Design of Liquid Crystal Based Self-Reporting System for Food Poisoning Bacteria

Abstract

Sensitive, selective, and rapid detection of salmonella which causes food-borne diseases is required in terms of food safety and prevention of pathogenic infection. However, previous methods like polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) require laborious and time-consuming process, and trained personnel. In this work, we offer simple and generalizable approach to realize rapid detection of specific food poisoning bacteria (salmonella) by liquid crystals (LCs) based system integrated with organic ionics (OIs). Specifically, OIs are self-assembled at the aqueous-LC interface and cause vertical LC ordering. Under the incubation of the LCs in the aqueous solution with peptides, however, we observe gradually reoriented LC, which leads to the formation and growth of birefringent domains after ~1.5 hours. Surprisingly, we observe the presence of salmonella to facilitate the formation of domains and their grow rate is dependent on the population of salmonella, which enables the rapid detection of target bacteria within 20 min without any complicated procedure. This work was supported by NRF-2021R1A4A1030944&2021R1A2C2095010