The ratiometric fluorescent detection of anthrax spore biomarker based on functionalized silicon nanodots

Silicon nanodots (SiNDs) as an excellent fluorescent nanomaterial have got more and more applications. In this work, the terbium-modified silicon nanodots (SiNDs-Tb) were synthesized and successfully applied to the detection of dipicolinic acid (DPA), a biomarker of anthrax spores. Here, SiNDs serve as scaffolds and a fluorescence reference ( F 445 ), coordinating with Tb 3+ ions, while terbium ions as specific recognition elements and response signals ( F 490 and F 547 ) with zero background fluorescence. The sensing process was easily operated in aqueous media and can be finished in a short time. With a concentration range of 0.2–10 μM of DPA, the fluorescence intensity ratio ( F 547 / F 445 ) correspondingly generated quantitative changes and the limit of detection was 24 nM. It is a rapid and sensitive sensing system and provides a new approach for full exploitation of SiNDs in fluorescence assay.