Germ must be found: The HNT@RhB@MOF-Tb polychromatic fluorescent nanoprobe is applied for the visual detection of 2,6-dipicolinic acid

A polychromatic fluorescent nanoprobe based on natural halloysite nanotubes with fluorescent dyes and porous metal–organic frameworks co-loaded on the surface and inner wall of the nanotubes was constructed for the highly sensitive visual identification of the Bacillus anthracis biomarker 2,6-dichlorophenolic acid (DPA). The limit of detection for DPA was 11.27 nM, which is significantly lower than the spore-borne dose for anthrax infection (60 uM). The multi-color fluorescent probe showed potential for rapid, accurate, and highly selective detection of Bacillus anthracis markers in actual samples. Besides, a portable fluorescence detection platform was developed in combination with a smartphone color scanning APP to simplify the detection process and realize real-time semi-quantitative analysis.