Polyethylenimine-Mediated Assembly of Dual-Emissive CsPbBr@SiO@EuWComposite Nanospheres for Ratiometric Detection of 2,6-Dipicolinic Acid.

Source: PubMed, NCBI / U.S. National Library of Medicine

, a highly pathogenic bacterium that causes anthrax, poses a bioterrorism threat to both wildlife and human health. Consequently, as a key biomarker for anthrax spores, quantitative and visual detection of 2,6-dipicolinic acid (DPA) is critical for biodefense and public health security. Herein, a dual-emissive CsPbBr@SiO@EuW(CPB@SiO@EuW) composite nanospheres were successfully prepared through the confinement effect of SiOon CsPbBrperovskite quantum dots (PQDs), followed by a polyethylenimine (PEI)-mediated ionic self-assembly (ISA) of EuWon the exterior surface of CsPbBr@SiO. The resultant CPB@SiO@EuWcomposite nanospheres exhibit a selective response to DPA with exceptional luminescent stability and good sensitivity. The green-emitting CsPbBrPQDs centered in the composite nanospheres can be quenched by DPA via the inner filter effect (IFE), while the antenna effect of DPA enhances the red fluorescence of Eu. The contrasting fluorescence response behaviors of CsPbBrand Eucenters endow the CPB@SiO@EuWcomposite nanospheres with a self-calibrated sensing mechanism for reliable DPA detection. The low detection limit (LOD) is 0.052 μM within a linear range of 10-120 μM. The ratiometric sensing of DPA based on the CPB@SiO@EuWfluorescent probe also shows a color shift from green to yellow, enabling visual detection and efficient identification of DPA in aqueous solutions.