Design of Liquid Crystal Based System for Food-Borne Bacteria

Abstract

Rapid, sensitive, and selective recognition of salmonella that causes food poisoning is necessary for food-safety and prevention of pathogenic infection. However, previous methods require laborious process, time-consuming process, and trained personnel. Here, we offer generalizable approach to realize rapid detection of food-borne bacteria (salmonella) by liquid crystals (LCs) based system integrated with organic ionics (OIs). Specifically, OIs are self-assembled at the aqueous-LC interface, causing vertical ordering of LC molecules. However, under the incubation of LCs in the aqueous solution with specific amino acids (Glutamic acid, Aspartic acid), we observed gradually reoriented LC, leading to formation of macroscopic optical signal within ~3.5 h. Surprisingly, we observed extremely low concentration (10 cfu/mL) of salmonella accelerates self-assembly of specific amino acids into the aqueous-LC interface and the formation of bright domains, which enables rapid and sensitive detection within 1.5 h without any complex procedure. This work was supported by NRF (2021R1A4A1030944, 2022M3C1A3081312) and Samsung Electronics Co., Ltd (4.0024479).