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Lateral flow assay-based bacterial detection using engineered cell wall binding domains of a phage endolysin
Diverse research is being conducted worldwide to secure food safety. One prominent area is the development of quick detection methods for pathogenic bacteria that cause food poisoning to counteract this threat to the health of the nation. According to the Health Industry Development Institute, the socioeconomic loss resulting from food poisoning in Korea amounts to 1.3 trillion won annually. Hence, there is an indispensable need to develop technology that can quickly and accurately detect food poisoning bacteria. Until recently, detection kits that include antibodies using biochemical characteristics have been used.
The laboratory headed by Professor Ryu, Sangryeol from Seoul National University is conducting research that uses bacteriophage in their research on food poisoning bacteria control. Bacillus cereus is a pathogenic microorganism that circulates throughout the world. Consuming foods contaminated by this microorganism leads to vomiting and diarrhea.
The research team led by Professors Ryu and Je-Kyun Park of KAIST has shown the potential for developing an economic and effective quick diagnosis kit for food poisoning bacteria through this study. The CBD (cell-wall binding domain) of endolysin, a host cell wall disassembly enzyme isolated from a new bacteriophage, binds specifically to Bacillus cereus. The CBD was separated and mass-produced from the E. coli to develop a lateral flow assay method that was applied to nitrocellulose paper.
Pregnancy test kits using HCG are a common example of the lateral flow assay method; it is an affordable and simple analysis method that provides a diagnosis through lines that appear on filter paper. Although it is based on the principle of detecting a target microorganism by binding with an antibody, the effectiveness of existing antibodies suffers, leading to low performance according to comparison tests. The large size of food poisoning bacteria makes it difficult to create lines on filter paper; therefore, the research team led by Professor Ryu developed a protein that only binds the specific food poisoning bacterium, Bacillus cereus, with higher affinity compared with antibody.
Existing standardized tests such as the selective culture medium method take at least 2-3 days, but the CBD-based lateral flow assay method shows results within 20 minutes, a significant reduction in time. Furthermore, the existing rapid method through gene diagnoses requires expensive equipment and experienced technicians, whereas the new detection method is much more economical and simple to use.
Professor Ryu stated that there must be active research on food poisoning bacteria, such as research on methods for the creation of food poisoning bacteria detection targets as the applicability of this method may differ for various types of food. Moreover, technology to generate proteins that bind to different types of food poisoning bacteria must also be established. This study showed the potential for producing diagnosis kits that can detect food poisoning bacteria directly, simply, quickly, and affordably on site and gave hope for a society that consumes safe food through grand developments in detection technology for food poisoning bacteria.
Student Reporter Lim, Dabin / Seong, Gayeong