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Güven E, Azizoglu RO. Enhancing gluten detection assay development through optimization of gliadin extraction conditions. Heliyon 2023; 9:e19432. [PMID: 37809800 PMCID: PMC10558502 DOI: 10.1016/j.heliyon.2023.e19432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/15/2023] [Accepted: 08/22/2023] [Indexed: 10/10/2023] Open
Abstract
Gluten consumption can lead to severe health conditions in certain individuals, and following a strict gluten-free diet is often the only effective treatment option. Therefore, it is crucial to develop a gluten detection method that is accurate, sensitive, and specific to ensure the absence of gluten. An important aspect of developing effective gluten detection tests is the implementation of an efficient gluten extraction method. In this study, we conducted an evaluation of various buffer conditions for gliadin extraction from both heat-treated and non-heat-treated food samples. These buffer conditions included ethanol, 2-mercaptoethanol, guanidine hydrochloride, detergents, chelating agents, and deep eutectic solvents. Among the tested conditions, a combination of 2-mercaptoethanol and guanidine hydrochloride demonstrated significantly higher extraction efficacy compared to most other conditions. Furthermore, we explored the use of a less toxic extraction buffer, choline chloride, which exhibited a 1.4-fold higher extraction efficiency than the combination of 2-mercaptoethanol and guanidine hydrochloride (p < 0.05). Choline chloride showed great potential as a preferred buffer for commercial gliadin extraction kits, suitable for both heat-treated and non-heat-treated food samples. Overall, our findings highlight the importance of optimizing the gluten extraction process to improve the accuracy and reliability of gluten detection methods, ultimately contributing to the development of effective tools for individuals following a strict gluten-free diet.
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Affiliation(s)
- Ece Güven
- Department of Gene and Cell Therapy, Mediterranean (Akdeniz) University, Antalya, Turkey
| | - Reha Onur Azizoglu
- Department of Gene and Cell Therapy, Mediterranean (Akdeniz) University, Antalya, Turkey
- Department of Food Engineering, Mediterranean (Akdeniz) University, Antalya, Turkey
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2
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Schirmer TM, Scherf KA. Influence of baking conditions on the extractability and immunochemical detection of wheat gluten proteins. Curr Res Food Sci 2022; 6:100431. [PMID: 36636725 PMCID: PMC9829696 DOI: 10.1016/j.crfs.2022.100431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/21/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022] Open
Abstract
Food processing conditions affect the accurate detection of gluten by ELISA, which is of importance for proper gluten-free labelling. We prepared different wheat flour-based and incurred baked goods (bread, crispbread, pretzel) to investigate the influence of baking conditions and alkali treatment on gluten quantitation by ELISA using different extraction solvents. Protein composition and extractability were determined (SDS-PAGE, RP-HPLC, GP-HPLC). The extraction solvents showed different performances; none of them could compensate the effect of baking on the detection. Dough preparation, baking and additional alkali treatment decreased protein extractability under reducing and non-reducing conditions. High temperature combined with alkali treatment resulted in the lowest protein extractabilities (<77% for bread crust, <61% for pretzel crust) due to the formation of disulfide and non-disulfide gluten crosslinks. There was no clear correlation between the protein composition and the extractability of alcohol- and SDS-soluble proteins of the baked goods. Thus, this research shows that gluten extractability rather than gluten composition is crucial for detection by ELISA in baked goods.
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Affiliation(s)
- Tanja Miriam Schirmer
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
| | - Katharina Anne Scherf
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany,Department of Bioactive and Functional Food Chemistry, Institute of Applied Biosciences, Karlsruhe Institute of Technology (KIT), Adenauerring 20 a, 76131, Karlsruhe, Germany,Corresponding author. Karlsruhe Institute of Technology (KIT), Adenauerring 20 a, 76131, Karlsruhe, Germany. https://bioactivefc.iab.kit.edu
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3
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Svigelj R, Dossi N, Grazioli C, Toniolo R. Paper-based aptamer-antibody biosensor for gluten detection in a deep eutectic solvent (DES). Anal Bioanal Chem 2021; 414:3341-3348. [PMID: 34617152 PMCID: PMC8494473 DOI: 10.1007/s00216-021-03653-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/02/2021] [Accepted: 09/06/2021] [Indexed: 12/18/2022]
Abstract
Paper has been widely employed as cheap material for the development of a great number of sensors such as pregnancy tests, strips to measure blood sugar, and COVID-19 rapid tests. The need for new low-cost analytical devices is growing, and consequently the use of these platforms will be extended to different assays, both for the final consumer and within laboratories. This work describes a paper-based electrochemical sensing platform that uses a paper disc conveniently modified with recognition molecules and a screen-printed carbon electrode (SPCE) to achieve the detection of gluten in a deep eutectic solvent (DES). This is the first method coupling a paper biosensor based on aptamers and antibodies with the DES ethaline. Ethaline proved to be an excellent extraction medium allowing the determination of very low gluten concentrations. The biosensor is appropriate for the determination of gluten with a limit of detection (LOD) of 0.2 mg L−1 of sample; it can detect gluten extracted in DES with a dynamic range between 0.2 and 20 mg L−1 and an intra-assay coefficient of 10.69%. This approach can be of great interest for highly gluten-sensitive people, who suffer from ingestion of gluten quantities well below the legal limit, which is 20 parts per million in foods labeled gluten-free and for which highly sensitive devices are essential.
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Affiliation(s)
- Rossella Svigelj
- Department of Agrifood, Environmental and Animal Science, University of Udine, via Cotonificio 108, 33100, Udine, Italy.
| | - Nicolò Dossi
- Department of Agrifood, Environmental and Animal Science, University of Udine, via Cotonificio 108, 33100, Udine, Italy
| | - Cristian Grazioli
- Department of Agrifood, Environmental and Animal Science, University of Udine, via Cotonificio 108, 33100, Udine, Italy
| | - Rosanna Toniolo
- Department of Agrifood, Environmental and Animal Science, University of Udine, via Cotonificio 108, 33100, Udine, Italy.
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Lee D, Ozkaya-Ahmadov T, Chu CH, Boya M, Liu R, Sarioglu AF. Capillary flow control in lateral flow assays via delaminating timers. SCIENCE ADVANCES 2021; 7:eabf9833. [PMID: 34597143 PMCID: PMC10938491 DOI: 10.1126/sciadv.abf9833] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 08/11/2021] [Indexed: 05/10/2023]
Abstract
Lateral flow assays (LFAs) use capillary flow of liquids for simple detection of analytes. While useful for spontaneously wicking samples, the capillary flow inherently limits performing complex reactions that require timely application of multiple solutions. Here, we introduce a technique to control capillary flow on paper by imprinting roadblocks on the flow path with water-insoluble ink and using the gradual formation of a void between a wetted paper and a sheath polymer tape to create timers. Timers are drawn at strategic nodes to hold the capillary flow for a desired period and thereby enable multiple liquids to be introduced into multistep chemical reactions following a programmed sequence. Using our technique, we developed (i) an LFA with built-in signal amplification to detect human chorionic gonadotropin with an order of magnitude higher sensitivity than the conventional assay and (ii) a device to extract DNA from bodily fluids without relying on laboratory instruments.
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Affiliation(s)
- Dohwan Lee
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Tevhide Ozkaya-Ahmadov
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Chia-Heng Chu
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Mert Boya
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Ruxiu Liu
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - A. Fatih Sarioglu
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, GA 30332, USA
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Segura V, Díaz J, Ruiz-Carnicer Á, Muñoz-Suano A, Carrillo-Carrión C, Sousa C, Cebolla Á, Comino I. Rapid, Effective, and Versatile Extraction of Gluten in Food with Application on Different Immunological Methods. Foods 2021; 10:foods10030652. [PMID: 33808639 PMCID: PMC8003464 DOI: 10.3390/foods10030652] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 12/22/2022] Open
Abstract
One of the main concerns in gluten analysis is to achieve efficient extraction of gluten proteins. Conventional ethanol-based extraction solutions are inefficient and, because of this, it is necessary to use reducing agents or acids for proper solubilization. The extraction recommended by CODEX Standard 118-1979 (revised 2008) utilizes Cocktail solution (patent WO 02/092633 A1). However, it is harmful with a disgusting odor and is not compatible with some immunological techniques. Here, the versatility and extraction capacity of a new Universal Gluten Extraction Solution (UGES) (patent ES 2 392 412 A1) were evaluated using different methodological conditions, food matrices, and various immunological methods. UGES includes safer compounds for both the user and the environment, and it displayed similar extraction efficiency to that of the extraction method recommended for sandwich enzyme-linked immunosorbent assay (ELISA). The extraction time was significantly reduced from 100 to 40 min, depending on the type of the sample. Furthermore, unlike the currently used solution, UGES is compatible with competitive ELISA.
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Affiliation(s)
- Verónica Segura
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain; (V.S.); (Á.R.-C.); (C.S.)
| | - Jacobo Díaz
- Clinical Analysis Service, Hospital Universitario INGESA, 51003 Ceuta, Spain;
| | - Ángela Ruiz-Carnicer
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain; (V.S.); (Á.R.-C.); (C.S.)
| | - Alba Muñoz-Suano
- Biomedal S.L., 41900 Seville, Spain; (A.M.-S.); (C.C.-C.); (Á.C.)
| | | | - Carolina Sousa
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain; (V.S.); (Á.R.-C.); (C.S.)
| | - Ángel Cebolla
- Biomedal S.L., 41900 Seville, Spain; (A.M.-S.); (C.C.-C.); (Á.C.)
| | - Isabel Comino
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain; (V.S.); (Á.R.-C.); (C.S.)
- Correspondence: ; Tel.: +34-954-556-452
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Pla L, Martínez-Bisbal MC, Aznar E, Sancenón F, Martínez-Máñez R, Santiago-Felipe S. A fluorogenic capped mesoporous aptasensor for gluten detection. Anal Chim Acta 2021; 1147:178-186. [PMID: 33485577 DOI: 10.1016/j.aca.2020.12.060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 12/21/2020] [Accepted: 12/27/2020] [Indexed: 10/22/2022]
Abstract
Celiac disease is a complex and autoimmune disorder caused by the ingestion of gluten affecting almost 1% of global population. Nowadays an effective treatment does not exist, and the only way to manage the disease is the removal of gluten from the diet. Owing the key role played by gluten, clear and regulated labelling of foodstuff and smart methods for gluten detection are needed to fight frauds on food industry and to avoid the involuntary ingestion of this protein by celiac patients. On that scope, the development of a novel detection system of gluten is here presented. The sensor consists of nanoporous anodic alumina films loaded with a fluorescent dye and capped with an aptamer that recognizes gliadin (gluten's soluble proteins). In the presence of gliadin, aptamer sequences displace from the surface of anodic alumina resulting in pore opening and dye delivery. The dispositive shows a limit of detection (LOD) of 100 μg kg-1 of gliadin, good selectivity and a detection time of approximately 60 min. Moreover, the sensor is validated in real food samples. This novel probe allows fast gluten detection through a simple signalling process with potential use for food control.
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Affiliation(s)
- Luis Pla
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) Av, Monforte de Lemos, 3-5. Pabellón 11, Planta 0 28029 Madrid, Spain; Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico, Universitat Politècnica de València, Universitat de València, Camino de Vera s/n, 46022, Valencia, Spain; Unidad Mixta de Investigación en Nanomedicina y Sensores. Universitat Politècnica de València, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell 106, Torre A, planta 6, 46026, Valencia, Spain.
| | - M Carmen Martínez-Bisbal
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) Av, Monforte de Lemos, 3-5. Pabellón 11, Planta 0 28029 Madrid, Spain; Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico, Universitat Politècnica de València, Universitat de València, Camino de Vera s/n, 46022, Valencia, Spain; Unidad Mixta de Investigación en Nanomedicina y Sensores. Universitat Politècnica de València, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell 106, Torre A, planta 6, 46026, Valencia, Spain; Departamento de Químiíca Física, Universitat de València, C/ Doctor Moliner, 50, 46100, Burjassot, Valencia, Spain; Unidad Mixta UPV-CIPF de Investigación en Mecanismos de Enfermedades y Nanomedicina. Universitat Politècnica de València, Centro de Investigación Príncipe Felipe, C/ Eduardo Primo Yúfera 3, 46012, Valencia, Spain.
| | - Elena Aznar
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) Av, Monforte de Lemos, 3-5. Pabellón 11, Planta 0 28029 Madrid, Spain; Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico, Universitat Politècnica de València, Universitat de València, Camino de Vera s/n, 46022, Valencia, Spain; Unidad Mixta de Investigación en Nanomedicina y Sensores. Universitat Politècnica de València, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell 106, Torre A, planta 6, 46026, Valencia, Spain.
| | - Félix Sancenón
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) Av, Monforte de Lemos, 3-5. Pabellón 11, Planta 0 28029 Madrid, Spain; Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico, Universitat Politècnica de València, Universitat de València, Camino de Vera s/n, 46022, Valencia, Spain; Unidad Mixta de Investigación en Nanomedicina y Sensores. Universitat Politècnica de València, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell 106, Torre A, planta 6, 46026, Valencia, Spain; Unidad Mixta UPV-CIPF de Investigación en Mecanismos de Enfermedades y Nanomedicina. Universitat Politècnica de València, Centro de Investigación Príncipe Felipe, C/ Eduardo Primo Yúfera 3, 46012, Valencia, Spain; Departamento de Química, Universitat Politècnica de València, Camino de Vera S/n, 46022, Valencia, Spain.
| | - Ramón Martínez-Máñez
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) Av, Monforte de Lemos, 3-5. Pabellón 11, Planta 0 28029 Madrid, Spain; Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico, Universitat Politècnica de València, Universitat de València, Camino de Vera s/n, 46022, Valencia, Spain; Unidad Mixta de Investigación en Nanomedicina y Sensores. Universitat Politècnica de València, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell 106, Torre A, planta 6, 46026, Valencia, Spain; Unidad Mixta UPV-CIPF de Investigación en Mecanismos de Enfermedades y Nanomedicina. Universitat Politècnica de València, Centro de Investigación Príncipe Felipe, C/ Eduardo Primo Yúfera 3, 46012, Valencia, Spain; Departamento de Química, Universitat Politècnica de València, Camino de Vera S/n, 46022, Valencia, Spain.
| | - Sara Santiago-Felipe
- CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) Av, Monforte de Lemos, 3-5. Pabellón 11, Planta 0 28029 Madrid, Spain; Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico, Universitat Politècnica de València, Universitat de València, Camino de Vera s/n, 46022, Valencia, Spain; Unidad Mixta de Investigación en Nanomedicina y Sensores. Universitat Politècnica de València, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell 106, Torre A, planta 6, 46026, Valencia, Spain.
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Production of a Recombinant Single-Domain Antibody for Gluten Detection in Foods Using the Pichia pastoris Expression System. Foods 2020; 9:foods9121838. [PMID: 33321826 PMCID: PMC7764234 DOI: 10.3390/foods9121838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/30/2020] [Accepted: 12/07/2020] [Indexed: 12/12/2022] Open
Abstract
The detection of gluten in foodstuffs has become a growing concern in food allergen management as a result of the high ratio of population sensitive to the main gluten-containing cereals. In this study, a promising single-domain antibody previously isolated by phage display (dAb8E) was produced in Pichia pastoris resulting in high levels of the antibody fragment expression (330 mg/L). The purified dAb8E was proved to specifically bind to gluten proteins from wheat, barley and rye, exhibiting no cross reaction to other heterologous species. The dynamic range of the sandwich enzyme-linked immunosorbent assay (ELISA) covered 0.1 to 10 µg/mL of gliadin, reaching a limit of detection of 0.12 µg/mL. When experimental binary mixtures of the target cereals were analyzed, the limit of detection was 0.13 mg/g, which would theoretically correspond to gluten concentrations of approximately 13 mg/kg. Finally, thirty commercially available food products were analyzed by means of the developed assay to further confirm the applicability of the dAb8E for gluten determination. The proposed methodology enabled the generation of a new gluten-specific nanobody which could be used to guarantee the appropriate labelling of gluten-free foods.
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8
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Osorio CE, Mejías JH, Rustgi S. Gluten Detection Methods and Their Critical Role in Assuring Safe Diets for Celiac Patients. Nutrients 2019; 11:E2920. [PMID: 31810336 PMCID: PMC6949940 DOI: 10.3390/nu11122920] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 11/20/2019] [Accepted: 11/26/2019] [Indexed: 12/16/2022] Open
Abstract
Celiac disease, wheat sensitivity, and allergy represent three different reactions, which may occur in genetically predisposed individuals on the ingestion of wheat and derived products with various manifestations. Improvements in the disease diagnostics and understanding of disease etiology unveiled that these disorders are widespread around the globe affecting about 7% of the population. The only known treatment so far is a life-long gluten-free diet, which is almost impossible to follow because of the contamination of allegedly "gluten-free" products. Accidental contamination of inherently gluten-free products could take place at any level from field to shelf because of the ubiquity of these proteins/grains. Gluten contamination of allegedly "gluten-free" products is a constant threat to celiac patients and a major health concern. Several detection procedures have been proposed to determine the level of contamination in products for celiac patients. The present article aims to review the advantages and disadvantages of different gluten detection methods, with emphasis on the recent technology that allows identification of the immunogenic-gluten peptides without the use of antibodies. The possibility to detect gluten contamination by different approaches with similar or better detection efficiency in different raw and processed foods will guarantee the safety of the foods for celiac patients.
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Affiliation(s)
- Claudia E. Osorio
- Agriaquaculture Nutritional Genomic Center, CGNA, Las Heras 350, Temuco 4781158, Chile
| | - Jaime H. Mejías
- Centro Regional de Investigación Carillanca, Instituto de Investigaciones Agropecuarias INIA, Temuco 4880000, Chile
| | - Sachin Rustgi
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA 99164, USA
- Department of Plant and Environmental Sciences, School of Health Research, Clemson University Pee Dee Research and Education Center, Florence, SC 29506, USA
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An Effective Gluten Extraction Method Exploiting Pure Choline Chloride-Based Deep Eutectic Solvents (ChCl-DESs). FOOD ANAL METHOD 2017. [DOI: 10.1007/s12161-017-0979-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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10
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Natural deep eutectic solvents in combination with ultrasonic energy as a green approach for solubilisation of proteins: application to gluten determination by immunoassay. Talanta 2017; 162:453-459. [DOI: 10.1016/j.talanta.2016.10.078] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 10/19/2016] [Accepted: 10/21/2016] [Indexed: 12/30/2022]
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11
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Miranda-Castro R, de-los-Santos-Álvarez N, Miranda-Ordieres AJ, Lobo-Castañón MJ. Harnessing Aptamers to Overcome Challenges in Gluten Detection. BIOSENSORS-BASEL 2016; 6:16. [PMID: 27104578 PMCID: PMC4931476 DOI: 10.3390/bios6020016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/13/2016] [Accepted: 04/15/2016] [Indexed: 12/13/2022]
Abstract
Celiac disease is a lifelong autoimmune disorder triggered by foods containing gluten, the storage protein in wheat, rye, and barley. The rapidly escalating number of patients diagnosed with this disease poses a great challenge to both food industry and authorities to guarantee food safety for all. Therefore, intensive efforts are being made to establish minimal disease-eliciting doses of gluten and consequently to improve gluten-free labeling. These efforts depend to a high degree on the availability of methods capable of detecting the protein in food samples at levels as low as possible. Current analytical approaches rely on the use of antibodies as selective recognition elements. With limited sensitivity, these methods exhibit some deficiencies that compromise the accuracy of the obtained results. Aptamers provide an ideal alternative for designing biosensors for fast and selective measurement of gluten in foods. This article highlights the challenges in gluten detection, the current status of the use of aptamers for solving this problem, and what remains to be done to move these systems into commercial applications.
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Affiliation(s)
- Rebeca Miranda-Castro
- Departamento de Química-Física y Analítica, Universidad de Oviedo, Julián Clavería, 8, 33006 Oviedo, Spain.
| | | | - Arturo J Miranda-Ordieres
- Departamento de Química-Física y Analítica, Universidad de Oviedo, Julián Clavería, 8, 33006 Oviedo, Spain.
| | - María Jesús Lobo-Castañón
- Departamento de Química-Física y Analítica, Universidad de Oviedo, Julián Clavería, 8, 33006 Oviedo, Spain.
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12
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Amaya-González S, de-Los-Santos-Álvarez N, Miranda-Ordieres AJ, Lobo-Castañón MJ. Sensitive gluten determination in gluten-free foods by an electrochemical aptamer-based assay. Anal Bioanal Chem 2015; 407:6021-9. [PMID: 26048055 DOI: 10.1007/s00216-015-8771-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 04/29/2015] [Accepted: 05/07/2015] [Indexed: 12/26/2022]
Abstract
Enzyme immunoassays are currently the methods of choice for gluten control in foods labelled as gluten free, providing a mechanism for assessing food safety for consumption by coeliac and other allergic patients. However, their limitations, many of them associated to the reactivity of the different antibodies used and their degree of specificity, have prevented the establishment of a standardised method of analysis. We explore new methods for quantitatively determining gluten content in foods based on the use of two recently described aptamers, raised against a 33-mer peptide recognised as the immunodominant fragment from α2-gliadin. The assays use the target peptide immobilised onto streptavidin-coated magnetic beads in combination with a limited amount of biotin-aptamer in a competitive format, followed by streptavidin-peroxidase labelling of the aptamer that remains bound to the magnetic beads. The enzyme activity onto the beads, measured by chronoamperometry in disposable screen-printed electrodes, is inversely related to the target concentration in the test solution. We find that while the assay using the aptamer with the highest affinity towards the target (Gli 4) achieves low detection limits (~0.5 ppm) and excellent analytical performance, when challenged in samples containing the intact protein, gliadin, it fails in detecting the peptide in solution. This problem is circumvented by employing another aptamer (Gli 1), the most abundant one in the SELEX pool, as a receptor. The proposed assays allow the convenient detection of the allergen in different kinds of food samples, including heat-treated and hydrolysed ones. The obtained results correlate with those of commercially available antibody-based assays, providing an alternative for ensuring the safety and quality of nominally gluten-free foods. Graphical Abstract Electrochemical magnetoassay for gluten determination using biotin-aptamers as receptors.
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Affiliation(s)
- Sonia Amaya-González
- Departamento de Química Física y Analítica, Universidad de Oviedo, Julián Clavería 8, 33006, Oviedo, Spain
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13
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Slot IDB, van der Fels-Klerx HJ, Bremer MGEG, Hamer RJ. Immunochemical Detection Methods for Gluten in Food Products: Where Do We Go from Here? Crit Rev Food Sci Nutr 2015; 56:2455-2466. [DOI: 10.1080/10408398.2013.847817] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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14
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Diaz-Amigo C, Popping B. Accuracy of ELISA detection methods for gluten and reference materials: a realistic assessment. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013; 61:5681-8. [PMID: 23713744 DOI: 10.1021/jf3046736] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The determination of prolamins by ELISA and subsequent conversion of the resulting concentration to gluten content in food appears to be a comparatively simple and straightforward process with which many laboratories have years-long experience. At the end of the process, a value of gluten, expressed in mg/kg or ppm, is obtained. This value often is the basis for the decision if a product can be labeled gluten-free or not. On the basis of currently available scientific information, the accuracy of the obtained values with commonly used commercial ELISA kits has to be questioned. Although recently several multilaboratory studies have been conducted in an attempt to emphasize and ensure the accuracy of the results, data suggest that it was the precision of these assays, not the accuracy, that was confirmed because some of the underlying assumptions for calculating the gluten content lack scientific data support as well as appropriate reference materials for comparison. This paper discusses the issues of gluten determination and quantification with respect to antibody specificity, extraction procedures, reference materials, and their commutability.
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Tanner GJ, Blundell MJ, Colgrave ML, Howitt CA. Quantification of Hordeins by ELISA: the correct standard makes a magnitude of difference. PLoS One 2013; 8:e56456. [PMID: 23509607 PMCID: PMC3585327 DOI: 10.1371/journal.pone.0056456] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 01/09/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Coeliacs require a life-long gluten-free diet supported by accurate measurement of gluten (hordein) in gluten-free food. The gluten-free food industry, with a value in excess of $6 billion in 2011, currently depends on two ELISA protocols calibrated against standards that may not be representative of the sample being assayed. AIM The factors affecting the accuracy of ELISA analysis of hordeins in beer were examined. RESULTS A simple alcohol-dithiothreitol extraction protocol successfully extracts the majority of hordeins from barley flour and malt. Primary hordein standards were purified by FPLC. ELISA detected different classes of purified hordeins with vastly different sensitivity. The dissociation constant (Kd) for a given ELISA reaction with different hordeins varied by three orders of magnitude. The Kd of the same hordein determined by ELISA using different antibodies varied by up to two orders of magnitude. The choice of either ELISA kit or hordein standard may bias the results and confound interpretation. CONCLUSIONS Accurate determination of hordein requires that the hordein standard used to calibrate the ELISA reaction be identical in composition to the hordeins present in the test substance. In practice it is not feasible to isolate a representative hordein standard from each test food. We suggest that mass spectrometry is more reliable than ELISA, as ELISA enumerates only the concentration of particular amino-acid epitopes which may vary between different hordeins and may not be related to the absolute hordein concentration. MS quantification is undertaken using peptides that are specific and unique enabling the quantification of individual hordein isoforms.
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Affiliation(s)
- Gregory J. Tanner
- Commonwealth Scientific and Industrial Research Organisation Plant Industry, Canberra, Australian Capital Territory, Australia
- Commonwealth Scientific and Industrial Research Organisation Food Futures Flagship, North Ryde, New South Wales, Australia
- * E-mail:
| | - Malcolm J. Blundell
- Commonwealth Scientific and Industrial Research Organisation Plant Industry, Canberra, Australian Capital Territory, Australia
- Commonwealth Scientific and Industrial Research Organisation Food Futures Flagship, North Ryde, New South Wales, Australia
| | - Michelle L. Colgrave
- Commonwealth Scientific and Industrial Research Organisation Plant Industry, Canberra, Australian Capital Territory, Australia
- Commonwealth Scientific and Industrial Research Organisation Animal, Food and Health Sciences, St Lucia, Queensland, Australia
| | - Crispin A. Howitt
- Commonwealth Scientific and Industrial Research Organisation Plant Industry, Canberra, Australian Capital Territory, Australia
- Commonwealth Scientific and Industrial Research Organisation Food Futures Flagship, North Ryde, New South Wales, Australia
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Mena MC, Lombardía M, Hernando A, Méndez E, Albar JP. Comprehensive analysis of gluten in processed foods using a new extraction method and a competitive ELISA based on the R5 antibody. Talanta 2012; 91:33-40. [DOI: 10.1016/j.talanta.2011.12.073] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 12/22/2011] [Accepted: 12/28/2011] [Indexed: 12/16/2022]
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Diaz-Amigo C. Towards a Comprehensive Validation of ELISA Kits for Food Allergens: Case 1—Egg. FOOD ANAL METHOD 2009. [DOI: 10.1007/s12161-009-9094-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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van den Broeck HC, America AHP, Smulders MJM, Bosch D, Hamer RJ, Gilissen LJWJ, van der Meer IM. A modified extraction protocol enables detection and quantification of celiac disease-related gluten proteins from wheat. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:975-82. [PMID: 19282254 DOI: 10.1016/j.jchromb.2009.02.035] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 02/12/2009] [Accepted: 02/19/2009] [Indexed: 01/31/2023]
Abstract
The detection, analysis, and quantification of individual celiac disease (CD) immune responsive gluten proteins in wheat and related cereals (barley, rye) require an adequate and reliable extraction protocol. Because different types of gluten proteins behave differently in terms of solubility, currently different extraction protocols exist. The performance of various documented gluten extraction protocols is evaluated for specificity and completeness by gel electrophoresis (SDS-PAGE), immunoblotting and RIDASCREEN Gliadin competitive ELISA. Based on these results, an optimized, two-step extraction protocol has been developed.
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Affiliation(s)
- Hetty C van den Broeck
- Plant Research International, Wageningen UR, PO Box 16, 6700 AA Wageningen, The Netherlands.
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Current awareness in phytochemical analysis. PHYTOCHEMICAL ANALYSIS : PCA 2008; 19:471-478. [PMID: 18773504 DOI: 10.1002/pca.1040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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