A terbium-functionalized ZIF-8 nanosensor for rapid and sensitive detection of an anthrax spore biomarker

Because anthrax spores are highly lethal to humans and animals as well as potential biological warfare agents, there is a great need for rapid, sensitive, and selective quantification of dipicolinic acid (DPA) as a biomarker for anthrax spores. Herein, we prepared a novel lanthanide-doped nanoprobe by coordination of Tb3+ ions with tannic acid (TA)-coated zeolitic imidazolate frameworks-8 (ZIF-8) (ZIF-8@Tb–TA). The proposed assay was derived from the unsaturated coordination of Tb3+ ions. In the presence of DPA, Tb3+ ions could be sensitized to emit inherent luminescence due to the energy transfer after coordination with DPA. The results illustrated that ZIF-8@Tb–TA could be used as a sensitive nanoprobe for detecting DPA with a broad linear range (0 μM to 12.0 μM), and the limit of detection (LOD) was 12.3 nM. Moreover, the specific recognition ability of DPA by ZIF-8@Tb–TA was much better than that of other interfering molecules. This study proposed a new strategy to establish lanthanide-functionalized nanoprobes for highly selective and sensitive detection of DPA.