Development of microfluidic paper-based analytical device to detect chemical hazards in food

Food safety remains one of the most challenging issues worldwide. To ensure food safety, regulatory authorities monitor the agri-food chain by detecting chemical hazards in foods. However, the current standard methods cannot handle large numbers of food commodities due to high cost, long analyzing time, and equipment limitations. The demand for rapid, portable, easy-to-use, and low-cost devices draws attention to the microfluidic paper-based analytical device (μPAD), a promising candidate to provide alternative solutions to the current commercial products. Previous studies of μPAD are limited to the detection of simple chemicals or the analysis of simple, lacking applications on real food samples. In the current study, a μPAD adopting the format of the conventional lateral flow immunoassay (LFI) was developed for rapid detection of chemical hazards in food. The major egg white protein, ovalbumin, was selected since egg is a common food ingredient listed in Canada’s eleven priority allergens. The patterning condition was first optimized for wax-printing and wax-stamping techniques on Grade 1 and Grade 42 filter papers. Immunological conjugates were prepared, and antibody pairs were screened for sandwiching the antigen. The surface modification solution and the geometry of patterns were optimized to functionalize the single piece of cellulose paper as an LFI-format μPAD. The developed μPAD could detect as low as 1 ppm ovalbumin solution, 0.01% (w/w) egg white protein in cake mix, and egg content in commercial food products within 15 min including sample preparation. The single-piece μPAD requires simpler fabrication procedures and much lower material cost, compared with that of the conventional LFI. With more optimizations, the developed μPAD can serve as the prototype for mass production and compete with the mature commercial products, providing an alternative food monitoring option to many sectors throughout the agri-food chain and contributing to improving food safety and public health.Land and Food Systems, Faculty ofGraduat