Ratiometric fluorescence detection of anthrax biomarker with Eu(III)-EDTA functionalized mixed poly(diacetylene) liposomes

Abstract

Anthrax, a bacteriogenic fatal infectious disease that is harmful to humans, requires the early and ready detection of its bacterial endospores. We report herein the use of poly(diacetylene acid) derived liposomes functionalized with EuIII-EDTA complexes as a ratiometric fluorescence detection system for dipicolinate, an anthrax biomarker and major component of the endospores. The red fluorescence of the polymerized liposomes provides a built-in reference signal to monitor the relative change of the europium luminescence sensitized by the bound dipicolinate relative to the reference liposome emission. The liposome-based integrated sensing system shows reasonable sensitivity as well as remarkable selectivity toward dipicolinate over other structurally related analytes. Paper strip sensors based on the polymerized liposomes are also prepared for the visible detection of dipicolinate.