Immunoassay of fumonisins by a surface plasmon resonance biosensor

A surface plasmon resonance (SPR) immunosensor is developed to determine concentrations of the mycotoxin, fumonisin B1 (FB1), in spiked samples. Polyclonal antibodies produced against FB1 are adsorbed onto a thin gold film substrate, which is coupled to a glass prism in the Kretschmann configuration. The output beam of a planar light-emitting diode is focused through the prism to excite SPR at the surface of the gold film. When a sample containing FB1 is added to a cell on the outside of the gold film, the angular profile of reflected light intensity shifts. This changes the resonance angle and the reflected beam intensity at a selected angle, both of which are proportional to the FB1 concentration. After optimization of the antibody overlayer, a detection limit of 50 ng/mL is obtained for the direct assay with an analysis time under 10 min. Multiple sample additions and large-volume sample circulation can be used with the high-affinity antibodies to achieve lower detection limits

Surface plasmon resonance-based immunoassays

Surface plasmon resonance (SPR) has been successfully incorporated into an immunosensor format for the simple, rapid, and nonlabeled assay of various biochemical analytes. Proteins, complex conjugates, toxins, allergens, drugs, and pesticides can be determined directly using either natural antibodies or synthetic receptors with high sensitivity and selectivity as the sensing element. Immunosensors are capable of real-time monitoring of the antigen-antibody reaction. A wide range of molecules can be detected with lower limits ranging between 10-9 and 10-13 mol/L. Several successful commercial developments of SPR immunosensors are available and their web pages are rich in technical information. This review highlights many recent developments in SPR-based immunoassay, functionalizations of the gold surface, novel receptors in molecular recognition, and advanced techniques for sensitivity enhancement. Furthermore, it describes the challenge of current problems and provides some insights toward the future technologies

Validation procedures for quantitative gluten ELISA methods: AOAC allergen community guidance and best practices

The food allergen analytical community is endeavoring to create harmonized guidelines for the validation of food allergen ELISA methodologies to help protect food-sensitive individuals and promote consumer confidence. This document provides additional guidance to existing method validation publications for quantitative food allergen ELISA methods. The gluten-specific criterion provided in this document is divided into sections for information required by the method developer about the assay and information for the implementation of the multilaboratory validation study. Many of these recommendations and guidance are built upon the widely accepted Codex Alimentarius definitions and recommendations for gluten-free foods. The information in this document can be used as the basis of a harmonized validation protocol for any ELISA method for gluten, whether proprietary or nonproprietary, that will be submitted to AOAC and/or regulatory authorities or other bodies for status recognition. Future work is planned for the implementation of this guidance document for the validation of gluten methods and the creation of gluten reference materials.JRC.D.5-Standards for Food Bioscienc

Validation Procedures for Quantitative Food Allergen ELISA Methods: Community Guidance and Best Practices

This document provides supplement guidance on specifications for the development and implementation of studies to validate the performance characteristics of quantitative ELISA methods for the determination of food allergens. It is intended as a companion document to the "AOAC Official Methods of Analysis Appendix D: Guidelines for Collaborative Study Procedures to Validate Characteristics of a Method of Analysis" www.aoac.org (1). The guidance is divided into two sections: information to be provided by the method developer on various characteristics of the method, and implementation of a multi-laboratory validation study. Certain criteria included in the guidance are allergen-specific. Two food allergens: egg and milk are used to demonstrate the criteria guidance. These recommendations will be the basis of the harmonized validation protocol for any food allergen ELISA method, whether proprietary or nonproprietary, that will be submitted to AOAC and/or regulatory authorities or other bodies for status recognition. It should be noted that regulatory authorities may have their own particular requiretments for data packages in addition to the guidance in this document. Future work is planned for the implementation and validation of this guidance. This future work will also inclkude guidance specific to other priority allergensJRC.D.5-Food Safety and Qualit