Stimulus response of HNT-CDs-Eu nano-sensor: Toward visual point-of-care monitoring of a bacterial spore biomarker with hypersensitive multi-color agarose gel based analytical device

Ultrasensitive visual detection of anthrax markers is of great significance for disease prevention and early warning of terrorist attacks. A novel of dual-emission ratiometric fluorescent nano-probe (HNT-CDs-Eu) has been elaborately tailored based on the direct in-situ growth of CDs on natural mineral nanotubes (HNTs) for the determination and visual assay of DPA concentrations, using DTPA as the efficient chelating agent and the raw material for the preparation of CDs. The rich carboxyl groups of DTPA also provide coordination sites for Eu 3+ to form highly sensitive recognition groups. This multi-color nano-sensor can not only realize ultra-sensitive trace detection of pure DPA, but also meet the feasibility of visual sensing of DPA in environmental water samples. Since the common filter paper has strong blue fluorescence under ultraviolet light irradiation at 365 nm, a color agarose gel for visual inspection and an advanced analytical device for one-to-two decoder are further prepared to realize the intelligent and real-time detection of DPA. • An innovative dual-emission ratiometric fluorescent nano-probe was elaborately tailored. • The fabrication included the direct in-situ growth of CDs on natural mineral nanotubes. • This multi-color nano-sensor can realize ultra-sensitive trace detection of DPA in environmental water. • An advanced analytical device based on agarose gel was further prepared and researched.