A fluorescence probe based on blue luminescent carbon dots for sensing Fe3+ in plants

Abstract

Iron is an essential nutrient for plants and plays a crucial role in many physiological processes. Achieving sensitive, rapid, and real-time sensing of Fe³⁺ within plant organisms using carbon dots remains an intriguing research challenge. In this study, blue-emitting carbon dots (B-CDs) with an average size of 2.22 nm were synthesized through a hydrothermal reaction of sodium citrate and glutathione. The B-CDs exhibited low cytotoxicity and demonstrated high sensitivity and selectivity in fluorescence response toward Fe³⁺. Experimental evidence indicated that the phenolic hydroxyl groups on the surface of B-CDs formed ground-state complexes with Fe³⁺, and static quenching was the main quenching mechanism. Furthermore, as a biophotonic probe, B-CDs entered plant organisms during the process of water absorption and accumulated in the vascular bundles, enabling the visualization of Fe³⁺ sensing. This work successfully achieved Fe³⁺ sensing within plant organisms using carbon dots, laying a foundation for future applications of carbon dots in visual sensing within plants.