A core-shell structure ratiometric fluorescent probe based on carbon dots and Tb3+for the detection of anthrax biomarker

A novel core-shell structure ratiometric fluorescent probe was developed, which can selectively and sensitively detect 2,6-dipicolinic acid (DPA) as an anthrax biomarker. Carbon dots (CDs) was embedded into SiO2 nanoparticles, which was acted as an internal reference signal. Tb3+ with green emission was connected to the carboxyl functionalized SiO2, which was acted as a responsive signal. With the addition of DPA, the emission of CDs at 340 nm was unchanged, while the fluorescence of Tb3+ at 544 nm was enhanced by the antenna effect. In the concentration range of 0.1-2 & mu;M, the fluorescence intensity ratio of I544/I340 showed a good linear relationship with the concentration of DPA, and the limit of detection (LOD) was 10.2 nM. In addition, the dualemission probe showed an obvious fluorescence color change from colourless to green with increasing DPA under UV light, which enabled visual detection.

Automated summary

A novel core-shell structure ratiometric fluorescent probe was developed for the selective and sensitive detection of 2,6-dipicolinic acid (DPA) as an anthrax biomarker. The probe consisted of carbon dots (CDs) embedded into SiO2 nanoparticles as an internal reference signal, and Tb3+ connected to carboxyl functionalized SiO2 as a responsive signal. The probe exhibited a good linear relationship between the fluorescence intensity ratio of I544/I340 and the concentration of DPA in the range of 0.1-2 μM, with a limit of detection (LOD) of 10.2 nM. Additionally, the probe showed a visible fluorescence color change from colourless to green with increasing DPA under UV light, enabling visual detection.