title: Giant magnetoresistive sensor array for sensitive and specific multiplexed food allergen detection.
abstract: Current common allergen detection methods, including enzyme-linked immunosorbent assays (ELISAs) and dip-stick methods, do not provide adequate levels of sensitivity and specificity for at-risk allergic patients. A method for performing highly sensitive and specific detection of multiple food allergens is thus imperative as food allergies are becoming increasingly recognized as a major healthcare concern, affecting an estimated 4% of the total population. We demonstrate first instance of sensitive and specific multiplexed detection of major peanut allergens Ara h 1 and Ara h 2, and wheat allergen Gliadin using giant magnetoresistive (GMR) sensor arrays. Commercialized ELISA kits for Ara h 1 and Ara h 2 report limits of detection (LODs) at 31.5 ng/mL and 0.2 ng/mL, respectively. In addition, the 96-well-based ELISA developed in-house for Gliadin was found to have a LOD of 40 ng/mL. Our multiplexed GMR-based assay demonstrates the ability to perform all three assays on the same chip specifically and with sensitivities at LODs about an order of magnitude lower than those of 96-well-based ELISAs. LODs of GMR-based assays developed for Ara h 1, Ara h 2, and Gliadin were 7.0 ng/mL, 0.2 ng/mL, and 1.5 ng/mL, respectively, with little to no cross-reactivity. These LODs are clinically important as some patients could react strongly against such low allergen levels. Given the limitations of current industrial detection technology, multiplexed GMR-based assays provide a method for highly sensitive and specific simultaneous detection of any combination of food-product allergens, thus protecting allergic patients from life-threatening events, including anaphylaxis, by unintentional consumption.
authors: Department of Bioengineering, Stanford University, Stanford, CA 94305, USA. Electronic address: elaineng@stanford.edu.
authors: Elaine
authors: E
authors: Ng
authors: Department of Pediatrics, Stanford University, Stanford, CA 94305, USA; Department of Otolaryngology, Stanford University, Stanford, CA 94305, USA.
authors: Kari C
authors: KC
authors: Nadeau
authors: Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA; Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
authors: Shan X
authors: SX
authors: Wang
mesh_terms: D055516:2S Albumins, Plant / Q000032:analysis*; D052179:Antigens, Plant / Q000032:analysis*; D010367:Arachis / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D005903:Gliadin / Q000032:analysis*; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D057230:Limit of Detection; D008280:Magnetics / Q000295:instrumentation; D008565:Membrane Proteins; D010940:Plant Proteins / Q000032:analysis*; D014908:Triticum / Q000737:chemistry*
chemical_list: D055516:2S Albumins, Plant; D052179:Antigens, Plant; C500889:Ara h 1 protein, Arachis hypogaea; C500890:Ara h 2 allergen, Arachis hypogaea; D006023:Glycoproteins; D008565:Membrane Proteins; D010940:Plant Proteins; D005903:Gliadin
keywords: Food allergens; Giant magnetoresistance; Magnetic-based immunoassays; Multiplexed immunoassays; Sensor arrays