Development of a novel chemosensor for photodynamic antimicrobial and fluorescence-colorimetric dual-mode sensing in food preservation and spoilage process monitoring.

Abstract

The integration of photodynamic antimicrobial with multimodal sensing technologies offers substantial potential applications across diverse stages of food production, storage, and transportation. Here, we have developed a novel colorimetric/fluorescent dual-mode sensing chemosensor, TIDOH, with photodynamic antimicrobial capabilities. TIDOH was synthesized by coupling triphenylamine, which exhibits photodynamic properties, with pH-sensitive reactive groups through Knoevenagel condensation. Under acidic conditions, TIDOH opens its ring to form a conjugated structure, while under alkaline conditions, it closes the ring, resulting in a blue shift in fluorescence emission. This behavior, confirmed by DFT calculations and fluorescent methods, allows TIDOH to detect volatile amines through significant color changes, aiding visual spoilage monitoring. Additionally, in vitro studies revealed TIDOH's photodynamic antimicrobial activity. By integrating it with biocompatible carboxymethyl chitosan and sodium alginate, we developed an antimicrobial film that effectively preserves strawberries. This research not only underscores TIDOH's utility in food safety but also advances food preservation technology.