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Christopher T Elliott - One of the best experts on this subject based on the ideXlab platform.
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Development and single laboratory validation of an Optical Biosensor assay for tetrodotoxin detection as a tool to combat emerging risks in European seafood
Analytical and Bioanalytical Chemistry, 2013Co-Authors: Katrina Campbell, Simon A Haughey, Kentaro Kawatsu, Paul Barnes, Cowan Higgins, Vitor Vasconcelos, Christopher T ElliottAbstract:Tetrodotoxin (TTX) is a potent neurotoxin emerging in European waters due to increasing ocean temperatures. Its detection in seafood is currently performed as a consequence of using the Association of Analytical Communities (AOAC) mouse bioassay (MBA) for paralytic shellfish poisoning (PSP) toxins, but TTX is not monitored routinely in Europe. Due to ethical and performance-related issues associated with this bioassay, the European Commission has recently published directives extending procedures that may be used for official PSP control. An AOAC-accredited high-performance liquid chromatography (HPLC) method has now been accepted by the European Union as a first action screening method for PSP toxins to replace the MBA. However, this AOAC HPLC method is not capable of detecting TTX, so this potent toxin would be undetected; thereby, a separate method of analysis is required. Surface plasmon resonance (SPR) Optical Biosensor technology has been proven as a potential alternative screening method to detect PSP toxins in seafood. The addition of a similar SPR inhibition assay for TTX would complement the PSP assay in removing the MBA. The present report describes the development and single laboratory validation in accordance with AOAC and IUPAC guidelines of an SPR method to be used as a rapid screening tool to detect TTX in the sea snail Charonia lampas lampas , a species which has been implicated in 2008 in the first case of human TTX poisoning in Europe. As no current regulatory limits are set for TTX in Europe, single laboratory validation was undertaken using those for PSP toxins at 800 μg/kg. The decision limit (CCα) was 100 μg/kg, with the detection capability (CCβ) found to be ≤200 μg/kg. Repeatability and reproducibility were assessed at 200, 400, and 800 μg/kg and showed relative standard deviations of 8.3, 3.8, and 5.4 % and 7.8, 8.3, and 3.7 % for both parameters at each level, respectively. At these three respective levels, the recovery of the assay was 112, 98, and 99 %.
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paralytic shellfish poisoning psp toxin binders for Optical Biosensor technology problems and possibilities for the future a review
Food Additives and Contaminants Part A-chemistry Analysis Control Exposure & Risk Assessment, 2011Co-Authors: Katrina Campbell, Dorothea F.k. Rawn, Barbara Niedzwiadek, Christopher T ElliottAbstract:This review examines the developments in Optical Biosensor technology, which uses the phenomenon of surface plasmon resonance, for the detection of paralytic shellfish poisoning (PSP) toxins. Optical Biosensor technology measures the competitive biomolecular interaction of a specific biological recognition element or binder with a target toxin immobilised onto a sensor chip surface against toxin in a sample. Different binders such as receptors and antibodies previously employed in functional and immunological assays have been assessed. Highlighted are the difficulties in detecting this range of low molecular weight toxins, with analogues differing at four chemical substitution sites, using a single binder. The complications that arise with the toxicity factors of each toxin relative to the parent compound, saxitoxin, for the measurement of total toxicity relative to the mouse bioassay are also considered. For antibodies, the cross-reactivity profile does not always correlate to toxic potency, but rather to the toxin structure to which it was produced. Restrictions and availability of the toxins makes alternative chemical strategies for the synthesis of protein conjugate derivatives for antibody production a difficult task. However, when two antibodies with different cross-reactivity profiles are employed, with a toxin chip surface generic to both antibodies, it was demonstrated that the cross-reactivity profile of each could be combined into a single-assay format. Difficulties with receptors for Optical Biosensor analysis of low molecular weight compounds are discussed, as are the potential of alternative non-antibody-based binders for future assay development in this area.
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the development of a multi nitroimidazole residue analysis assay by Optical Biosensor via a proof of concept project to develop and assess a prototype test kit
Analytica Chimica Acta, 2007Co-Authors: Lisa Connolly, Simon A Haughey, Colin S Thompson, Imelda M Traynor, Sheryl Tittlemeier, Christopher T ElliottAbstract:Abstract An assay based on Optical Biosensor technology has been developed to detect a broad range of nitroimidazole drug residues and their metabolites (dimetridazole (DMZ), metronidazole (MNZ), ronidazole (RNZ), hydroxymetronidazole (HO-MNZ) and hydroxydimetridazole (HO-DMZ)) in chicken muscle. The detection limit for the procedure was determined as 0.5 ppb for DMZ and detection capabilities (CCβs) ranged from A prototype kit based on this assay was produced and a multinational study was undertaken to independently evaluate its performance. The resulting data showed that the kit can be implemented with little difficulty in laboratories of varying expertise and is sensitive enough to meet the standards required by international law. Feedback from this study led to the incorporation of some minor improvements to the kit. The commercial partner in the project, XenoSense Ltd., was consulted with regards to producing a commercial test kit based on the prototype assay. As feedback from the collaborative study had been positive with respect to speed, ease of use and performance of the kit, the decision to commercialise the kit was taken. In conclusion, the prototype nitroimidazole kit was shown to offer numerous advantages over existing analytical techniques.
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assessment of specific binding proteins suitable for the detection of paralytic shellfish poisons using Optical Biosensor technology
Analytical Chemistry, 2007Co-Authors: Katrina Campbell, Linda D Stewart, Gregory J Doucette, Terence L Fodey, Simon A Haughey, Natalia Vilarino, Kentaro Kawatsu, Christopher T ElliottAbstract:Paralytic shellfish poisoning (PSP) toxin monitoring in shellfish is currently performed using the internationally accredited AOAC mouse bioassay. Due to ethical and performance-related issues associated with this bioassay, the European Commission has recently published directives extending procedures that may be used for official PSP control. The feasibility of using a surface plasmon resonance Optical Biosensor to detect PSP toxins in shellfish tissue below regulatory levels was examined. Three different PSP toxin protein binders were investigated: a sodium channel receptor (SCR) preparation derived from rat brains, a monoclonal antibody (GT13-A) raised to gonyautoxin 2/3, and a rabbit polyclonal antibody (R895) raised to saxitoxin (STX). Inhibition assay formats were used throughout. Immobilization of STX to the Biosensor chip surface was achieved via amino-coupling. Specific binding and inhibition of binding to this surface was achieved using all proteins tested. For STX calibration curves, 0-1000 ng/mL, IC50 values for each binder were as follows: SCR 8.11 ng/mL; GT13-A 5.77 ng/mL; and R895 1.56 ng/mL. Each binder demonstrated a different cross-reactivity profile against a range of STX analogues. R895 delivered a profile that was most likely to detect the widest range of PSP toxins at or below the internationally adopted regulatory limits.
Katrina Campbell - One of the best experts on this subject based on the ideXlab platform.
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Development and single laboratory validation of an Optical Biosensor assay for tetrodotoxin detection as a tool to combat emerging risks in European seafood
Analytical and Bioanalytical Chemistry, 2013Co-Authors: Katrina Campbell, Simon A Haughey, Kentaro Kawatsu, Paul Barnes, Cowan Higgins, Vitor Vasconcelos, Christopher T ElliottAbstract:Tetrodotoxin (TTX) is a potent neurotoxin emerging in European waters due to increasing ocean temperatures. Its detection in seafood is currently performed as a consequence of using the Association of Analytical Communities (AOAC) mouse bioassay (MBA) for paralytic shellfish poisoning (PSP) toxins, but TTX is not monitored routinely in Europe. Due to ethical and performance-related issues associated with this bioassay, the European Commission has recently published directives extending procedures that may be used for official PSP control. An AOAC-accredited high-performance liquid chromatography (HPLC) method has now been accepted by the European Union as a first action screening method for PSP toxins to replace the MBA. However, this AOAC HPLC method is not capable of detecting TTX, so this potent toxin would be undetected; thereby, a separate method of analysis is required. Surface plasmon resonance (SPR) Optical Biosensor technology has been proven as a potential alternative screening method to detect PSP toxins in seafood. The addition of a similar SPR inhibition assay for TTX would complement the PSP assay in removing the MBA. The present report describes the development and single laboratory validation in accordance with AOAC and IUPAC guidelines of an SPR method to be used as a rapid screening tool to detect TTX in the sea snail Charonia lampas lampas , a species which has been implicated in 2008 in the first case of human TTX poisoning in Europe. As no current regulatory limits are set for TTX in Europe, single laboratory validation was undertaken using those for PSP toxins at 800 μg/kg. The decision limit (CCα) was 100 μg/kg, with the detection capability (CCβ) found to be ≤200 μg/kg. Repeatability and reproducibility were assessed at 200, 400, and 800 μg/kg and showed relative standard deviations of 8.3, 3.8, and 5.4 % and 7.8, 8.3, and 3.7 % for both parameters at each level, respectively. At these three respective levels, the recovery of the assay was 112, 98, and 99 %.
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Paralytic shellfish poisoning (PSP) toxin binders for Optical Biosensor analysis: problems and possibilities for the future, a review.
Food Additives and Contaminants, 2011Co-Authors: Katrina Campbell, Dorothea F.k. Rawn, Barbara Niedzwiadek, Chris ElliottAbstract:This review examines the developments in Optical Biosensor technology, which uses the phenomenon of surface plasmon resonance, for the detection of PSP toxins. Optical Biosensor technology measures the competitive biomolecular interaction of a specific biological recognition element or binder with a target toxin immobilized onto a sensor chip surface against toxin in a sample. Different binders such as receptors and antibodies previously employed in functional and immunological assays have been assessed. Highlighted are the difficulties in detecting this range of low molecular weight toxins, with analogues differing at four chemical substitution sites, using a single binder. The complications that arise with the toxicity factors of each toxin relative to the parent compound, saxitoxin, for the measurement of total toxicity relative to the mouse bioassay are also considered. For antibodies, the cross-reactivity profile does not always correlate with the toxic potency but rather to the toxin structure to which it was produced. Restrictions and availability of the toxins makes alternative chemical strategies for the synthesis of protein conjugate derivatives for antibody production a difficult task. However, when two antibodies with different cross-reactivity profiles are employed, with a toxin chip surface generic to both antibodies, it was demonstrated that the cross-reactivity profile of each could be combined into a single assay format. Difficulties with receptors for Optical Biosensor analysis of low molecular weight compounds are discussed as are the potential of alternative non-antibody based binders for future assay development in this area.
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paralytic shellfish poisoning psp toxin binders for Optical Biosensor technology problems and possibilities for the future a review
Food Additives and Contaminants Part A-chemistry Analysis Control Exposure & Risk Assessment, 2011Co-Authors: Katrina Campbell, Dorothea F.k. Rawn, Barbara Niedzwiadek, Christopher T ElliottAbstract:This review examines the developments in Optical Biosensor technology, which uses the phenomenon of surface plasmon resonance, for the detection of paralytic shellfish poisoning (PSP) toxins. Optical Biosensor technology measures the competitive biomolecular interaction of a specific biological recognition element or binder with a target toxin immobilised onto a sensor chip surface against toxin in a sample. Different binders such as receptors and antibodies previously employed in functional and immunological assays have been assessed. Highlighted are the difficulties in detecting this range of low molecular weight toxins, with analogues differing at four chemical substitution sites, using a single binder. The complications that arise with the toxicity factors of each toxin relative to the parent compound, saxitoxin, for the measurement of total toxicity relative to the mouse bioassay are also considered. For antibodies, the cross-reactivity profile does not always correlate to toxic potency, but rather to the toxin structure to which it was produced. Restrictions and availability of the toxins makes alternative chemical strategies for the synthesis of protein conjugate derivatives for antibody production a difficult task. However, when two antibodies with different cross-reactivity profiles are employed, with a toxin chip surface generic to both antibodies, it was demonstrated that the cross-reactivity profile of each could be combined into a single-assay format. Difficulties with receptors for Optical Biosensor analysis of low molecular weight compounds are discussed, as are the potential of alternative non-antibody-based binders for future assay development in this area.
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assessment of specific binding proteins suitable for the detection of paralytic shellfish poisons using Optical Biosensor technology
Analytical Chemistry, 2007Co-Authors: Katrina Campbell, Linda D Stewart, Gregory J Doucette, Terence L Fodey, Simon A Haughey, Natalia Vilarino, Kentaro Kawatsu, Christopher T ElliottAbstract:Paralytic shellfish poisoning (PSP) toxin monitoring in shellfish is currently performed using the internationally accredited AOAC mouse bioassay. Due to ethical and performance-related issues associated with this bioassay, the European Commission has recently published directives extending procedures that may be used for official PSP control. The feasibility of using a surface plasmon resonance Optical Biosensor to detect PSP toxins in shellfish tissue below regulatory levels was examined. Three different PSP toxin protein binders were investigated: a sodium channel receptor (SCR) preparation derived from rat brains, a monoclonal antibody (GT13-A) raised to gonyautoxin 2/3, and a rabbit polyclonal antibody (R895) raised to saxitoxin (STX). Inhibition assay formats were used throughout. Immobilization of STX to the Biosensor chip surface was achieved via amino-coupling. Specific binding and inhibition of binding to this surface was achieved using all proteins tested. For STX calibration curves, 0-1000 ng/mL, IC50 values for each binder were as follows: SCR 8.11 ng/mL; GT13-A 5.77 ng/mL; and R895 1.56 ng/mL. Each binder demonstrated a different cross-reactivity profile against a range of STX analogues. R895 delivered a profile that was most likely to detect the widest range of PSP toxins at or below the internationally adopted regulatory limits.
Sandeep Kumar Jha - One of the best experts on this subject based on the ideXlab platform.
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smartphone based Optical Biosensor for the detection of urea in saliva
Sensors and Actuators B-chemical, 2018Co-Authors: Anuradha Soni, Rajat Kumar Surana, Sandeep Kumar JhaAbstract:Abstract In the present study, we have developed a smartphone based handheld Optical Biosensor for determination of urea in saliva. A simple strategy was adopted by immobilization of urease enzyme along with a pH indicator on a filter paper based strip. The strip changed color upon the reaction with urea present in saliva and the color change can be estimated using our smartphone based application based on RGB profiling. Calibration of the Biosensor was carried out using spiked saliva samples and an exponentially decreasing calibration curve has been obtained for green pixel intensity in the broad range (10–1000 mgdL−1) with a linear detection range of 10–260 mgdL−1 and a response time of 20 s. The sensitivity reported for the Biosensor in the clinically significant range was −0.005 average pixels sec−1/mgdL−1 with a LOD of 10.4 mgdL−1. Studies carried out on spiked saliva samples showed a good correlation between salivary urea estimated using our Biosensor against phenol-hypochlorite based spectroscopic procedure. Development of a smartphone based Biosensor for urea estimation eliminates the need for procuring a dedicated instrument as well as trained technician for daily monitoring and saves time as compared to traditional laboratory methods of analysis.
David G. Myszka - One of the best experts on this subject based on the ideXlab platform.
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Survey of the 2009 commercial Optical Biosensor literature: SURVEY OF THE 2009 COMMERCIAL Optical Biosensor LITERATURE
Journal of molecular recognition : JMR, 2011Co-Authors: Rebecca L. Rich, David G. MyszkaAbstract:We took a different approach to reviewing the commercial Biosensor literature this year by inviting 22 Biosensor users to serve as a review committee. They set the criteria for what to expect in a publication and ultimately decided to use a pass/fail system for selecting which papers to include in this year's reference list. Of the 1514 publications in 2009 that reported using commercially available Optical Biosensor technology, only 20% passed their cutoff. The most common criticism the reviewers had with the literature was that "the Biosensor experiments could have been done better." They selected 10 papers to highlight good experimental technique, data presentation, and unique applications of the technology. This communal review process was educational for everyone involved and one we will not soon forget.
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grading the commercial Optical Biosensor literature class of 2008 the mighty binders
Journal of Molecular Recognition, 2009Co-Authors: Rebecca L. Rich, David G. MyszkaAbstract:Optical Biosensor technology continues to be the method of choice for label-free, real-time interaction analysis. But when it comes to improving the quality of the Biosensor literature, education should be fundamental. Of the 1413 articles published in 2008, less than 30% would pass the requirements for high-school chemistry. To teach by example, we spotlight 10 papers that illustrate how to implement the technology properly. Then we grade every paper published in 2008 on a scale from A to F and outline what features make a Biosensor article fabulous, middling or abysmal. To help improve the quality of published data, we focus on a few experimental, analysis and presentation mistakes that are alarmingly common. With the literature as a guide, we want to ensure that no user is left behind. Copyright © 2009 John Wiley & Sons, Ltd.
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survey of the year 2003 commercial Optical Biosensor literature
Journal of Molecular Recognition, 2005Co-Authors: Rebecca L. Rich, David G. MyszkaAbstract:In the year 2003 there was a 17% increase in the number of publications citing work performed using Optical Biosensor technology compared with the previous year. We collated the 962 total papers for 2003, identified the geographical regions where the work was performed, highlighted the instrument types on which it was carried out, and segregated the papers by biological system. In this overview, we spotlight 13 papers that should be on everyone's 'must read' list for 2003 and provide examples of how to identify and interpret high-quality Biosensor data. Although we still find that the literature is replete with poorly performed experiments, over-interpreted results and a general lack of understanding of data analysis, we are optimistic that these shortcomings will be addressed as Biosensor technology continues to mature.
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Survey of the 1998 Optical Biosensor literature.
Journal of molecular recognition : JMR, 1999Co-Authors: David G. MyszkaAbstract:The utilization of Optical Biosensors to study molecular interactions continues to expand. In 1998, 384 articles relating to the use of commercial Biosensors were published in 130 different journals. While significant strides in new applications and methodology were made, a majority of the Biosensor literature is of rather poor quality. Basic information about experimental conditions is often not presented and many publications fail to display the experimental data, bringing into question the credibility of the results. This review provides suggestions on how to collect, analyze and report Biosensor data.
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Interpreting kinetic rate constants from Optical Biosensor data recorded on a decaying surface.
Analytical biochemistry, 1998Co-Authors: Lisa Joss, Michael L Doyle, Thomas A Morton, David G. MyszkaAbstract:Abstract A capturing assay was used to monitor a Fab-antigen interaction using a BIACORE Optical Biosensor. The antigen, a truncated single-site mutant (F43V) version of the CD4 receptor, was captured onto the sensor surface using an immobilized nonneutralizing monoclonal antibody. While this assay design created an oriented antigen surface, the antigen slowly dissociated during subsequent binding of the Fab, thus complicating the binding responses. In this paper, we illustrate how binding events occurring on a decaying surface can be accurately described by globally fitting the response data to a model that accounts for the background surface decay. Support for the method was obtained by showing the equilibrium dissociation constant calculated from the kinetic rate constants ( K d = 2.20 ± 0.01 nM) was similar to the value measured in solution using titration calorimetry ( K d = 2.6 ± 0.5 nM). The ability to interpret rate constants from decaying surfaces significantly extends the types of experimental systems that can be quantitatively studied on Optical Biosensors.
Simon A Haughey - One of the best experts on this subject based on the ideXlab platform.
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Development and single laboratory validation of an Optical Biosensor assay for tetrodotoxin detection as a tool to combat emerging risks in European seafood
Analytical and Bioanalytical Chemistry, 2013Co-Authors: Katrina Campbell, Simon A Haughey, Kentaro Kawatsu, Paul Barnes, Cowan Higgins, Vitor Vasconcelos, Christopher T ElliottAbstract:Tetrodotoxin (TTX) is a potent neurotoxin emerging in European waters due to increasing ocean temperatures. Its detection in seafood is currently performed as a consequence of using the Association of Analytical Communities (AOAC) mouse bioassay (MBA) for paralytic shellfish poisoning (PSP) toxins, but TTX is not monitored routinely in Europe. Due to ethical and performance-related issues associated with this bioassay, the European Commission has recently published directives extending procedures that may be used for official PSP control. An AOAC-accredited high-performance liquid chromatography (HPLC) method has now been accepted by the European Union as a first action screening method for PSP toxins to replace the MBA. However, this AOAC HPLC method is not capable of detecting TTX, so this potent toxin would be undetected; thereby, a separate method of analysis is required. Surface plasmon resonance (SPR) Optical Biosensor technology has been proven as a potential alternative screening method to detect PSP toxins in seafood. The addition of a similar SPR inhibition assay for TTX would complement the PSP assay in removing the MBA. The present report describes the development and single laboratory validation in accordance with AOAC and IUPAC guidelines of an SPR method to be used as a rapid screening tool to detect TTX in the sea snail Charonia lampas lampas , a species which has been implicated in 2008 in the first case of human TTX poisoning in Europe. As no current regulatory limits are set for TTX in Europe, single laboratory validation was undertaken using those for PSP toxins at 800 μg/kg. The decision limit (CCα) was 100 μg/kg, with the detection capability (CCβ) found to be ≤200 μg/kg. Repeatability and reproducibility were assessed at 200, 400, and 800 μg/kg and showed relative standard deviations of 8.3, 3.8, and 5.4 % and 7.8, 8.3, and 3.7 % for both parameters at each level, respectively. At these three respective levels, the recovery of the assay was 112, 98, and 99 %.
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development of an Optical Biosensor based immunoassay to screen infant formula milk samples for adulteration with melamine
Analytical Chemistry, 2011Co-Authors: Terence L Fodey, Simon A Haughey, Colin S Thompson, Imelda M Traynor, Glenn D Kennedy, Steven R H CrooksAbstract:The illegal adulteration of milk with melamine in 2008 in China led to adverse kidney and urinary tract effects in hundreds of thousands of children and the reported deaths of six. The milk had been deliberately adulterated to elevate the apparent protein content, and subsequently melamine was detected in many milk-related products which had been exported. This led to the banning of imports of milk and milk products from China intended for the nutritional use of children and to the implementation of analytical methods to test products containing milk products. An Optical Biosensor inhibition immunoassay has been developed as a rapid and robust method for the analysis of infant formula and infant liquid milk samples. A compound with a chemical structure similar to that of melamine was employed as a hapten to raise a polyclonal antibody and as the immobilized antigen on the surface of a Biosensor chip. The sensitivity of the assay, given as an IC(50), was calculated to be 67.9 ng mL(-1) in buffer. The antibody did not cross-react with any of the byproducts of melamine manufacture; however, significant cross-reactivity was observed with the insecticide cyromazine of which melamine is a metabolite. When sample matrix was applied to the assay, a limit of detection of <0.5 μg mL(-1) was determined in both infant formula and infant liquid milk. The development of the immunoassay and validation data for the detection of melamine is presented together with the results obtained following the analysis of melamine-contaminated milk powder.
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the development of a multi nitroimidazole residue analysis assay by Optical Biosensor via a proof of concept project to develop and assess a prototype test kit
Analytica Chimica Acta, 2007Co-Authors: Lisa Connolly, Simon A Haughey, Colin S Thompson, Imelda M Traynor, Sheryl Tittlemeier, Christopher T ElliottAbstract:Abstract An assay based on Optical Biosensor technology has been developed to detect a broad range of nitroimidazole drug residues and their metabolites (dimetridazole (DMZ), metronidazole (MNZ), ronidazole (RNZ), hydroxymetronidazole (HO-MNZ) and hydroxydimetridazole (HO-DMZ)) in chicken muscle. The detection limit for the procedure was determined as 0.5 ppb for DMZ and detection capabilities (CCβs) ranged from A prototype kit based on this assay was produced and a multinational study was undertaken to independently evaluate its performance. The resulting data showed that the kit can be implemented with little difficulty in laboratories of varying expertise and is sensitive enough to meet the standards required by international law. Feedback from this study led to the incorporation of some minor improvements to the kit. The commercial partner in the project, XenoSense Ltd., was consulted with regards to producing a commercial test kit based on the prototype assay. As feedback from the collaborative study had been positive with respect to speed, ease of use and performance of the kit, the decision to commercialise the kit was taken. In conclusion, the prototype nitroimidazole kit was shown to offer numerous advantages over existing analytical techniques.
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assessment of specific binding proteins suitable for the detection of paralytic shellfish poisons using Optical Biosensor technology
Analytical Chemistry, 2007Co-Authors: Katrina Campbell, Linda D Stewart, Gregory J Doucette, Terence L Fodey, Simon A Haughey, Natalia Vilarino, Kentaro Kawatsu, Christopher T ElliottAbstract:Paralytic shellfish poisoning (PSP) toxin monitoring in shellfish is currently performed using the internationally accredited AOAC mouse bioassay. Due to ethical and performance-related issues associated with this bioassay, the European Commission has recently published directives extending procedures that may be used for official PSP control. The feasibility of using a surface plasmon resonance Optical Biosensor to detect PSP toxins in shellfish tissue below regulatory levels was examined. Three different PSP toxin protein binders were investigated: a sodium channel receptor (SCR) preparation derived from rat brains, a monoclonal antibody (GT13-A) raised to gonyautoxin 2/3, and a rabbit polyclonal antibody (R895) raised to saxitoxin (STX). Inhibition assay formats were used throughout. Immobilization of STX to the Biosensor chip surface was achieved via amino-coupling. Specific binding and inhibition of binding to this surface was achieved using all proteins tested. For STX calibration curves, 0-1000 ng/mL, IC50 values for each binder were as follows: SCR 8.11 ng/mL; GT13-A 5.77 ng/mL; and R895 1.56 ng/mL. Each binder demonstrated a different cross-reactivity profile against a range of STX analogues. R895 delivered a profile that was most likely to detect the widest range of PSP toxins at or below the internationally adopted regulatory limits.
