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Ultrasensitive Detection of Biomarkers by Using a Molecular Imprinting Based Capacitive Biosensor
Published on: February 16, 2018
Anthrax biomarker: An ultrasensitive fluorescent ratiometry of dipicolinic acid by using terbium(III)-modified carbon
Meng Li Liu1, Bin Bin Chen1, Jia Hui He2
1Key Laboratory on Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
Abstract:
The highly sensitive detection of dipicolinic acid (DPA), a biomarker of the biological threat-agent anthrax, is strongly associated with the sensing of Bacillus anthracis (B. anthracis) in environmental and food samples. In this study, we developed a novel, ultrasensitive method for the detection of DPA by using a ratiometric fluorescent terbium ions modified carbon dots (CDs-Tb). The CDs-Tb showed two fluorescent emission bands at 459 nm and 495 nm when excited at the single wavelength of 260 nm. DPA could specifically bind with terbium ions on the surface of CDs through strong chelate-conjugation to produce antenna effect, resulting in significantly enhancement of the 495 nm emission peak without affecting the 459 nm emission peak. The fluorescence intensity ratio (I495/I459) of CDs-Tb was proportional to the concentration of DPA in the range of 0.5 nM to 2.5 μM with the limit of detection as low as 100 pM. This selective and ultrasensitive assay had a great application prospect in the complex matrixes owing to its simplicity and specificity for DPA. Meanwhile, the CDs-Tb-based paper sensor was successfully developed for sensitive and visual detection of DPA.
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