Understanding the hierarchical assembly of proteins, including amorphous to crystalline phase transit, is critical to utilize their functionality for engineering purposes properly. Among many structural proteins, researches have extensively explored silk fibroin for the generation of various advanced material formats via control of polymorphisms (amorphous to crystalline transition) and forms (sol-gel-solid transition). Beyond traditional utilization of silk fibroinsâ mechanical properties, recent studies have focused on the non-toxic and edible nature of silk fibroins extracted from Bombyx mori
silkworm cocoons for food contact applications. In this study, we present a microneedle injection system for food bacteria detection by leveraging water-based processing of Bombyx mori
silk fibroin. The porous microneedle structure was developed by the water-annealing process, which increases fibroin crystallinity. The microneedles extracted internal food fluid into the pores. The capillary action transported the fluid to a colorimetric sensor on the backside of the needle array. Within a day of injection, we identified E. coli
contamination in fish fillets by color changes of the polydiacetylene-based sensor. We were able to distinguish this response by E. coli
contamination from common food spoilage. We also showed that the microneedle sensor could pierce commercial food packaging, implying a successful adaptation of the technology downstream in conventional food supply chains. Therefore, this study provides insights into food quality monitoring and global food safety by minimizing food loss and waste.
Dr. Doyoon Kim (Ph.D. in Energy, Environmental, & Chemical Engineering, 2018) is interested in exploring nucleation and crystallization phenomena occurring at water-inorganic-organic interfaces. He aims to apply principles of interfacial chemistry from multiscale observations on these interfaces to various fields of engineering. In his previous studies, Dr. Kim investigated the nucleation of calcium phosphate mineralization in organic templates for biomedical engineering (bone regeneration) and environmental engineering (phosphorous removal).
Based on his expertise, Dr. Doyoon Kim will be a suitable faculty candidate for teaching courses such as Aquatic Chemistry, Environmental Nanochemistry. Also, he is interested in teaching fundamental chemical engineering courses for undergraduate, such as Kinetics and Reaction Engineering, Transport Processes, Mathematical Methods in Engineering, and Micro and Nanofabrication.