Development of Semiconductor-Based Biosensor for Detection of Buckwheat Allergenic Protein in Food Products
Authors: Hideshima Sho , Saito Mai , Harada Yoshitaka , Tsuna Mika , Kuroiwa Shigeki , Nakanishi Takuya , Osaka Tetsuya 
Published: February 2020

People all over the world have recently suffered from food allergies, thus allergenic substances in raw materials need to be severely controlled in food manufacturing factories. To regulate food safety, food manufactures are required to label allergenic information on their products. In the United States, labeling for seven kinds of food materials, milk, fish, crustacean shellfish, tree nuts, peanut, wheat, and soy, are required, and in Japan similar seven kinds of food materials such as milk, egg, shrimp, crab, peanut, wheat, and buckwheat, are listed. The Japanese food labeling law defines that the labeling is mandatory when the amount of proteins of an allergenic food is equal to or over 10 μg per gram amount of food product. According to the above criteria, food manufacturers always check materials purchased for food production and inspect the production facilities of these materials. Representative detection methods for food allergens used in food factories are ELISA test or lateral flow test strip, although they are some drawbacks such as complicated operation steps and large analysis equipment. To overcome these drawbacks, a simple label-free allergen detection technique is desirable. A field effect transistor (FET) biosensor is a promising platform because it can be used in mass production and for large-scale integration. FET biosensors may directly detect the intrinsic charge of proteins captured by immobilized receptors, suggesting that it has the potential to eliminate some of the steps involved in conventional allergen detection processes. In our previous study, an allergenic buckwheat protein, BWp16, was successfully detected by the FET biosensor. Soba, buckwheat noodle, is one of the most popular Japanese dishes. It should be noted that soba may cause serious allergic reactions like peanuts. To detect the BWp16 protein which does not possess its intrinsic charge enough to be detected by the FET biosensor, we achieved the signal amplification by coupling of the negatively charged surfactant with the BWp16 protein. Toward the practical application of the FET biosensor to food inspection, extract and specific detection of allergens from processed foods are important steps to be optimized. In this presentation, we evaluated an availability of the FET biosensing system for the detection of buckwheat protein in processed foods. First, to achieve significant signal amplification by using the SDS surfactant, the concentration of the surfactant was optimized. Second, the FET responses obtained for the target protein treated with anionic, cationic, and nonionic surfactants were compared to verify the effect of electric charge derived from surfactant on the signal amplification. In addition, the attachment of surfactant to protein was examined by fluorescence spectroscopy. Finally, the specific detection of the buckwheat protein in food extracts or processed foods was examined.
Acknowledgement
This work is partly supported by the Center of Innovation Program, Building of Consortia for the Development of Human Resources in Science and Technology, Program on Open Innovation Platform with Enterprises, Research Institute and Academia and Grant-in-Aid for Young Scientists (B), all from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.