Design of Liquid Crystals Based Rapid Detection for Food Poisoning Bacteria

Abstract

Sensitive and selective detection of salmonella that causes food-borne diseases is necessary for food safety and prevention of pathogenic infection. Previous methods like polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) require laborious process and long assay time, hence, reduction in detection time is still controversial issues.1 Here we design liquid crystals (LCs) with organic ionics (OIs) system which can realize simple and rapid bacteria detection. Specifically, OIs are self-assembled at the aqueous-LC interface and cause vertical LC ordering, so that light cannot pass through the film; it appears dark. With injection of tryptone which is one of the components of cell culture media, however, LC is gradually reoriented, which leads to formation of domains. Salmonella population rather than motility facilitates LC reorientation and bright texture is observed as light can pass through the film, which enables rapid and sensitive detection. In addition, functionalized or head group modified OIs are expected to improve selectivity of detection as well as sensitivity depending on length of OIs carbon tail in further studies. The exploration of interaction between OIs, tryptone and bacteria can lead to effective biosensor for detection.