Team:Linkoping Sweden/Description

The challenge

Food allergies are an increasing health issue in several countries and the number of children affected has been doubled between the years of 1997 and 20111, 2, 3. It has been calculated that 4 % of the world population have some kind of food allergy4, 5, 6. The most common food allergies are caused by proteins, so called allergens, from tree nuts, peanuts, milk, eggs, fish, shellfish, wheat and soy6. Peanut allergy is not the most common of these food allergies, but it is the food allergy that causes the largest number of deaths due to anaphylaxis7, where blood pressure drops abruptly and severe breathing difficulties occur. Peanut allergy is a chronic condition in the majority of cases, less than 20% outgrow their allergy8. Today there is no cure for food allergies; avoidance of food allergens is therefore the main solution available for those living with food allergies to prevent serious health consequences9, which is not an easy task.

The solution

The aim of LiU iGEM:s project 2015 is to create a portable and for the consumer easy to use allergen detector, specific for the most prevalent peanut allergen, Ara h 1. The detection system can be described as consisting of two parts, one biological and one electrical. The biological part is an epitope-antibody complex, designed by LiU iGEM team. The epitope-antibody complex consists of two parts, the first part is Ara h 1 specific antibodies linked to the fluorescent protein Fluorescein isothiocyanate (FITC). The second part is made up by red fluorescent protein (RFP) linked to our constructed epitope.

 

The epitope emulates the Ara h 1 protein, thus binding to the antibodies. When the two parts of the complex are bound, the close proximity of the fluorophores allows Förster resonance energy transfer or FRET to occur. This energy transfer allows photons absorbed by FITC to be transferred to RFP where the emission wavelength is greater than it would be if emitted from FITC. If the sample of interest, e.g. a chocolate bar, contains Ara h 1, i.e. peanuts, the allergen will bind to the antibody complex instead of the constructed epitope. This change of bound protein hinders FRET, causing a change in fluorescent emission which can be detected and processed by the electrical system of the detector. The detector indicates to the user if there has occurred a shift in emission wavelength by lighting small LEDs on the detector, where a red light indicates contamination of peanuts and green indicates that it is safe to eat.

References

  • 1. Sicherer S.H. (2002). Food allergy. Lancet 360:701-710.
  • 2. Sicherer S.H., Munoz-Furlong A. and Sampson H.A (2003). Prevalence of peanut and tree nut allergy in the United States determined by means of random digit dial telephone survey: a 5-year follow-up study. Journal of Allergy and Clinical Immunology 112:1203-1207.
  • 3. Jackson K. et al. (2013) Trends in Allergic Conditions among Children: United States, 1997-2011. National Center for Health Statistics Data Brief: www.cdc.gov/nchs/data/databriefs/db10.htm
  • 4. National Institute of Allergy and Infectious Diseases: http://www3.niaid.nih.gov/
  • 5. The Food Allergy and Anaphylaxis Network (FAAN): http://www.foodallergy.org
  • 6. Burks A.W. (2009). Early peanut consumption: postpone or promote? Journal of Allergy and Clinical Immunology 123(2): 424-425.
  • 7. Astma and allergy Foundation of America (AAFA): http://www.aafa.org/display.cfm?id=9&sub=20&cont=517
  • 8. Fleischer D.M. et al. (2007). The natural history of peanut and tree allergy. Current Allergy and Asthma Reports 7(3): 175-181
  • 9. U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition. Food allergies: What you need to know: http://www.cfsan.fda.gov/~dms/ffalrgn.html