Self-Assembled Conjugated Polymer/Chitosan-graft-Oleic Acid Micelles for Fast Visible Detection of Aliphatic Biogenic Amines by "Turn-On" FRET.

A fluorescent "turn-on" sensor for fast measurement of aliphatic biogenic amines (BAs) was developed based on fluorescent carboxylated polyfluorene (PFTBTCOOH)/chitosan-graft-oleic acid (CS-graft-OA) micelles. In this system, biobased CS-graft-OA micelles, prepared by graft modification of CS with OA, serve as the vector of the hydrophobic fluorescent probe. Bright turn-on fluorescence was achieved by the intermolecular fluorescence resonance energy transfer of the encapsulated PFTBTCOOH, driven by the formation of an electrostatic complex with aliphatic BAs, which facilitate visual identification. The peak intensity ratio of the PFTBTCOOH/CS-graft-OA micelles toward an increasing amount of aliphatic BAs was calibrated, giving a linear relationship. The fluorescence response of PFTBTCOOH/CS-graft-OA micelles to aliphatic BAs in milk and yogurt matrixes reaches a detection concentration as low as 10 μM, showing that the PFTBTCOOH/CS-graft-OA micelle solution is a potential chemosensor for fast and selective detection of trace aliphatic BAs, which is of great significance to public health and food safety.