Versatile Tb3+–carbon-dot nanoplatform for fluorescence detection and in situ inactivation of bacterial spores

Pathogenic bacterial spores pose a considerable threat to human health due to their ability to survive extreme environmental conditions. Thus, sensitive detection and efficient inactivation of these spores are essential for preventing disease transmission. However, most existing studies have predominantly concentrated on detection alone. Herein, we developed a versatile nanoplatform that integrates sensitive bacterial spore sensing and in situ spore inactivation capabilities by assembling terbium ions (Tb³⁺) with photosensitizing carbon dots (CDs), referred to as Tb-CDs nanoassemblies (NAs). By leveraging the unique optical properties of CDs and Tb³⁺ ions, along with the antenna effect of lanthanides, Tb-CDs NAs demonstrated highly sensitive visual detection of the key bacterial spore biomarker, pyridinedicarboxylic acid (DPA), achieving a low detection limit of 0.68 μM and excellent selectivity. Additionally, Tb-CDs NAs exhibited practical sensing capabilities in various environments, including spore suspensions and real samples, while monitoring bacterial spore germination. Further studies confirmed that the DPA-triggered disassembly of Tb-CDs NAs led to the release of CDs, enabling higher affinity for spores and in situ inactivation through singlet oxygen generation. This work underscores the potential of CDs-based assemblies for simultaneous pathogen detection and inactivation, providing promising tools for preventing bacterial spread and contamination.