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

Abstract

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.