is essential for early diagnosis of HCC. Biomaterial-functionalized magnetic particles have been utilized as solid supports with good biological compatibility for sensitive immunoassay. Here, the magnetic nanoparticles (MnPs and magnetic microparticles (MmPs with carboxyl groups were further modified with streptavidin, and applied for the development of chemiluminescence enzyme immunoassay (CLEIA. After comparing between MnPs- and MmPs-based CLEIA, MnPs-based CLEIA was proved to be a better method with less assay time, greater sensitivity, better linearity and longer chemiluminescence platform. MnPs-based CLEIA was applied for detection of sGPC3 in normal liver, hepatocirrhosis, secondary liver cancer and HCC serum samples. The results indicated that sGPC3 was effective in diagnosis of HCC with high performance. Keywords: Magnetic nanoparticle, Magnetic microparticle, Chemiluminescence enzyme immunoassay, Glypican-3, Hepatocellular carcinoma

  10. A Novel Colorimetric Immunoassay Utilizing the Peroxidase Mimicking Activity of Magnetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hyun Gyu Park

    2013-05-01

    Full Text Available A simple colorimetric immunoassay system, based on the peroxidase mimicking activity of Fe3O4 magnetic nanoparticles (MNPs, has been developed to detect clinically important antigenic molecules. MNPs with ca. 10 nm in diameter were synthesized and conjugated with specific antibodies against target molecules, such as rotaviruses and breast cancer cells. Conjugation of the MNPs with antibodies (MNP-Abs enabled specific recognition of the corresponding target antigenic molecules through the generation of color signals arising from the colorimetric reaction between the selected peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB and H2O2. Based on the MNP-promoted colorimetric reaction, the target molecules were detected and quantified by measuring absorbance intensities corresponding to the oxidized form of TMB. Owing to the higher stabilities and economic feasibilities of MNPs as compared to horseradish peroxidase (HRP, the new colorimetric system employing MNP-Abs has the potential of serving as a potent immunoassay that should substitute for conventional HRP-based immunoassays. The strategy employed to develop the new methodology has the potential of being extended to the construction of simple diagnostic systems for a variety of biomolecules related to human cancers and infectious diseases, particularly in the realm of point-of-care applications.

  11. Performing the Super Instrument

    DEFF Research Database (Denmark)

    Kallionpaa, Maria

    2016-01-01

    can empower performers by producing super instrument works that allow the concert instrument to become an ensemble controlled by a single player. The existing instrumental skills of the performer can be multiplied and the qualities of regular acoustic instruments extended or modified. Such a situation......The genre of contemporary classical music has seen significant innovation and research related to new super, hyper, and hybrid instruments, which opens up a vast palette of expressive potential. An increasing number of composers, performers, instrument designers, engineers, and computer programmers...... have become interested in different ways of “supersizing” acoustic instruments in order to open up previously-unheard instrumental sounds. Super instruments vary a great deal but each has a transformative effect on the identity and performance practice of the performing musician. Furthermore, composers...

  12. Quantum dots-based lateral flow immunoassay combined with image analysis for semiquantitative detection of IgE antibody to mite

    Directory of Open Access Journals (Sweden)

    Zhao Y

    2017-07-01

    Full Text Available Yan Zhao,1,* Qiang Zhang,2,* Qingfeng Meng,3 Fenglian Wu,4 Lihua Zhang,1 Yao Tang,1 Yuanyuan Guan,1 Lixin An1 1Department of Allergy, The First Affiliated Hospital, Harbin Medical University, Harbin, 2Department of Otorhinolaryngology Head and Neck Surgery, The Affiliated Yantai Yuhuangding Hospital, Qingdao University, Yantai, 3Department of Ophthalmology, The First Affiliated Hospital, Harbin Medical University, Harbin, 4Department of Burn and Plastic Surgery, The First Affiliated Hospital of Qinhuangdao, Qinhuangdao, People’s Republic of China *These authors contributed equally to this work Abstract: Semiquantitative and rapid detection of specific IgE (sIgE with well clinical relevance to house dust mite (HDM are promising for prevalence rhinitis and asthma patients due to the increasing air pollution. However, the conventional IgE measurement systems are time-consuming, complicated and require special instruments. Herein, we overcome the above limitations of sIgE to HDM detection system by developing a quantum dot nanobeads-based lateral flow immunoassay and an image analysis procedure. The proposed detection system could semiquantitatively measure the IgE in a linear range of 0.2–10 U/mL. Moreover, there is a well correlation between the developed detection system and the clinical symptoms by a comparison study using 56 positive patients’ sera and 40 healthy control sera. The proposed detection system is simple, robust and easy-to-use and promising for in home test. Keywords: lateral flow immunoassay, quantum dots, house dust mite, IgE 

  13. Evaluation of the highly sensitive chemiluminescent enzyme immunoassay "Lumipulse HBsAg-HQ" for hepatitis B virus screening.

    Science.gov (United States)

    Deguchi, Matsuo; Kagita, Masanori; Yoshioka, Nori; Tsukamoto, Hiroko; Takao, Miyuki; Tahara, Kazuko; Maeda, Ikuhiro; Hidaka, Yoh; Yamauchi, Satoshi; Kaneko, Atsushi; Miyakoshi, Hideo; Isomura, Mitsuo

    2017-10-06

    Ongoing efforts in the development of HBsAg detection kits are focused on improving sensitivity and specificity. The purpose of this study was to evaluate an improved, highly sensitive quantitative assay, "Lumipulse HBsAg-HQ", a chemiluminescent enzyme immunoassay designed for a fully automated instrument, the "Lumipulse G1200". Serum samples for reproducibility, dilution, correlation, sensitivity, and specificity studies were obtained from patients at the Osaka University Hospital. Seroconversion and sensitivity panels were purchased from a commercial vender. Subtype, sensitivity panels, and HBsAg recombinant proteins with one or two amino acid substitutions were prepared in-house. The coefficients of variation for the low, medium, and high concentration samples ranged from 1.93 to 2.55%. The HBsAg-HQ reagent for dilution testing showed good linearity in the 0.005-150 HBsAg IU/mL range and no prozone phenomenon. All 102 HBV carrier samples were positive by HBsAg-HQ, while other commercial reagents showed one or more to be negative. In the seroconversion panel, the 14-day blood sample was positive. The sensitivity against HBsAg-HQ "ad" and "ay" subtypes was 0.025 ng/mL. Comparisons among the HBsAg-HQ, HISCL, and Architect HBsAg reagents were performed using the Bland-Altman plot. Specificity for 1000 seronegative individuals was 99.7%. HBsAg-HQ detected 29 positive serum among 12 231 routinely obtained serum samples, which showed concentrations of 0.005-0.05 HBsAg IU/mL. According to these results, the Lumipulse HBsAg-HQ assay, with a highly sensitive limit of detection of 0.005 IU/mL, may facilitate the development of a better management strategy for a considerable proportion of infected patients. © 2017 Wiley Periodicals, Inc.

  14. Instrument Modeling and Synthesis

    Science.gov (United States)

    Horner, Andrew B.; Beauchamp, James W.

    During the 1970s and 1980s, before synthesizers based on direct sampling of musical sounds became popular, replicating musical instruments using frequency modulation (FM) or wavetable synthesis was one of the “holy grails” of music synthesis. Synthesizers such as the Yamaha DX7 allowed users great flexibility in mixing and matching sounds, but were notoriously difficult to coerce into producing sounds like those of a given instrument. Instrument design wizards practiced the mysteries of FM instrument design.

  15. Nuclear reactor instrumentation

    International Nuclear Information System (INIS)

    Duncombe, E.; McGonigal, G.

    1975-01-01

    A liquid metal cooled nuclear reactor is described which has an equal number of fuel sub-assemblies and sensing instruments. Each instrument senses temperature and rate of coolant flow of a coolant derived from a group of three sub-assemblies so that an abnormal value for one sub-assembly will be indicated on three instruments thereby providing for redundancy of up to two of the three instruments. The abnormal value may be a precurser to unstable boiling of coolant

  16. Aeroacoustics of Musical Instruments

    NARCIS (Netherlands)

    Fabre, B.; Gilbert, J.; Hirschberg, Abraham; Pelorson, X.

    2012-01-01

    We are interested in the quality of sound produced by musical instruments and their playability. In wind instruments, a hydrodynamic source of sound is coupled to an acoustic resonator. Linear acoustics can predict the pitch of an instrument. This can significantly reduce the trial-and-error process

  17. Status of safeguards instrumentation

    International Nuclear Information System (INIS)

    Higinbotham, W.A.

    The International Atomic Energy Agency is performing safeguards at some nuclear power reactors, 50 bulk processing facilities, and 170 research facilities. Its verification activities require the use of instruments to measure nuclear materials and of surveillance instruments to maintain continuity of knowledge of the locations of nuclear materials. Instruments that are in use and under development to measure weight, volume, concentration, and isotopic composition of nuclear materials, and the major surveillance instruments, are described in connection with their uses at representative nuclear facilities. The current status of safeguards instrumentation and the needs for future development are discussed

  18. Early modern mathematical instruments.

    Science.gov (United States)

    Bennett, Jim

    2011-12-01

    In considering the appropriate use of the terms "science" and "scientific instrument," tracing the history of "mathematical instruments" in the early modern period is offered as an illuminating alternative to the historian's natural instinct to follow the guiding lights of originality and innovation, even if the trail transgresses contemporary boundaries. The mathematical instrument was a well-defined category, shared across the academic, artisanal, and commercial aspects of instrumentation, and its narrative from the sixteenth to the eighteenth century was largely independent from other classes of device, in a period when a "scientific" instrument was unheard of.

  19. Electrochemical immunoassay using magnetic beads for the determination of zearalenone in baby food: An anticipated analytical tool for food safety

    International Nuclear Information System (INIS)

    Hervas, Miriam; Lopez, Miguel Angel; Escarpa, Alberto

    2009-01-01

    In this work, electrochemical immunoassay involving magnetic beads to determine zearalenone in selected food samples has been developed. The immunoassay scheme has been based on a direct competitive immunoassay method in which antibody-coated magnetic beads were employed as the immobilisation support and horseradish peroxidase (HRP) was used as enzymatic label. Amperometric detection has been achieved through the addition of hydrogen peroxide substrate and hydroquinone as mediator. Analytical performance of the electrochemical immunoassay has been evaluated by analysis of maize certified reference material (CRM) and selected baby food samples. A detection limit (LOD) of 0.011 μg L -1 and EC 50 0.079 μg L -1 were obtained allowing the assessment of the detection of zearalenone mycotoxin. In addition, an excellent accuracy with a high recovery yield ranging between 95 and 108% has been obtained. The analytical features have shown the proposed electrochemical immunoassay to be a very powerful and timely screening tool for the food safety scene.

  20. Immunoassay for Capsular Antigen of Bacillus anthracis Enables Rapid Diagnosis in a Rabbit Model of Inhalational Anthrax.

    Directory of Open Access Journals (Sweden)

    Marcellene A Gates-Hollingsworth

    Full Text Available Inhalational anthrax is a serious biothreat. Effective antibiotic treatment of inhalational anthrax requires early diagnosis; the further the disease has progressed, the less the likelihood for cure. Current means for diagnosis such as blood culture require several days to a result and require advanced laboratory infrastructure. An alternative approach to diagnosis is detection of a Bacillus anthracis antigen that is shed into blood and can be detected by rapid immunoassay. The goal of the study was to evaluate detection of poly-γ-D-glutamic acid (PGA, the capsular antigen of B. anthracis, as a biomarker surrogate for blood culture in a rabbit model of inhalational anthrax. The mean time to a positive blood culture was 26 ± 5.7 h (mean ± standard deviation, whereas the mean time to a positive ELISA was 22 ± 4.2 h; P = 0.005 in comparison with blood culture. A lateral flow immunoassay was constructed for detection of PGA in plasma at concentrations of less than 1 ng PGA/ml. Use of the lateral flow immunoassay for detection of PGA in the rabbit model found that antigen was detected somewhat earlier than the earliest time point at which the blood culture became positive. The low cost, ease of use, and rapid time to result of the lateral flow immunoassay format make an immunoassay for PGA a viable surrogate for blood culture for detection of infection in individuals who have a likelihood of exposure to B. anthracis.

  1. The management of isolated positive syphilis enzyme immunoassay results in HIV-negative patients attending a sexual health clinic.

    Science.gov (United States)

    Thorley, Nicola; Adebayo, Michael; Smit, Erasmus; Radcliffe, Keith

    2016-08-01

    An unconfirmed positive treponemal enzyme immunoassay (enzyme immunoassay positive, Treponema pallidum particle agglutination negative and rapid plasma reagin negative) presents a clinical challenge to distinguish early syphilis infection from false-positive results. These cases are referred for syphilis line assay (INNO-LIA) and recalled for repeat syphilis serology. We performed a retrospective audit to establish the proportion of HIV-negative cases with unconfirmed positive enzyme immunoassay results, the proportion of these cases that received an INNO-LIA test and repeat syphilis serology testing and reviewed the clinical outcomes; 0.35% (80/22687) cases had an unconfirmed positive treponemal enzyme immunoassay result. Repeat syphilis serology was performed in 80% (64/80) cases, but no additional cases of syphilis were identified. Eighty-eight per cent (70/80) received an INNO-LIA test; 14% (5/37) unconfirmed enzyme immunoassay-positive cases with no prior history of syphilis were confirmed on INNO-LIA assay, supporting a diagnosis of latent syphilis. As a confirmatory treponemal test, the INNO-LIA assay may be more useful than repeat syphilis serological testing. © The Author(s) 2016.

  2. Electrochemical immunoassay using magnetic beads for the determination of zearalenone in baby food: An anticipated analytical tool for food safety

    Energy Technology Data Exchange (ETDEWEB)

    Hervas, Miriam; Lopez, Miguel Angel [Departamento Quimica Analitica, Universidad de Alcala, Ctra. Madrid-Barcelona, Km. 33600, E-28871 Alcala de Henares, Madrid (Spain); Escarpa, Alberto, E-mail: alberto.escarpa@uah.es [Departamento Quimica Analitica, Universidad de Alcala, Ctra. Madrid-Barcelona, Km. 33600, E-28871 Alcala de Henares, Madrid (Spain)

    2009-10-27

    In this work, electrochemical immunoassay involving magnetic beads to determine zearalenone in selected food samples has been developed. The immunoassay scheme has been based on a direct competitive immunoassay method in which antibody-coated magnetic beads were employed as the immobilisation support and horseradish peroxidase (HRP) was used as enzymatic label. Amperometric detection has been achieved through the addition of hydrogen peroxide substrate and hydroquinone as mediator. Analytical performance of the electrochemical immunoassay has been evaluated by analysis of maize certified reference material (CRM) and selected baby food samples. A detection limit (LOD) of 0.011 {mu}g L{sup -1} and EC{sub 50} 0.079 {mu}g L{sup -1} were obtained allowing the assessment of the detection of zearalenone mycotoxin. In addition, an excellent accuracy with a high recovery yield ranging between 95 and 108% has been obtained. The analytical features have shown the proposed electrochemical immunoassay to be a very powerful and timely screening tool for the food safety scene.

  3. False-positive ethyl glucuronide immunoassay screening caused by a propyl alcohol-based hand sanitizer.

    Science.gov (United States)

    Arndt, Torsten; Grüner, Joachim; Schröfel, Stefanie; Stemmerich, Karsten

    2012-11-30

    Urine ethyl glucuronide (EtG) is considered as a specific marker of recent ethanol consumption. We describe false-positive DRI(®) EIA EtG enzyme immunoassay results caused by propyl glucuronides in urine after using a propanol-based hand sanitizer. EtG screening was done with the DRI(®) EIA EtG assay (Microgenics), using a cut-off of 0.5 mg/L as recommended by the manufacturer and of 0.1 mg/L as demanded by the German Regulations for Reissuing Drivers Licenses. Confirmatory EtG analysis was done with the ClinMass(®) EtG LC-MS/MS testkit (Recipe), extended by the mass transitions 235.1→75.1, 235.1→85.1, and 235.1→113.1 for the detection of the 1- and 2-propyl glucuronides. Self-experiments were done by staff members of our lab (n=7), using 3 mL Sterillium(®) Classic Pure (30 g/100 g 1-propanol and 45 g/100 g 2-propanol) for hand sanitation every quarter of an hour for 8 h according to DIN EN 1500:2011-05 with and without an exhauster and by passive inhalation of the sanitizer vapor. Spot urine samples were taken immediately before and up to 24 h after the first sanitizer use. False-positive immunoassay results of up to 4 mg/L or 2.3 mg/g creatinine were obtained after normal use of the sanitizer and also after passive inhalation of the sanitizer vapor (up to 0.89 mg/L or 0.61 mg/g). Immunoassay results were positive even after 4-fold use of the sanitizer (up to 0.14 mg/L or 0.38 mg/g) and up to 6 h after the last sanitizer contact (maximum 0.63 mg/L and 0.33 mg/g for sanitizer users and 0.25 mg/g after passive inhalation). Spiking of EtG-free urine with 1-propyl glucuronide (Athena Environmental Sciences) between 0.05 and 10 mg/L clearly demonstrated a cross reaction of the immunoassay of approx. 10% as compared to EtG. LC-MS/MS of urines with a positive immunoassay EtG result did not show EtG signals, but distinct signals of 1-propyl glucuronide (n-propyl glucuronide) and 2-propyl glucuronide (iso-propyl glucuronide). An exhauster effectively prevented

  4. Development of nanobody-based flow injection chemiluminescence immunoassay for sensitive detection of human prealbumin.

    Science.gov (United States)

    Ma, Lei; Sun, Yanyan; Kang, Xuejun; Wan, Yakun

    2014-11-15

    Nanobodies, derived from camelid heavy-chain antibodies, have novel and impactful applications in clinical diagnostics. Our objective is to develop a nanobody-based chemiluminescence immunoassay for sensitive detection of human prealbumin (PA). In this context, a phage display nanobody library is constructed via immunizing dromedary camel with human prealbumin. Three nanobodies have been identified by five successive bio-panning steps. Based on their high expression level and good affinity, two out of three are chosen for further study. Magnetic beads (MBs) were functionalized with PEI by acylamide bond formed between the carboxyl group on the surface of the MB. Then, an anti-PA nanobody (Nb1) can be effectively immobilized onto the surface of the functionalized MB using glutaradehyde as the link. The modified MBs with Nb1 can specifically capture the target PA and reacted with silica nanoparticles with co-immobilized HRP and anti-PA nanobody (Nb2). The concentration of PA was detected by flow injection chemiluminescence. When using MB/PEI as the carrier of anti-PA Nb1, the CL signal significantly increased to 4-fold compared with the signal using MB without PEI modification. The CL signal was further amplified to 5-fold when Si/Nb2 was used as the signal probe. Under optimized conditions, the present immunoassay exhibited a wide quantitative range from 0.05 to 1000 μg L(-1) with a detection limit of 0.01 μg L(-1). The sensitivity of the proposed immunoassay offers great promises in providing a sensitive, specific, time saving, and potential method for detecting PA in clinical settings. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Structural basis for the high specificity of a Trypanosoma congolense immunoassay targeting glycosomal aldolase.

    Directory of Open Access Journals (Sweden)

    Joar Pinto

    2017-09-01

    Full Text Available Animal African trypanosomosis (AAT is a neglected tropical disease which imposes a heavy burden on the livestock industry in Sub-Saharan Africa. Its causative agents are Trypanosoma parasites, with T. congolense and T. vivax being responsible for the majority of the cases. Recently, we identified a Nanobody (Nb474 that was employed to develop a homologous sandwich ELISA targeting T. congolense fructose-1,6-bisphosphate aldolase (TcoALD. Despite the high sequence identity between trypanosomatid aldolases, the Nb474-based immunoassay is highly specific for T. congolense detection. The results presented in this paper yield insights into the molecular principles underlying the assay's high specificity.The structure of the Nb474-TcoALD complex was determined via X-ray crystallography. Together with analytical gel filtration, the structure reveals that a single TcoALD tetramer contains four binding sites for Nb474. Through a comparison with the crystal structures of two other trypanosomatid aldolases, TcoALD residues Ala77 and Leu106 were identified as hot spots for specificity. Via ELISA and surface plasmon resonance (SPR, we demonstrate that mutation of these residues does not abolish TcoALD recognition by Nb474, but does lead to a lack of detection in the Nb474-based homologous sandwich immunoassay.The results show that the high specificity of the Nb474-based immunoassay is not determined by the initial recognition event between Nb474 and TcoALD, but rather by its homologous sandwich design. This (i provides insights into the optimal set-up of the assay, (ii may be of great significance for field applications as it could explain the potential detection escape of certain T. congolense strains, and (iii may be of general interest to those developing similar assays.

  6. Comparison of Immunoassay methods for T3, T4 and TSH

    International Nuclear Information System (INIS)

    Alonso Rodríguez, Celia A.

    2016-01-01

    Measurements of T3, T4 and TSH have been considered very important in the diagnosis and monitoring of thyroid diseases both overt and subclinical. These subclinical diseases are actively seeking for years, both in healthy patients and hospitalized for other illnesses; and in the population over 35 years, especially women, in health checkups. The active search for these diseases requires the use of rapid and reliable techniques; that can be developed massively, with good level of detectability and comparable. The overall objective is to present the evaluation of different immunoassay techniques with respect to the RIA and IRMA: ELISA, chemiluminescence, Amplified Chemiluminescence, electrochemiluminescence Immunofluorescence. Compare including automatic methods and analyze the cost and feasibility of them for laboratory immunoassay. ELISA colorimetric technique for dosing was comparable to RIA T4, not for T3. Chemiluminescence (AMERLITE) compared to dosing RIA and IRMA T4 to TSH proved to be valid for both. Amplified Chemiluminescence (Immulite) compared to IRMA for TSH was no significant difference. Electrochemiluminescence (Elecsys 2010) compared to T3 and T4 RIA and IRMA for TSH, no significant differences for T4 and TSH; but no variation to T3. Immunofluorescence (AIA-600) used to compare with RIA for T3 and T4, and TSH IRMA, no significant differences for the measured analytes. Benchmarking of automatic methods suggests that the most thrifty of trials is Immunofluorescence the AIA-600, regarding calibration and control, programming time, randomization and the ability to save the value of the fluorescence deferred calculations for tests without valid at the time of realizing calibration. Analyzing the cost and feasibility of these methods for laboratory immunoassay, we must consider that their characteristics electrochemiluminescence is the fastest, but its price is prohibitive for our health systems. The AIA-600 appears to be the method of choice for its

  7. A competitive immunoassay for sensitive detection of small molecules chloramphenicol based on luminol functionalized silver nanoprobe.

    Science.gov (United States)

    Yu, Xiuxia; He, Yi; Jiang, Jie; Cui, Hua

    2014-02-17

    Chloramphenicol (CHL) as a broad-spectrum antibiotic has a broad action spectrum against Gram-positive and Gram-negative bacteria, as well as anaerobes. The use of CHL is strictly restricted in poultry because of its toxic effect. However, CHL is still illegally used in animal farming because of its accessibility and low cost. Therefore, sensitive methods are highly desired for the determination of CHL in foodstuffs. The immunoassays based on labeling as an important tool have been reported for the detection of CHL residues in food-producing animals. However, most of the labeling procedures require multi-step reactions and purifications and thus they are complicated and time-consuming. Recently, in our previous work, luminol functionalized silver nanoparticles have been successfully synthesized, which exhibits higher CL efficiency than luminol functionalized gold nanoparticles. In this work, the new luminol functionalized silver nanoparticles have been used for the labeling of small molecules CHL for the first time and a competitive chemiluminescent immunoassay has been developed for the detection of CHL. Owing to the amplification of silver nanoparticles, high sensitivity for CHL could be achieved with a low detection limit of 7.6×10(-9) g mL(-1) and a wide linear dynamic range of 1.0×10(-8)-1.0×10(-6) g mL(-1). This method has also been successfully applied to determine CHL in milk and honey samples with a good recoveries (92% and 102%, 99% and 107% respectively), indicating that the method is feasible for the determination of CHL in real milk and honey samples. The labeling procedure is simple, convenient and fast, superior to previously reported labeling procedures. The immunoassay is also simple, fast, sensitive and selective. It is of application potential for the determination of CHL in foodstuffs. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Accuracy of immunoassay and mass spectrometry urinary free cortisol in the diagnosis of Cushing's syndrome.

    Science.gov (United States)

    Aranda, G; Careaga, M; Hanzu, F A; Patrascioiu, I; Ríos, P; Mora, M; Morales-Romero, B; Jiménez, W; Halperin, I; Casals, G

    2016-10-01

    Urinary free cortisol (UFC) determination by highly specific methods as mass spectrometry instead of commercially available antibody-based immunoassays is increasingly recommended. However, clinical comparisons of both analytical approaches in the screening of Cushing's syndrome (CS) are not available. The aim of this study was to evaluate the diagnostic value of mass spectrometry versus immunoassay measurements of 24 h-UFC in the screening of CS. Cross-sectional study of 33 histologically confirmed CS patients: 25 Cushing's disease, 5 adrenal CS and 3 ectopic CS; 92 non-CS patients; and 35 healthy controls. UFC by immunoassay (UFCxIA) and mass spectrometry (UFCxMS), urinary free cortisone (UFCo) and UFC:UFCo ratio were measured, together with creatinine-corrected values. Sensitivity, specificity, AUC and Landis and Koch concordance index were determined. AUC for UFCxIA and UFCxMS were 0.77 (CI 0.68-0.87) and 0.77 (CI 0.67-0.87) respectively, with a kappa coefficient 0.60 and strong Landis and Koch concordance index. The best calculated cutoff values were 359 nmol/24 h for UFCxIA (78 % sensitivity, 62 % specificity) and 258.1 nmol/24 h for UCFxMS (53 % sensitivity, 86 % specificity). The upper limit of UFCxIA and UCFxMS reference ranges were 344.7 and 169.5 nmol/24 h respectively. Sensitivity and specificity for CS diagnosis at these cutpoints were 84 and 56 % for UFCxIA and 81 and 54 % for UFCxMS. According to our data, both methods present a very similar diagnostic value. However, results suggest that lower cutoff points for mass spectrometry may be necessary in order to improve clinical sensitivity.

  9. Design of novel hybrid organic-inorganic nanostructured biomaterials for immunoassay applications

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, G [Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, PO Box 486, 31270.901, Belo Horizonte, MG (Brazil); Barbosa-Stancioli, E F [Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, PO Box 486, 31270.901, Belo Horizonte, MG (Brazil); Piscitelli Mansur, A A [Department of Metallurgical and Materials Engineering, Biomaterials and Tissue Engineering Laboratory, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil); Vasconcelos, W L [Department of Metallurgical and Materials Engineering, Biomaterials and Tissue Engineering Laboratory, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil); Mansur, H S [Department of Metallurgical and Materials Engineering, Biomaterials and Tissue Engineering Laboratory, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil)

    2006-12-01

    The purpose of this study was to develop novel hybrid organic-inorganic materials based on poly(vinyl alcohol) (PVA) polymer chemically crosslinked network to be tested as solid support on bovine herpesvirus immunoassay. Hybrids were synthesized by reacting PVA with three different alkoxysilanes modifying chemical groups: tetraethoxysilane (TEOS), 3-mercaptopropyltrimethoxysilane (MPTMS) and 3-glycidoxypropyltrimethoxysilane (GPTMS). PVA-derived hybrids were also modified by chemically crosslinking with glutaraldehyde (GA) during the synthesis reaction. In order to investigate the structure in the nanometer-scale, PVA-derived hybrids were characterized by using small-angle x-ray scattering synchrotron radiation (SAXS) and x-ray diffraction (XRD). PVA hybrids' chemical functionalities and their interaction with herpesviruses were also characterized by Fourier transform infrared spectroscopy (FTIR). The bioactivity assays were tested through enzyme linked immunosorbent assay (ELISA). SAXS results have indicated nano-ordered disperse domains for PVA hybrids with different x-ray scattering patterns for PVA polymer and PVA-derived hybrids. FTIR spectra have shown major vibration bands associated with organic-inorganic chemical groups present in the PVA, PVA-derived by silane modifier and PVA chemically crosslinked by GA. The immunoassay results have shown that PVA hybrids with chemically functionalized structures regulated to some extent the specific bioimmobilization of herpesvirus onto solid phase. We think that it is due to the overall balance of forces associated with van der Waals interaction, hydrophilic and hydrophobic forces and steric hindrance acting at the surface. PVA and PVA-derived hybrid materials were successfully produced with GA crosslinking in a nanometer-scale network. Also, such a PVA-based material could be advantageously used in immunoassays with enhanced specificity for diagnosis.

  10. Evaluation of the Lumipulse G TP-N Chemiluminescent Immunoassay as a Syphilis Screening Test.

    Science.gov (United States)

    Ortiz, Daniel A; Loeffelholz, Michael J

    2017-11-01

    A syphilis diagnosis is often aided by the detection of treponemal and nontreponemal antibodies. Automated treponemal antibody detection systems enable high-volume clinical laboratories to perform syphilis screening at a faster pace with lower labor costs. The Lumipulse G TP-N chemiluminescent immunoassay is an automated system that qualitatively detects IgG and IgM antibodies against Treponema pallidum antigens in human serum and plasma. To assess performance characteristics and workflow efficiency, the Lumipulse G TP-N assay was compared to the Bioplex 2200 Syphilis IgG multiplex flow immunoassay. Among the 4,134 routine and HIV samples tested by the two automated assays, the percentage of agreement was excellent at 99.0% (95% confidence interval [CI], 98.6% to 99.2%; κ, 0.89), with the Lumipulse G TP-N having a shorter time to first and subsequent results. All specimens with reactive syphilis screening results were further tested by rapid plasma reagin (RPR) and Treponema pallidum particle agglutination (TP·PA) testing ( n = 231). The results from the RPR-reactive samples ( n = 82) showed complete concordance with the two automated assays, while the TP·PA assay displayed some discrepancies. The positive percent agreement (PPA) and negative percent agreement (NPA) between the TP·PA test and the Lumipulse G TP-N test were 98.9% and 77.3%, respectively. The Bioplex 2200 Syphilis IgG immunoassay displayed a similar PPA (100%) but a substantially lower NPA (15.9%). Patient chart reviews of discrepant results suggested that the Lumipulse G TP-N assay produced 27 fewer falsely reactive results and can reduce the amount of additional confirmatory RPR and TP·PA testing needed. The analogous performance characteristics of the two automated systems indicate that the Lumipulse G TP-N assay is suitable for high-throughput syphilis screening. Copyright © 2017 American Society for Microbiology.

  11. Design of novel hybrid organic-inorganic nanostructured biomaterials for immunoassay applications

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, G [Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, PO Box 486, 31270.901, Belo Horizonte, MG (Brazil); Barbosa-Stancioli, E F [Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, PO Box 486, 31270.901, Belo Horizonte, MG (Brazil); Piscitelli Mansur, A A [Department of Metallurgical and Materials Engineering, Biomaterials and Tissue Engineering Laboratory, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil); Vasconcelos, W L [Department of Metallurgical and Materials Engineering, Biomaterials and Tissue Engineering Laboratory, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil); Mansur, H S [Department of Metallurgical and Materials Engineering, Biomaterials and Tissue Engineering Laboratory, Federal University of Minas Gerais, Belo Horizonte, MG (Brazil)

    2006-12-01

    The purpose of this study was to develop novel hybrid organic-inorganic materials based on poly(vinyl alcohol) (PVA) polymer chemically crosslinked network to be tested as solid support on bovine herpesvirus immunoassay. Hybrids were synthesized by reacting PVA with three different alkoxysilanes modifying chemical groups: tetraethoxysilane (TEOS), 3-mercaptopropyltrimethoxysilane (MPTMS) and 3-glycidoxypropyltrimethoxysilane (GPTMS). PVA-derived hybrids were also modified by chemically crosslinking with glutaraldehyde (GA) during the synthesis reaction. In order to investigate the structure in the nanometer-scale, PVA-derived hybrids were characterized by using small-angle x-ray scattering synchrotron radiation (SAXS) and x-ray diffraction (XRD). PVA hybrids' chemical functionalities and their interaction with herpesviruses were also characterized by Fourier transform infrared spectroscopy (FTIR). The bioactivity assays were tested through enzyme linked immunosorbent assay (ELISA). SAXS results have indicated nano-ordered disperse domains for PVA hybrids with different x-ray scattering patterns for PVA polymer and PVA-derived hybrids. FTIR spectra have shown major vibration bands associated with organic-inorganic chemical groups present in the PVA, PVA-derived by silane modifier and PVA chemically crosslinked by GA. The immunoassay results have shown that PVA hybrids with chemically functionalized structures regulated to some extent the specific bioimmobilization of herpesvirus onto solid phase. We think that it is due to the overall balance of forces associated with van der Waals interaction, hydrophilic and hydrophobic forces and steric hindrance acting at the surface. PVA and PVA-derived hybrid materials were successfully produced with GA crosslinking in a nanometer-scale network. Also, such a PVA-based material could be advantageously used in immunoassays with enhanced specificity for diagnosis.

  12. Good performance of an immunoassay based method for nevirapine measurements in human breast milk

    DEFF Research Database (Denmark)

    Salado-Rasmussen, Kirsten; Theilgaard, Zahra Persson; Chiduo, Mercy

    2011-01-01

    from HIV-uninfected women. Clinical samples from HIV-infected women receiving a single-dose of nevirapine were analyzed. Results: Precision and accuracy were evaluated with two concentrations of quality control materials analyzed in three replicates on four different days and was......, requires complicated extraction techniques. The ARK method employs an immunoassay technology and requires a small sample volume (40 μL) and no pre-treatment of the samples. Methods: Commercial enzyme and antibody were used and calibration standards and quality controls were prepared from pooled breast milk...

  13. The Use of Recombinant Hemagglutinine Protein of Rinderpest Virus in Enzyme Immunoassay

    OpenAIRE

    BULUT, Hakan; BOLAT, Yusuf

    2003-01-01

    In this study, Rinderpest virus (RPV) recombinant hemagglutinine protein (rH) fused with protein A region of Staphylococcus aureus was expressed in Escherichia coli and purified by IgG affinity chromatography. rH protein was also used to establish enzyme immunoassay. Therefore, to prevent IgG binding to the protein A the wells coated with the rH proteins were blocked by human serum. Afterwards, RPV antigens were added to the wells to evaluate this assay. To this end, serum from mice immunized...

  14. Solid-Phase Immunoassay of Polystyrene-Encapsulated Semiconductor Coreshells for Cardiac Marker Detection

    Directory of Open Access Journals (Sweden)

    Sanghee Kim

    2012-01-01

    Full Text Available A solid-phase immunoassay of polystyrene-encapsulated semiconductor nanoparticles was demonstrated for cardiac troponin I (cTnI detection. CdSe/ZnS coreshells were encapsulated with a carboxyl-functionalized polystyrene nanoparticle to capture the target antibody through a covalent bonding and to eliminate the photoblinking and toxicity of semiconductor luminescent immunosensor. The polystyrene-encapsulated CdSe/ZnS fluorophores on surface-modified glass chip identified cTnI antigens at the level of ~ng/mL. It was an initial demonstration of diagnostic chip for monitoring a cardiovascular disease.

  15. Upconverting nanophosphors as reporters in a highly sensitive heterogeneous immunoassay for cardiac troponin I

    Energy Technology Data Exchange (ETDEWEB)

    Sirkka, Nina, E-mail: nkelon@utu.fi; Lyytikäinen, Annika; Savukoski, Tanja; Soukka, Tero

    2016-06-21

    Photon upconverting nanophosphors (UCNPs) have a unique capability to produce anti-Stokes emission at visible wavelengths via sequential multiphoton absorption upon infrared excitation. Since the anti-Stokes emission can be easily spectrally resolved from the Stokes' shifted autofluorescence, the upconversion luminescence (UCL) is a highly attractive reporter technology for optical biosensors and biomolecular binding assays – potentially enabling unprecedented sensitivity in separation-based solid-phase immunoassays. UCL technology has not previously been applied in sensitive detection of cardiac troponin I (cTnI), which requires highly sensitive detection to enable accurate and timely diagnosis of myocardial infarction. We have developed an UCL-based immunoassay for cTnI using NaYF{sub 4}: Yb{sup 3+}, Er{sup 3+} UCNPs as reporters. Biotinylated anti-cTnI monoclonal antibody (Mab) and Fab fragment immobilized to streptavidin-coated wells were used to capture cTnI. Captured cTnI was detected from dry well surface after a 15 min incubation with poly(acrylic acid) coated UCNPs conjugated to second anti-cTnI Mab. UCL was measured with a dedicated UCL microplate reader. The UCL-based immunoassay allowed sensitive detection of cTnI. The limit of detection was 3.14 ng L{sup −1}. The calibration curve was linear up to cTnI concentration 50,000 ng L{sup −1}. Plasma recoveries of added cTnI were 92–117%. Obtained cTnI concentrations from five normal plasma samples were 4.13–10.7 ng L{sup −1} (median 5.06 ng L{sup −1}). There is yet significant potential for even further improved limit of detection by reducing non-specifically bound fraction of the Mab-conjugated UCNPs. The assay background with zero calibrator was over 40-fold compared to the background obtained from wells where the reporter conjugate had been excluded. - Highlights: • Detection of attomole analyte quantity in microwell using upconversion luminescence. • Upconverting

  16. Results of the HPL determination using a new enzymatic immunoassay - comparison with a commercial radioimmunoassay

    International Nuclear Information System (INIS)

    Leis, D.; Schneider, B.; Keller, A.; Braun, S.

    1982-01-01

    An enzymatic immunoassay recently developed by the firm Organon, Oss, Netherlands, to determine HPL in the serum of pregnant women was compared to a widely used radioimmunoassay marketed by the firm Amersham-Buchler, Braunschweig. The values determined showed a good correlation. The accuracy of measurement was within the generally accepted range for immunological assays of this kind. The assay procedures are comparable with regard to the expenditure of time and work. A great advantage of the EIA is due to the absence of radioactive substances, which permits this test to be performed in any laboratory equipped with a centrifuge and photometer. (orig.) [de

  17. Dot immunoassay for the simultaneous determination of postvaccination immunity against pertussis, diphtheria, and tetanus.

    Science.gov (United States)

    Khramtsov, Pavel; Bochkova, Maria; Timganova, Valeria; Zamorina, Svetlana; Rayev, Mikhail

    2017-06-01

    A dot immunoassay for simultaneous semiquantitative detection of IgG against tetanus toxoid (Ttx) and diphtheria toxoid (Dtx) and qualitative detection of anti-Bordetella pertussis IgGs in human blood serum using carbon nanoparticles functionalized with streptococcal protein G was developed. Inactivated B. pertussis cells in suspension form were used as an antigen in the immunoassay. Pertussis, tetanus, and diphtheria antigens were separately spotted onto nitrocellulose strips, and then the immunostrips were successively incubated with blood sera and a suspension of carbon nanoparticles. The immunostrips were then scanned with a flatbed scanner, and the images obtained were processed with ImageJ. One hundred fifty-five venous blood serum samples from children vaccinated with diphtheria, tetanus, and whole-cell pertussis (DTwP) vaccine were tested in comparison with a conventional ELISA and agglutination test. The total time required for analysis of 32 serum samples was less than 3 h. Comparison between the results of the dot immunoassay and the corresponding ELISA/agglutination test revealed a high level of agreement (Cohen's kappa between 0.765 and 0.813). The lower limit of quantification was 0.06 IU/ml for anti-Ttx and anti-Dtx. The intra-assay coefficients of variation were less than 15% for anti-Ttx and anti-Dtx and less than 10% for anti-pertussis. The diagnostic sensitivity of detection of the antibody protection level was 93.5% for anti-Ttx [95% confidence interval (CI) 83.5-97.9%], 92.4% for anti-Dtx (95% CI 80.9297.5%), and 90.2% for anti-pertussis (95% CI 75.9-96.8%). The diagnostic specificity was 90.9% for anti-Ttx (95% CI 57.1-99.5%), 85% for anti-Dtx (95% CI 61.1-96.0%), and 89.3% for anti-pertussis (95%CI 80.8-94.5%). The dot immunoassay developed does not require expensive reading equipment, and allows detection of antibodies against three antigens in a single analysis. The immunostrips can be stored for a long time without changes in the

  18. A competitive enzyme immunoassay for the quantitative detection of cocaine from banknotes and latent fingermarks.

    Science.gov (United States)

    van der Heide, Susan; Garcia Calavia, Paula; Hardwick, Sheila; Hudson, Simon; Wolff, Kim; Russell, David A

    2015-05-01

    A sensitive and versatile competitive enzyme immunoassay (cEIA) has been developed for the quantitative detection of cocaine in complex forensic samples. Polyclonal anti-cocaine antibody was purified from serum and deposited onto microtiter plates. The concentration of the cocaine antibody adsorbed onto the plates, and the dilution of the cocaine-HRP hapten were both studied to achieve an optimised immunoassay. The method was successfully used to quantify cocaine in extracts taken from both paper currency and latent fingermarks. The limit of detection (LOD) of 0.162ngmL(-1) achieved with the assay compares favourably to that of conventional chromatography-mass spectroscopy techniques, with an appropriate sensitivity for the quantification of cocaine at the low concentrations present in some forensic samples. The cEIA was directly compared to LC-MS for the analysis of ten UK banknote samples. The results obtained from both techniques were statistically similar, suggesting that the immunoassay was unaffected by cross-reactivity with potentially interfering compounds. The cEIA was used also for the detection of cocaine in extracts from latent fingermarks. The results obtained were compared to the cocaine concentrations detected in oral fluid sampled from the same individual. Using the cEIA, we have shown, for the first time, that endogeneously excreted cocaine can be detected and quantified from a single latent fingermark. Additionally, it has been shown that the presence of cocaine, at similar concentrations, in more than one latent fingermark from the same individual can be linked with those concentrations found in oral fluid. These results show that detection of drugs in latent fingermarks could directly indicate whether an individual has consumed the drug. The specificity and feasibility of measuring low concentrations of cocaine in complex forensic samples demonstrate the effectiveness and robustness of the assay. The immunoassay presents a simple and cost

  19. Radio-immunoassay of plasma arginine vasopressin in man. Comparison of two methods of extraction

    International Nuclear Information System (INIS)

    Wolf, J.P.; Dumoulin, G.; Henriet, M.T.; Baulay, A.; Berthelay, S.

    1987-01-01

    Two methods of extraction, prior to radio-immunoassay (RIA) of human plasma arginine vasopressin (AVP) were tested: ethanol extraction (ETH), chromatography with ODS-Silice (ODS-Sil). Recovery of 125 I AVP was higher when using ODS-Sil than when using ETH. Recovery of standard AVP was found to be more efficient and reproducible for ODS-Sil. However, the RIA used, performed after chromatography with ODS-Sil, is not enough sensitive to detect low concentrations but is able to detect high concentrations and physiological variations of plasma AVP [fr

  20. A direct radio-immunoassay for plasma aldosterone: significance of endogenous cortisol

    International Nuclear Information System (INIS)

    Man, A.J.M. de; Hofman, J.A.; Hendriks, Th.; Rosmalen, F.M.A.; Ross, H.A.; Benraad, Th.J.

    1980-01-01

    A direct radio-immunoassay for plasma aldosterone was developed, using a highly specific antiserum raised in sheep. An excellent correlation was observed between its results and the levels measured after extraction and chromatography. The necessity of including a blocking agent to inhibit the binding of aldosterone to plasma proteins was investigated. It was found that in low-cortisol ( 10 μg/100 ml) the final assay result was independent of the presence of ANS. The effect of cortisol was interpreted in terms of its influence on aldosterone binding to plasma proteins in the absence of a blocking agent. (Auth.)

  1. Synthesis of polycyclic aromatic hydrocarbon-protein conjugates for preparation and immunoassay of antibodies.

    Science.gov (United States)

    Glushkov, Andrey N; Kostyanko, Mikhail V; Cherno, Sergey V; Vasilchenko, Ilya L

    2002-04-01

    The method is described dealing with the synthesis of conjugates protein-polycyclic aromatic hydrocarbons (PAHs), highly soluble in water, stable without special stabilizers and containing the minimum quantity of cross-linked products. The reaction of protein with PAH containing an aldehyde group, has been carried out in an alkaline solution, and stabilization of the conjugate has been achieved by reduction with sodium borohydride in the presence of a compound blocking the formation of an insoluble polymeric fraction. The efficiency of synthesized conjugates for the induction and immunoassay of Abs to PAH for benzo[a]pyrene is shown.

  2. Enzyme immunoassay of oestrogen receptors in needle biopsies from human liver

    DEFF Research Database (Denmark)

    Becker, U; Andersen, J; Poulsen, H S

    1991-01-01

    For quantitative assessments of sex hormone receptors in liver tissue, ligand binding assays are inconvenient, as they require large biopsies (0.5-1.0 g). The present study shows that it is possible to measure oestrogen receptors (ER) quantitatively in needle biopsy specimens as small as 10 mg...... by modifications of a commercial enzyme immunoassay employing monoclonal antibodies. Sucrose gradient centrifugation and the dextran charcoal method served as reference methods. A consecutive series of needle biopsies from patients suspected of liver disease were investigated. The biopsies (n = 37) had a median...

  3. Instrumentation a reader

    CERN Document Server

    Pope, P

    1990-01-01

    This book contains a selection of papers and articles in instrumentation previously pub­ lished in technical periodicals and journals of learned societies. Our selection has been made to illustrate aspects of current practice and applications of instrumentation. The book does not attempt to be encyclopaedic in its coverage of the subject, but to provide some examples of general transduction techniques, of the sensing of particular measurands, of components of instrumentation systems and of instrumentation practice in two very different environments, the food industry and the nuclear power industry. We have made the selection particularly to provide papers appropriate to the study of the Open University course T292 Instrumentation. The papers have been chosen so that the book covers a wide spectrum of instrumentation techniques. Because of this, the book should be of value not only to students of instrumen­ tation, but also to practising engineers and scientists wishing to glean ideas from areas of instrumen...

  4. Instrumentation for Nuclear Applications

    International Nuclear Information System (INIS)

    1998-01-01

    The objective of this project was to develop and coordinate nuclear instrumentation standards with resulting economies for the nuclear and radiation fields. There was particular emphasis on coordination and management of the Nuclear Instrument Module (NIM) System, U.S. activity involving the CAMAC international standard dataway system, the FASTBUS modular high-speed data acquisition and control system and processing and management of national nuclear instrumentation and detector standards, as well as a modest amount of assistance and consultation services to the Pollutant Characterization and Safety Research Division of the Office of Health and Environmental Research. The principal accomplishments were the development and maintenance of the NIM instrumentation system that is the predominant instrumentation system in the nuclear and radiation fields worldwide, the CAMAC digital interface system in coordination with the ESONE Committee of European Laboratories, the FASTBUS high-speed system and numerous national and international nuclear instrumentation standards

  5. VIRUS instrument enclosures

    Science.gov (United States)

    Prochaska, T.; Allen, R.; Mondrik, N.; Rheault, J. P.; Sauseda, M.; Boster, E.; James, M.; Rodriguez-Patino, M.; Torres, G.; Ham, J.; Cook, E.; Baker, D.; DePoy, Darren L.; Marshall, Jennifer L.; Hill, G. J.; Perry, D.; Savage, R. D.; Good, J. M.; Vattiat, Brian L.

    2014-08-01

    The Visible Integral-Field Replicable Unit Spectrograph (VIRUS) instrument will be installed at the Hobby-Eberly Telescope† in the near future. The instrument will be housed in two enclosures that are mounted adjacent to the telescope, via the VIRUS Support Structure (VSS). We have designed the enclosures to support and protect the instrument, to enable servicing of the instrument, and to cool the instrument appropriately while not adversely affecting the dome environment. The system uses simple HVAC air handling techniques in conjunction with thermoelectric and standard glycol heat exchangers to provide efficient heat removal. The enclosures also provide power and data transfer to and from each VIRUS unit, liquid nitrogen cooling to the detectors, and environmental monitoring of the instrument and dome environments. In this paper, we describe the design and fabrication of the VIRUS enclosures and their subsystems.

  6. Radiation protection instrument 1993

    International Nuclear Information System (INIS)

    1993-04-01

    The Radiation Protection Instrument, 1993 (Legislative Instrument 1559) prescribes the powers and functions of the Radiation Protection Board established under the Ghana Atomic Energy Commission by the Atomic Energy Commission (Amendment) Law, 1993 (P.N.D.C. Law 308). Also included in the Legislative Instrument are schedules on control and use of ionising radiation and radiation sources as well as procedures for notification, licensing and inspection of ionising radiation facilities. (EAA)

  7. 340 nm pulsed UV LED system for europium-based time-resolved fluorescence detection of immunoassays

    DEFF Research Database (Denmark)

    Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter

    2016-01-01

    We report on the design, development and investigation of an optical system based on UV light emitting diode (LED) excitation at 340 nm for time-resolved fluorescence detection of immunoassays. The system was tested to measure cardiac marker Troponin I with a concentration of 200 ng....../L in immunoassay. The signal-to-noise ratio was comparable to state-of-the-art Xenon flash lamp based unit with equal excitation energy and without overdriving the LED. We performed a comparative study of the flash lamp and the LED based system and discussed temporal, spatial, and spectral features of the LED...... excitation for time-resolved fluorimetry. Optimization of the suggested key parameters of the LED promises significant increase of the signal-to-noise ratio and hence of the sensitivity of immunoassay systems....

  8. 340 nm pulsed UV LED system for europium-based time-resolved fluorescence detection of immunoassays.

    Science.gov (United States)

    Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter; Petersen, Paul Michael; Pedersen, Christian

    2016-09-19

    We report on the design, development and investigation of an optical system based on UV light emitting diode (LED) excitation at 340 nm for time-resolved fluorescence detection of immunoassays. The system was tested to measure cardiac marker Troponin I with a concentration of 200 ng/L in immunoassay. The signal-to-noise ratio was comparable to state-of-the-art Xenon flash lamp based unit with equal excitation energy and without overdriving the LED. We performed a comparative study of the flash lamp and the LED based system and discussed temporal, spatial, and spectral features of the LED excitation for time-resolved fluorimetry. Optimization of the suggested key parameters of the LED promises significant increase of the signal-to-noise ratio and hence of the sensitivity of immunoassay systems.

  9. Dual-Mode SERS-Fluorescence Immunoassay Using Graphene Quantum Dot Labeling on One-Dimensional Aligned Magnetoplasmonic Nanoparticles.

    Science.gov (United States)

    Zou, Fengming; Zhou, Hongjian; Tan, Tran Van; Kim, Jeonghyo; Koh, Kwangnak; Lee, Jaebeom

    2015-06-10

    A novel dual-mode immunoassay based on surface-enhanced Raman scattering (SERS) and fluorescence was designed using graphene quantum dot (GQD) labels to detect a tuberculosis (TB) antigen, CFP-10, via a newly developed sensing platform of linearly aligned magnetoplasmonic (MagPlas) nanoparticles (NPs). The GQDs were excellent bilabeling materials for simultaneous Raman scattering and photoluminescence (PL). The one-dimensional (1D) alignment of MagPlas NPs simplified the immunoassay process and enabled fast, enhanced signal transduction. With a sandwich-type immunoassay using dual-mode nanoprobes, both SERS signals and fluorescence images were recognized in a highly sensitive and selective manner with a detection limit of 0.0511 pg mL(-1).

  10. The fabrication of magnetic particle-based chemiluminescence immunoassay for human epididymis protein-4 detection in ovarian cancer

    Directory of Open Access Journals (Sweden)

    Xiaoling Fu

    2018-03-01

    Full Text Available The magnetic particles have a significant influence on the immunoassay detection and cancer therapy. Herein, the chemiluminescence immunoassay combined with the magnetic particles (MPCLIA was presented for the clinical determination and analysis of human epididymis protein 4 (HE4 in the human serum. Under the optimized experiment conditions, the secure MPCLIA method can detect HE4 in the broader range of 0–1000 pmol/L, with a lower detection limit of 1.35 pmol/L. The satisfactory recovery rate of the method in the serum ranged from 83.62% to 105.10%, which was well within the requirement of clinical analysis. Moreover, the results showed the good correlation with enzyme-linked immunosorbent assay (ELISA, with the correlation coefficient of 0.9589. This proposed method has been successfully applied to the clinical determination of HE4 in the human serum. Keywords: Chemiluminescence immunoassay, Magnetic particles, Human epididymis protein 4

  11. Networked Instrumentation Element

    Data.gov (United States)

    National Aeronautics and Space Administration — Armstrong researchers have developed a networked instrumentation system that connects modern experimental payloads to existing analog and digital communications...

  12. Instrument validation project

    International Nuclear Information System (INIS)

    Reynolds, B.A.; Daymo, E.A.; Geeting, J.G.H.; Zhang, J.

    1996-06-01

    Westinghouse Hanford Company Project W-211 is responsible for providing the system capabilities to remove radioactive waste from ten double-shell tanks used to store radioactive wastes on the Hanford Site in Richland, Washington. The project is also responsible for measuring tank waste slurry properties prior to injection into pipeline systems, including the Replacement of Cross-Site Transfer System. This report summarizes studies of the appropriateness of the instrumentation specified for use in Project W-211. The instruments were evaluated in a test loop with simulated slurries that covered the range of properties specified in the functional design criteria. The results of the study indicate that the compact nature of the baseline Project W-211 loop does not result in reduced instrumental accuracy resulting from poor flow profile development. Of the baseline instrumentation, the Micromotion densimeter, the Moore Industries thermocouple, the Fischer and Porter magnetic flow meter, and the Red Valve Pressure transducer meet the desired instrumental accuracy. An alternate magnetic flow meter (Yokagawa) gave nearly identical results as the baseline fischer and Porter. The Micromotion flow meter did not meet the desired instrument accuracy but could potentially be calibrated so that it would meet the criteria. The Nametre on-line viscometer did not meet the desired instrumental accuracy and is not recommended as a quantitative instrument although it does provide qualitative information. The recommended minimum set of instrumentation necessary to ensure the slurry meets the Project W-058 acceptance criteria is the Micromotion mass flow meter and delta pressure cells

  13. Instrument performance evaluation

    International Nuclear Information System (INIS)

    Swinth, K.L.

    1993-03-01

    Deficiencies exist in both the performance and the quality of health physics instruments. Recognizing the implications of such deficiencies for the protection of workers and the public, in the early 1980s the DOE and the NRC encouraged the development of a performance standard and established a program to test a series of instruments against criteria in the standard. The purpose of the testing was to establish the practicality of the criteria in the standard, to determine the performance of a cross section of available instruments, and to establish a testing capability. Over 100 instruments were tested, resulting in a practical standard and an understanding of the deficiencies in available instruments. In parallel with the instrument testing, a value-impact study clearly established the benefits of implementing a formal testing program. An ad hoc committee also met several times to establish recommendations for the voluntary implementation of a testing program based on the studies and the performance standard. For several reasons, a formal program did not materialize. Ongoing tests and studies have supported the development of specific instruments and have helped specific clients understand the performance of their instruments. The purpose of this presentation is to trace the history of instrument testing to date and suggest the benefits of a centralized formal program

  14. [Controlling instruments in radiology].

    Science.gov (United States)

    Maurer, M

    2013-10-01

    Due to the rising costs and competitive pressures radiological clinics and practices are now facing, controlling instruments are gaining importance in the optimization of structures and processes of the various diagnostic examinations and interventional procedures. It will be shown how the use of selected controlling instruments can secure and improve the performance of radiological facilities. A definition of the concept of controlling will be provided. It will be shown which controlling instruments can be applied in radiological departments and practices. As an example, two of the controlling instruments, material cost analysis and benchmarking, will be illustrated.

  15. Ocean Optics Instrumentation Systems

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides instrumentation suites for a wide variety of measurements to characterize the ocean’s optical environment. These packages have been developed to...

  16. 340 nm pulsed UV LED system for europium-based time-resolved fluorescence detection of immunoassays

    OpenAIRE

    Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter; Petersen, Paul Michael; Pedersen, Christian

    2016-01-01

    We report on the design, development and investigation of an optical system based on UV light emitting diode (LED) excitation at 340 nm for time-resolved fluorescence detection of immunoassays. The system was tested to measure cardiac marker Troponin I with a concentration of 200 ng/L in immunoassay. The signal-to-noise ratio was comparable to state-of-the-art Xenon flash lamp based unit with equal excitation energy and without overdriving the LED. We performed a comparative study of the flas...

  17. Detection of Avian Influenza Virus by Fluorescent DNA Barcode-based Immunoassay with Sensitivity Comparable to PCR

    DEFF Research Database (Denmark)

    Cao, Cuong; Dhumpa, Raghuram; Bang, Dang Duong

    2010-01-01

    involves the sandwiching of the target AIV between magnetic immunoprobes and barcode-carrying immunoprobes. Because each barcode-carrying immunoprobe is functionalized with a multitude of fluorophore-DNA barcode strands, many DNA barcodes are released for each positive binding event resulting......In this paper, a coupling of fluorophore-DNA barcode and bead-based immunoassay for detecting avian influenza virus (AIV) with PCR-like sensitivity is reported. The assay is based on the use of sandwich immunoassay and fluorophore-tagged oligonucleotides as representative barcodes. The detection...

  18. Rapid screening of aflatoxin B1 in beer by fluorescence polarization immunoassay.

    Science.gov (United States)

    Beloglazova, N V; Eremin, S A

    2015-09-01

    This manuscript describes the development of a sensitive, fast and easily-performed fluorescence polarization immunoassay (FPIA) for the mycotoxin aflatoxin B1 (AFB1) in various beer samples, both lager and dark. The highest sensitivity was determined for six poly- and monoclonal antibodies selective towards aflatoxins. The sample pretreatment design was emphasized since beer samples are characterized by extremely diverse matrices. Herein, the choice of sorbent for effective removal of matrix interferences prior to analysis was crucial. The samples were diluted with a borate buffer solution containing 1% PEG 6000 and passed through the clean-up column packed with NH2-derivated silica. This sample pretreatment technique was perfectly suitable for the FPIA of lager beer samples, but for dark beer and ale it did not suffice. An artificial matrix was constructed to plot a calibration curve and quantify the results of the latter samples. The developed immunoassay was characterized by a limit of detection of 1 ng mL(-1). Apparent recovery values of 89-114% for lager and 80-125% for dark beer were established. The FPIA data for AFB1 was characterized by elevated linear regression coefficients, 0.9953 for spiked lager and 0.9895 for dark beer samples respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. A harmonized immunoassay with liquid chromatography-mass spectrometry analysis in egg allergen determination.

    Science.gov (United States)

    Nimata, Masaomi; Okada, Hideki; Kurihara, Kei; Sugimoto, Tsukasa; Honjoh, Tsutomu; Kuroda, Kazuhiko; Yano, Takeo; Tachibana, Hirofumi; Shoji, Masahiro

    2018-01-01

    Food allergy is a serious health issue worldwide. Implementing allergen labeling regulations is extremely challenging for regulators, food manufacturers, and analytical kit manufacturers. Here we have developed an "amino acid sequence immunoassay" approach to ELISA. The new ELISA comprises of a monoclonal antibody generated via an analyte specific peptide antigen and sodium lauryl sulfate/sulfite solution. This combination enables the antibody to access the epitope site in unfolded analyte protein. The newly developed ELISA recovered 87.1%-106.4% ovalbumin from ovalbumin-incurred model processed foods, thereby demonstrating its applicability as practical egg allergen determination. Furthermore, the comparison of LC-MS/MS and the new ELISA, which targets the amino acid sequence conforming to the LC-MS/MS detection peptide, showed a good agreement. Consequently the harmonization of two methods was demonstrated. The complementary use of the new ELISA and LC-MS analysis can offer a wide range of practical benefits in terms of easiness, cost, accuracy, and efficiency in food allergen analysis. In addition, the new assay is attractive in respect to its easy antigen preparation and predetermined specificity. Graphical abstract The ELISA composing of the monoclonal antibody targeting the amino acid sequence conformed to LC-MS detection peptide, and the protein conformation unfolding reagent was developed. In ovalbumin determination, the developed ELISA showed a good agreement with LC-MS analysis. Consequently the harmonization of immunoassay with LC-MS analysis by using common target amino acid sequence was demonstrated.

  20. Plasma exchange to remove HIT antibodies: dissociation between enzyme-immunoassay and platelet activation test reactivities.

    Science.gov (United States)

    Warkentin, Theodore E; Sheppard, Jo-Ann I; Chu, F Victor; Kapoor, Anil; Crowther, Mark A; Gangji, Azim

    2015-01-01

    Repeated therapeutic plasma exchange (TPE) has been advocated to remove heparin-induced thrombocytopenia (HIT) IgG antibodies before cardiac/vascular surgery in patients who have serologically-confirmed acute or subacute HIT; for this situation, a negative platelet activation assay (eg, platelet serotonin-release assay [SRA]) has been recommended as the target serological end point to permit safe surgery. We compared reactivities in the SRA and an anti-PF4/heparin IgG-specific enzyme immunoassay (EIA), testing serial serum samples in a patient with recent (subacute) HIT who underwent serial TPE precardiac surgery, as well as for 15 other serially-diluted HIT sera. We observed that post-TPE/diluted HIT sera-when first testing SRA-negative-continue to test strongly positive by EIA-IgG. This dissociation between the platelet activation assay and a PF4-dependent immunoassay for HIT antibodies indicates that patients with subacute HIT undergoing repeated TPE before heparin reexposure should be tested by serial platelet activation assays even when their EIAs remain strongly positive. © 2015 by The American Society of Hematology.

  1. Simplified immunoassay for rapid Dengue serotype diagnosis, revealing insensitivity to non-specific binding interference

    Directory of Open Access Journals (Sweden)

    Fernanda C.C.L. Loureiro

    2017-04-01

    Full Text Available Proof of concept of an immunoassay, which is easy to implement, for rapid Dengue virus (DENV serotype diagnosis, in the early infection stage, is reported. The four-layer assay is immobilized onto a thin gold film and relies on a low cost, disposable polymer biochip for optical surface plasmon resonance sensing and detection. The protocol comprises Neutravidin-Biotin mediated monoclonal antibody (MAB attachment as the functionalized sensing element. Formation of the MAB-DENV complex results in a pronounced thickness change that is optically recorded in real time, employing a microfluidic set-up. Virus presence is confirmed by atomic force microscopy from the same sample. Serum samples were collected from a patient in acute febrile state. Simultaneous serological analysis by means of the reverse transcription polymerase chain reaction, independently, confirmed presence of DENV2 and DENV3. The protocol proved applicable in presence of strong non-specific binding interference that originates from, and is caused by, various blood, serum and other body fluid constituents. False positive indications for both, negative serum and blood control samples were not observed. The achievable limit of detection was estimated to be 2×104 particles/ml. Eventually, the method can be modified towards detection of other viruses by using the same protocol. Keywords: Immuno-assay, Dengue virus detection, Non-specific binding

  2. Enhanced Plasmonic Biosensors of Hybrid Gold Nanoparticle-Graphene Oxide-Based Label-Free Immunoassay

    Science.gov (United States)

    Chiu, Nan-Fu; Chen, Chi-Chu; Yang, Cheng-Du; Kao, Yu-Sheng; Wu, Wei-Ren

    2018-05-01

    In this study, we propose a modified gold nanoparticle-graphene oxide sheet (AuNP-GO) nanocomposite to detect two different interactions between proteins and hybrid nanocomposites for use in biomedical applications. GO sheets have high bioaffinity, which facilitates the attachment of biomolecules to carboxyl groups and has led to its use in the development of sensing mechanisms. When GO sheets are decorated with AuNPs, they introduce localized surface plasmon resonance (LSPR) in the resonance energy transfer of spectral changes. Our results suggest a promising future for AuNP-GO-based label-free immunoassays to detect disease biomarkers and rapidly diagnose infectious diseases. The results showed the detection of antiBSA in 10 ng/ml of hCG non-specific interfering protein with dynamic responses ranging from 1.45 nM to 145 fM, and a LOD of 145 fM. Considering the wide range of potential applications of GO sheets as a host material for a variety of nanoparticles, the approach developed here may be beneficial for the future integration of nanoparticles with GO nanosheets for blood sensing. The excellent anti-interference characteristics allow for the use of the biosensor in clinical analysis and point-of-care testing (POCT) diagnostics of rapid immunoassay products, and it may also be a potential tool for the measurement of biomarkers in human serum.

  3. Highly sensitive immunoassay of protein molecules based on single nanoparticle fluorescence detection in a nanowell

    Science.gov (United States)

    Han, Jin-Hee; Kim, Hee-Joo; Lakshmana, Sudheendra; Gee, Shirley J.; Hammock, Bruce D.; Kennedy, Ian M.

    2011-03-01

    A nanoarray based-single molecule detection system was developed for detecting proteins with extremely high sensitivity. The nanoarray was able to effectively trap nanoparticles conjugated with biological sample into nanowells by integrating with an electrophoretic particle entrapment system (EPES). The nanoarray/EPES is superior to other biosensor using immunoassays in terms of saving the amounts of biological solution and enhancing kinetics of antibody binding due to reduced steric hindrance from the neighboring biological molecules. The nanoarray patterned onto a layer of PMMA and LOL on conductive and transparent indium tin oxide (ITO)-glass slide by using e-beam lithography. The suspension of 500 nm-fluorescent (green emission)-carboxylated polystyrene (PS) particles coated with protein-A followed by BDE 47 polyclonal antibody was added to the chip that was connected to the positive voltage. The droplet was covered by another ITO-coated-glass slide and connected to a ground terminal. After trapping the particles into the nanowells, the solution of different concentrations of anti-rabbit- IgG labeled with Alexa 532 was added for an immunoassay. A single molecule detection system could quantify the anti-rabbit IgG down to atto-mole level by counting photons emitted from the fluorescent dye bound to a single nanoparticle in a nanowell.

  4. Characterization of hapten-protein conjugates: antibody generation and immunoassay development for chlorophenoxyacetic acid pesticides.

    Science.gov (United States)

    Boro, Robin C; Singh, K Vikas; Suri, C Raman

    2009-01-01

    The generation of specific and sensitive antibodies against small molecules is greatly dependent upon the characteristics of the hapten-protein conjugates. In this study, we report a new fluorescence-based method for the characterization of hapten-protein conjugates. The method is based on an effect promoted by hapten-protein conjugation density upon the fluorescence intensity of the intrinsic tryptophan chromophore molecules of the protein. The proposed methodology is applied to quantify the hapten-protein conjugation density for two different chlorophenoxyacetic acid pesticides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenoxybutyric acid (2,4-DB), coupled to carrier protein. Highly sensitive anti-2,4-D and anti-2,4-DB antibodies were obtained using these well-characterized hapten-protein conjugates. The generated antibodies were used in an immunoassay format demonstrating inhibitory concentration (IC50) values equal to 30 and 7 ng/mL for 2,4-D and 2,4-DB, respectively. Linearity was observed in the concentration range between 0.1-500 nglmL with LODs around 4 and 3 ng/mL for 2,4-D and 2,4-DB, respectively, in standard water samples. The proposed method was successfully applied for the determination of the extent of hapten-protein conjugation to produce specific antibodies for immunoassay development against pesticides.

  5. Myeloma-Derived Light Chain Paired with a Diagnostic Monoclonal Antibody Hinders Immunoassay Performance.

    Science.gov (United States)

    Tu, Bailin; Tieman, Bryan; Moore, Jeffrey; Pan, You; Muerhoff, A Scott

    2017-06-01

    Monoclonal antibodies are widely used as the capture and detection reagents in diagnostic immunoassays. In the past, myeloma fusion partners expressing endogenous heavy and/or light chains were often used to generate hybridoma cell lines. As a result, mixed populations of antibodies were produced that can cause inaccurate test results, poor antibody stability, and significant lot-to-lot variability. We describe one such scenario where the P3U1 (P3X63Ag8U.1) myeloma fusion partner was used in the generation of a hybridoma producing protein induced vitamin K absence/antagonist-II (PIVKA II) antibody. The hybridoma produces three subpopulations of immunoglobulin as determined by ion exchange (IEx) chromatography that exhibit varying degrees of immunoreactivity (0%, 50%, or 100%) to the target antigen as determined by Surface Plasmon Resonance. To produce an antibody with the highest possible sensitivity and specificity, the antigen-specific heavy and light chain variable domains (VH and VL) were cloned from the hybridoma and tethered to murine IgG1 and kappa scaffolds. The resulting recombinant antibody was expressed in Chinese hamster ovary cells and is compatible for use in a diagnostic immunoassay.

  6. New antibody and immunoassay pretreatment strategy to screen polychlorinated biphenyls in Korean transformer oil.

    Science.gov (United States)

    Terakado, Shingo; Ohmura, Naoya; Park, Seok-Un; Lee, Seung-Min; Glass, Thomas R

    2013-01-01

    Development and modifications are described that expand the application of an immunoassay from the detection of Kanechlors (Japanese technical PCBs mixtures) to the detection of Aroclors (U. S. technical PCB mixtures, used in Korea) in contaminated Korean transformer oil. The first necessary modification was the development of a new antibody with a reactivity profile favorable for Aroclors. The second modification was the addition of a second column to the solid-phase extraction method to reduce assay interference caused by the Korean oil matrix. The matrix interference is suspected to be caused by the presence of synthetic oils (or similar materials) present as contaminants. The modified assay was validated by comparison to high-resolution gas chromatography/high-resolution mass spectrometry analysis, and was shown to be tolerant of up to 10% of several common synthetic insulating oils. Finally the screening performance of the modified assay was evaluated using 500 used transformer oil samples of Korean origin, and was shown to have good performance in terms of false positive and false negative rates. This report provides evidence for the first establishment of immunoassay screening for Aroclor based PCB contamination in Korean transformer oil.

  7. A summary report on the 23rd quality control survey for immunoassays in Japan, 2001

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-10-01

    The purpose of the survey is to improve the quality of in vitro tests and this report is its summary of immunoassays (the old name: RI in vitro tests) conducted in 2001. The survey was performed in 143 facilities out of 1,655 in Japan, which involved 20 national and public university hospitals, 16 private university hospitals, 21 national and public hospitals, 26 private hospitals, 41 hygiene test institutes and 19 reagent manufacturers. Tests examined were on 6 substances related to functions of pituitary, 5 of thyroid, 1 of parathyroid, 4 of gastro-intestine and pancreas, 5 of gonad and placenta, 4 of adrenal, 1 of renal-blood pressure regulation, on IgE, on digoxin and on 12 tumor-related substances. Tests were done on 2-3 samples supplied from the Committee and the mean, standard deviation and coefficient of variation were calculated for one way analysis of variance of within- and between-kit. Methods included those (65.4% vs 62.7% in 2000) with non-radioisotope like enzyme immunoassay (non-RI) and with radioisotopes like radioimmunoassay (RI). Dissociation between manufacturers of non-RI values without a common standard substance and between non-RI and RI values even with the same antibody was noted: the Committee considered these problems as their future task. (K.H.)

  8. Photoelectrochemical detection of enzymatically generated CdS nanoparticles: Application to development of immunoassay.

    Science.gov (United States)

    Barroso, Javier; Saa, Laura; Grinyte, Ruta; Pavlov, Valeri

    2016-03-15

    We report an innovative photoelectrochemical process (PEC) based on graphite electrode modified with electroactive polyvinylpyridine bearing osmium complex (Os-PVP). The system relies on the in situ enzymatic generation of CdS quantum dots (QDs). Alkaline phosphatase (ALP) catalyzes the hydrolisis of sodium thiophosphate (TP) to hydrogen sulfide (H2S) which in the presence Cd(2+) ions yields CdS semiconductor nanoparticles (SNPs). Irradiation of SNPs with the standard laboratory UV-illuminator (wavelength of 365 nm) results in photooxidation of 1-thioglycerol (TG) mediated by Os-PVP complex on the surface of graphite electrode at applied potential of 0.31 V vs. Ag/AgCl. A novel immunoassay based on specific enzyme linked immunosorbent assay (ELISA) combined with the PEC methodology was developed. Having selected the affinity interaction between bovine serum albumine (BSA) with anti-BSA antibody (AB) as a model system, we built the PEC immunoassay for AB. The new assay displays a linear range up to 20 ngmL(-1) and a detection limit (DL) of 2 ngmL(-1) (S/N=3) which is lower 5 times that of the traditional chromogenic ELISA test employing p-nitro-phenyl phosphate (pNPP). Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Development of a simple extraction procedure for chlorpyrifos determination in food samples by immunoassay.

    Science.gov (United States)

    Gabaldón, J A; Maquieira, A; Puchades, R

    2007-02-28

    The suitability of immunoassay methodology for rapid and accurate determination of chlorpyrifos in vegetables was tested. The optimised ELISA detection limit was 0.32ng/ml, with a working range from 0.69 to 6.21ng/ml and an immunoassay test-mid point (IC(50)) of 2.08ng/ml. A rapid sample preparation procedure considering different parameters such as the amount of sample, volume of extractant, extraction time and dilution factor was optimised. The developed direct extraction (DE) and multiresidue (ME) standard procedures were performed in different fortified fresh and processed vegetable samples (tomato, bonnet pepper, bean, pea, asparagus, broccoli, watermelon, melon, lettuce, cucumber, celery and red pepper). Recoveries were in all cases in the whole range 85.2-108.9% for both DE and ME extracts. Also, the comparison of the results obtained by both immunochemical and chromatographic methods for spiked fruits and vegetables were good with a correlation coefficient (r) of 0.97.

  10. Dog cloning with in vivo matured oocytes obtained using electric chemiluminescence immunoassay-predicted ovulation method.

    Science.gov (United States)

    Lee, Seunghoon; Zhao, Minghui; No, Jingu; Nam, Yoonseok; Im, Gi-Sun; Hur, Tai-Young

    2017-01-01

    Radioactive immunoassay (RIA) is a traditional serum hormone assay method, but the application of the method in reproductive studies is limited by the associated radioactivity. The aim of present study was to evaluate the reliability of RIA and to compare its canine serum progesterone concentration determination accuracy to that of the electric chemiluminescence immunoassay (ECLI). In vivo matured oocytes were utilized for canine somatic cell nuclear transfer (SCNT), and serum progesterone levels were assessed to accurately determine ovulation and oocyte maturation. Canine serum progesterone concentrations during both proestrus and estrus were analyzed by RIA and ECLI to determine the ovulation day. Although both methods detected similar progesterone levels before ovulation, the mean progesterone concentration determined using ECLI was significantly higher than of RIA three days before ovulation. Following ovulation, oocytes were collected by surgery, and a lower percentage of mature oocytes were observed using ECLI (39%) as compared to RIA (67%) if 4-8ng/ml of progesterone were used for determination of ovulation. A high percentage of mature oocytes was observed using ECLI when 6-15 ng/mL of progesterone was used for ovulation determination. To determine whether ECLI could be used for canine cloning, six canines were selected as oocyte donors, and two puppies were obtained after SCNT and embryo transfer. In conclusion, compared to the traditional RIA method, the ECLI method is a safe and reliable method for canine cloning.

  11. Screening for cocaine on Euro banknotes by a highly sensitive enzyme immunoassay.

    Science.gov (United States)

    Abdelshafi, Nahla A; Panne, Ulrich; Schneider, Rudolf J

    2017-04-01

    This study focused on quantitative detection of cocaine on Euro banknotes in Germany. A sensitive direct competitive immunoassay was developed and optimized with a limit of detection (LOD) of 5.6ng/L. Exhaustive cocaine extraction by solvent was tested using different methanol concentrations and buffered solutions. Cross-reactivity studies were performed to determine the degree of interference of cocaine metabolites with the immunoassay. Sixty-five Euro banknotes obtained from different districts in Berlin were evaluated. A 100% contamination frequency with cocaine was detected. A comparison between the amount of cocaine extracted by cotton swabbing of one square centimeter of the banknote showed a good correlation for lower contamination levels. This assay showed high sensitivity of detecting pg of cocaine per 1cm 2 of one banknote by swabbing 1cm 2 : 0, 14, and 21pg/cm 2 . Moreover, three notes of different denominations revealed high cocaine concentration; 1.1mg/note, and twice 55µg/note. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Evaluation and comparison of radio-, fluorescence, and enzyme-linked immunoassays for serum thyroxine

    International Nuclear Information System (INIS)

    Kaplan, L.A.; Gau, N.; Fearn, J.; Steain, E.A.; Chen, I.W.; Maxon, H.; Volle, C.

    1981-01-01

    We have compared three analytical systems for the measurement of serum thyroxine: enzyme-linked immunoassay (EIA), fluorescent immunoassay (FIA) and a radioimmunoassay (RIA). These were evaluated with respect to their precision, accuracy, analytical sensitivity and sample throughput. The RIA is more sensitive than the EIA (10 μg/L vs. 35 μg/L). Both systems have excellent precision (X=86 μg/L, C.V.sub(RIA)=C.V.sub(EIA)=4.6 percent). Both the EIA and RIA demonstrate good accuracy with recovery of between 97-98 percent of added thyroxine. The FIA has an apparent sensitiviity between that of the RIA and EIA (25 μg/L), but a precision consistently lower than the other two systems (C.V. =7.4 percent, X=86 μg/L). Patients' results by RIA compared well with those from EIA (r=0.91,P 0.05). Although not fully automated, the EIA performed on the Abbott ABA-100 analyzer has a sample throughput equal to the automated RIA system (Micromedic, Concept 4)

  13. Alkaline phosphatase labeled SERS active sandwich immunoassay for detection of Escherichia coli

    Science.gov (United States)

    Bozkurt, Akif Goktug; Buyukgoz, Guluzar Gorkem; Soforoglu, Mehmet; Tamer, Ugur; Suludere, Zekiye; Boyaci, Ismail Hakki

    2018-04-01

    In this study, a sandwich immunoassay method utilizing enzymatic activity of alkaline phosphatase (ALP) on 5-bromo-4-chloro-3-indolyl phosphate (BCIP) for Escherichia coli (E. coli) detection was developed using surface enhanced Raman spectroscopy (SERS). For this purpose, spherical magnetic gold coated core-shell nanoparticles (MNPs-Au) and rod shape gold nanoparticles (Au-NRs) were synthesized and modified for immunomagnetic separation (IMS) of E. coli from the solution. In order to specify the developed method to ALP activity, Au-NRs were labeled with this enzyme. After successful construction of the immunoassay, BCIP substrate was added to produce the SERS-active product; 5-bromo-4-chloro-3-indole (BCI). A good linearity (R2 = 0.992) was established between the specific SERS intensity of BCI at 600 cm- 1 and logarithmic E. coli concentration in the range of 1.7 × 101-1.7 × 106 cfu mL- 1. LOD and LOQ values were also calculated and found to be 10 cfu mL- 1 and 30 cfu mL- 1, respectively.

  14. Comparison of immunoassays for differentiation of herpes simplex virus type 1 and 2 antibodies

    International Nuclear Information System (INIS)

    Klapper, Paul E.; Valley, Pam J.; Cleator, Gerham M.; Mandall, D.; Qutub, Mohammed O.

    2006-01-01

    To asses the commercial available enzyme-linked immunosorbent assays (ELISA) for differentiation of herpes simplex virus type 1 (Hs-1) and type 2 (HSV-2) antibodies. The study was performed between January 1997 to November 2002 in the Division ofVirology,Department of Pathological Sciences, Central Manchester Healthcare Trust and University of Manchester, Manchester, United Kingdom. Assays based upon type-specific glycoprotein G-1 (gG-1) for HSV-1, and glycoprotein G-2 (gG-2) from HSV-2 were evaluated to differentiate between HSV-1 and HSV-2 antibodies. Using 5 different ELISA tests, 2 panels of serum samples were tested. Panel one consisted of 88 sera, selected from the serum bank of the Clinical Virology Laboratory, Manchester Royal Infirmary; panel 2 comprised of 90 sera selected from samples collected from Bangladeshi female commercial workers.The data of this study showed that a high rate of gG-1 based immunoassays ranged from 87.9-100% for sensitivity and 51.5-100% specificity. Although there are several immunoassays were claimed to differentiate between HSV-1 and HSV-2 antibodies, selection of these assays should be carefully interpreted with the overall clinical framework provided by detailed sexual history and genital examination. (author)

  15. Development of a mass spectrometry immunoassay for unambiguous detection of egg allergen traces in wines.

    Science.gov (United States)

    Pilolli, Rosa; Chaudhari, Ravindra; Palmisano, Francesco; Monaci, Linda

    2017-02-01

    A mass spectrometry immunoassay (MSIA) specifically designed for the detection of egg allergens in wines is described. MSIA is based on an immunoaffinity enrichment procedure combined with targeted MS/MS detection of selected egg peptide markers. Polyclonal antibodies raised against native ovalbumin, chosen as the target protein tracing for egg powder, were immobilized onto low backpressure monolithic MSIA customized disposable tips. Ovalbumin-free wine samples were fortified with standard protein at different concentrations in the low microgram-per-milliliter range. A simple protocol was devised consisting of a 1:4 dilution of the wine sample with a basic solution for pH adjustment, followed by a semi-automated purification/enrichment step on MSIA customized disposable tips fitted on a multichannel electronic pipette. Among the main figures of merit, LOD and LOQ values as low as 0.01 and 0.03 μg/mL, respectively, and within-day precision of 18% should be noticed. Noteworthy, the developed assay outperformed current MS-based methods for the detection of allergenic protein in wine matrices, thanks to the immunoaffinity enrichment. In addition, compared to other immunoassays, the present approach boasts the unquestionable advantage of providing an unambiguous identification of the target protein by simultaneous detection of three unique peptide markers each giving three specific MS/MS transitions.

  16. Enzyme immunoassay

    DEFF Research Database (Denmark)

    Feldt-Rasmussen, B; Dinesen, B; Deckert, M

    1985-01-01

    variation of the 24 h urine albumin excretion of different days was high in patients with incipient diabetic nephropathy (51.5%) and was only slightly reduced by taking the variation of creatinine excretion into account (39.5%). No correlation was found between albumin excretion, and HbA1c or urine glucose...

  17. Immunoassay technique

    International Nuclear Information System (INIS)

    Goodearl, P.D.

    1981-01-01

    For quantitatively assaying antigen in a fluid, a mixture thereof with further antigen, labelled for example by substitution or addition of a radioactive molecule is caused to flow along a paper wick or other carrier on which antibodies to the antigen have been immobilised, e.g. by activating the paper by application of cyanogen bromide, then bringing it into contact with a solution of the antibodies. The paper wick or other carrier is developed by causing a glycerol/water solution to rise through the wick by capillary action, and there is measured the distance travelled along the wick by the labelled antigen. (author)

  18. Correlation of antinuclear antibody immunofluorescence patterns with immune profile using line immunoassay in the Indian scenario

    Directory of Open Access Journals (Sweden)

    Sebastian Wendy

    2010-07-01

    Full Text Available Background: Immunity status, individual response to disease and types of antibodies produced are well known to vary from person to person, place to place and probably from population to population. A broad spectrum of specific auto antibodies that have so far been associated with specific rheumatic diseases, as noted in Western literature, has been well taken as a reference standard all over the world. There is neither research work nor any data correlating the auto antibodies and their antinuclear antibody (ANA patterns with the immunoprofile in the Indian population to date. Aims: To understand a definite association between ANA patterns and specific antibodies in the serum in the Indian study population and to document similarities / differences with the West. Settings and Design: This prospective and retrospective double blind study was undertaken on the South Indian population referred for ANA testing by Indirect Immunofluorescence method and by immunoline methods. Materials and Methods: Serum samples of patients from a random South Indian population who sought medical help for rheumatic disease were subjected for ANA testing by indirect immunofluorescence (IIF method and line immunoassay during the study period of 27 months. Serum samples were processed in dilution of 1:100 using HEp - 2010 / liver biochip (Monkey (EUROIMMUN AG. The serum samples which were further processed for line immunoassay were treated in 1:100 dilution on nylon strips coated with recombinant and purified antigens as discrete lines with plastic backing (EUROIMMUN AG coated with antigens nRNP / Sm, Sm, SSA, Ro-52, SSB, Scl-70, PM-Scl, PCNA, Jo-1, CENP-B, dsDNA, nucleosomes, histones, ribosomal protein-P, anti-mitochondrial antibodies (AMA-M2 along with a control band. The analysis was done by comparing the intensity of the reaction with positive control line by image analysis. Results: The antinuclear antibody indirect immunofluorescence (ANA - IIF patterns obtained

  19. Overview of LOFT instrumentation

    International Nuclear Information System (INIS)

    Bixby, W.W.

    1979-01-01

    A description of instrumentation used in the Loss-of-Fluid Test (LOFT) large break Loss-of-Coolant Experiments is presented. Emphasis is placed on hydraulic and thermal measurements in the primary system piping and components, reactor vessel, and pressure suppression system. In addition, instrumentation which is being considered for measurement of phenomena during future small break testing is discussed

  20. Help in the Choice of Automated or Semiautomated Immunoassays for Serological Diagnosis of Toxoplasmosis: Evaluation of Nine Immunoassays by the French National Reference Center for Toxoplasmosis.

    Science.gov (United States)

    Villard, O; Cimon, B; L'Ollivier, C; Fricker-Hidalgo, H; Godineau, N; Houze, S; Paris, L; Pelloux, H; Villena, I; Candolfi, E

    2016-12-01

    Toxoplasmosis, a benign infection, is asymptomatic or paucisymptomatic in over 80% of cases, except in immunocompetent patients suffering from ocular toxoplasmosis or in immunocompromised patients with opportunistic or congenital toxoplasmosis. Diagnosis is based mainly on serology testing. Thus, we compared the performance of the nine most commonly used commercial automated or semiautomated immunoassays for IgG and IgM Toxoplasma gondii antibody detection, that is, the Advia Centaur, Architect, AxSYM, Elecsys, Enzygnost, Liaison, Platelia, VIDAS, and VIDIA assays. The assays were conducted on four panels of serum samples derived during routine testing from patients with an interfering disease and who exhibited a low IgG antibody level in one of two clinical settings, namely, acute or chronic toxoplasmosis. As a result, IgG sensitivities ranged from 97.1% to 100%, and IgG specificities ranged from 99.5% to 100%. For IgG quantification, strong differences in IgG titers (expressed in IU/ml) were noted depending on the assay used. IgM sensitivities ranged from 65% to 97.9%, and IgM specificities ranged from 92.6% to 100%. For defining the best serological strategies to be implemented, it appears crucial to compare the diagnostic performance of the different tests with respect to their specificity and sensitivity in detecting the presence of IgG and IgM antibodies. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  1. An accurate, specific, sensitive, high-throughput method based on a microsphere immunoassay for multiplex detection of three viruses and bacterial fruit blotch bacterium in cucurbits.

    Science.gov (United States)

    Charlermroj, Ratthaphol; Makornwattana, Manlika; Himananto, Orawan; Seepiban, Channarong; Phuengwas, Sudtida; Warin, Nuchnard; Gajanandana, Oraprapai; Karoonuthaisiri, Nitsara

    2017-09-01

    To employ a microsphere immunoassay (MIA) to simultaneously detect multiple plant pathogens (potyviruses, Watermelon silver mottle virus, Melon yellow spot virus, and Acidovorax avenae subsp. citrulli) in actual plant samples, several factors need to be optimized and rigorously validated. Here, a simple extraction method using a single extraction buffer was successfully selected to detect the four pathogens in various cucurbit samples (cucumber, cantaloupe, melon, and watermelon). The extraction method and assay performance were validated with inoculated and field cucurbit samples. The MIA showed 98-99% relative accuracy, 97-100% relative specificity and 92-100% relative sensitivity when compared to commercial ELISA kits and reverse transcription PCR. In addition, the MIA was also able to accurately detect multiple-infected field samples. The results demonstrate that one common extraction method for all tested cucurbit samples could be applied to detect multiple pathogens; avoiding the need for multiple protocols to be employed. This multiplex method can therefore be instrumental for high-throughput screening of multiple plant pathogens with many advantages such as a shorter assay time (2.5h) with single assay format, a lower cost of detection ($5 vs $19.7 for 4 pathogens/sample) and less labor requirement. Its multiplex capacity can also be expanded to detect up to 50 different pathogens upon the availability of specific antibodies. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Instrumentation reference book

    CERN Document Server

    Boyes, Walt

    2002-01-01

    Instrumentation is not a clearly defined subject, having a 'fuzzy' boundary with a number of other disciplines. Often categorized as either 'techniques' or 'applications' this book addresses the various applications that may be needed with reference to the practical techniques that are available for the instrumentation or measurement of a specific physical quantity or quality. This makes it of direct interest to anyone working in the process, control and instrumentation fields where these measurements are essential.* Comprehensive and authoritative collection of technical information* Writte

  3. The latest radiation instrument

    International Nuclear Information System (INIS)

    Kang, Se Sik; Gwon, Dal Gwan; Kim, Gyeong Geum

    2008-08-01

    This book deals with the latest radiation instrument, which is comprised of eight chapters. It explains X rays instrument for medial treatment, X-ray tube instrument and permissible burden with its history, structure and characteristic high voltage apparatus with high voltage rectifier circuit, X-ray control apparatus for medical treatment, X-ray image equipment X-ray television apparatus and CCD 205, X-ray apparatus of install and types, Digital X-ray apparatus with CR 261 and DR 269, performance management on X-ray for medical treatment with its history, necessity and management in the radiation field.

  4. Soil monitoring instrumentation

    International Nuclear Information System (INIS)

    Umbarger, C.J.

    1980-01-01

    The Los Alamos Scientific Laboratory (LASL) has an extensive program for the development of nondestructive assay instrumentation for the quantitative analysis of transuranic (TRU) materials found in bulk solid wastes generated by Department of Energy facilities and by the commercial nuclear power industry. Included are wastes generated in decontamination and decommissioning of outdated nuclear facilities as well as wastes from old waste burial ground exhumation programs. The assay instrumentation is designed to have detection limits below 10 nCi/g wherever practicable. Because of the topic of this workshop, only the assay instrumentation applied specifically to soil monitoring will be discussed here. Four types of soil monitors are described

  5. Soil monitoring instrumentation

    International Nuclear Information System (INIS)

    Umbarger, C.J.

    1981-01-01

    The Los Alamos Scientific Laboratory (LASL) has an extensive program for the development of nondestructive assay instrumentation for the quantitative analysis of transuranic (TRU) materials found in bulk solid wastes generated by Department of Energy facilities and by the commercial nuclear power industry. Included are wastes generated in decontamination and decommissioning of outdated nuclear facilities, as well as from old waste-burial-ground exhumation programs. The assay instrumentation is designed to have detection limits below 10 nCi/g wherever practicable. The assay instrumentation that is applied specifically to soil monitoring is discussed

  6. Jones' instrument technology

    CERN Document Server

    Jones, Ernest Beachcroft; Kingham, Edward G; Radnai, Rudolf

    1985-01-01

    Jones' Instrument Technology, Volume 5: Automatic Instruments and Measuring Systems deals with general trends in automatic instruments and measuring systems. Specific examples are provided to illustrate the principles of such devices. A brief review of a considerable number of standards is undertaken, with emphasis on the IEC625 Interface System. Other relevant standards are reviewed, including the interface and backplane bus standards. This volume is comprised of seven chapters and begins with a short introduction to the principles of automatic measurements, classification of measuring system

  7. Medical instruments in museums

    DEFF Research Database (Denmark)

    Söderqvist, Thomas; Arnold, Ken

    2011-01-01

    This essay proposes that our understanding of medical instruments might benefit from adding a more forthright concern with their immediate presence to the current historical focus on simply decoding their meanings and context. This approach is applied to the intriguingly tricky question of what...... actually is meant by a "medical instrument." It is suggested that a pragmatic part of the answer might lie simply in reconsidering the holdings of medical museums, where the significance of the physical actuality of instruments comes readily to hand....

  8. Nanobody-based electrochemical immunoassay for Bacillus thuringiensis Cry1Ab toxin by detecting the enzymatic formation of polyaniline

    International Nuclear Information System (INIS)

    Zhu, Min; Li, Guanghui; Li, Min; Zhou, Zikai; Liu, Hong; Lei, Hongtao; Shen, Yanfei; Wan, Yakun

    2015-01-01

    We describe an electrochemical immunoassay for the Cry1Ab toxin that is produced by Bacillus thuringiensis. It is making use of a nanobody (a heavy-chain only antibody) that was selected from an immune phage displayed library. A biotinylated primary nanobody and a HRP-conjugated secondary nanobody were applied in a sandwich immunoassay where horseradish peroxidase (HRP) is used to produce polyaniline (PANI) from aniline. PANI can be easily detected by differential pulse voltammetry at a working voltage as low as 40 mV (vs. Ag/AgCl) which makes the assay fairly selective. This immunoassay for Cry1Ab has an analytical range from 0.1 to 1000 ng∙mL -1 and a 0.07 ng∙mL -1 lower limit of detection. The average recoveries of the toxin from spiked samples are in the range from 102 to 114 %, with a relative standard deviation of <7.5 %. The results demonstrated that the assay represented an attractive alternative to existing immunoassays in enabling affordable, sensitive, robust and specific determination of this toxin. (author)

  9. Tuberculin purified protein derivative (PPD) immunoassay as an in vitro alternative assay for identity and confirmation of potency.

    Science.gov (United States)

    Ho, Mei M; Kairo, Satnam K; Corbel, Michael J

    2006-01-01

    Tuberculin purified protein derivative (PPD) currently can only be standardised by delayed hypersensitivity skin reactions in sensitised guinea pigs. An in vitro dot blot immunoassay was developed for both identity and confirmation of potency estimation of PPD. Polyclonal antibodies (mainly IgG) were generated and immunoreacted with human, bovine and, to lesser extent, avian PPD preparations. Combining size exclusion chromatography (FPLC-SEC) and dot blot immunoassay, the results showed that PPD preparations were mixtures of very heterogeneous tuberculoproteins ranging in size from very large aggregates to very small degraded molecules. All individual fractions of PPD separated by size were immunoreactive, although those of the largest molecular sizes appeared the most immunoreactive in this in vitro dot blot immunoassay. This method is very sensitive and specific to tuberculoproteins and can be an in vitro alternative for the in vivo intradermal skin assay which uses guinea pigs for identity of PPD preparations. Although the capacity of PPD to elicit cell-mediated immune responses on intradermal testing has to be confirmed by in vivo assay, the dot blot immunoassay offers a rapid, sensitive and animal-free alternative to in vivo testing for confirming the identity of PPD preparations with appropriate potencies. This alternative assay would be particularly useful for national regulatory laboratories for confirming the data of manufacturers and thus reducing the use of animals.

  10. Detection of hidden hazelnut protein in food by IgY-based indirect competitive enzyme-immunoassay

    NARCIS (Netherlands)

    Baumgartner, S.; Bremer, M.G.E.G.; Kemmers - Voncken, A.E.M.; Smits, N.G.E.; Haasnoot, W.; Banks, J.; Reece, P.; Danks, C.; Tomkies, V.; Immer, U.; Schmitt, K.; Krska, R.

    2004-01-01

    The development of an indirect competitive enzyme-immunoassay for the detection of hidden hazelnut protein in complex food matrices is described. A sensitive and selective polyclonal antibody was raised by immunisation of laying hens with protein extracts from roasted hazelnuts. In contrast to

  11. Plasmon enhanced fluoro-immunoassay using egg yolk antibodies for ultra-sensitive detection of herbicide diuron.

    Science.gov (United States)

    Sharma, Priyanka; Kukkar, Manil; Ganguli, Ashok K; Bhasin, Aman; Suri, C Raman

    2013-08-07

    Plasmon enhanced fluorescence immunoassay (PEFI) format has been reported in developing a sensitive heterogeneous fluoroimmunoassay for monitoring the phenylurea herbicide diuron. Computer-assisted molecular modeling was carried out to study the conformational and electrostatic effects of synthesized hapten for producing highly specific egg yolk antibody against a phenyl urea herbicide diuron. The generated antibodies were labeled with fluorescein isothiocyanate at different molar ratios and used as tracer in the developed fluorescence based immunoassay. The sensitivity of the assay format was enhanced by using silver nanoparticles tagged with bovine serum albumin as a new blocking reagent in the developed PEFI format. Enhancer treatment on the developed immunoassay showed a significant improvement of fluorescence signal intensity with approximately 10 fold increase in assay sensitivity. The immunoassay has a detection limit of 0.01 ng mL(-1) with good signal precision (~2%) in the optimum working concentration range between 1 pg mL(-1) to 10 μg mL(-1) of diuron. These findings facilitate high throughput fluorescence-based processes that could be useful in biology, drug discovery and compound screening applications.

  12. Evaluation of a fluorescence polarographic immunoassay with increased sensitivity for measurement of low concentrations of tobramycin in serum

    NARCIS (Netherlands)

    Touw, D J; de Graaf, A I; de Goede, P

    The limits of quantitation of the assay of tobramycin in serum by the fluorescence polarization immunoassay system marketed by Abbott Laboratories (TDxFLx system) are 0.1 and 10.0 mg/L. For some pharmacokinetic studies, however, a more sensitive analysis is needed. The sensitivity of the TDxFLx

  13. Development of a nucleic acid lateral flow immunoassay for simultaneous detection of Listeria spp. and Listeriamonocytogenes in food

    NARCIS (Netherlands)

    Blazkova, M.; Koets, M.; Rauch, P.; Amerongen, van A.

    2009-01-01

    We present a new nucleic acid lateral flow immunoassay (NALFIA) for the assessment of listeria contamination. The detection procedure starts with enrichment of sample in Half Fraser broth (24 h). Following isolation of DNA, a duplex PCR is performed with two labelled primer sets, one generic and

  14. Fabrication and characterization of tosyl-activated magnetic and nonmagnetic monodisperse microspheres for use in microfluic-based ferritin immunoassay

    Czech Academy of Sciences Publication Activity Database

    Reymond, F.; Vollet, Ch.; Plichta, Zdeněk; Horák, Daniel

    2013-01-01

    Roč. 29, č. 2 (2013), s. 532-542 ISSN 8756-7938 R&D Projects: GA MŠk 7E12053; GA ČR GAP503/10/0664 EU Projects: European Commission(XE) 246513 - NADINE Institutional support: RVO:61389013 Keywords : biosensors * electrochemistry * immunoassays Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.883, year: 2013

  15. Strip-based immunoassay for the simultaneous detection of the neonicotinoid insecticides imidacloprid and thiamethoxam in agricultural products

    Science.gov (United States)

    A semiquantitative strip immunoassay was developed for the rapid detection of imidacloprid and thiamethoxam in agricultural products using specific nanocolloidal gold-labeled monoclonal antibodies. The conjugates of imidacloprid-BSA and thiamethoxam-BSA and goat anti-mouse IgG were coated on the ni...

  16. Evaluation of two automated enzyme-immunoassays for detection of thermophilic campylobacters in faecal samples from cattle and swine

    DEFF Research Database (Denmark)

    Hoorfar, Jeffrey; Nielsen, E.M.; Stryhn, H.

    1999-01-01

    We evaluated the performance of two enzyme-immunoassays (EIA) for the detection of naturally occurring, thermophilic Campylobacter spp. found in faecal samples from cattle (n = 21 and n = 26) and swine (n = 43) relative to the standard culture method, and also assuming that none of the tests...

  17. Quantification of patient specific assay interference in different formats of enzyme linked immunoassays for therapeutic monoclonal antibodies

    NARCIS (Netherlands)

    Grebenchtchikov, N.J.; Geurts-Moespot, A.; Heijmen, L.; Laarhoven, H.W.M. van; Herpen, C.M.L. van; Thijs, A.M.J.; Span, P.N.; Sweep, F.C.

    2014-01-01

    BackgroundThe use of therapeutic monoclonal antibodies for clinical purposes has significantly increased in recent years, and so has the need to monitor antibody concentrations. This may be achieved using the well-established enzyme linked immunoassay (ELISA) methods; however, these assays are

  18. Quantification of patient-specific assay interference in different formats of enzyme-linked immunoassays for therapeutic monoclonal antibodies

    NARCIS (Netherlands)

    Grebenchtchikov, Nicolai; Geurts-Moespot, Anneke J.; Heijmen, Linda; van Laarhoven, Hanneke W. M.; van Herpen, Carla M. L.; Thijs, Annemarie M. J.; Span, Paul N.; Sweep, Fred C. G. J.

    2014-01-01

    The use of therapeutic monoclonal antibodies for clinical purposes has significantly increased in recent years, and so has the need to monitor antibody concentrations. This may be achieved using the well-established enzyme linked immunoassay (ELISA) methods; however, these assays are subject to a

  19. Development of a Nanobody-Based Lateral Flow Immunoassay for Detection of Human Norovirus.

    Science.gov (United States)

    Doerflinger, Sylvie Y; Tabatabai, Julia; Schnitzler, Paul; Farah, Carlo; Rameil, Steffen; Sander, Peter; Koromyslova, Anna; Hansman, Grant S

    2016-01-01

    Human noroviruses are the dominant cause of outbreaks of acute gastroenteritis. These viruses are usually detected by molecular methods, including reverse transcriptase PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Human noroviruses are genetically and antigenically diverse, with two main genogroups that are further subdivided into over 40 different genotypes. During the past decade, genogroup 2 genotype 4 (GII.4) has dominated in most countries, but recently, viruses belonging to GII.17 have increased in prevalence in a number of countries. A number of commercially available ELISAs and lateral flow immunoassays were found to have lower sensitivities to the GII.17 viruses, indicating that the antibodies used in these methods may not have a high level of cross-reactivity. In this study, we developed a rapid Nanobody-based lateral flow immunoassay (Nano-immunochromatography [Nano-IC]) for the detection of human norovirus in clinical specimens. The Nano-IC assay detected virions from two GII.4 norovirus clusters, which included the current dominant strain and a novel variant strain. The Nano-IC method had a sensitivity of 80% and specificity of 86% for outbreak specimens. Norovirus virus-like particles (VLPs) representing four genotypes (GII.4, GII.10, GII.12, and GII.17) could be detected by this method, demonstrating the potential in clinical screening. However, further modifications to the Nano-IC method are needed in order to improve this sensitivity, which may be achieved by the addition of other broadly reactive Nanobodies to the system. IMPORTANCE We previously identified a Nanobody (termed Nano-85) that bound to a highly conserved region on the norovirus capsid. In this study, the Nanobody was biotinylated and gold conjugated for a lateral flow immunoassay (termed Nano-IC). We showed that the Nano-IC assay was capable of detecting at least four antigenically distinct GII genotypes, including the newly emerging GII.17. In the clinical setting, the

  20. Rapid and Highly Sensitive Non-Competitive Immunoassay for Specific Detection of Nodularin

    Directory of Open Access Journals (Sweden)

    Sultana Akter

    2017-09-01

    Full Text Available Nodularin (NOD is a cyclic penta-peptide hepatotoxin mainly produced by Nodularia spumigena, reported from the brackish water bodies of various parts of the world. It can accumulate in the food chain and, for safety reasons, levels of NOD not only in water bodies but also in food matrices are of interest. Here, we report on a non-competitive immunoassay for the specific detection of NOD. A phage display technique was utilized to interrogate a synthetic antibody phage library for binders recognizing NOD bound to an anti-ADDA (3-Amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4(E,6(E-dienoic acid monoclonal antibody (Mab. One of the obtained immunocomplex binders, designated SA32C11, showed very high specificity towards nodularin-R (NOD-R over to the tested 10 different microcystins (microcystin-LR, -dmLR, -RR, -dmRR, -YR, -LY, -LF, -LW, -LA, -WR. It was expressed in Escherichia coli as a single chain antibody fragment (scFv fusion protein and used to establish a time-resolved fluorometry-based assay in combination with the anti-ADDA Mab. The detection limit (blank + 3SD of the immunoassay, with a total assay time of 1 h 10 min, is 0.03 µg/L of NOD-R. This represents the most sensitive immunoassay method for the specific detection of NOD reported so far. The assay was tested for its performance to detect NOD using spiked (0.1 to 3 µg/L of NOD-R water samples including brackish sea and coastal water and the recovery ranged from 79 to 127%. Furthermore, a panel of environmental samples, including water from different sources, fish and other marine tissue specimens, were analyzed for NOD using the assay. The assay has potential as a rapid screening tool for the analysis of a large number of water samples for the presence of NOD. It can also find applications in the analysis of the bioaccumulation of NOD in marine organisms and in the food chain.

  1. Sequential injection chemiluminescence immunoassay for nonionic surfactants by using magnetic microbeads

    International Nuclear Information System (INIS)

    Zhang Ruiq; Nakajima, Hizuru; Soh, Nobuaki; Nakano, Koji; Masadome, Takashi; Nagata, Kazumi; Sakamoto, Kazuhira; Imato, Toshihiko

    2007-01-01

    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

  2. Environment for the instruments

    International Nuclear Information System (INIS)

    Ambro, P.

    1992-01-01

    A properly conditioned AC power supply is necessary for reliable functioning of instruments. Electric mains power is produced primarily for industry, workshops, lighting and household uses. Its quality is adjusted to these uses. In areas sand countries with a fast growing demand for electric power, these requirements are far from being met. Electronic instruments and computers, especially in these countries, need protection against disturbances of the mains supply. A clean and dry environment is needed for reliable functioning and long life of instruments. High humidity, specially at higher temperatures, changes the characteristics of electronic components. Moreover, under these conditions fungal growth causes leakage of currents and corrosion causes poor contacts. The presence of dust enhances these effects. They give rise to malfunction of instruments, particularly of high voltage equipment

  3. CCAT Heterodyne Instrument Development

    Data.gov (United States)

    National Aeronautics and Space Administration — This work will extend and proof-out the design concept for a high pixel count (128 pixels in 2 bands) submillimeter-wave heterodyne receiver array instrument for the...

  4. Environment for the instruments

    Energy Technology Data Exchange (ETDEWEB)

    Ambro, P

    1993-12-31

    A properly conditioned AC power supply is necessary for reliable functioning of instruments. Electric mains power is produced primarily for industry, workshops, lighting and household uses. Its quality is adjusted to these uses. In areas sand countries with a fast growing demand for electric power, these requirements are far from being met. Electronic instruments and computers, especially in these countries, need protection against disturbances of the mains supply. A clean and dry environment is needed for reliable functioning and long life of instruments. High humidity, specially at higher temperatures, changes the characteristics of electronic components. Moreover, under these conditions fungal growth causes leakage of currents and corrosion causes poor contacts. The presence of dust enhances these effects. They give rise to malfunction of instruments, particularly of high voltage equipment

  5. Fiber Optics Instrumentation Development

    Science.gov (United States)

    Chan, Patrick Hon Man; Parker, Allen R., Jr.; Richards, W. Lance

    2010-01-01

    This is a general presentation of fiber optics instrumentation development work being conducted at NASA Dryden for the past 10 years and recent achievements in the field of fiber optics strain sensors.

  6. Nuclear instrument technician training

    International Nuclear Information System (INIS)

    Wollesen, E.S.

    1991-01-01

    This paper reports on Nuclear Instrument Technician (NIT) training that has developed at an accelerated rate over the past three decades. During the 1960's commercial nuclear power plants were in their infancy. For that reason, there is little wonder that NIT training had little structure and little creditability. NIT training, in many early plants, was little more than On-The Job Training (OJT). The seventies brought changes in Instrumentation and Controls as well as emphasis on the requirements for more in depth training and documentation. As in the seventies, the eighties saw not only changes in technologies but tighter requirements, standardized training and the development of accredited Nuclear Instrument Training; thus the conclusion: Nuclear Instrument Training Isn't What It Used To Be

  7. Carbon Footprint Reduction Instruments

    Science.gov (United States)

    This page outlines the major differences between Renewable Energy Certificates (REC) and Project Offsets and what types of claims each instrument allows the organization to make in regards to environmental emissions claims.

  8. Instrument care: everyone's responsibility

    Directory of Open Access Journals (Sweden)

    Renée du Toit

    2011-12-01

    Full Text Available Everyone working in an ophthalmic operating theatre must be competent in the care, handling, storage, and maintenance of instruments. This will help to improve surgical outcomes, maintain an economic and affordable service for patients, and provide a safe environment for the wellbeing of patients and staff.Including instrument care in theatre courses and in-service training is one way of ensuring staff competence.

  9. Instrument uncertainty predictions

    International Nuclear Information System (INIS)

    Coutts, D.A.

    1991-07-01

    The accuracy of measurements and correlations should normally be provided for most experimental activities. The uncertainty is a measure of the accuracy of a stated value or equation. The uncertainty term reflects a combination of instrument errors, modeling limitations, and phenomena understanding deficiencies. This report provides several methodologies to estimate an instrument's uncertainty when used in experimental work. Methods are shown to predict both the pretest and post-test uncertainty

  10. Experimenting with woodwind instruments

    Science.gov (United States)

    Lo Presto, Michael C.

    2007-05-01

    Simple experiments involving musical instruments of the woodwind family can be used to demonstrate the basic physics of vibrating air columns in resonance tubes using nothing more than straightforward measurements and data collection hardware and software. More involved experimentation with the same equipment can provide insight into the effects of holes in the tubing and other factors that make simple tubes useful as musical instruments.

  11. Maintenance of scientific instruments

    International Nuclear Information System (INIS)

    Lucero, E.

    1986-01-01

    During the last years Colombia has increased the use of nuclear techniques, instruments and equipment in ambitious health programs, as well as in research centers, industry and education; this has resulted in numerous maintenance problems. As an alternative solution IAN has established a Central Maintenance Laboratory for nuclear instruments within an International Atomic Energy Agency program for eight Latin American and nine Asian Countries. Established strategies and some results are detailed in this writing

  12. Parallel workflow for high-throughput (>1,000 samples/day quantitative analysis of human insulin-like growth factor 1 using mass spectrometric immunoassay.

    Directory of Open Access Journals (Sweden)

    Paul E Oran

    Full Text Available Insulin-like growth factor 1 (IGF1 is an important biomarker for the management of growth hormone disorders. Recently there has been rising interest in deploying mass spectrometric (MS methods of detection for measuring IGF1. However, widespread clinical adoption of any MS-based IGF1 assay will require increased throughput and speed to justify the costs of analyses, and robust industrial platforms that are reproducible across laboratories. Presented here is an MS-based quantitative IGF1 assay with performance rating of >1,000 samples/day, and a capability of quantifying IGF1 point mutations and posttranslational modifications. The throughput of the IGF1 mass spectrometric immunoassay (MSIA benefited from a simplified sample preparation step, IGF1 immunocapture in a tip format, and high-throughput MALDI-TOF MS analysis. The Limit of Detection and Limit of Quantification of the resulting assay were 1.5 μg/L and 5 μg/L, respectively, with intra- and inter-assay precision CVs of less than 10%, and good linearity and recovery characteristics. The IGF1 MSIA was benchmarked against commercially available IGF1 ELISA via Bland-Altman method comparison test, resulting in a slight positive bias of 16%. The IGF1 MSIA was employed in an optimized parallel workflow utilizing two pipetting robots and MALDI-TOF-MS instruments synced into one-hour phases of sample preparation, extraction and MSIA pipette tip elution, MS data collection, and data processing. Using this workflow, high-throughput IGF1 quantification of 1,054 human samples was achieved in approximately 9 hours. This rate of assaying is a significant improvement over existing MS-based IGF1 assays, and is on par with that of the enzyme-based immunoassays. Furthermore, a mutation was detected in ∼1% of the samples (SNP: rs17884626, creating an A→T substitution at position 67 of the IGF1, demonstrating the capability of IGF1 MSIA to detect point mutations and posttranslational modifications.

  13. Advanced optical instruments technology

    Science.gov (United States)

    Shao, Mike; Chrisp, Michael; Cheng, Li-Jen; Eng, Sverre; Glavich, Thomas; Goad, Larry; Jones, Bill; Kaarat, Philip; Nein, Max; Robinson, William

    1992-08-01

    The science objectives for proposed NASA missions for the next decades push the state of the art in sensitivity and spatial resolution over a wide range of wavelengths, including the x-ray to the submillimeter. While some of the proposed missions are larger and more sensitive versions of familiar concepts, such as the next generation space telescope, others use concepts, common on the Earth, but new to space, such as optical interferometry, in order to provide spatial resolutions impossible with other concepts. However, despite their architecture, the performance of all of the proposed missions depends critically on the back-end instruments that process the collected energy to produce scientifically interesting outputs. The Advanced Optical Instruments Technology panel was chartered with defining technology development plans that would best improve optical instrument performance for future astrophysics missions. At this workshop the optical instrument was defined as the set of optical components that reimage the light from the telescope onto the detectors to provide information about the spatial, spectral, and polarization properties of the light. This definition was used to distinguish the optical instrument technology issues from those associated with the telescope, which were covered by a separate panel. The panel identified several areas for optical component technology development: diffraction gratings; tunable filters; interferometric beam combiners; optical materials; and fiber optics. The panel also determined that stray light suppression instruments, such as coronagraphs and nulling interferometers, were in need of general development to support future astrophysics needs.

  14. Rapid Salmonella detection in experimentally inoculated equine faecal and veterinary hospital environmental samples using commercially available lateral flow immunoassays.

    Science.gov (United States)

    Burgess, B A; Noyes, N R; Bolte, D S; Hyatt, D R; van Metre, D C; Morley, P S

    2015-01-01

    Salmonella enterica is the most commonly reported cause of outbreaks of nosocomial infections in large animal veterinary teaching hospitals and the closure of equine hospitals. Rapid detection may facilitate effective control practices in equine populations. Shipping and laboratory testing typically require ≥48 h to obtain results. Lateral flow immunoassays developed for use in food-safety microbiology provide an alternative that has not been evaluated for use with faeces or environmental samples. We aimed to identify enrichment methods that would allow commercially available rapid Salmonella detection systems (lateral flow immunoassays) to be used in clinical practice with equine faecal and environmental samples, providing test results in 18-24 h. In vitro experiment. Equine faecal and environmental samples were inoculated with known quantities of S. enterica serotype Typhimurium and cultured using 2 different enrichment techniques for faeces and 4 enrichment techniques for environmental samples. Samples were tested blindly using 2 different lateral flow immunoassays and plated on agar media for confirmatory testing. In general, commercial lateral flow immunoassays resulted in fewer false-negative test results with enrichment of 1 g faecal samples in tetrathionate for 18 h, while all environmental sample enrichment techniques resulted in similar detection rates. The limit of detection from spiked samples, ∼4 colony-forming units/g, was similar for all methods evaluated. The lateral flow immunoassays evaluated could reliably detect S. enterica within 18 h, indicating that they may be useful for rapid point-of-care testing in equine practice applications. Additional evaluation is needed using samples from naturally infected cases and the environment to gain an accurate estimate of test sensitivity and specificity and to substantiate further the true value of these tests in clinical practice. © 2014 EVJ Ltd.

  15. Modification of a deoxynivalenol-antigen-mimicking nanobody to improve immunoassay sensitivity by site-saturation mutagenesis.

    Science.gov (United States)

    Qiu, Yu-Lou; He, Qing-Hua; Xu, Yang; Wang, Wei; Liu, Yuan-Yuan

    2016-01-01

    A nanobody (N-28) which can act as a deoxynivalenol (DON) antigen has been generated, and its residues Thr102-Ser106 were identified to bind with anti-DON monoclonal antibody by alanine-scanning mutagenesis. Site-saturation mutagenesis was used to analyze the plasticity of five residues and to improve the sensitivity of the N-28-based immunoassay. After mutagenesis, three mutants were selected by phage immunoassay and were sequenced. The half-maximal inhibitory concentrations of the immunoassay based on mutants N-28-T102Y, N-28-V103L, and N-28-Y105F were 24.49 ± 1.0, 51.83 ± 2.5, and 35.65 ± 1.6 ng/mL, respectively, showing the assay was, respectively, 3.2, 1.5, and 2.2 times more sensitive than the wild-type-based assay. The best mutant, N-28-T102Y, was used to develop a competitive phage ELISA to detect DON in cereals with high specificity and accuracy. In addition, the structural properties of N-28-T102Y and N-28 were investigated, revealing that the affinity of N-28-T102Y decreased because of increased steric hindrance with the large side chain. The lower-binding-affinity antigen mimetic may contribute to the improvement of the sensitivity of competitive immunoassays. These results demonstrate that nanobodies would be a favorable tool for engineering. Moreover, our results have laid a solid foundation for site-saturation mutagenesis of antigen-mimicking nanobodies to improve immunoassay sensitivity for small molecules.

  16. Comparison of infrared-excited up-converting phosphors and europium nanoparticles as labels in a two-site immunoassay

    International Nuclear Information System (INIS)

    Ukonaho, Telle; Rantanen, Terhi; Jaemsen, Laura; Kuningas, Katri; Paekkilae, Henna; Loevgren, Timo; Soukka, Tero

    2007-01-01

    Research in the field of immunoassays and labels used in the detection has been recently focused on particulate reporters, which possess very high specific activity that excludes the label as a sensitivity limiting factor. However, the large size and shape of the particulate labels may produce additional problems to immunoassay performance. The aim of this work was to study with two identical non-competitive two-site immunoassays whether up-converting phosphor (UCP) particles are comparable in performance with europium(III) chelate-dyed nanoparticles as particulate labels. In addition we strived to verify the common assumption of the photostability of up-converting phosphor particles supporting their potential applicability in imaging. Detection limits in two-site immunoassay for free prostate-specific antigen (free-PSA) were 0.53 ng L -1 and 1.3 ng L -1 using two different up-converting phosphors and 0.16 ng L -1 using europium(III) nanoparticle. Large size distribution and non-specific binding of up-converting phosphor particles caused assay variation in low analyte concentrations and limited the analytical detection limit. The non-specific binding was the major factor limiting the analytical sensitivity of the immunoassay. The results suggests the need for nanoscaled and uniformely sized UCP-particles to increace the sensitivity and applicability of up-converting phosphor particles. Anti-Stokes photoluminescence of up-converting phosphor particles did not photobleach when measured repeatedly, on the contrary, the time-resolved fluorescence of europium nanoparticles photobleached relatively rapidly

  17. Problems with radiological surveillance instrumentation

    International Nuclear Information System (INIS)

    Swinth, K.L.; Tanner, J.E.; Fleming, D.M.

    1984-09-01

    Many radiological surveillance instruments are in use at DOE facilities throughout the country. These instruments are an essential part of all health physics programs, and poor instrument performance can increase program costs or compromise program effectiveness. Generic data from simple tests on newly purchased instruments shows that many instruments will not meet requirements due to manufacturing defects. In other cases, lack of consideration of instrument use has resulted in poor acceptance of instruments and poor reliability. The performance of instruments is highly variable for electronic and mechanical performance, radiation response, susceptibility to interferences and response to environmental factors. Poor instrument performance in these areas can lead to errors or poor accuracy in measurements

  18. Problems with radiological surveillance instrumentation

    International Nuclear Information System (INIS)

    Swinth, K.L.; Tanner, J.E.; Fleming, D.M.

    1985-01-01

    Many radiological surveillance instruments are in use at DOE facilities throughout the country. These instruments are an essential part of all health physics programs, and poor instrument performance can increase program costs or compromise program effectiveness. Generic data from simple tests on newly purchased instruments shows that many instruments will not meet requirements due to manufacturing defects. In other cases, lack of consideration of instrument use has resulted in poor acceptance of instruments and poor reliability. The performance of instruments is highly variable for electronic and mechanical performance, radiation response, susceptibility to interferences and response to environmental factors. Poor instrument performance in these areas can lead to errors or poor accuracy in measurements

  19. Development of Fully Automated Low-Cost Immunoassay System for Research Applications.

    Science.gov (United States)

    Wang, Guochun; Das, Champak; Ledden, Bradley; Sun, Qian; Nguyen, Chien

    2017-10-01

    Enzyme-linked immunosorbent assay (ELISA) automation for routine operation in a small research environment would be very attractive. A portable fully automated low-cost immunoassay system was designed, developed, and evaluated with several protein analytes. It features disposable capillary columns as the reaction sites and uses real-time calibration for improved accuracy. It reduces the overall assay time to less than 75 min with the ability of easy adaptation of new testing targets. The running cost is extremely low due to the nature of automation, as well as reduced material requirements. Details about system configuration, components selection, disposable fabrication, system assembly, and operation are reported. The performance of the system was initially established with a rabbit immunoglobulin G (IgG) assay, and an example of assay adaptation with an interleukin 6 (IL6) assay is shown. This system is ideal for research use, but could work for broader testing applications with further optimization.

  20. Homogenous 96-plex PEA immunoassay exhibiting high sensitivity, specificity, and excellent scalability

    DEFF Research Database (Denmark)

    Assarsson, Erika; Lundberg, Martin; Holmquist, Göran

    2014-01-01

    reporters, shown potential to relieve the shortcomings of antibodies and their inherent cross-reactivity in multiplex protein quantification applications. The aim of the present study was to develop a robust 96-plex immunoassay based on the proximity extension assay (PEA) for improved high throughput...... detection of protein biomarkers. This was enabled by: (1) a modified design leading to a reduced number of pipetting steps compared to the existing PEA protocol, as well as improved intra-assay precision; (2) a new enzymatic system that uses a hyper-thermostabile enzyme, Pwo, for uniting the two probes......, such as serum and plasma, and also in xenografted mice and resuspended dried blood spots, consuming only 1 µL sample per test. All-in-all, the development of the current multiplex technique is a step toward robust high throughput protein marker discovery and research....

  1. Development of a highly sensitive and specific immunoassay for enrofloxacin based on heterologous coating haptens.

    Science.gov (United States)

    Wang, Zhanhui; Zhang, Huiyan; Ni, Hengjia; Zhang, Suxia; Shen, Jianzhong

    2014-04-11

    In the paper, an enzyme-linked immunosorbent immunoassay (ELISA) for detection of enrofloxacin was described using one new derivative of enrofloxacin as coating hapten, resulting in surprisingly high sensitivity and specificity. Incorporation of aminobutyric acid (AA) in the new derivative of enrofloxacin had decreased the IC50 of the ELISA for enrofloxacin from 1.3 μg L(-1) to as low as 0.07 μg L(-1). The assay showed neglect cross-reactivity for other fluoroquinolones but ofloxacin (8.23%), marbofloxacin (8.97%) and pefloxacin (7.29%). Analysis of enrofloxacin fortified chicken muscle showed average recoveries from 81 to 115%. The high sensitivity and specificity of the assay makes it a suitable screening method for the determination of low levels of enrofloxacin in chicken muscle without clean-up step. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Optimization of condition for conjugation of enrofloxacin to enzymes in chemiluminescence enzyme immunoassay

    Science.gov (United States)

    Yu, Songcheng; Yu, Fei; Zhang, Hongquan; Qu, Lingbo; Wu, Yongjun

    2014-06-01

    In this study, in order to find out a proper method for conjugation of enrofloxacin to label enzymes, two methods were compared and carbodiimide condensation was proved to be better. The results showed that the binding ratio of enrofloxacin and alkaline phosphatase (ALP) was 8:1 and that of enrofloxacin and horseradish peroxidase (HRP) was 5:1. This indicated that conjugate synthesized by carbodiimide condensation was fit for chemiluminescence enzyme immunoassay (CLEIA). Furthermore, data revealed that dialysis time was an important parameter for conjugation and 6 days was best. Buffer to dilute conjugate had little effect on CLEIA. The storage condition for conjugates was also studied and it was shown that the conjugate was stable at 4 °C with no additive up to 30 days. These data were valuable for establishing CLEIA to quantify enrofloxacin.

  3. Detection of Pesticides and Pesticide Metabolites Using the Cross Reactivity of Enzyme Immunoassays

    Science.gov (United States)

    Thurman, E.M.; Aga, D.S.

    2001-01-01

    Enzyme immunoassay is an important environmental analysis method that may be used to identify many pesticide analytes in water samples. Because of similarities in chemical structure between various members of a pesticide class, there often may be an unwanted response that is characterized by a percentage of cross reactivity. Also, there may be cross reactivity caused by degradation products of the target analyte that may be present in the sample. In this paper, the concept of cross reactivity caused by degradation products or by nontarget analytes is explored as a tool for identification of metabolites or structurally similar compounds not previously known to be present in water samples. Two examples are examined in this paper from various water quality studies. They are alachlor and its metabolite, alachlor ethane sulfonic acid, and atrazine and its class members, prometryn and propazine. A method for using cross reactivity for the detection of these compounds is explained in this paper.

  4. Vertical microreactor stack consist of poly-(tetrafluoroethylene) microfluidics for immunoassay

    International Nuclear Information System (INIS)

    Ukita, Yoshiaki; Kondo, Saki; Utsumi, Yuichi; Takeo, Masahiro; Negoro, Seiji; Kataoka, Chiwa

    2010-01-01

    This paper reports the first application of high-aspect ratio PTFE microstruscute, which fabricated by synchrotron radiation induced photo-evaporation process, to enzyme-linked immunosorvent assay. The advantages of PTFE microstructure for the development of lab-on-a-chip due to the extremely high-aspect ratio microstructure and chemical stability of PTFE is discussed. The results of immunoassay shows the successful detection of analyte (mouse IgG) with detection range with 0-100ng/ml. This result suggests the successful immobilization of antibody (anti-mouse IgG goat antibody) onto the x-ray exposed surface of PTFE microstructure and successful demonstration of antigen-antibody reaction in the PTFE high-aspect ratio microstructure. We also demonstrated the detection of polychlorinated biphenyl (PCB). As the result of demonstration, we successfully detected PCB with ranging analyte concentration of 0.1-10 ng/ml. (author)

  5. Rapid bead-based immunoassay for measurement of mannose-binding lectin

    DEFF Research Database (Denmark)

    Bay, J T; Garred, P

    2009-01-01

    have been developed more automated platforms for MBL analysis is urgently needed. To pursue this, we set out to develop a flexible bead-based MBL immunoassay. Serum was obtained from 98 healthy individuals and 50 patients investigated for possible immunodeficiencies. We used the Luminex xMAP bead array...... coefficient were found be 7.88% and 5.70%, respectively. A close correlation between the new assay and a reference MBL measurement ELISA was found (rho 0.9381, P bead-based assay was less sensitive to interfering anti-murine antibodies in the blood samples than when the antibodies employed were...... used in the reference polystyrene-based ELISA. The new assay could be performed in 3 h with less than 25 microl serum required of each sample. These results show that MBL can be measured readily using a bead-based platform, which may form an efficient basis for a multiplex approach to measure different...

  6. Mapping of Epitopes Occurring in Bovine α(s1)-Casein Variants by Peptide Microarray Immunoassay.

    Science.gov (United States)

    Lisson, Maria; Erhardt, Georg

    2016-01-01

    Immunoglobulin E epitope mapping of milk proteins reveals important information about their immunologic properties. Genetic variants of αS1-casein, one of the major allergens in bovine milk, are until now not considered when discussing the allergenic potential. Here we describe the complete procedure to assess the allergenicity of αS1-casein variants B and C, which are frequent in most breeds, starting from milk with identification and purification of casein variants by isoelectric focusing (IEF) and anion-exchange chromatography, followed by in vitro gastrointestinal digestion of the casein variants, identification of the resulting peptides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), in silico analysis of the variant-specific peptides as allergenic epitopes, and determination of their IgE-binding properties by microarray immunoassay with cow's milk allergic human sera.

  7. Time-Resolved Fluorescence Immunoassay for C-Reactive Protein Using Colloidal Semiconducting Nanoparticles

    Directory of Open Access Journals (Sweden)

    Pekka Hänninen

    2011-11-01

    Full Text Available Besides the typical short-lived fluorescence with decay times in the nanosecond range, colloidal II/VI semiconductor nanoparticles dispersed in buffer also possess a long-lived fluorescence component with decay times in the microsecond range. Here, the signal intensity of the long-lived luminescence at microsecond range is shown to increase 1,000-fold for CdTe nanoparticles in PBS buffer. This long-lived fluorescence can be conveniently employed for time-gated fluorescence detection, which allows for improved signal-to-noise ratio and thus the use of low concentrations of nanoparticles. The detection principle is demonstrated with a time-resolved fluorescence immunoassay for the detection of C-reactive protein (CRP using CdSe-ZnS nanoparticles and green light excitation.

  8. Synthesis-based approach toward direct sandwich immunoassay for ciguatoxin CTX3C.

    Science.gov (United States)

    Oguri, Hiroki; Hirama, Masahiro; Tsumuraya, Takeshi; Fujii, Ikuo; Maruyama, Megumi; Uehara, Hisatoshi; Nagumo, Yoko

    2003-06-25

    Ciguatoxins are the major causative toxins of ciguatera seafood poisoning. Limited availability of ciguatoxins has hampered the development of a reliable and specific immunoassay for detecting these toxins in contaminated fish. Monoclonal antibodies (mAbs) specific against both ends of ciguatoxin CTX3C were prepared by immunization of mice with protein conjugates of rationally designed synthetic haptens, 3 and 4, in place of the natural toxin. Haptenic groups that possess a surface area larger than 400 A(2) were required to produce mAbs that can bind strongly to CTX3C itself. A direct sandwich enzyme-linked immunosorbent assay (ELISA) using these mAbs was established to detect CTX3C at the ppb level with no cross-reactivity against other related marine toxins, including brevetoxin A, brevetoxin B, okadaic acid, or maitotoxin.

  9. Enzymatic amplification of a flow-injected thermometric enzyme-linked immunoassay for human insulin.

    Science.gov (United States)

    Mecklenburg, M; Lindbladh, C; Li, H; Mosbach, K; Danielsson, B

    1993-08-01

    A flow-injected thermometric enzyme linked immunoassay for human insulin which employs the lactate dehydrogenase/lactate oxidase (LDH/LOD) substrate recycling system for signal amplification is described. The system is composed of two columns, an immunosorbent column containing immobilized anti-insulin antibodies for sensing and a recycling column containing immobilized LDH/LOD/Catalase for detection. The effect of flow rates, conjugate concentrations, and chromatographic support material upon the sensitivity of the assay are investigated. The assay has a detection limit of 0.025 microgram/ml and a linear range from 0.05 to 2 micrograms/ml. This corresponds to a 10-fold increase in sensitivity over the unamplified system. A recombinant human insulin-proinsulin conjugate was also tested. The results show that enzymatic amplification can be employed to increase the sensitivity and reproducibility of flow injection assay-based biosensors. The implications of these results upon on-line analysis are discussed.

  10. Developments of sensitive immunoassays for detection of antibodies against hepatitis B surface antigen

    Energy Technology Data Exchange (ETDEWEB)

    Ionescu-Matiu, I; Sanchez, Y; Dreesman, G R [Baylor Univ., Houston, TX (USA). Coll. of Medicine; Fields, H A [Centers for Disease Control, Public Health Service, Department of Health and Human Services, Phoenix, AZ (USA)

    1983-01-01

    Three micro solid phase immunoassays (a micro-SPRIA and two ELISA techniques) were developed and tested for the detection of anti-HBs antibodies. Two different crosslinkers (glutaraldehyde and N-succinimidyl 3-(2-pyridyldithio) propionate) were used to couple a goat anti-mouse IgG reagent to alkaline phosphatase for use as enzyme-labeled probes in the two ELISA tests. With the latter cross-linker, a defined conjugate with a 1 : 1 antibody-enzyme molar ratio was obtained. The sensitivities of micro-SPRIA and the two types of ELISA were compared to that of the commercial solid phase radioimmunoassay AUSAB test. All three microtests were significantly more sensitive than the AUSAB test. The ELISA using the glutaraldehyde cross-linked conjugate was 3-5 times less sensitive than micro-SPRIA, while the ELISA using the disulfide-linked conjugate was 2.6-4.0 times more sensitive than micro-SPRIA.

  11. Specific T-cell epitopes for immunoassay-based diagnosis of Mycobacterium tuberculosis infection

    DEFF Research Database (Denmark)

    Brock, I; Weldingh, K; Leyten, EM

    2004-01-01

    Specific T-cell epitopes for immunoassay-based diagnosis of Mycobacterium tuberculosis infection.Brock I, Weldingh K, Leyten EM, Arend SM, Ravn P, Andersen P. Department of Infectious Disease Immunology, Statens Serum Institute, Artillerivej 5, DK-2300 Copenhagen S, Denmark. The currently used...... method for immunological detection of tuberculosis infection, the tuberculin skin test, has low specificity. Antigens specific for Mycobacterium tuberculosis to replace purified protein derivative are therefore urgently needed. We have performed a rigorous assessment of the diagnostic potential of four...... recently identified antigens (Rv2653, Rv2654, Rv3873, and Rv3878) from genomic regions that are lacking from the Mycobacterium bovis bacillus Calmette-Guerin (BCG) vaccine strains as well as from the most common nontuberculous mycobacteria. The fine specificity of potential epitopes in these molecules...

  12. Estrogen receptor determination in endometrial carcinoma: ligand binding assay versus enzyme immunoassay

    DEFF Research Database (Denmark)

    Nyholm, H C; Nielsen, Anette Lynge; Lyndrup, J

    1995-01-01

    We compared concentrations of cytosolic estrogen receptors (ERc) measured in 35 postmenopausal endometrial carcinomas by ligand binding method (LBA) (dextran-coated charcoal assay) and enzyme immunoassay (EIA). Correlations between ERc, nuclear estrogen receptors (ERn) determined by EIA......, and cytosolic progesterone receptors (PR) measured by LBA were also studied. While ERc concentrations determined by LBA and EIA were highly correlated (r: 0.94), ERc values detected by LBA were approximately twice those found by EIA (median values of ERc: 155 vs. 64 fmol/mg cytosol protein, DCC vs. EIA......). The percentages of ERc positive tumors were 89% by LBA and 77% by EIA. The median fraction of total ER present as ERn was 63%. PR levels correlated positively with ERn concentrations (r: 0.73). We explore possible reasons why greater concentrations of ERc are determined by estradiol binding than by the ER-EIA kit...

  13. Concordance Between Different Amyloid Immunoassays and Visual Amyloid Positron Emission Tomographic Assessment.

    Science.gov (United States)

    Janelidze, Shorena; Pannee, Josef; Mikulskis, Alvydas; Chiao, Ping; Zetterberg, Henrik; Blennow, Kaj; Hansson, Oskar

    2017-12-01

    Visual assessment of amyloid positron emission tomographic (PET) images has been approved by regulatory authorities for clinical use. Several immunoassays have been developed to measure β-amyloid (Aβ) 42 in cerebrospinal fluid (CSF). The agreement between CSF Aβ42 measures from different immunoassays and visual PET readings may influence the use of CSF biomarkers and/or amyloid PET assessment in clinical practice and trials. To determine the concordance between CSF Aβ42 levels measured using 5 different immunoassays and visual amyloid PET analysis. The study included 262 patients with mild cognitive impairment or subjective cognitive decline from the Swedish BioFINDER (Biomarkers for Identifying Neurodegenerative Disorders Early and Reliably) cohort (recruited from September 1, 2010, through December 31, 2014) who had undergone flutemetamol F 18 ([18F]flutemetamol)-labeled PET. Levels of CSF Aβ42 were analyzed using the classic INNOTEST and the newer modified INNOTEST, fully automated Lumipulse (FL), EUROIMMUN (EI), and Meso Scale Discovery (MSD) assays. Concentrations of CSF Aβ were assessed using an antibody-independent mass spectrometry-based reference measurement procedure. The concordance of CSF Aβ42 levels and Aβ42:Aβ40 and Aβ42:tau ratios with visual [18F]flutemetamol PET status. Of 262 participants (mean [SD] age, 70.9 [5.5] years), 108 were women (41.2%) and 154 were men (58.8%). The mass spectrometry-derived Aβ42 values showed higher correlations with the modified Aβ42-INNOTEST (r = 0.97), Aβ42-FL (r = 0.93), Aβ42-EI (r = 0.93), and Aβ42-MSD (r = 0.95) assays compared with the classic Aβ42-INNOTEST assay (r = 0.88; P ≤ .01). The signal in the classic Aβ42-INNOTEST assay was partly quenched by recombinant Aβ1-40 peptide. However, the classic Aβ42-INNOTEST assay showed better concordance with visual [18F]flutemetamol PET status (area under the receiver operating characteristic curve [AUC], 0.92) compared with the

  14. Specific T-cell epitopes for immunoassay-based diagnosis of Mycobacterium tuberculosis infection

    DEFF Research Database (Denmark)

    Brock, I; Weldingh, K; Leyten, EM

    2004-01-01

    Specific T-cell epitopes for immunoassay-based diagnosis of Mycobacterium tuberculosis infection.Brock I, Weldingh K, Leyten EM, Arend SM, Ravn P, Andersen P. Department of Infectious Disease Immunology, Statens Serum Institute, Artillerivej 5, DK-2300 Copenhagen S, Denmark. The currently used...... method for immunological detection of tuberculosis infection, the tuberculin skin test, has low specificity. Antigens specific for Mycobacterium tuberculosis to replace purified protein derivative are therefore urgently needed. We have performed a rigorous assessment of the diagnostic potential of four...... selected and combined the specific peptide stretches from the four proteins not recognized by M. bovis BCG-vaccinated individuals. These peptide stretches were tested with peripheral blood mononuclear cells obtained from patients with microscopy- or culture-confirmed tuberculosis and from healthy M. bovis...

  15. A Homogeneous Time-Resolved Fluorescence Immunoassay Method for the Measurement of Compound W.

    Science.gov (United States)

    Huang, Biao; Yu, Huixin; Bao, Jiandong; Zhang, Manda; Green, William L; Wu, Sing-Yung

    2018-01-01

    Using compound W (a 3,3'-diiodothyronine sulfate [T 2 S] immuno-crossreactive material)-specific polyclonal antibodies and homogeneous time-resolved fluorescence immunoassay assay techniques (AlphaLISA) to establish an indirect competitive compound W (ICW) quantitative detection method. Photosensitive particles (donor beads) coated with compound W or T 2 S and rabbit anti-W antibody were incubated with biotinylated goat anti-rabbit antibody. This constitutes a detection system with streptavidin-coated acceptor particle. We have optimized the test conditions and evaluated the detection performance. The sensitivity of the method was 5 pg/mL, and the detection range was 5 to 10 000 pg/mL. The intra-assay coefficient of variation averages W levels in extracts of maternal serum samples. This may have clinical application to screen congenital hypothyroidism in utero.

  16. A reactor/separator device for use in automated solid phase immunoassay

    International Nuclear Information System (INIS)

    Farina, P.R.; Ordonez, K.P.; Siewers, I.J.

    1979-01-01

    A reactor/separator device is described for use in automated solid phase immunoassay, including radioimmunoassays. The device is a column fitted at the bottom portion with a water impermeable disc which can hold, for example, immunoabsorbents, immobilized antisera or ion exchange resins. When the contents of the column supported by the disc are brought into contact with an aqueous phase containing reagents or reactants, a chemical reaction is initiated. After the reaction, centrifugally applied pressure forces the aqueous phase through the filter disc making it water permeable and separating a desired component for subsequent analysis. The reactor/separator device of the present invention permits kinetic solid phase assays (non-equilibrium conditions) to be carried out which would be difficult to perform by other conventional methods. (author)

  17. Analytical validation of Gentian NGAL particle-enhanced enhanced turbidimetric immunoassay (PETIA

    Directory of Open Access Journals (Sweden)

    Gian Luca Salvagno

    2017-08-01

    Full Text Available Objectives: This study was designed to validate the analytical performance of the new Gentian particle-enhanced enhanced turbidimetric immunoassay (PETIA for measuring neutrophil gelatinase-associated lipocalin (NGAL in serum samples. Design and methods: Analytical validation of the Gentian NGAL assay was carried out on a Roche Cobas c501 and was based on assessment of limit of blank (LOB, limit of detection (LOD, functional sensitivity, imprecision, linearity and concordance with the BioPorto NGAL test. Results: The LOB and LOD of Gentian NGAL were found to be 3.8 ng/mL and 6.3 ng/mL, respectively. An analytical coefficient of variation (CV of 20% corresponded to a NGAL value of 10 ng/mL. The intra-assay and inter-assay imprecision (CV was between 0.4 and 5.2% and 0.6 and 7.1% and the total imprecision (CV was 3.7%. The linearity was optimal at NGAL concentrations between 37 and 1420 ng/mL (r=1.00; p<0.001. An excellent correlation was observed between values measured with Gentian NGAL and BioPorto NGAL in 74 routine serum samples (r=0.993. The mean percentage bias of the Gentian assay versus the Bioporto assay was +3.1% (95% CI, +1.6% to +4.5%. Conclusions: These results show that Gentian NGAL may be a viable option to other commercial immunoassays for both routine and urgent assessment of serum NGAL. Keywords: Neutrophil gelatinase-associated lipocalin, NGAL, Analytical validation, Acute kidney injury

  18. Development and statistical assessment of a paper-based immunoassay for detection of tumor markers

    Energy Technology Data Exchange (ETDEWEB)

    Mazzu-Nascimento, Thiago [Instituto de Química de São Carlos, Universidade de São Paulo, 13566-590, São Carlos, SP (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas, SP (Brazil); Morbioli, Giorgio Gianini [Instituto de Química de São Carlos, Universidade de São Paulo, 13566-590, São Carlos, SP (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas, SP (Brazil); School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Milan, Luis Aparecido [Departamento de Estatística, Universidade Federal de São Carlos, São Carlos, SP (Brazil); Donofrio, Fabiana Cristina [Instituto de Ciências da Saúde, Universidade Federal de Mato Grosso, 78557-267, Sinop, MT (Brazil); Mestriner, Carlos Alberto [Wama Produtos para Laboratório Ltda, 13560-971, São Carlos, SP (Brazil); Carrilho, Emanuel, E-mail: emanuel@iqsc.usp.br [Instituto de Química de São Carlos, Universidade de São Paulo, 13566-590, São Carlos, SP (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas, SP (Brazil)

    2017-01-15

    Paper-based assays are an attractive low-cost option for clinical chemistry testing, due to characteristics such as short time of analysis, low consumption of samples and reagents, and high portability of assays. However, little attention has been given to the evaluation of the performance of these simple tests, which should include the use of a statistical approach to define the choice of best cut-off value for the test. The choice of the cut-off value impacts on the sensitivity and specificity of the bioassay. Here, we developed a paper-based immunoassay for the detection of the carcinoembryonic antigen (CEA) and performed a statistical assessment to establish the assay's cut-off value using the Youden's J index (68.28 A.U.), what allowed for a gain in sensibility (0.86) and specificity (1.0). We also discuss about the importance of defining a gray zone as a safety margin for test (±12% over the cut-off value), eliminating all false positives and false negatives outcomes and avoiding misleading results. The test accuracy was calculated as the area under the curve (AUC) of the receiver operating characteristic (ROC) curve, presenting a value of 0.97, what classifies this test as highly accurate. We propose here a low-cost method capable of detecting carcinoembryonic antigen (CEA) in human serum samples, highlighting the importance of statistical tools to evaluate a new low-cost diagnostic method. - Highlights: • A paper-based sandwich immunoassay protocol for detection of tumor markers. • A statistical approach to define cut-off values and measuring test's sensitivity, specificity and accuracy. • A simple way to create a gray zone, avoiding false positive and false negative outcomes.

  19. System-on-fluidics immunoassay device integrating wireless radio-frequency-identification sensor chips.

    Science.gov (United States)

    Yazawa, Yoshiaki; Oonishi, Tadashi; Watanabe, Kazuki; Shiratori, Akiko; Funaoka, Sohei; Fukushima, Masao

    2014-09-01

    A simple and sensitive point-of-care-test (POCT) device for chemiluminescence (CL) immunoassay was devised and tested. The device consists of a plastic flow-channel reactor and two wireless-communication sensor chips, namely, a photo-sensor chip and a temperature-sensor chip. In the flow-channel reactor, a target antigen is captured by an antibody immobilized on the inner wall of the flow-channel and detected with enzyme labeled antibody by using CL substrate. The CL signal corresponding to the amount of antigen is measured by a newly developed radio-frequency-identification (RFID) sensor, which enables batteryless operation and wireless data communication with an external reader. As for the POCT device, its usage environment, especially temperature, varies for each measurement. Hence, temperature compensation is a key issue in regard to eliminating dark-signal fluctuation, which is a major factor in deterioration of the precision of the POCT device. A two-stage temperature-compensation scheme was adopted. As for the first stage, the signals of two photodiodes, one with an open window and one with a sealed window, integrated on the photo-sensor chip are differentiated to delete the dark signal. As for the second stage, the differentiated signal fluctuation caused by a temperature variation is compensated by using the other sensor chip (equipped with a temperature sensor). The dark-level fluctuation caused by temperature was reduced from 0.24 to 0.02 pA/°C. The POCT device was evaluated as a CL immunoassay of thyroid-stimulating hormone (TSH). The flow rate of the CL reagent in the flow channel was optimized. As a result, the detection limit of the POCT device was 0.08 ng/ml (i.e., 0.4 μIU/ml). Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  20. A Nanoparticle-Lectin Immunoassay Improves Discrimination of Serum CA125 from Malignant and Benign Sources.

    Science.gov (United States)

    Gidwani, Kamlesh; Huhtinen, Kaisa; Kekki, Henna; van Vliet, Sandra; Hynninen, Johanna; Koivuviita, Niina; Perheentupa, Antti; Poutanen, Matti; Auranen, Annika; Grenman, Seija; Lamminmäki, Urpo; Carpen, Olli; van Kooyk, Yvette; Pettersson, Kim

    2016-10-01

    Measurement of serum cancer antigen 125 (CA125) is the standard approach for epithelial ovarian cancer (EOC) diagnostics and follow-up. However, the clinical specificity is not optimal because increased values are also detected in healthy controls and in benign diseases. CA125 is known to be differentially glycosylated in EOC, potentially offering a way to construct CA125 assays with improved cancer specificity. Our goal was to identify carbohydrate-reactive lectins for discriminating between CA125 originating from EOC and noncancerous sources. CA125 from the OVCAR-3 cancer cell line, placental homogenate, and ascites fluid from patients with cirrhosis were captured on anti-CA125 antibody immobilized on microtitration wells. A panel of lectins, each coated onto fluorescent europium-chelate-doped 97-nm nanoparticles (Eu(+3)-NPs), was tested for detection of the immobilized CA125. Serum samples from high-grade serous EOC or patients with endometriosis and healthy controls were analyzed. By using macrophage galactose-type lectin (MGL)-coated Eu(+3)-NPs, an analytically sensitive CA125 assay (CA125(MGL)) was achieved that specifically recognized the CA125 isoform produced by EOC, whereas the recognition of CA125 from nonmalignant conditions was reduced. Serum CA125(MGL) measurement better discriminated patients with EOC from endometriosis compared to conventional immunoassay. The discrimination was particularly improved for marginally increased CA125 values and for earlier detection of EOC progression. The new CA125(MGL) assay concept could help reduce the false-positive rates of conventional CA125 immunoassays. The improved analytical specificity of this test approach is dependent on a discriminating lectin immobilized in large numbers on Eu(+3)-NPs, providing both an avidity effect and signal amplification. © 2016 American Association for Clinical Chemistry.

  1. Design of a surface plasmon resonance immunoassay for therapeutic drug monitoring of amikacin.

    Science.gov (United States)

    Losoya-Leal, Adrian; Estevez, M-Carmen; Martínez-Chapa, Sergio O; Lechuga, Laura M

    2015-08-15

    The therapeutic drug monitoring (TDM) of pharmaceutical drugs with narrow therapeutic ranges is of great importance in the clinical setting. It provides useful information towards the enhancement of drug therapies, aiding in dosage control and toxicity risk management. Amikacin is an aminoglycoside antibiotic commonly used in neonatal therapies that is indicated for TDM due to the toxicity risks inherent in its use. Current techniques for TDM such as high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) are costly, time consuming, and cannot be performed at the site of action. Over the last decades, surface plasmon resonance (SPR) biosensors have become increasingly popular in clinical diagnostics due to their ability to detect biomolecular interactions in real-time. We present an SPR-based competitive immunoassay for the detection of the antibiotic amikacin, suitable for TDM in both adults and neonates. We have obtained high specificity and sensitivity levels with an IC50 value of 1.4ng/mL and a limit of detection of 0.13ng/mL, which comfortably comply with the drug's therapeutic range. Simple dilution of serum can therefore be sufficient to analyze low-volume real samples from neonates, increasing the potential of the methodology for TDM. Compared to current TDM conventional methods, this SPR-based immunoassay can provide advantages such as simplicity, potential portability, and label-free measurements with the possibility of high throughput. This work is the foundation towards the development of an integrated, simple use, highly sensitive, fast, and point-of-care sensing platform for the opportune TDM of antibiotics and other drugs in a clinical setting. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Mobile Phone Ratiometric Imaging Enables Highly Sensitive Fluorescence Lateral Flow Immunoassays without External Optical Filters.

    Science.gov (United States)

    Shah, Kamal G; Singh, Vidhi; Kauffman, Peter C; Abe, Koji; Yager, Paul

    2018-05-14

    Paper-based diagnostic tests based on the lateral flow immunoassay concept promise low-cost, point-of-care detection of infectious diseases, but such assays suffer from poor limits of detection. One factor that contributes to poor analytical performance is a reliance on low-contrast chromophoric optical labels such as gold nanoparticles. Previous attempts to improve the sensitivity of paper-based diagnostics include replacing chromophoric labels with enzymes, fluorophores, or phosphors at the expense of increased fluidic complexity or the need for device readers with costly optoelectronics. Several groups, including our own, have proposed mobile phones as suitable point-of-care readers due to their low cost, ease of use, and ubiquity. However, extant mobile phone fluorescence readers require costly optical filters and were typically validated with only one camera sensor module, which is inappropriate for potential point-of-care use. In response, we propose to couple low-cost ultraviolet light-emitting diodes with long Stokes-shift quantum dots to enable ratiometric mobile phone fluorescence measurements without optical filters. Ratiometric imaging with unmodified smartphone cameras improves the contrast and attenuates the impact of excitation intensity variability by 15×. Practical application was shown with a lateral flow immunoassay for influenza A with nucleoproteins spiked into simulated nasal matrix. Limits of detection of 1.5 and 2.6 fmol were attained on two mobile phones, which are comparable to a gel imager (1.9 fmol), 10× better than imaging gold nanoparticles on a scanner (18 fmol), and >2 orders of magnitude better than gold nanoparticle-labeled assays imaged with mobile phones. Use of the proposed filter-free mobile phone imaging scheme is a first step toward enabling a new generation of highly sensitive, point-of-care fluorescence assays.

  3. Development of monoclonal antibody-based immunoassays for the analysis of bisphenol A in canned vegetables.

    Science.gov (United States)

    Moreno, María J; D'Arienzo, Pasquale; Manclús, Juan J; Montoya, Angel

    2011-01-01

    The aim of this work was the development of monoclonal antibodies (MAbs) and highly sensitive immunoassays (ELISAs) to bisphenol A (BPA), a well-known endocrine disruptor able to migrate from the internal coating of cans to food contained inside, particularly vegetables. To produce MAbs to BPA, four synthetic compounds were conjugated to proteins and used as immunizing haptens in mice. By applying hybridoma technology, several MAbs were produced and selected. These antibodies were characterized in the conjugate-coated and in the antibody-coated formats, using both homologous and heterologous conjugates. Three indirect ELISA based on the MAbs showing the highest affinity to BPA were selected. The limit of detection of the most sensitive ELISA was 0.22 nM (0.05 ng/mL), with an I₅₀ value of around 1 nM (0.23 ng/mL). An homologous ELISA based on the MAb BPAB-11 was applied to the simple, direct determination of BPA in the liquid portion of canned artichoke, peas, and sweet corn. Only sample dilution in an appropriate saline buffer was required to minimize matrix effects and to enter the ELISA working range. Recovery and precision of the method were evaluated by spiking the liquid portion of these cans with BPA at 20, 50, and 100 ng/mL. Coefficients of variation were below 20% in most cases. With regard to recovery, the analytical data obtained were also acceptable. This immunoassay has therefore proved its potential as a new tool for the rapid, sensitive and accurate determination of BPA in canned food.

  4. A Portable Immunoassay Platform for Multiplexed Detection of Biotoxins in Clinical and Environmental Samples

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Chung-Yan [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Piccini, Matthew Ernest [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Cepheid, Sunnyvale, CA (United States); Schaff, Ulrich Y. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandstone Diagnostics, Livermore, CA (United States); Stanker, Larry H. [US Dept. of Agriculture, Albany, CA (United States). Western Regional Research Center, Foodborne Contaminants Research Unit; Cheng, Luisa W. [US Dept. of Agriculture, Albany, CA (United States). Western Regional Research Center, Foodborne Contaminants Research Unit; Ravichandran, Easwaran [Univ. of Massachusetts, Dartmouth, MA (United States); Singh, Bal-Ram [Univ. of Massachusetts, Dartmouth, MA (United States); Sommer, Greg J. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandstone Diagnostics, Livermore, CA (United States); Singh, Anup K. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2015-01-01

    Multiple cases of attempted bioterrorism events using biotoxins have highlighted the urgent need for tools capable of rapid screening of suspect samples in the field (e.g., mailroom and public events). We present a portable microfluidic device capable of analyzing environmental (e.g., white powder), food (e.g., milk) and clinical (e.g., blood) samples for multiplexed detection of biotoxins. The device is rapid (<15-30 min sample-to-answer), sensitive (< 0.08 pg/mL detection limit for botulinum toxin), multiplexed (up to 64 parallel assays) and capable of analyzing small volume samples (< 20 μL total sample input). The immunoassay approach (SpinDx) is based on binding of toxins in a sample to antibody-laden capture particles followed by sedimentation of particles through a density-media in a microfluidic disk and quantification using a laser-induced fluorescence detector. A direct, blinded comparison with a gold standard ELISA revealed a 5-fold more sensitive detection limit for botulinum toxin while requiring 250-fold less sample volume and a 30 minute assay time with a near unity correlation. A key advantage of the technique is its compatibility with a variety of sample matrices with no additional sample preparation required. Ultrasensitive quantification has been demonstrated from direct analysis of multiple clinical, environmental and food samples, including white powder, whole blood, saliva, salad dressing, whole milk, peanut butter, half and half, honey, and canned meat. We believe that this device can met an urgent need in screening both potentially exposed people as well as suspicious samples in mail-rooms, airports, public sporting venues and emergency rooms. The general-purpose immunodiagnostics device can also find applications in screening of infectious and systemic diseases or serve as a lab device for conducting rapid immunoassays.

  5. Some emergency instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, P H

    1986-10-01

    The widespread release of activity and the resultant spread of contamination after the Chernobyl accident resulted in requests to NRPB to provide instruments for, and expertise in, the measurement of radiation. The most common request was for advice on the usefulness of existing instruments, but Board staff were also involved in their adaptation or in the development of new instruments specially to meet the circumstances of the accident. The accident occurred on 26 April. On 1 May, NRPB was involved at Heathrow Airport in the monitoring of the British students who had returned from Kiev and Minsk. The main purpose was to reassure the students by checking that their persons and belongings did not have significant surface contamination. Additional measurements were also made of iodine activity in thyroid using hand-held detectors or a mobile body monitor. This operation was arranged with the Foreign and Commonwealth Office, which had also received numerous requests for instruments from embassies and consulates in countries close to the scene of the accident. There was concern for the well-being of staff and other United Kingdom nationals who resided in or intended to visit the most affected countries. The board supplied suitable instruments, and the FCO distributed them to embassies. The frequency of environmental monitoring was increased from 29 April in anticipation of contamination and appropriate Board instrumentation was deployed. After the Chernobyl cloud arrived in the UK on 2 May, there were numerous requests from local government, public authorities, private companies and members of the public for information and advice on monitoring equipment and procedures. Some of these requirements could be met with existing equipment but members of the public were usually advised not to proceed. At a later stage, the contamination of foodstuffs and livestock required the development of an instrument capable of detecting low levels of {sup 137}Cs and {sup 134}Cs in food

  6. Reactor instrumentation and control

    International Nuclear Information System (INIS)

    Wach, D.; Beraha, D.

    1980-01-01

    The methods for measuring radiation are shortly reviewed. The instrumentation for neutron flux measurement is classified into out-of-core and in-core instrumentation. The out-of-core instrumentation monitors the operational range from the subcritical reactor to full power. This large range is covered by several measurement channels which derive their signals from counter tubes and ionization chambers. The in-core instrumentation provides more detailed information on the power distribution in the core. The self-powered neutron detectors and the aeroball system in PWR reactors are discussed. Temperature and pressure measurement devices are briefly discussed. The different methods for leak detection are described. In concluding the plant instrumentation part some new monitoring systems and analysis methods are presented: early failure detection methods by noise analysis, acoustic monitoring and vibration monitoring. The presentation of the control starts from an qualitative assessment of the reactor dynamics. The chosen control strategy leads to the definition of the part-load diagram, which provides the set-points for the different control systems. The tasks and the functions of these control systems are described. In additiion to the control, a number of limiting systems is employed to keep the reactor in a safe operating region. Finally, an outlook is given on future developments in control, concerning mainly the increased application of process computers. (orig./RW)

  7. Instrumental analysis, second edition

    International Nuclear Information System (INIS)

    Christian, G.D.; O'Reilly, J.E.

    1988-01-01

    The second edition of Instrumental Analysis is a survey of the major instrument-based methods of chemical analysis. It appears to be aimed at undergraduates but would be equally useful in a graduate course. The volume explores all of the classical quantitative methods and contains sections on techniques that usually are not included in a semester course in instrumentation (such as electron spectroscopy and the kinetic methods). Adequate coverage of all of the methods contained in this book would require several semesters of focused study. The 25 chapters were written by different authors, yet the style throughout the book is more uniform than in the earlier edition. With the exception of a two-chapter course in analog and digital circuits, the book purports to de-emphasize instrumentation, focusing more on the theory behind the methods and the application of the methods to analytical problems. However, a detailed analysis of the instruments used in each method is by no means absent. The book has the favor of a user's guide to analysis

  8. Biochemistry Instrumentation Core Technology Center

    Data.gov (United States)

    Federal Laboratory Consortium — The UCLA-DOE Biochemistry Instrumentation Core Facility provides the UCLA biochemistry community with easy access to sophisticated instrumentation for a wide variety...

  9. Heat Flux Instrumentation Laboratory (HFIL)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: The Heat Flux Instrumentation Laboratory is used to develop advanced, flexible, thin film gauge instrumentation for the Air Force Research Laboratory....

  10. Characteristics of protective instrumentation

    International Nuclear Information System (INIS)

    Reichart, G.

    1982-01-01

    Protective Instrumentation (PI) for Nuclear Power Plants (NPP) is a general term for an highly reliable instrumentation, which provides information for keeping the system within safe limits, for initation of countermeasures in the case of an incident or for mitigation of consequences of an accident. In German NPPs one can find a hierarchical structure of protective instrumentation, wherein the Reactor Protection System (RPS) has the highest priority. To meet the reliability requirements different design principles are used, like - redundancy - diversity - fail safe - decoupling. The presentation gives an overview about the different design principles and characterizes their reliability aspects. As an example for the technical realization the RPS of a German NPP is discussed in some detail. Furthermore some information about other type of PI is given and reliability aspects of the interaction of operating personell with these systems are mentioned. (orig.)

  11. Aethalometer™ Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, Arthur J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-04-01

    The Aethalometer is an instrument that provides a real-time readout of the concentration of “Black” or “Elemental” carbon aerosol particles (BC or E) in an air stream (see Figure 1 and Figure 2). It is a self-contained instrument that measures the rate of change of optical transmission through a spot on a filter where aerosol is being continuously collected and uses the information to calculate the concentration of optically absorbing material in the sampled air stream. The instrument measures the transmitted light intensities through the “sensing” portion of the filter, on which the aerosol spot is being collected, and a “reference” portion of the filter as a check on the stability of the optical source. A mass flowmeter monitors the sample air flow rate. The data from these three measurements is used to determine the mean BC content of the air stream.

  12. The IKARUS instrument

    International Nuclear Information System (INIS)

    Gerster, H.J.; Stein, G.

    1994-01-01

    When the Federal Government decided on a 25% reduction of CO 2 emissions till 2005 in 1990 the necessity resulted that an instrument has to be developed for the analysis and assessment of the ecological, economic and energetic impact of different reduction strategies. The development task was awarded by the BMFT to the Research Centre Juelich in cooperation with well-known institutions of energy system research. The total instrument is scheduled to be finished by the end of 1994. For the decentral use of the instrument by a wide specialist public the developed models and data banks which are equipped with a user-friendly surface are suited for larger PCs (486, 16 MB RAM/500-1000 MB ROM). (orig.) [de

  13. ISSUERS OF FINANCIAL INSTRUMENTS

    Directory of Open Access Journals (Sweden)

    Cristian GHEORGHE

    2016-05-01

    Full Text Available The rules laid down by Romanian Capital Market Law and the regulations put in force for its implementation apply to issuers of financial instruments admitted to trading on the regulated market established in Romania. But the issuers remain companies incorporated under Company Law of 1990. Such dual regulations need increased attention in order to observe the legal status of the issuers/companies and financial instruments/shares. Romanian legislator has chosen to implement in Capital Market Law special rules regarding the administration of the issuers of financial instruments, not only rules regarding admitting and maintaining to a regulated market. Thus issuers are, in Romanian Law perspective, special company that should comply special rule regarding board of administration and general shareholders meeting.

  14. Virtual Sensor Test Instrumentation

    Science.gov (United States)

    Wang, Roy

    2011-01-01

    Virtual Sensor Test Instrumentation is based on the concept of smart sensor technology for testing with intelligence needed to perform sell-diagnosis of health, and to participate in a hierarchy of health determination at sensor, process, and system levels. A virtual sensor test instrumentation consists of five elements: (1) a common sensor interface, (2) microprocessor, (3) wireless interface, (4) signal conditioning and ADC/DAC (analog-to-digital conversion/ digital-to-analog conversion), and (5) onboard EEPROM (electrically erasable programmable read-only memory) for metadata storage and executable software to create powerful, scalable, reconfigurable, and reliable embedded and distributed test instruments. In order to maximize the efficient data conversion through the smart sensor node, plug-and-play functionality is required to interface with traditional sensors to enhance their identity and capabilities for data processing and communications. Virtual sensor test instrumentation can be accessible wirelessly via a Network Capable Application Processor (NCAP) or a Smart Transducer Interlace Module (STIM) that may be managed under real-time rule engines for mission-critical applications. The transducer senses the physical quantity being measured and converts it into an electrical signal. The signal is fed to an A/D converter, and is ready for use by the processor to execute functional transformation based on the sensor characteristics stored in a Transducer Electronic Data Sheet (TEDS). Virtual sensor test instrumentation is built upon an open-system architecture with standardized protocol modules/stacks to interface with industry standards and commonly used software. One major benefit for deploying the virtual sensor test instrumentation is the ability, through a plug-and-play common interface, to convert raw sensor data in either analog or digital form, to an IEEE 1451 standard-based smart sensor, which has instructions to program sensors for a wide variety of

  15. ICFA: Instrumentation school

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1987-10-15

    74 students, including 45 from developing countries, ten lecturers and nine laboratory instructors participated in the novel instrumentation school held in June at the International Centre for Theoretical Physics (ICTP), Trieste, Italy, sponsored by ICTP and arranged through the Instrumentation Panel of the International Committee for Future Accelerators (ICF). During the two weeks of the course, students had the chance to construct and test a proportional chamber, measure the lifetime of cosmic ray muons, operate and analyse the performance of an 8-wire imaging drift chamber, or study noise and signal processing using a silicon photodiode.

  16. Interfacing to accelerator instrumentation

    International Nuclear Information System (INIS)

    Shea, T.J.

    1995-01-01

    As the sensory system for an accelerator, the beam instrumentation provides a tremendous amount of diagnostic information. Access to this information can vary from periodic spot checks by operators to high bandwidth data acquisition during studies. In this paper, example applications will illustrate the requirements on interfaces between the control system and the instrumentation hardware. A survey of the major accelerator facilities will identify the most popular interface standards. The impact of developments such as isochronous protocols and embedded digital signal processing will also be discussed

  17. Spectroelectrochemical Instrument Measures TOC

    Science.gov (United States)

    Kounaves, Sam

    2011-01-01

    A spectroelectrochemical instrument has been developed for measuring the total organic carbon (TOC) content of an aqueous solution. Measurements of TOC are frequently performed in environmental, clinical, and industrial settings. Until now, techniques for performing such measurements have included, various ly, the use of hazardous reagents, ultraviolet light, or ovens, to promote reactions in which the carbon contents are oxidized. The instrument now being developed is intended to be a safer, more economical means of oxidizing organic carbon and determining the TOC levels of aqueous solutions and for providing a low power/mass unit for use in planetary missions.

  18. Neutron multiplication measurement instrument

    International Nuclear Information System (INIS)

    Nixon, K.V.; Dowdy, E.J.; France, S.W.; Millegan, D.R.; Robba, A.A.

    1983-01-01

    The Advanced Nuclear Technology Group of the Los Alamos National Laboratory is now using intelligent data-acquisition and analysis instrumentation for determining the multiplication of nuclear material. Earlier instrumentation, such as the large NIM-crate systems, depended on house power and required additional computation to determine multiplication or to estimate error. The portable, battery-powered multiplication measurement unit, with advanced computational power, acquires data, calculates multiplication, and completes error analysis automatically. Thus, the multiplication is determined easily and an available error estimate enables the user to judge the significance of results

  19. Standard NIM instrumentation system

    International Nuclear Information System (INIS)

    1990-05-01

    NIM is a standard modular instrumentation system that is in wide use throughout the world. As the NIM system developed and accommodations were made to a dynamic instrumentation field and a rapidly advancing technology, additions, revisions and clarifications were made. These were incorporated into the standard in the form of addenda and errata. This standard is a revision of the NIM document, AEC Report TID-20893 (Rev. 4) dated July 1974. It includes all the addenda and errata items that were previously issued as well as numerous additional items to make the standard current with modern technology and manufacturing practice

  20. Virtual Reality Musical Instruments

    DEFF Research Database (Denmark)

    Serafin, Stefania; Erkut, Cumhur; Kojs, Juraj

    2016-01-01

    The rapid development and availability of low-cost technologies have created a wide interest in virtual reality. In the field of computer music, the term “virtual musical instruments” has been used for a long time to describe software simulations, extensions of existing musical instruments......, and ways to control them with new interfaces for musical expression. Virtual reality musical instruments (VRMIs) that include a simulated visual component delivered via a head-mounted display or other forms of immersive visualization have not yet received much attention. In this article, we present a field...

  1. ICFA: Instrumentation school

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    74 students, including 45 from developing countries, ten lecturers and nine laboratory instructors participated in the novel instrumentation school held in June at the International Centre for Theoretical Physics (ICTP), Trieste, Italy, sponsored by ICTP and arranged through the Instrumentation Panel of the International Committee for Future Accelerators (ICF). During the two weeks of the course, students had the chance to construct and test a proportional chamber, measure the lifetime of cosmic ray muons, operate and analyse the performance of an 8-wire imaging drift chamber, or study noise and signal processing using a silicon photodiode

  2. Instrumentation Cables Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Muna, Alice Baca [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); LaFleur, Chris Bensdotter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-10-01

    A fire at a nuclear power plant (NPP) has the potential to damage structures, systems, and components important to safety, if not promptly detected and suppressed. At Browns Ferry Nuclear Power Plant on March 22, 1975, a fire in the reactor building damaged electrical power and control systems. Damage to instrumentation cables impeded the function of both normal and standby reactor coolant systems, and degraded the operators’ plant monitoring capability. This event resulted in additional NRC involvement with utilities to ensure that NPPs are properly protected from fire as intended by the NRC principle design criteria (i.e., general design criteria 3, Fire Protection). Current guidance and methods for both deterministic and performance based approaches typically make conservative (bounding) assumptions regarding the fire-induced failure modes of instrumentation cables and those failure modes effects on component and system response. Numerous fire testing programs have been conducted in the past to evaluate the failure modes and effects of electrical cables exposed to severe thermal conditions. However, that testing has primarily focused on control circuits with only a limited number of tests performed on instrumentation circuits. In 2001, the Nuclear Energy Institute (NEI) and the Electric Power Research Institute (EPRI) conducted a series of cable fire tests designed to address specific aspects of the cable failure and circuit fault issues of concern1. The NRC was invited to observe and participate in that program. The NRC sponsored Sandia National Laboratories to support this participation, whom among other things, added a 4-20 mA instrumentation circuit and instrumentation cabling to six of the tests. Although limited, one insight drawn from those instrumentation circuits tests was that the failure characteristics appeared to depend on the cable insulation material. The results showed that for thermoset insulated cables, the instrument reading tended to drift

  3. Celadon Figurines Play Instruments

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    This group of figurines, each 0.15m tall, were unearthed from a Tang Dynasty tomb in Changsha in 1977. Music was very developed in the Tang Dynasty. Colorful musical instruments and dances were popular both among the people and in the palace. These vivid-looking figurines wear pleated skirts with small sleeves and open chest, a style influenced by the non-Han nationalities living in the north and west of China. Some of the musical instruments were brought from the Western Regions. The figurines are playing the xiao (a vertical bamboo flute), the konghou (an

  4. Inspector-instrument interface in portable NDA instrumentation

    International Nuclear Information System (INIS)

    Halbig, J.K.; Klosterbuer, S.F.

    1981-01-01

    Recent electronics technology advances make it possible to design sophisticated instruments in small packages for convenient field implementation. An inspector-instrument interface design that allows communication of procedures, responses, and results between the instrument and user is presented. This capability has been incorporated into new spent-fuel instrumentation and a battery-powered multichannel analyzer

  5. Inspector-instrument interface in portable NDA instrumentation

    International Nuclear Information System (INIS)

    Halbig, J.K.; Klosterbuer, S.F.

    1981-01-01

    Recent electronics technology advances make it possible to design sophisticated instruments in small packages for convenient field implementation. This report describes an inspector-instrument interface design which allows communication of procedures, responses, and results between the instrument and user. The interface has been incorporated into new spent-fuel instrumentation and a battery-powered multichannel analyzer

  6. Triple-channel portable capillary electrophoresis instrument with individual background electrolytes for the concurrent separations of anionic and cationic species

    Energy Technology Data Exchange (ETDEWEB)

    Mai, Thanh Duc; Le, Minh Duc [Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi (Viet Nam); Sáiz, Jorge [Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá, Ctra. Madrid-Barcelona Km 33.6, Alcalá de Henares, Madrid (Spain); Duong, Hong Anh [Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi (Viet Nam); Koenka, Israel Joel [University of Basel, Department of Chemistry, Spitalstrasse 51, 4056 Basel (Switzerland); Pham, Hung Viet, E-mail: phamhungviet@hus.edu.vn [Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Nguyen Trai Street 334, Hanoi (Viet Nam); Hauser, Peter C., E-mail: Peter.Hauser@unibas.ch [University of Basel, Department of Chemistry, Spitalstrasse 51, 4056 Basel (Switzerland)

    2016-03-10

    The portable capillary electrophoresis instrument is automated and features three independent channels with different background electrolytes to allow the concurrent optimized determination of three different categories of charged analytes. The fluidic system is based on a miniature manifold which is based on mechanically milled channels for injection of samples and buffers. The planar manifold pattern was designed to minimize the number of electronic valves required for each channel. The system utilizes pneumatic pressurization to transport solutions at the grounded as well as the high voltage side of the separation capillaries. The instrument has a compact design, with all components arranged in a briefcase with dimensions of 45 (w) × 35 (d) × 15 cm (h) and a weight of about 15 kg. It can operate continuously for 8 h in the battery-powered mode if only one electrophoresis channel is in use, or for about 2.5 h in the case of simultaneous employment of all three channels. The different operations, i.e. capillary flushing, rinsing of the interfaces at both capillary ends, sample injection and electrophoretic separation, are activated automatically with a control program featuring a graphical user interface. For demonstration, the system was employed successfully for the concurrent separation of different inorganic cations and anions, organic preservatives, additives and artificial sweeteners in various beverage and food matrices. - Highlights: • The use of parallel channels allows the concurrent separation of different classes of analytes. • Separate background electrolytes allow individual optimization. • The instrument is compact and field portable.

  7. Triple-channel portable capillary electrophoresis instrument with individual background electrolytes for the concurrent separations of anionic and cationic species

    International Nuclear Information System (INIS)

    Mai, Thanh Duc; Le, Minh Duc; Sáiz, Jorge; Duong, Hong Anh; Koenka, Israel Joel; Pham, Hung Viet; Hauser, Peter C.

    2016-01-01

    The portable capillary electrophoresis instrument is automated and features three independent channels with different background electrolytes to allow the concurrent optimized determination of three different categories of charged analytes. The fluidic system is based on a miniature manifold which is based on mechanically milled channels for injection of samples and buffers. The planar manifold pattern was designed to minimize the number of electronic valves required for each channel. The system utilizes pneumatic pressurization to transport solutions at the grounded as well as the high voltage side of the separation capillaries. The instrument has a compact design, with all components arranged in a briefcase with dimensions of 45 (w) × 35 (d) × 15 cm (h) and a weight of about 15 kg. It can operate continuously for 8 h in the battery-powered mode if only one electrophoresis channel is in use, or for about 2.5 h in the case of simultaneous employment of all three channels. The different operations, i.e. capillary flushing, rinsing of the interfaces at both capillary ends, sample injection and electrophoretic separation, are activated automatically with a control program featuring a graphical user interface. For demonstration, the system was employed successfully for the concurrent separation of different inorganic cations and anions, organic preservatives, additives and artificial sweeteners in various beverage and food matrices. - Highlights: • The use of parallel channels allows the concurrent separation of different classes of analytes. • Separate background electrolytes allow individual optimization. • The instrument is compact and field portable.

  8. Dynamics of serum testosterone during the menstrual cycle evaluated by daily measurements with an ID-LC-MS/MS method and a 2nd generation automated immunoassay

    NARCIS (Netherlands)

    Bui, Hong N.; Sluss, Patrick M.; Blincko, Stuart; Knol, Dirk L.; Blankenstein, Marinus A.; Heijboer, Annemieke C.

    2013-01-01

    Testosterone concentrations in normally cycling women are assumed to be elevated around the time of ovulation. The clinical relevance of changing testosterone concentrations during the menstrual cycle, however, is unclear. Poor performance of current direct immunoassays for testosterone at low

  9. Development and validation of a direct sandwich chemiluminescence immunoassay for measuring DNA adducts of benzo[a]pyrene and other polycyclic aromatic hydrocarbons

    DEFF Research Database (Denmark)

    Georgiadis, Panagiotis; Kovács, Katalin; Kaila, Stella

    2012-01-01

    We have developed and validated a sandwich chemiluminescence immunoassay (SCIA) which measures polycyclic aromatic hydrocarbon (PAH)-DNA adducts combining high throughput and adequate sensitivity, appropriate for evaluation of adduct levels in human population studies. Fragmented DNA is incubated...

  10. Power station instrumentation

    International Nuclear Information System (INIS)

    Jervis, M.W.

    1993-01-01

    Power stations are characterized by a wide variety of mechanical and electrical plant operating with structures, liquids and gases working at high pressures and temperatures and with large mass flows. The voltages and currents are also the highest that occur in most industries. In order to achieve maximum economy, the plant is operated with relatively small margins from conditions that can cause rapid plant damage, safety implications, and very high financial penalties. In common with other process industries, power stations depend heavily on control and instrumentation. These systems have become particularly significant, in the cost-conscious privatized environment, for providing the means to implement the automation implicit in maintaining safety standards, improving generation efficiency and reducing operating manpower costs. This book is for professional instrumentation engineers who need to known about their use in power stations and power station engineers requiring information about the principles and choice of instrumentation available. There are 8 chapters; chapter 4 on instrumentation for nuclear steam supply systems is indexed separately. (Author)

  11. University Reactor Instrumentation Program

    International Nuclear Information System (INIS)

    Vernetson, W.G.

    1992-11-01

    Recognizing that the University Reactor Instrumentation Program was developed in response to widespread needs in the academic community for modernization and improvement of research and training reactors at institutions such as the University of Florida, the items proposed to be supported by this grant over its two year period have been selected as those most likely to reduce foreed outages, to meet regulatory concerns that had been expressed in recent years by Nuclear Regulatory Commission inspectors or to correct other facility problems and limitations. Department of Energy Grant Number DE-FG07-90ER129969 was provided to the University of Florida Training Reactor(UFTR) facility through the US Department of Energy's University Reactor Instrumentation Program. The original proposal submitted in February, 1990 requested support for UFTR facility instrumentation and equipment upgrades for seven items in the amount of $107,530 with $13,800 of this amount to be the subject of cost sharing by the University of Florida and $93,730 requested as support from the Department of Energy. A breakdown of the items requested and total cost for the proposed UFTR facility instrumentation and equipment improvements is presented

  12. Neutron instrumentation for biology

    Energy Technology Data Exchange (ETDEWEB)

    Mason, S.A. [Institut Laue-Langevin, Grenoble (France)

    1994-12-31

    In the October 1994 round of proposals at the ILL, the external biology review sub- committee was asked to allocate neutron beam time to a wide range of experiments, on almost half the total number of scheduled neutron instruments: on 3 diffractometers, on 3 small angle scattering instruments, and on some 6 inelastic scattering spectrometers. In the 3.5 years since the temporary reactor shutdown, the ILL`s management structure has been optimized, budgets and staff have been trimmed, the ILL reactor has been re-built, and many of the instruments up-graded, many powerful (mainly Unix) workstations have been introduced, and the neighboring European Synchrotron Radiation Facility has established itself as the leading synchrotron radiation source and has started its official user program. The ILL reactor remains the world`s most intense dedicated neutron source. In this challenging context, it is of interest to review briefly the park of ILL instruments used to study the structure and energetics of small and large biological systems. A brief summary will be made of each class of experiments actually proposed in the latest ILL proposal round.

  13. The ozone monitoring instrument

    NARCIS (Netherlands)

    Levelt, P.F.; Oord, G.H.J. van den; Dobber, M.R.; Mälkki, A.; Visser, H.; Vries, J. de; Stammes, P.; Lundell, J.O.V.; Saari, H.

    2006-01-01

    The Ozone Monitoring Instrument (OMI) flies on the National Aeronautics and Space Adminsitration's Earth Observing System Aura satellite launched in July 2004. OMI is a ultraviolet/visible (UV/VIS) nadir solar backscatter spectrometer, which provides nearly global coverage in one day with a spatial

  14. Economic Policy Instruments

    DEFF Research Database (Denmark)

    Klemmensen, Børge

    2007-01-01

    Økonomiske instrumenter begrundes med behovet for politiske indgreb, der muliggør internaliseringen af omkostningerne ved de miljøpåvirkninger, produktion and levevis afstedkommer, således at hensyntagen til miljøet bliver en del af virksomheders og husholdningers omkostninger og dermed en tilsky...

  15. Radiometric well logging instruments

    International Nuclear Information System (INIS)

    Davydov, A.V.

    1975-01-01

    The technical properties of well instruments for radioactive logging used in the radiometric logging complexes PKS-1000-1 (''Sond-1'') and PRKS-2 (''Vitok-2'') are described. The main features of the electric circuit of the measuring channels are given

  16. Advanced instrumentation and teleoperation

    International Nuclear Information System (INIS)

    Decreton, M.

    1998-01-01

    SCK-CEN's advanced instrumentation and teleoperation project aims at evaluating the potential of a telerobotic approach in a nuclear environment and, in particular, the use of remote-perception systems. Main achievements in 1997 in the areas of R and D on radiation tolerance for remote sensing, optical fibres and optical-fibre sensors, and computer-aided teleoperation are reported

  17. Health physics instrumentation needs

    International Nuclear Information System (INIS)

    Selby, J.M.; Swinth, K.L.; Kenoyer, J.L.

    1984-10-01

    Deficiencies and desirable improvements can be identified in every technical area in which health physics instruments are employed. The needed improvements cover the full spectrum including long-term reliability, human factors, accuracy, ruggedness, ease of calibration, improved radiation response, and improved mixed field response. Some specific areas of deficiency noted along with needed improvements. 17 references

  18. Virtual reality musical instruments

    DEFF Research Database (Denmark)

    Serafin, Stefania; Erkut, Cumhur; Kojs, Juraj

    2016-01-01

    The rapid development and availability of low cost technologies has created a wide interest in virtual reality (VR), but how to design and evaluate multisensory interactions in VR remains as a challenge. In this paper, we focus on virtual reality musical instruments, present an overview of our...

  19. Creating a Super Instrument

    DEFF Research Database (Denmark)

    Kallionpää, Maria; Gasselseder, Hans-Peter

    2015-01-01

    Thanks to the development of new technology, musical instruments are no more tied to their existing acoustic or technical limitations as almost all parameters can be augmented or modified in real time. An increasing number of composers, performers, and computer programmers have thus become intere...

  20. CMO Site: Ocean Instrumentation

    Science.gov (United States)

    1997-02-01

    Precipitation , Lightning, Visibility 0150 A InterOcea Hawser Strain 1.. systems, inc. and more... n 1946 3540 aero court san diego ca 92123-1799 usa phone: (619...AGU’s Microgal culture Association, P.O. Box 1004, April 8-10, 1997-Underwater Gravimetry : Instruments, Observa- Niland, CA 92257; (619) 359-3474

  1. Instrumentation in thermoluminescence dosimetry

    International Nuclear Information System (INIS)

    Julius, H.W.

    1986-01-01

    In the performance of a thermoluminescence dosimetry (TLD) system the equipment plays an important role. Crucial parameters of instrumentation in TLD are discussed in some detail. A review is given of equipment available on the market today - with some emphasis on automation - which is partly based on information from industry and others involved in research and development. (author)

  2. Ion chamber instrument

    International Nuclear Information System (INIS)

    Stephan, D.H.

    1975-01-01

    An electrical ionization chamber is described having a self-supporting wall of cellular material which is of uniform areal density and formed of material, such as foamed polystyrene, having an average effective atomic number between about 4 and about 9, and easily replaceable when on the instrument. (auth)

  3. Integrating Nephelometer Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Uin, J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-01

    The Integrating Nephelometer (Figure 1) is an instrument that measures aerosol light scattering. It measures aerosol optical scattering properties by detecting (with a wide angular integration – from 7 to 170°) the light scattered by the aerosol and subtracting the light scattered by the carrier gas, the instrument walls and the background noise in the detector (zeroing). Zeroing is typically performed for 5 minutes every day at midnight UTC. The scattered light is split into red (700 nm), green (550 nm), and blue (450 nm) wavelengths and captured by three photomultiplier tubes. The instrument can measure total scatter as well as backscatter only (from 90 to 170°) (Heintzenberg and Charlson 1996; Anderson et al. 1996; Anderson and Ogren 1998; TSI 3563 2015) At ARM (Atmospheric Radiation Measurement), two identical Nephelometers are usually run in series with a sample relative humidity (RH) conditioner between them. This is possible because Nephelometer sampling is non-destructive and the sample can be passed on to another instrument. The sample RH conditioner scans through multiple RH values in cycles, treating the sample. This kind of setup allows to study how aerosol particles’ light scattering properties are affected by humidification (Anderson et al. 1996). For historical reasons, the two Nephelometers in this setup are labeled “wet” and “dry”, with the “dry” Nephelometer usually being the one before the conditioner and sampling ambient air (the names are switched for the MAOS measurement site due to the high RH of the ambient air).

  4. Measurement and Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Kirkham, Harold

    2018-01-02

    This is a chapter for a book called the Standard Handbook for Electrical Engineering. Though it is not obvious from the title, the book deals mainly with power engineering. The first chapter (not mine) is about the fundamental quantities used in measurement. This chapter is about the process and the instrumentation.

  5. Analytical chemistry instrumentation

    International Nuclear Information System (INIS)

    Laing, W.R.

    1986-01-01

    In nine sections, 48 chapters cover 1) analytical chemistry and the environment 2) environmental radiochemistry 3) automated instrumentation 4) advances in analytical mass spectrometry 5) fourier transform spectroscopy 6) analytical chemistry of plutonium 7) nuclear analytical chemistry 8) chemometrics and 9) nuclear fuel technology

  6. CRISP instrument manual

    International Nuclear Information System (INIS)

    Bucknall, D.G.; Langridge, Sean

    1997-05-01

    This document is a user manual for CRISP, one of the two neutron reflectomers at ISIS. CRISP is highly automated allowing precision reproducible measurements. The manual provides detailed instructions for the setting-up and running of the instrument and advice on data analysis. (UK)

  7. Performance of hepatitis B assays on the Bayer ADVIA Centaur Immunoassay System.

    Science.gov (United States)

    van Helden, Josef; Denoyel, Gérard; Karwowska, Sylwia; Reamer, Randy; Schmalz, John; Wright, Ted; Preisel-Simmons, Barbara

    2004-01-01

    Bayer HealthCare LLC, Diagnostics Division, has developed several new assays on the ADVIA Centaur immunoassay system for the detection of markers of hepatitis B virus infection in human serum and plasma. This panel includes assays for: hepatitis B surface antigen (HBsAg), a confirmatory test method for HBsAg, antibodies to hepatitis B surface antigen (anti-HBs), IgM and IgG antibodies to hepatitis B core antigen (anti-HBc Total) and IgM antibodies to hepatitis B core antigen (anti-HBc IgM). These assays employ magnetic particle separation technology with direct chemiluminescence for optimal assay performance. All of the assays are fully automated, require sample volumes ranging from 15 microl to 100 microl (with the exception of the ADVIA Centaur HBsAg Confirmatory Assay, which requires 2 x 100 microl), and have throughputs of up to 240 tests per hour. The five ADVIA Centaur HBV assays were tested in extensive performance evaluations conducted at two sites in Europe. The performance evaluations, which included samples from HBV-infected individuals, blood donors, hospitalized/clinical patients, and HBV vaccinees (for Anti-HBs evaluation), generated performance data in support of obtaining the Communautés Européennes (CE) mark for European market distribution. The HBV performance evaluations resulted in an overall diagnostic specificity > 99%, i.e. 99.94% for the ADVIA Centaur HBsAg Assay, 100% for the ADVIA Centaur Anti-HBs Assay, 100% for the ADVIA Centaur HBc IgM Assay and 99.94% for the ADVIA Centaur HBc Total Assay. All of the ADVIA Centaur assays showed a very good diagnostic sensitivity on these populations with 100% for the ADVIA Centaur HBsAg Assay, 99.0% for the ADVIA Centaur Anti-HBs Assay, 98.53% for the ADVIA Centaur HBc IgM Assay and 100% for the ADVIA Centaur HBc Total Assay. The ADVIA Centaur HBsAg Confirmatory Test confirmed 100% of the positive HBsAg samples. Testing of interfering substances and potential cross-reacting samples for all ADVIA

  8. The Science of String Instruments

    CERN Document Server

    Rossing, Thomas D

    2010-01-01

    Many performing musicians, as well as instrument builders, are coming to realize the importance of understanding the science of musical instruments. This book explains how string instruments produce sound. It presents basic ideas in simple language, and it also translates some more sophisticated ideas in non-technical language. It should be of interest to performers, researchers, and instrument makers alike.

  9. 340nm UV LED excitation in time-resolved fluorescence system for europium-based immunoassays detection

    DEFF Research Database (Denmark)

    Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter

    2017-01-01

    In immunoassay analyzers for in-vitro diagnostics, Xenon flash lamps have been widely used as excitation light sources. Recent advancements in UV LED technology and its advantages over the flash lamps such as smaller footprint, better wall-plug efficiency, narrow emission spectrum......, and no significant afterglow, have made them attractive light sources for gated detection systems. In this paper, we report on the implementation of a 340 nm UV LED based time-resolved fluorescence system based on europium chelate as a fluorescent marker. The system performance was tested with the immunoassay based...... on the cardiac marker, TnI. The same signal-to-noise ratio as for the flash lamp based system was obtained, operating the LED below specified maximum current. The background counts of the system and its main contributors were measured and analyzed. The background of the system of the LED based unit was improved...

  10. Giant unilamellar vesicles containing Rhodamine 6G as a marker for immunoassay of bovine serum albumin and lipocalin-2.

    Science.gov (United States)

    Sakamoto, Misato; Shoji, Atsushi; Sugawara, Masao

    2016-07-15

    Functionalized giant unilamellar vesicles (GUVs) containing a fluorescence dye Rhodamine 6G is proposed as a marker in sandwich-type immunoassay for bovine serum albumin (BSA) and lipocalin-2 (LCN2). The GUVs were prepared by the electroformation method and functionalized with anti-BSA antibody and anti-LCN2 antibody, respectively. The purification of antibody-modified GUVs was achieved by conventional centrifugation and a washing step in a flow system. To antigen on an antibody slip, antibody-modified GUVs were added as a marker and incubated. After wash-out of excess reagents and lysis of the bound GUVs with Triton X-100, the fluorescence image was captured. The fluorometric immunoassays for BSA and LCN2 exhibited lower detection limits of 4 and 80 fg ml(-)(1), respectively. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Increasing of sensitivity of fluorescent immunoassay analysis of alpha-fetoprotein by means of plasmonical silver nanoparticles

    International Nuclear Information System (INIS)

    Vashchenko, S.V.; Min'ko, A.A.; Romanenko, A.A.; Gaponenko, S.V.; Kulakovich, O.S.

    2014-01-01

    A test system is proposed based on metal enhanced fluorescence to analyze low concentrations of alpha-fetoprotein (AFP), a tumor marker. Antigen-antibody reaction was performed on polystyrene plates coated with silver nanoparticles to increase sensitivity of fluorescent immunoassay and signal-to-noise ratio as compared to silver-free system. As compared to widely used ELISA technique and other immunoassay techniques the proposed approach is characterized by smaller probe volume, fast analysis and simplicity. The proposed test system uses layer-by-layer assembly approach, LED excitation and nanowatt photodetection set-up. The proposed test system offers AFP detection at concentrations used in clinical practice. Fluorescence enhancement for labeled AFP antibodies on a silver substrate was found to depend on antibodies concentration and was up to 6 times. (authors)

  12. The fabrication of magnetic particle-based chemiluminescence immunoassay for human epididymis protein-4 detection in ovarian cancer.

    Science.gov (United States)

    Fu, Xiaoling; Liu, Yangyang; Qiu, Ruiyun; Foda, Mohamed F; Zhang, Yong; Wang, Tao; Li, Jinshan

    2018-03-01

    The magnetic particles have a significant influence on the immunoassay detection and cancer therapy. Herein, the chemiluminescence immunoassay combined with the magnetic particles (MPCLIA) was presented for the clinical determination and analysis of human epididymis protein 4 (HE4) in the human serum. Under the optimized experiment conditions, the secure MPCLIA method can detect HE4 in the broader range of 0-1000 pmol/L, with a lower detection limit of 1.35 pmol/L. The satisfactory recovery rate of the method in the serum ranged from 83.62% to 105.10%, which was well within the requirement of clinical analysis. Moreover, the results showed the good correlation with enzyme-linked immunosorbent assay (ELISA), with the correlation coefficient of 0.9589. This proposed method has been successfully applied to the clinical determination of HE4 in the human serum.

  13. Performance characteristics of bioassay, radioenzymatic assay, homogeneous enzyme immunoassay, and high-performance liquid chromatographic determination of serum gentamicin

    International Nuclear Information System (INIS)

    Delaney, C.J.; Opheim, K.E.; Smith, A.L.; Plorde, J.J.

    1982-01-01

    We compared the accuracy, precision, and between-method error of the microbiological assay, the radioenzymatic assay, the homogeneous enzyme immunoassay, and the high-performance liquid chromatographic assay for the quantitation of gentamicin in serum. Precision and accuracy were evaluated by reference samples prepared to contain 0.0 to 32.7 micrograms of gentamicin per ml. Correlations between the methods utilized patient sera with gentamicin concentrations ranging from 0.6 to 13.3 micrograms/ml. All methods were reliable within acceptable limits for routine clinical use; intermethod correlation coefficients exceeded 0.96. Relative to the microbiological assay, the alternative methods offer the advantage of rapid analysis. The elapsed times for acquiring data on a set of 10 specimens under routine operating conditions were 0.5 h by the enzyme immunoassay, 4 h by the radioenzymatic assay, 5 h by the high-performance liquid chromatographic assay, and 10 h by the microbiological assay

  14. Color encoded microbeads-based flow cytometric immunoassay for polycyclic aromatic hydrocarbons in food

    International Nuclear Information System (INIS)

    Meimaridou, Anastasia; Haasnoot, Willem; Noteboom, Linda; Mintzas, Dimitrios; Pulkrabova, Jana; Hajslova, Jana; Nielen, Michel W.F.

    2010-01-01

    Food contamination caused by chemical hazards such as persistent organic pollutants (POPs) is a worldwide public health concern and requires continuous monitoring. The chromatography-based analysis methods for POPs are accurate and quite sensitive but they are time-consuming, laborious and expensive. Thus, there is a need for validated simplified screening tools, which are inexpensive, rapid, have automation potential and can detect multiple POPs simultaneously. In this study we developed a flow cytometry-based immunoassay (FCIA) using a color-encoded microbeads technology to detect benzo[a]pyrene (BaP) and other polycyclic aromatic hydrocarbons (PAHs) in buffer and food extracts as a starting point for the future development of rapid multiplex assays including other POPs in food, such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). A highly sensitive assay for BaP was obtained with an IC 50 of 0.3 μg L -1 using a monoclonal antibody (Mab22F12) against BaP, similar to the IC 50 of a previously described enzyme-linked immunosorbent assay (ELISA) using the same Mab. Moreover, the FCIA was 8 times more sensitive for BaP compared to a surface plasmon resonance (SPR)-based biosensor immunoassay (BIA) using the same reagents. The selectivity of the FCIAs was tested, with two Mabs against BaP for 25 other PAHs, including two hydroxyl PAH metabolites. Apart from BaP, the FCIAs can detect PAHs such as indenol[1,2,3-cd]pyrene (IP), benz[a]anthracene (BaA), and chrysene (CHR) which are also appointed by the European Food Safety Authority (EFSA) as suitable indicators of PAH contamination in food. The FCIAs results were in agreement with those obtained with gas chromatography-mass spectrometry (GC-MS) for the detection of PAHs in real food samples of smoked carp and wheat flour and has great potential for the future routine application of this assay in a simplex or multiplex format in combination with simplified extraction procedure which are

  15. Multiplex competitive microbead-based flow cytometric immunoassay using quantum dot fluorescent labels

    International Nuclear Information System (INIS)

    Yu, Hye-Weon; Kim, In S.; Niessner, Reinhard; Knopp, Dietmar

    2012-01-01

    Highlights: ► First time, duplex competitive bead-based flow cytometric immunoassay was developed using ODs. ► Antibody-coated QD detection probes and antigen-immobilized microspheres were synthesized. ► The two model target analytes were low molecular weight compounds of microbial and chemical origin. ► The determination of different water types was possible after simple filtration of samples. - Abstract: In answer to the ever-increasing need to perform the simultaneous analysis of environmental hazards, microcarrier-based multiplex technologies show great promise. Further integration with biofunctionalized quantum dots (QDs) creates new opportunities to extend the capabilities of multicolor flow cytometry with their unique fluorescence properties. Here, we have developed a competitive microbead-based flow cytometric immunoassay using QDs fluorescent labels for simultaneous detection of two analytes, bringing the benefits of sensitive, rapid and easy-of-manipulation analytical tool for environmental contaminants. As model target compounds, the cyanobacterial toxin microcystin-LR and the polycyclic aromatic hydrocarbon compound benzo[a]pyrene were selected. The assay was carried out in two steps: the competitive immunological reaction of multiple targets using their exclusive sensing elements of QD/antibody detection probes and antigen-coated microsphere, and the subsequent flow cytometric analysis. The fluorescence of the QD-encoded microsphere was thus found to be inversely proportional to target analyte concentration. Under optimized conditions, the proposed assay performed well within 30 min for the identification and quantitative analysis of the two environmental contaminants. For microcystin-LR and benzo[a]pyrene, dose–response curves with IC 50 values of 5 μg L −1 and 1.1 μg L −1 and dynamic ranges of 0.52–30 μg L −1 and 0.13–10 μg L −1 were obtained, respectively. Recovery was 92.6–106.5% for 5 types of water samples like bottled

  16. Optimization and validation of CEDIA drugs of abuse immunoassay tests in serum on Hitachi 912.

    Science.gov (United States)

    Kirschbaum, Katrin M; Musshoff, Frank; Schmithausen, Ricarda; Stockhausen, Sarah; Madea, Burkhard

    2011-10-10

    Due to sensitive limits of detection of chromatographic methods and low limit values regarding the screening of drugs under the terms of impairment in safe driving (§ 24a StVG, Street Traffic Law in Germany), preliminary immunoassay (IA) tests should be able to detect also low concentrations of legal and illegal drugs in serum in forensic cases. False-negatives should be avoided, the rate of false-positive samples should be low due to cost and time. An optimization of IA cutoff values and a validation of the assay is required for each laboratory. In a retrospective study results for serum samples containing amphetamine, methylenedioxy derivatives, cannabinoids, benzodiazepines, cocaine (metabolites), methadone and opiates obtained with CEDIA drugs of abuse reagents on a Hitachi 912 autoanalyzer were compared with quantitative results of chromatographic methods (gas or liquid chromatography coupled with mass spectrometry (GC/MS or LC/MS)). Firstly sensitivity, specificity, positive and negative predictive values and overall misclassification rates were evaluated by contingency tables and compared to ROC-analyses and Youden-Indices. Secondly ideal cutoffs were statistically calculated on the basis of sensitivity and specificity as decisive statistical criteria with focus on a high sensitivity (low rates of false-negatives), i.e. using the Youden-Index. Immunoassay (IA) and confirmatory results were available for 3014 blood samples. Sensitivity was 90% or more for nearly all analytes: amphetamines (IA cutoff 9.5 ng/ml), methylenedioxy derivatives (IA cutoff 5.5 ng/ml), cannabinoids (IA cutoff 14.5 ng/ml), benzodiazepines (IA cutoff >0 ng/ml). Test of opiates showed a sensitivity of 86% for a IA cutoff value of >0 ng/ml. Values for specificity ranged between 33% (methadone, IA cutoff 10 ng/ml) and 90% (cocaine, IA cutoff 20 ng/ml). Lower cutoff values as recommended by ROC analyses were chosen for most tests to decrease the rate of false-negatives. Analyses enabled

  17. Erythema migrans and serodiagnosis by enzyme immunoassay and immunoblot with three borrelia species.

    Science.gov (United States)

    Stanek, G; Breier, F; Menzinger, G; Schaar, B; Hafner, M; Partsch, H

    1999-12-10

    There is wide divergence of opinion between physicians regarding the use of serological measures for the diagnosis and treatment of erythema migrans, the hallmark of Lyme borreliosis. We studied the outcome of an enzyme immunoassay and immunoblot (Western blot) used on the sera of patients who had suffered tick bite and erythema migrans, and had been subsequently treated with various antibiotics. Ninety-nine consecutive patients presenting with erythema migrans after tick bite were prospectively recruited at the outpatient department of two Vienna City hospitals and at the consultation office for Lyme borreliosis of the Institute of Hygiene. University Vienna. Blood samples were taken before antibiotic treatment and 3 and 6 months thereafter. Blood samples from 100 blood donors served as controls. Antibodies against Borrelia burgdorferi sensu lato were determined by enzyme immunoassay (IgG and IgM EIA) and by IgG immunoblot. The latter was performed with isolates of B. alzelii (H2) B. burgdorferi sensu stricto (Le) and B. garinii (W) from Austrian patients. The 4 interpretation criteria for immunoblot results were: A (3 bands out of 8), B (2 bands out of 9), C and D (1 band out of 6). In all patients, the erythema resolved within the treatment period. No complications secondary to the borrelia infection were registered. After treatment there was no significant change in titre, nor was there a difference in the immunoblot pattern between the first, second and third serum samples. Serum antibodies to B. burgdorferi were positive by EIA in 22.9% (IgG) and 2.5% (IgM). Immunoblot results offered by borrelia species and by the interpretation criteria, ranging between 8.3% (criterion A, strain Le) and 44.2% (criterion D, strain H2). By EIA, control samples were IgG and IgM positive in 5% and 1%, respectively. Positive immunoblot results with strain H2 were found in 9%, 13%, 18%, and 20% by the criteria A through D respectively. After antibiotic treatment of erythema

  18. 340nm UV LED excitation in time-resolved fluorescence system for europium-based immunoassays detection

    OpenAIRE

    Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter; Pedersen, Christian

    2017-01-01

    In immunoassay analyzers for in-vitro diagnostics, Xenon flash lamps have been widely used as excitation light sources. Recent advancements in UV LED technology and its advantages over the flash lamps such as smaller footprint, better wall-plug efficiency, narrow emission spectrum, and no significant afterglow, have made them attractive light sources for gated detection systems. In this paper, we report on the implementation of a 340 nm UV LED based time-resolved fluorescence system based on ...

  19. NiCoBP-doped carbon nanotube hybrid: A novel oxidase mimetic system for highly efficient electrochemical immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bing; He, Yu; Liu, Bingqian; Tang, Dianping, E-mail: dianping.tang@fzu.edu.cn

    2014-12-03

    Highlights: • We report a new oxidase mimetic system for highly efficient electrochemical immunoassay. • NiCoBP-doped carbon nanotube hybrids were used as the nanocatalysts. • NiCoBP-doped carbon nanotube hybrids were used as the mimic oxidase. - Abstract: NiCoBP-doped multi-walled carbon nanotube (NiCoBP–MWCNT) was first synthesized by using induced electroless-plating method and functionalized with the biomolecules for highly efficient electrochemical immunoassay of prostate-specific antigen (PSA, used as a model analyte). We discovered that the as-synthesized NiCoBP–MWCNT had the ability to catalyze the glucose oxidization with a stable and well-defined redox peak. The catalytic current increased with the increment of the immobilized NiCoBP–MWCNT on the electrode. Transmission electron microscope (TEM) and energy dispersive X-ray spectrometry (EDX) were employed to characterize the as-prepared NiCoBP–MWCNT. Using the NiCoBP–MWCNT-conjugated anti-PSA antibody as the signal-transduction tag, a new enzyme-free electrochemical immunoassay protocol could be designed for the detection of target PSA on the capture antibody-functionalized immunosensing interface. Experimental results revealed that the designed immunoassay system could exhibit good electrochemical responses toward target PSA, and allowed the detection of PSA at a concentration as low as 0.035 ng mL{sup −1}. More importantly, the NiCoBP-MWCNT-based oxidase mimetic system could be further extended for the monitoring of other low-abundance proteins or disease-related biomarkers by tuning the target antibody.

  20. Positive predictive value of the immunoassay for Clostridium difficile toxin A and B detection at a private hospital.

    Science.gov (United States)

    Pérez-Topete, S E; Miranda-Aquino, T; Hernández-Portales, J A

    Clostridium difficile (C. difficile) is a Gram-positive bacillus that is a common cause of diarrhea in the hospital environment, with a documented incidence of up to 10%. There are different methods to detect it, but a widely used test in our environment is the immunoassay for toxins A and B. The aim of our study was to 1) estimate the positive predictive value of the immunoassay for the detection of the C. difficile toxins A and B, 2) to establish the incidence of C. difficile-associated diarrhea in the hospital, and 3) to know the most common associated factors. A diagnostic test accuracy study was conducted within the time frame of January 2010 to August 2013 at the Hospital Christus Muguerza® Alta Especialidad on patients with symptoms suggestive of C. difficile-associated diarrhea that had a positive immunoassay test and confirmation of C. difficile through colon biopsy and stool culture. The immunoassay for toxins A and B was performed in 360 patients. Fifty-five of the cases had positive results, 35 of which showed the presence of C. difficile. Incidence was 10.2% and the positive predictive value of the test for C. difficile toxins A and B was 0.64 (95% CI, 0.51-0.76). Previous antibiotic therapy (n=29) and proton pump inhibitor use (n=19) were the most common associated factors. C. difficile incidence in our environment is similar to that found in the literature reviewed, but the positive predictive value of the test for toxin A and B detection was low. Copyright © 2016 Asociación Mexicana de Gastroenterología. Publicado por Masson Doyma México S.A. All rights reserved.

  1. High-sensitivity detection of cardiac troponin I with UV LED excitation for use in point-of-care immunoassay

    OpenAIRE

    Rodenko, Olga; Eriksson, Susann; Tidemand-Lichtenberg, Peter; Troldborg, Carl Peder; Fodgaard, Henrik; van Os, Sylvana; Pedersen, Christian

    2017-01-01

    High-sensitivity cardiac troponin assay development enables determination of biological variation in healthy populations, more accurate interpretation of clinical results and points towards earlier diagnosis and rule-out of acute myocardial infarction. In this paper, we report on preliminary tests of an immunoassay analyzer employing an optimized LED excitation to measure on a standard troponin I and a novel research high-sensitivity troponin I assay. The limit of detection is improved by fac...

  2. Comparison between Amnisure Placental Alpha Microglobulin-1 Rapid Immunoassay and Standard Diagnostic Methods for Detection of Rupture of Membranes

    Directory of Open Access Journals (Sweden)

    Beng Kwang Ng

    2013-01-01

    Full Text Available Objective. To determine the diagnostic accuracy of placental alpha microglobulin-1 assay and standard diagnostic methods for detecting rupture of membrane. Study Design. Prospective diagnostic study, between June 2011 to November 2011 at a tertiary centre. Initial evaluation included both the standard diagnostic methods for rupture of membranes and placental alpha microglobulin-1 immunoassay. The actual rupture of membranes was diagnosed on review of the medical records after delivery (absence of membrane or a positive pad chart. Main Outcome Measures. Placental alpha microglobulin-1 immunoassay and standard diagnostic methods for diagnosis of rupture of membrane. Results. A total of 211 patients were recruited. At initial presentation, 187 patients (88.6% had ruptured membranes, while 24 patients (11.4% had intact membranes. Placental alpha microglobulin-1 immunoassay confirmed rupture of membranes at initial presentation with a sensitivity of 95.7% (179 of 187, specificity of 100% (24 of 24, positive predictive value of 100% (179 of 179, and negative predictive value of 75.0% (24 of 32. By comparison, the conventional standard diagnostic methods had a sensitivity of 78.1% (146 of 187, specificity of 100% (24 of 24, positive predictive value of 100% (146 of 146, and negative predictive value of 36.9% (24 of 65 in diagnosing rupture of membrane. Conclusion. Placental alpha-microglobulin-1 immunoassay is a rapid and accurate method for confirming the diagnosis of rupture of membrane. It was superior to conventional standard diagnostic methods (pooling, nitrazine, and ferning, the nitrazine test alone or fern test alone.

  3. Magnetic bead and gold nanoparticle probes based immunoassay for β-casein detection in bovine milk samples.

    Science.gov (United States)

    Li, Y S; Meng, X Y; Zhou, Y; Zhang, Y Y; Meng, X M; Yang, L; Hu, P; Lu, S Y; Ren, H L; Liu, Z S; Wang, X R

    2015-04-15

    In this work, a double-probe based immunoassay was developed for rapid and sensitive determination of β-casein in bovine milk samples. In the method, magnetic beads (MBs), employed as supports for the immobilization of anti-β-casein polyclonal antibody (PAb), were used as the capture probe. Colloidal gold nanoparticles (AuNPs), employed as a bridge for loading anti-β-casein monoclonal antibody (McAb) and horseradish peroxidase (HRP), were used as the amplification probe. The presence of β-casein causes the sandwich structures of MBs-PAb-β-casein-McAb-AuNPs through the interaction between β-casein and the anti-β-casein antibodies. The HRP, used as an enzymatic-amplified tracer, can catalytically oxidize the substrate 3,3',5,5'-tetramethylbenzidine (TMB), generating optical signals that are proportional to the quantity of β-casein. The linear range of the immunoassay was from 6.5 to 1520ngmL(-1). The limit of detection (LOD) was 4.8ngmL(-1) which was 700 times lower than that of MBs-antibody-HRP based immunoassay and 6-7 times lower than that from the microplate-antibody-HRP based assay. The recoveries of β-casein from bovine milk samples were from 95.0% to 104.3% that had a good correlation coefficient (R(2)=0.9956) with those obtained by an official standard Kjeldahl method. For higher sensitivity, simple sample pretreatment and shorter time requirement of the antigen-antibody reaction, the developed immunoassay demonstrated the viability for detection of β-casein in bovine milk samples. Copyright © 2014. Published by Elsevier B.V.

  4. Detection of soluble antigens of Toxoplasma gondii by a four-layer modification of an enzyme immunoassay.

    OpenAIRE

    Turunen, H J

    1983-01-01

    A sensitive four-layer modification of an enzyme immunoassay for the detection of soluble antigens of Toxoplasma gondii is described. Microtiter plates were sensitized with rabbit anti-toxoplasma immunoglobulins (6 micrograms/ml) used as the primary antibodies; guinea pig anti-toxoplasma immunoglobulins (6 micrograms/ml) were used as the secondary trapping antibodies. Horseradish peroxidase-conjugated anti-guinea pig immunoglobulins were used as the indicator antibodies. The specificity of th...

  5. Multicentric Evaluation of New Commercial Enzyme Immunoassays for the Detection of Immunoglobulin M and Total Antibodies against Hepatitis A Virus▿

    Science.gov (United States)

    Arcangeletti, M. C.; Dussaix, E.; Ferraglia, F.; Roque-Afonso, A. M.; Graube, A.; Chezzi, C.

    2011-01-01

    A multicentric clinical study was conducted on representative sera from 1,738 European and U.S. subjects for the evaluation of new anti-hepatitis A virus enzyme immunoassays from Bio-Rad Laboratories. Comparison with reference DiaSorin S.p.A. tests confirmed the good performance of Bio-Rad assays (99.85% and 99.47% overall agreement in detecting total antibodies and IgM, respectively). PMID:21653739

  6. Mass cytometry: technique for real time single cell multitarget immunoassay based on inductively coupled plasma time-of-flight mass spectrometry.

    Science.gov (United States)

    Bandura, Dmitry R; Baranov, Vladimir I; Ornatsky, Olga I; Antonov, Alexei; Kinach, Robert; Lou, Xudong; Pavlov, Serguei; Vorobiev, Sergey; Dick, John E; Tanner, Scott D

    2009-08-15

    A novel instrument for real time analysis of individual biological cells or other microparticles is described. The instrument is based on inductively coupled plasma time-of-flight mass spectrometry and comprises a three-aperture plasma-vacuum interface, a dc quadrupole turning optics for decoupling ions from neutral components, an rf quadrupole ion guide discriminating against low-mass dominant plasma ions, a point-to-parallel focusing dc quadrupole doublet, an orthogonal acceleration reflectron analyzer, a discrete dynode fast ion detector, and an 8-bit 1 GHz digitizer. A high spectrum generation frequency of 76.8 kHz provides capability for collecting multiple spectra from each particle-induced transient ion cloud, typically of 200-300 micros duration. It is shown that the transients can be resolved and characterized individually at a peak frequency of 1100 particles per second. Design considerations and optimization data are presented. The figures of merit of the instrument are measured under standard inductively coupled plasma (ICP) operating conditions ( 900 for m/z = 159, the sensitivity with a standard sample introduction system of >1.4 x 10(8) ion counts per second per mg L(-1) of Tb and an abundance sensitivity of (6 x 10(-4))-(1.4 x 10(-3)) (trailing and leading masses, respectively) are shown. The mass range (m/z = 125-215) and abundance sensitivity are sufficient for elemental immunoassay with up to 60 distinct available elemental tags. When 500) can be used, which provides >2.4 x 10(8) cps per mg L(-1) of Tb, at (1.5 x 10(-3))-(5.0 x 10(-3)) abundance sensitivity. The real-time simultaneous detection of multiple isotopes from individual 1.8 microm polystyrene beads labeled with lanthanides is shown. A real time single cell 20 antigen expression assay of model cell lines and leukemia patient samples immuno-labeled with lanthanide-tagged antibodies is presented.

  7. netherland hydrological modeling instrument

    Science.gov (United States)

    Hoogewoud, J. C.; de Lange, W. J.; Veldhuizen, A.; Prinsen, G.

    2012-04-01

    Netherlands Hydrological Modeling Instrument A decision support system for water basin management. J.C. Hoogewoud , W.J. de Lange ,A. Veldhuizen , G. Prinsen , The Netherlands Hydrological modeling Instrument (NHI) is the center point of a framework of models, to coherently model the hydrological system and the multitude of functions it supports. Dutch hydrological institutes Deltares, Alterra, Netherlands Environmental Assessment Agency, RWS Waterdienst, STOWA and Vewin are cooperating in enhancing the NHI for adequate decision support. The instrument is used by three different ministries involved in national water policy matters, for instance the WFD, drought management, manure policy and climate change issues. The basis of the modeling instrument is a state-of-the-art on-line coupling of the groundwater system (MODFLOW), the unsaturated zone (metaSWAP) and the surface water system (MOZART-DM). It brings together hydro(geo)logical processes from the column to the basin scale, ranging from 250x250m plots to the river Rhine and includes salt water flow. The NHI is validated with an eight year run (1998-2006) with dry and wet periods. For this run different parts of the hydrology have been compared with measurements. For instance, water demands in dry periods (e.g. for irrigation), discharges at outlets, groundwater levels and evaporation. A validation alone is not enough to get support from stakeholders. Involvement from stakeholders in the modeling process is needed. There fore to gain sufficient support and trust in the instrument on different (policy) levels a couple of actions have been taken: 1. a transparent evaluation of modeling-results has been set up 2. an extensive program is running to cooperate with regional waterboards and suppliers of drinking water in improving the NHI 3. sharing (hydrological) data via newly setup Modeling Database for local and national models 4. Enhancing the NHI with "local" information. The NHI is and has been used for many

  8. Developments in analytical instrumentation

    Science.gov (United States)

    Petrie, G.

    The situation regarding photogrammetric instrumentation has changed quite dramatically over the last 2 or 3 years with the withdrawal of most analogue stereo-plotting machines from the market place and their replacement by analytically based instrumentation. While there have been few new developments in the field of comparators, there has been an explosive development in the area of small, relatively inexpensive analytical stereo-plotters based on the use of microcomputers. In particular, a number of new instruments have been introduced by manufacturers who mostly have not been associated previously with photogrammetry. Several innovative concepts have been introduced in these small but capable instruments, many of which are aimed at specialised applications, e.g. in close-range photogrammetry (using small-format cameras); for thematic mapping (by organisations engaged in environmental monitoring or resources exploitation); for map revision, etc. Another innovative and possibly significant development has been the production of conversion kits to convert suitable analogue stereo-plotting machines such as the Topocart, PG-2 and B-8 into fully fledged analytical plotters. The larger and more sophisticated analytical stereo-plotters are mostly being produced by the traditional mainstream photogrammetric systems suppliers with several new instruments and developments being introduced at the top end of the market. These include the use of enlarged photo stages to handle images up to 25 × 50 cm format; the complete integration of graphics workstations into the analytical plotter design; the introduction of graphics superimposition and stereo-superimposition; the addition of correlators for the automatic measurement of height, etc. The software associated with this new analytical instrumentation is now undergoing extensive re-development with the need to supply photogrammetric data as input to the more sophisticated G.I.S. systems now being installed by clients, instead

  9. Silver nanoparticles deposited on graphene oxide for ultrasensitive surface-enhanced Raman scattering immunoassay of cancer biomarker.

    Science.gov (United States)

    Yang, Lin; Zhen, Shu Jun; Li, Yuan Fang; Huang, Cheng Zhi

    2018-06-14

    Graphene oxide (GO) exhibits distinctive Raman scattering features for its high frequency D (disordered) and tangential modes (G-band), which are characteristically sharp at 1580 cm-1 and 1350 cm-1, respectively, but are too weak for sensitive quantitation purposes. By depositing silver nanoparticles on the surface of GO in this contribution, both D and G bands of GO become enhanced. The enzyme label of this method controls the dissolution of silver nanoparticles on the surface of GO through hydrogen peroxide which is produced by the oxidation of the enzyme substrate. With the dissolution of the silver nanoparticles a greatly decreased SERS signal of GO was obtained. This strategy involves dual signal amplification of the enzyme and nanocomposites to improve the detection sensitivity. As a proof of concept, prostate specific antigen (PSA), a biomarker for prostate cancer, is successfully detected as a target by forming a sandwich structure in immunoassay. The SERS immunoassay possesses excellent analytical performance in the range 0.5 pg mL-1 to 500 pg mL-1 with a limit of detection of 0.23 pg mL-1, making the detection of PSA serum samples from prostate cancer patients satisfactory, demonstrating that the sensitive enzyme-assisted dissolved AgNPs SERS immunoassay of PSA has potential applications in clinical diagnosis.

  10. A sulfhydryl-reactive ruthenium (II complex and its conjugation to protein G as a universal reagent for fluorescent immunoassays.

    Directory of Open Access Journals (Sweden)

    Jing-Tang Lin

    Full Text Available To develop a fluorescent ruthenium complex for biosensing, we synthesized a novel sulfhydryl-reactive compound, 4-bromophenanthroline bis-2,2'-dipyridine Ruthenium bis (hexafluorophosphate. The synthesized Ru(II complex was crosslinked with thiol-modified protein G to form a universal reagent for fluorescent immunoassays. The resulting Ru(II-protein G conjugates were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE. The emission peak wavelength of the Ru(II-protein G conjugate was 602 nm at the excitation of 452 nm which is similar to the spectra of the Ru(II complex, indicating that Ru(II-protein G conjugates still remain the same fluorescence after conjugation. To test the usefulness of the conjugate for biosensing, immunoglobulin G (IgG binding assay was conducted. The result showed that Ru(II-protein G conjugates were capable of binding IgG and the more cross-linkers to modify protein G, the higher conjugation efficiency. To demonstrate the feasibility of Ru(II-protein G conjugates for fluorescent immunoassays, the detection of recombinant histidine-tagged protein using the conjugates and anti-histidine antibody was developed. The results showed that the histidine-tagged protein was successfully detected with dose-response, indicating that Ru(II-protein G conjugate is a useful universal fluorescent reagent for quantitative immunoassays.

  11. Accurate Point-of-Care Detection of Ruptured Fetal Membranes: Improved Diagnostic Performance Characteristics with a Monoclonal/Polyclonal Immunoassay

    Directory of Open Access Journals (Sweden)

    Linda C. Rogers

    2016-01-01

    Full Text Available Objective Accurate and timely diagnosis of rupture of membranes (ROM is imperative to allow for gestational age-specific interventions. This study compared the diagnostic performance characteristics between two methods used for the detection of ROM as measured in the same patient. Methods Vaginal secretions were evaluated using the conventional fern test as well as a point-of-care monoclonal/polyclonal immunoassay test (ROM Plus® in 75 pregnant patients who presented to labor and delivery with complaints of leaking amniotic fluid. Both tests were compared to analytical confirmation of ROM using three external laboratory tests. Diagnostic performance characteristics were calculated including sensitivity, specificity, positive predictive value (PPV, negative predictive value (NPV, and accuracy. Results Diagnostic performance characteristics uniformly favored ROM detection using the immunoassay test compared to the fern test: sensitivity (100% vs. 77.8%, specificity (94.8% vs. 79.3%, PPV (75% vs. 36.8%, NPV (100% vs. 95.8%, and accuracy (95.5% vs. 79.1%. Conclusions The point-of-care immunoassay test provides improved diagnostic accuracy for the detection of ROM compared to fern testing. It has the potential of improving patient management decisions, thereby minimizing serious complications and perinatal morbidity.

  12. Homogeneous immunoassay for human IgG using oriented hen egg IgY immobilized on gold sol nanoparticles

    International Nuclear Information System (INIS)

    Yeritsyan, H.E.; Gasparyan, V.K.

    2012-01-01

    Homogeneous immunoassays using (red) gold nanoparticles represent an attractive detection scheme because of the option of photometric readout. We have applied oriented immobilization of hen egg immunoglobulin Y (IgY) on gold nanoparticles when developing a homogeneous immunoassay for human IgG. In oriented immobilization, as opposed to random immobilization, the antigen binding capabilities of the antibodies are retained. It is shown that such immunoassay has significantly better sensitivity in comparison with methods based on conventional immobilization of affinity-purified antibodies. It is also shown that hen egg IgY is better suited than rabbit antibodies, because much more antibody can be immobilized on gold nanoparticles without any destabilization, probably because of the more acidic nature of these antibodies. In addition, hen egg IgY can be supplied in higher quantity and can be prepared more easily than IgG from rabbits. Bleeding and slaughtering of animals is not needed. The assay presented here has a wide detection range (30-500 ng. mL -1 ) and a limit of detection as low as 30 ng. mL -1 of human IgG. (author)

  13. Oriented antibody immobilization to polystyrene macrocarriers for immunoassay modified with hydrazide derivatives of poly(methacrylic acid

    Directory of Open Access Journals (Sweden)

    Vinokurova Ludmila G

    2001-08-01

    Full Text Available Abstract Background Hydrophobic polystyrene is the most common material for solid phase immunoassay. Proteins are immobilized on polystyrene by passive adsorption, which often causes considerable denaturation. Biological macromolecules were found to better retain their functional activity when immobilized on hydrophilic materials. Polyacrylamide is a common material for solid-phase carriers of biological macromolecules, including immunoreagents used in affinity chromatography. New macroformats for immunoassay modified with activated polyacrylamide derivatives seem to be promising. Results New polymeric matrices for immunoassay in the form of 0.63-cm balls which contain hydrazide functional groups on hydrophilic polymer spacer arms at their surface shell are synthesized by modification of aldehyde-containing polystyrene balls with hydrazide derivatives of poly(methacrylic acid. The beads contain up to 0.31 μmol/cm2 active hydrazide groups accessible for covalent reaction with periodate-oxidized antibodies. The matrices obtained allow carrying out the oriented antibody immobilization, which increases the functional activity of immunosorbents. Conclusions An efficient site-directed antibody immobilization on a macrosupport is realized. The polymer hydrophilic spacer arms are the most convenient and effective tools for oriented antibody coupling with molded materials. The suggested scheme can be used for the modification of any other solid supports containing electrophilic groups reacting with hydrazides.

  14. Inkjet-printed point-of-care immunoassay on a nanoscale polymer brush enables subpicomolar detection of analytes in blood

    Science.gov (United States)

    Joh, Daniel Y.; Hucknall, Angus M.; Wei, Qingshan; Mason, Kelly A.; Lund, Margaret L.; Fontes, Cassio M.; Hill, Ryan T.; Blair, Rebecca; Zimmers, Zackary; Achar, Rohan K.; Tseng, Derek; Gordan, Raluca; Freemark, Michael; Ozcan, Aydogan; Chilkoti, Ashutosh

    2017-08-01

    The ELISA is the mainstay for sensitive and quantitative detection of protein analytes. Despite its utility, ELISA is time-consuming, resource-intensive, and infrastructure-dependent, limiting its availability in resource-limited regions. Here, we describe a self-contained immunoassay platform (the “D4 assay”) that converts the sandwich immunoassay into a point-of-care test (POCT). The D4 assay is fabricated by inkjet printing assay reagents as microarrays on nanoscale polymer brushes on glass chips, so that all reagents are “on-chip,” and these chips show durable storage stability without cold storage. The D4 assay can interrogate multiple analytes from a drop of blood, is compatible with a smartphone detector, and displays analytical figures of merit that are comparable to standard laboratory-based ELISA in whole blood. These attributes of the D4 POCT have the potential to democratize access to high-performance immunoassays in resource-limited settings without sacrificing their performance.

  15. A GC Instrument Simulator

    Science.gov (United States)

    Armitage, D. Bruce

    1999-02-01

    This simulator was developed to help students beginning the study of gas chromatographic instruments to understand their operation. It is not meant to teach chromatographic theory. The instrument simulator is divided into 5 sections. One is for sample preparation. Another is used to manage carrier gases and choose a detector and column. The third sets the conditions for either isothermal or programmed temperature operation. A fourth section models manual injections, and the fifth is the autosampler. The operator has a choice among 6 columns of differing diameters and packing polarities and a choice of either isothermal or simple one-stage temperature programming. The simulator can be operated in either single-sample mode or as a 10-sample autosampler. The integrator has two modes of operation, a "dumb" mode in which only the retention time, area of the peak, and percentage area are listed and a "smart" mode that also lists the components' identities. The identities are obtained from a list of names and retention times created by the operator. Without this list only the percentages and areas are listed. The percentages are based on the areas obtained from the chromatogram and not on the actual percentages assigned during sample preparation. The data files for the compounds used in the simulator are ASCII files and can be edited easily to add more compounds than the 11 included with the simulator. A maximum of 10 components can be used in any one sample. Sample mixtures can be made on a percent-by-volume basis, but not by mass of sample per volume of solvent. A maximum of 30 compounds can be present in any one file, but the number of files is limited only by the operating system. (I suggest that not more than 20 compounds be used in any one file, as scrolling through large numbers of compounds is annoying to say the least.) File construction and layout are discussed in detail in the User's Manual. Chromatograms are generated by calculating a retention time based on

  16. Data acquisition instruments: Psychopharmacology

    Energy Technology Data Exchange (ETDEWEB)

    Hartley, D.S. III

    1998-01-01

    This report contains the results of a Direct Assistance Project performed by Lockheed Martin Energy Systems, Inc., for Dr. K. O. Jobson. The purpose of the project was to perform preliminary analysis of the data acquisition instruments used in the field of psychiatry, with the goal of identifying commonalities of data and strategies for handling and using the data in the most advantageous fashion. Data acquisition instruments from 12 sources were provided by Dr. Jobson. Several commonalities were identified and a potentially useful data strategy is reported here. Analysis of the information collected for utility in performing diagnoses is recommended. In addition, further work is recommended to refine the commonalities into a directly useful computer systems structure.

  17. Social Responsibility Instruments

    Directory of Open Access Journals (Sweden)

    Katarzyna Mizera

    2008-09-01

    Full Text Available Responsible business notion is more and more present in Polish economy, however the results of the research carried out in Polish business still shows a low level of CRS idea knowledge, especially in small and medium companies. Although responsible business notion is generally known, its details, ways of preparing strategy, instruments and what is more its benefits are still narrowly spread. Many business people face the lack of knowledge and information, which on one hand make it easier to spread and deepen wrong stereotypes connected with this notion and on the other hand make business people unwilling to implement CRS in their companies. The subjects of this article are examples of instruments which are responsible for realization of social responsibility strategy.

  18. Radiation measuring instrument

    International Nuclear Information System (INIS)

    Genrich, V.

    1985-01-01

    A highly sensitive and compactly structured radiation measuring instrument for detecting ionizing radiation, in particular for measuring dose rates and contamination. The laminar structure of the associated counter tube, using only a few, simple plastic parts and a highly elastic counter wire, makes it possible to use the simplest manufacturing techniques. The service life of the counter tube construction, which is completely and permanently sealed and filled with gas, is expected to be more than 12 years. The described counter tube can be adapted in optimal fashion to the available space in a pocket instrument if it is used in combination with a specialized high-voltage generator which is low in interference voltage and with a pulse evaluation circuit having a means of compensating for interference voltage

  19. Radon-Instrumentation

    International Nuclear Information System (INIS)

    Moreno y Moreno, A.

    2003-01-01

    The presentation of the active and passive methods for radon, their identification and measure, instrumentation and characteristics are the objectives of this work. Active detectors: Active Alpha Cam Continuous Air Monitor, Model 758 of Victoreen, Model CMR-510 Continuous Radon Monitor of the Signature Femto-Tech. Passive detectors: SSNTD track detectors in solids Measurement Using Charcoal Canisters, disk of activated coal deposited in a metallic box Electrets Methodology. (Author)

  20. Testing Aircraft Instruments.

    Science.gov (United States)

    1981-02-11

    1. Have test data been collected, recorded, and presented in accordance with this TOP? Yes No Comment : 2. Were the facilities, test equipment...instrumentation, and support accommodations adequate to accomplish the test objectives? Yes No Comment : 3. Have all data collected been reviewed for...correctness and completeness? Yes No Comment : 4. Were the test results compromised in any way due to insufficient test planning? Yes No Comment : 5. Were the

  1. Transgressive or Instrumental?

    DEFF Research Database (Denmark)

    Chemi, Tatiana

    2018-01-01

    Contemporary practices that connect the arts with learning are widespread at all level of educational systems and in organisations, but they include very diverse approaches, multiple methods and background values. Regardless of explicit learning benefits, the arts/learning partnerships bring about...... creativity and the other on practices of arts-integration. My final point rests on the belief that the opposition of transgression and instrumentality is a deceiving perspective on the arts, against the background of the aesthetic plurality and hybridity....

  2. Evaluation of enzyme immunoassay techniques for diagnosis of the most common intestinal protozoa in fecal samples.

    Science.gov (United States)

    Gaafar, Maha R

    2011-08-01

    This study was designed to evaluate the antigen capture enzyme immunoassays (EIAs) Triage parasite panel and TechLab Entamoeba histolytica II in detecting Giardia intestinalis, Cryptosporidium sp, and Entamoeba histolytica in fecal samples in comparison to microscopy, and in differentiating Entamoeba histolytica from Entamoeba dispar. The Triage EIA was evaluated using 100 stool specimens that were tested by standard ova and parasite examination, including staining with both trichrome and modified acid-fast stains. Differentiation between E. histolytica and E. dispar was performed using TechLab. Microscopic examination revealed that 19% of the samples were positive for Giardia, 4% for Cryptosporidium, and 1% for E. histolytica/E. dispar, and other parasites were found in 5%. By Triage, 23% of the samples were infected with Giardia, 5% with Cryptosporidium, and 2% with E. histolytica/E. dispar. Triage showed a sensitivity of 100% and specificity of 91.5%. The TechLab assay was negative for both samples diagnosed as E. histolytica/E. dispar by Triage, which suggested that they were E. dispar. Both tests showed no cross-reactivity with other intestinal protozoa. These results indicate that antigen detection by EIA has the potential to become a valuable tool, capable of making stool diagnostics more effective. Copyright © 2011 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  3. Nanobody-based enzyme immunoassay for ochratoxin A in cereal with high resistance to matrix interference.

    Science.gov (United States)

    Liu, Xing; Tang, Zongwen; Duan, Zhenhua; He, Zhenyun; Shu, Mei; Wang, Xianxian; Gee, Shirley J; Hammock, Bruce D; Xu, Yang

    2017-03-01

    A sensitive indirect competitive nanobody-based enzyme linked immunosorbent assay (Nb-ELISA) for ochratoxin A (OTA) with high resistance to cereal matrix interference was developed. Nanobodies against OTA (Nb15, Nb28, Nb32, Nb36) were expressed in E. coli cells and their thermal stabilities were compared with that of an OTA-specific monoclonal antibody 6H8. All nanobodies could still retain their antigen-binding activity after exposure to temperature 95°C for 5min or to 90°C for 75min. Nb28 that exhibited the highest sensitivity in ELISA was selected for further research. An indirect competitive ELISA based on Nb28 was developed for OTA, with an IC 50 of 0.64ng/mL and a linear range (IC 20 -IC 80 ) of 0.27-1.47ng/mL. Cereal samples were analyzed following a 2.5 fold dilution of sample extracts, showing the good resistance to matrix interference of the Nb-ELSIA. The recovery of spiked cereal samples (rice, oats, barley) ranged from 80% to 105% and the Nb-ELISA results of OTA content in naturally contamined samples were in good agreement with those determined by a commercial ELISA kit. The results indicated the reliablity of nanobody as a promising immunoassay reagent for detection of mycotoxins in food matrix and its potential in biosensor development. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. An efficient enzyme immunoassay for glutamate using glutaraldehyde coupling of the hapten to microtiter plates.

    Science.gov (United States)

    Ordronneau, P; Abdullah, L H; Petrusz, P

    1991-09-13

    In order to coat microtiter plates for enzyme immunoassays (EIAs), amino acids and other haptens are usually coupled to larger protein molecules. The formation of such conjugates is not always reproducible. This may lead to inconsistent hapten-protein stoichiometries, unfavorable orientation of the hapten on the protein and/or well-to-well variation in the concentration of the available hapten. In the assay described here the excitatory amino acid (EAA) Glu is coupled directly to polystyrene microtiter wells with GA. Each step of the assay was tested for maximum efficiency. The resulting EIA with Glu as a competitor gave excellent reproducibility (coefficient of variation = 5.87%), an EC50 of 2.02 X 10(-5) M and a detection limit of 1.26 X 10(-6) M. This EIA method is generally useful for a variety of antisera to amino acids and small peptides and a wide range of competing substances. It can be used to characterize the conformational requirements for antigen binding, to assay for glutamate or to identify compounds with glutamate-like structure in unknown solutions.

  5. Biconically Tapered Fiber Optic Probes for Rapid Label-Free Immunoassays

    Directory of Open Access Journals (Sweden)

    John Miller

    2015-04-01

    Full Text Available We report use of U-shaped biconically tapered optical fibers (BTOF as probes for label-free immunoassays. The tapered regions of the sensors were functionalized by immobilization of immunoglobulin-G (Ig-G and tested for detection of anti-IgG at concentrations of 50 ng/mL to 50 µg/mL. Antibody-antigen reaction creates a biological nanolayer modifying the waveguide structure leading to a change in the sensor signal, which allows real-time monitoring. The kinetics of the antibody (mouse Ig-G-antigen (rabbit anti-mouse IgG reactions was studied. Hydrofluoric acid treatment makes the sensitive region thinner to enhance sensitivity, which we confirmed by experiments and simulations. The limit of detection for the sensor was estimated to be less than 50 ng/mL. Utilization of the rate of the sensor peak shift within the first few minutes of the antibody-antigen reaction is proposed as a rapid protein detection method.

  6. A sensitive chemiluminescent immunoassay to detect Chromotrope FB (Chr FB) in foods.

    Science.gov (United States)

    Xu, Kun; Long, Hao; Xing, Rongge; Yin, Yongmei; Eremin, Sergei A; Meng, Meng; Xi, Rimo

    2017-03-01

    Chromotrope FB (Chr FB) is a synthetic azo dye permitted for use in foods and medicines. An acceptable daily intake (ADI) of Chr FB was 0-0.5mg/kg in China. In this study, we synthesized a Chr FB hapten with an amino group to prepare its artificial immunogen. Polyclonal antibodies obtained from New Zealand rabbits were applied to develop an indirect competitive chemiluminescent immunoassay (icCLIA) to detect Chr FB in foods. A horseradish peroxidase (HRP)-luminol-H 2 O 2 system was used to yield CL signal with p-iodophenol as an enhancement reagent. The method showed good specificity towards Chr FB and could detect as low as 0.02ngmL -1 Chr FB in buffer, 0.07ngg -1 in yoghurt candy, 0.07ngg -1 in vitamin drink and 0.13ngg -1 in bread. Compared with HPLC method, the proposed method is more sensitive by two orders of magnitude. The accuracy and precision of this method are acceptable and comparable with HPLC method. Therefore, the proposed method could be used for rapid screening of Chr FB in the mentioned foodstuffs. Copyright © 2016. Published by Elsevier B.V.

  7. Capillary electrochromatography immunoassay for alpha-fetoprotein based on poly(guanidinium ionic liquid) monolithic material.

    Science.gov (United States)

    Liu, Cuicui; Deng, Qiliang; Fang, Guozhen; Dang, Meng; Wang, Shuo

    2017-08-01

    Alpha-fetoprotein (AFP) is widely used as a tumor marker for the serum diagnosis of primary hepatoma. Sensitive detection of AFP level plays an important role in the early diagnosis of disease and highly reliable prediction. In this study, a novel non-competitive immunoassay (IA) based on poly(guanidinium ionic liquid) monolithic material was developed for detecting ultra trace levels of AFP in capillary electrochromatography (CEC) mode. The AFP was mixed with an excess amount of fluorescently labeled antibody. After incubation, the immunocomplex was separated from the free labeled antibody and detected by CEC coupled with laser-induced fluorescence detector. Under the optimized conditions, the developed CEC-IA performed a low detection limit of 0.05 μg L -1  (S/N = 3) and a wide linearity ranging from 0.1 to 1000 μg L -1 for AFP, which can be largely attributed to the high separation and enrichment efficiency of poly(guanidinium ionic liquid) monolithic material for the targets. The application of this method was demonstrated by determining AFP in human serum. Copyright © 2017. Published by Elsevier Inc.

  8. Development of a Smartphone-based reading system for lateral flow immunoassay.

    Science.gov (United States)

    Lee, Sangdae; Kim, Giyoung; Moon, Jihea

    2014-11-01

    This study was conducted to develop and evaluate the performance of the Smartphone-based reading system for the lateral flow immunoassay (LFIA). Smartphone-based reading system consists of a Samsung Galaxy S2 Smartphone, Smartphone application, and a LFIA reader. LFIA reader is composed of the close-up lens with a focal length up to 30 mm, white LED light, lithium polymer battery, and main body. The Smartphone application for image acquisition and data analysis was developed on the Android platform. The standard curve was obtained by plotting the measured P(T)/P(c) or A(T)/A(c) ratio versus Salmonella standard concentration. The mean, standard deviation (SD), recovery, and relative standard deviation (RSD) were also calculated using additional experimental results. These data were compared with that obtained from the benchtop LFIA reader. The LOD in both systems was observed with 10(6) CFU/mL. The results show high accuracy and good reproducibility with a RSD less than 10% in the range of 10(6) to 10(9) CFU/mL. Due to the simple structure, good sensitivity, and high accuracy of the Smartphone-based reading system, this system can be substituted for the benchtop LFIA reader for point-of-care medical diagnostics.

  9. [Use of monoclonal antibodies against horse immunoglobulin in an enzyme immunoassay of bacterial toxins and anatoxins].

    Science.gov (United States)

    Burkin, M A; Gal'vidis, I A; Iakovleva, I V; Sviridov, V V

    2007-01-01

    Immunization of BALB/c mice by horse antiserum against diphtheria made it possible to obtain IgG1 monoclonal antibodies (MoAbs) 2B7E4 specific for light chains of horse immunoglobulin (Ig). Unlike commercial preparations of anti-horse immunoglobulin antibodies, which are specific for the whole Ig molecule or its Fc-fragment, the peroxidase (HRP) conjugate of the MoAb, 2B7E4-HRP did not interact with human, mouse, rabbit, and sheep Igs, or horse albumin. The conjugate obtained was used with MoAbs against bacterial toxins and commercial horse anatoxins, as a universal reagent in sandwich enzyme immunoassay (ELISA) for bacterial toxins and anatoxins. The detection sensitivity of diphtheria toxin/anatoxin equaled 0.0005 Lf/ml; tetanus toxin and anatoxin were detected with sensitivities of 20 LD50/ml and 0.005 UI/ml, respectively. A similar sandwich ELISA for botulinum anatoxins (group measurement) allowed types A, B, and E to be detected at 0.02, 0.002, and 0.001 UI/ml, respectively; selective measurement was only possible in the case of type E anatoxin (0.001 UI/ml).

  10. Fieldable, real-time enzyme immunoassay kits for drugs on surfaces

    Science.gov (United States)

    Chiappini, Michele W.; Wendel, Gregory J.; Duquette, Peter H.; Hamilton, Martha J.; Chudzik, Stephen J.; Chappa, Ralph A.

    1994-03-01

    Immunoassays (e.g., RIA, EIA) have been demonstrated to be useful for rapid, convenient detection and semiquantitative analysis of drugs. Thermedics Detection, Inc. manufactures a rapid, sensitive, self-contained, disposable, EIA device, developed by Bio-Metric Systems, Inc., designed to allow untrained personnel to perform in field situations. This format has been developed for drugs in biological fluids and on surfaces. The analyte in the test sample competes with an enzyme-analyte conjugate for a limited number of immobilized antibody sites. The AccuPRESS Test format can detect analytes at 10 ppb in biological fluids, water, and soil, and on surfaces, such as suitcases, vehicles, tables and hands, with positive results indicated by clearly visible color development within 5 minutes. This format is designed to have all dry components and to have an ambient shelf life of greater than one year. The format is available for cocaine and opiate derivatives, including heroin, and is readily adaptable for use with numerous other drugs, explosives, and environmental pollutants.

  11. Microsphere-based immunoassay integrated with a microfluidic network to perform logic operations

    International Nuclear Information System (INIS)

    Sabhachandani, Pooja; Cohen, Noa; Sarkar, Saheli; Konry, Tania

    2015-01-01

    Lab on a chip (LOC) intelligent diagnostics can be described by molecular logic-based circuits. We report on the development of an LOC approach with logic capability for screening combinations of antigen and antibody in the same sample. A microsphere-based immunoassay was integrated with a microfluidic network device to perform the logic operations AND and INHIBIT. Using the clinically relevant biomarkers TNF-α cytokine and anti-TNF-α antibody, we obtained a fluorescent output in the presence of both inputs. This results in an AND operation, while the presence of only one specific input results in a different fluorescent signal, thereby indicating the INHIBIT operation. This approach demonstrates the effective use of molecular logic computation for developing portable, point-of-care technologies for diagnostic purposes due to fast detection times, minimal reagent consumption and low costs. This model system may be further expanded to screening of multiple disease markers, combinatorial logic applications, and developing “smart” sensors and therapeutic technologies. (author)

  12. Electrochemical Immunoassay Using Open Circuit Potential Detection Labeled by Platinum Nanoparticles

    Directory of Open Access Journals (Sweden)

    Kanokwan Charoenkitamorn

    2018-02-01

    Full Text Available In this work, a simple electrochemical immunoassay based on platinum nanoparticles (PtNPs using open circuit potential (OCP detection was developed. The detection of human chorionic gonadotropin hormone (hCG as a model analyte, was demonstrated by direct electrical detection of PtNPs in hydrazine solution using OCP measurement without any application of either potential or current to the system. Disposable screen-printed carbon electrodes (SPCEs were utilized for the development of our immunosensor, which required a sample volume as small as 2 μL. After preparation of a sandwich-type immunosystem, hydrazine solution was dropped on the electrode’s surface, which was followed immediately by electrical detection using OCP. The change of the OCP signal originated from electrocatalytic oxidation of the hydrazine on PtNPs. Under the optimal conditions of a pH of 6.0 and a hydrazine concentration of 1 mM, a detection limit of 0.28 ng mL−1 and a linearity of 0–10 ng mL−1 were obtained. The PtNP-based OCP method is a simpler electrochemical detection procedure than those obtained from other electrochemical methods and has an acceptable sensitivity and reproducibility. The simplicity of the detection procedure and the cost-effectiveness of the disposable SPCE illustrate the attractive benefits of this sensor. Moreover, it could be applied to a simplified and miniaturized diagnostic system with minimal user manipulation.

  13. Pharmacokinetic analysis of topical tobramycin in equine tears by automated immunoassay.

    Science.gov (United States)

    Czerwinski, Sarah L; Lyon, Andrew W; Skorobohach, Brian; Léguillette, Renaud

    2012-08-21

    Ophthalmic antibiotic therapy in large animals is often used empirically because of the lack of pharmacokinetics studies. The purpose of the study was to determine the pharmacokinetics of topical tobramycin 0.3% ophthalmic solution in the tears of normal horses using an automated immunoassay analysis. The mean tobramycin concentrations in the tears at 5, 10, 15, 30 minutes and 1, 2, 4, 6 hours after administration were 759 (±414), 489 (±237), 346 (±227), 147 (±264), 27.6 (±28.4), 14.8 (±66.6), 6.7 (±18.6), and 23.4 (±73.4) mg/L. Mean tobramycin concentration was maintained above the MIC90 for commonly isolated bacteria for 68.5 min. A single dose of topical tobramycin resulted in therapeutic concentrations of tobramycin in the tears for 1 h after administration. Therapeutic levels of tobramycin remained in equine tears 6 times longer than was reported in rabbit tears.

  14. The Role of Nanoparticle Design in Determining Analytical Performance of Lateral Flow Immunoassays.

    Science.gov (United States)

    Zhan, Li; Guo, Shuang-Zhuang; Song, Fayi; Gong, Yan; Xu, Feng; Boulware, David R; McAlpine, Michael C; Chan, Warren C W; Bischof, John C

    2017-12-13

    Rapid, simple, and cost-effective diagnostics are needed to improve healthcare at the point of care (POC). However, the most widely used POC diagnostic, the lateral flow immunoassay (LFA), is ∼1000-times less sensitive and has a smaller analytical range than laboratory tests, requiring a confirmatory test to establish truly negative results. Here, a rational and systematic strategy is used to design the LFA contrast label (i.e., gold nanoparticles) to improve the analytical sensitivity, analytical detection range, and antigen quantification of LFAs. Specifically, we discovered that the size (30, 60, or 100 nm) of the gold nanoparticles is a main contributor to the LFA analytical performance through both the degree of receptor interaction and the ultimate visual or thermal contrast signals. Using the optimal LFA design, we demonstrated the ability to improve the analytical sensitivity by 256-fold and expand the analytical detection range from 3 log 10 to 6 log 10 for diagnosing patients with inflammatory conditions by measuring C-reactive protein. This work demonstrates that, with appropriate design of the contrast label, a simple and commonly used diagnostic technology can compete with more expensive state-of-the-art laboratory tests.

  15. Specific detection of Vibrio parahaemolyticus by fluorescence quenching immunoassay based on quantum dots.

    Science.gov (United States)

    Wang, Ling; Zhang, Junxian; Bai, Haili; Li, Xuan; Lv, Pintian; Guo, Ailing

    2014-07-01

    In this study, anti-Vibrio parahaemolyticus polyclonal and monoclonal antibodies were prepared through intradermal injection immune and lymphocyte hybridoma technique respectively. CdTe quantum dots (QDs) were synthesized at pH 9.3, 98 °C for 1 h with stabilizer of 2.7:1. The fluorescence intensity was 586.499, and the yield was 62.43%. QD probes were successfully prepared under the optimized conditions of pH 7.4, 37 °C for 1 h, 250 μL of 50 mg/mL EDC · HCl, 150 μL of 4 mg/mL NHS, buffer system of Na2HPO4-citric acid, and 8 μL of 2.48 mg/mL polyclonal antibodies. As gold nanoparticles could quench fluorescence of quantum dots, the concentration of V. parahaemolyticus could be detected through measuring the reduction of fluorescence intensity in immune sandwich reaction composed of quantum dot probe, gold-labeled antibody, and the sample. For pure culture, fluorescence intensity of the system was proportional with logarithm concentration of antigen, and the correlation coefficient was 99.764%. The fluorescence quenching immunoassay based on quantum dots is established for the first time to detect Vibrio parahaemolyticus. This method may be used as rapid testing procedure due to its high simplicity and sensitivity.

  16. Rapid detection of fumonisin B1 using a colloidal gold immunoassay strip test in corn samples.

    Science.gov (United States)

    Ling, Sumei; Wang, Rongzhi; Gu, Xiaosong; Wen, Can; Chen, Lingling; Chen, Zhibin; Chen, Qing-Ai; Xiao, Shiwei; Yang, Yanling; Zhuang, Zhenhong; Wang, Shihua

    2015-12-15

    Fumonisin B1 (FB1) is the most common and highest toxic of fumonisins species, exists frequently in corn and corn-based foods, leading to several animal and human diseases. Furthermore, FB1 was reported that it was associated with the human esophageal cancer. In view of the harmful of FB1, it is urgent to develop a feasible and accuracy method for rapid detection of FB1. In this study, a competitive immunoassay for FB1 detection was developed based on colloidal gold-antibody conjugate. The FB1-keyhole limpet hemoeyanin (FB1-KLH) conjugate was embedded in the test line, and goat anti-mouse IgG antibody embedded in the control line. The color density of the test line correlated with the concentration of FB1 in the range from 2.5 to 10 ng/mL, and the visual limit detection of test for FB1 was 2.5 ng/mL. The results indicated that the test strip is specific for FB1, and no cross-reactivity to other toxins. The quantitative detection for FB1 was simple, only needing one step without complicated assay performance and expensive equipment, and the total time of visual evaluation was less than 5 min. Hence, the developed colloidal gold-antibody assay can be used as a feasible method for FB1 rapid and quantitative detection in corn samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Multi-sample immunoassay inside optical fiber capillary enabled by evanescent wave detection

    Directory of Open Access Journals (Sweden)

    Chun-Wei Wang

    2016-03-01

    Full Text Available A novel evanescent wave-based (EW microfluidic capillary fiber-optic biosensor (MCFOB has been developed using capillaries as a transducer embedded in a multichannel device to enhance the collection efficiency of the fluorescence signal. The capillary serves dual roles as a waveguide and a container, enabling more straightforward, consistent, and compact biosensor packaging compared to conventional optical fiber biosensors and microfluidic systems. In order to detect multiple samples in one device, the biosensor incorporates a polydimethysiloxane (PDMS multi-channel device, which also serves as cladding for the biosensor. In addition, this biosensor only consumes 10 μl of a sample and does not require hydrofluoric acid etching in the fabrication process. The orientation for signal collection is optimized by comparing the lateral and normal signal directions for detected glyceraldehyde 3-phosphate dehydrogenase (GAPDH. C-reactive protein (CRP is used to validate the MCFOB, and the limit of detection (LOD for CRP in the MCFOB is 1.94 ng/ml (74 pM. Moreover, the real-time measurement is demonstrated to verify that the evanescent wave is the only exciting light source in the MCFOB, which gives the potential for real-time measurement applications. Keywords: C-reactive protein, Capillary, Fiber-optic, Microfluidic, Evanescent wave, Immunoassay

  18. Effects of saliva collection using cotton swab on cortisol enzyme immunoassay.

    Science.gov (United States)

    Kozaki, Tomoaki; Hashiguchi, Nobuko; Kaji, Yumi; Yasukouchi, Akira; Tochihara, Yutaka

    2009-12-01

    Cotton swabs are among the most commonly used devices for collecting saliva, but various studies have reported that their use impacts the results of salivary cortisol assays. These studies, however, estimated this impact by comparing the average of the concentration and/or scatter plots. In the present study, we estimated the impact of cotton swabs on the results of salivary cortisol enzyme immunoassay (EIA) by Bland-Altman plot. Eight healthy males (aged 20-23 years) provided four saliva samples on different days to yield a total of 32 samples. Saliva samples were collected directly in plastic tubes using plastic straws and then pipetted onto cotton swabs (cotton saliva collection) and into clear sterile tubes (passive saliva collection). There was a lower correlation between cotton and passive saliva collection. Individually, four subjects showed a negative correlation between passive and cotton saliva collection. A Bland-Altman plot indicated that cotton swabs causes a proportional bias on the EIA assay result. Our findings indicate a considerable effect of using cotton swabs for saliva collection, and subject-specific variability in the impact. A Bland-Altman plot further suggests possible reasons for this effect.

  19. Toward development of a surface-enhanced Raman scattering (SERS)-based cancer diagnostic immunoassay panel.

    Science.gov (United States)

    Granger, Jennifer H; Granger, Michael C; Firpo, Matthew A; Mulvihill, Sean J; Porter, Marc D

    2013-01-21

    Proteomic analyses of readily obtained human fluids (e.g., serum, urine, and saliva) indicate that the diagnosis of complex diseases will be enhanced by the simultaneous measurement of multiple biomarkers from such samples. This paper describes the development of a nanoparticle-based multiplexed platform that has the potential for simultaneous read-out of large numbers of biomolecules. For this purpose, we have chosen pancreatic adenocarcinoma (PA) as a test bed for diagnosis and prognosis. PA is a devastating form of cancer in which an estimated 86% of diagnoses resulted in death in the United States in 2010. The high mortality rate is due, in part, to the asymptomatic development of the disease and the dearth of sensitive diagnostics available for early detection. One promising route lies in the development of a serum biomarker panel that can generate a signature unique to early stage PA. We describe the design and development of a proof-of-concept PA biomarker immunoassay array coupled with surface-enhanced Raman scattering (SERS) as a sensitive readout method.

  20. Fluorescently labelled multiplex lateral flow immunoassay based on cadmium-free quantum dots.

    Science.gov (United States)

    Beloglazova, Natalia V; Sobolev, Aleksander M; Tessier, Mickael D; Hens, Zeger; Goryacheva, Irina Yu; De Saeger, Sarah

    2017-03-01

    A sensitive tool for simultaneous qualitative detection of two mycotoxins based on use of non-cadmium quantum dots (QDs) is presented for the first time. QDs have proven themselves as promising fluorescent labels for biolabeling and chemical analysis. With an increasing global tendency to regulate and limit the use of hazardous elements, indium phosphide (InP) QDs are highlighted as environmentally-friendly alternatives to the highly efficient and well-studied, but potentially toxic Cd- and Pb-based QDs. Here, we developed water-soluble InP QDs-based fluorescent nanostructures. They consisted of core/shell InP/ZnS QDs enrobed in a silica shell that allowed the water solubility (QD@SiO 2 ). Then we applied the QD@SiO 2 as novel, silica shell-encapsulated fluorescent labels in immunoassays for rapid multiplexed screening. Two mycotoxins, zearalenone and deoxynivalenol, were simultaneously detected in maize and wheat, since the two QD@SiO 2 labelled conjugates emit at two different, individually detectable wavelengths. The cutoff values for the simultaneous determination were 50 and 500μgkg -1 for zearalenone and deoxynivalenol, respectively, in both maize and wheat. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to confirm the result. Copyright © 2017 Elsevier Inc. All rights reserved.