Water-dispersible chlorophyll-based fluorescent material derived from willow seeds for sensitive analysis of copper ions and biothiols in food and living cells

Abstract The environmental risk of artificial synthetic dyes sparked interest in exploring high-security fluorescent materials for suitable analysis applications. Chlorophyll-based fluorescent material is a good candidate but subjects to inferior dispersibility and low fluorescence efficiency in water. In this work, we successfully prepared a water-dispersible chlorophyll-based fluorescent material through simple solvent extraction of willow seeds. Compared to other conventional sources of chlorophyll, such as willow leaves, metasequoia, and green algae, only the chlorophyll-based material from willow seeds (C-WS) can retain good near-infrared fluorescence performance with an emission wavelength of 677 nm in the water phase, which can promote the practical application of chlorophyll-based fluorescent materials. An “on-off-on” sensing system was constructed based on C-WS for the highly sensitive and selective detection of Cu2+ and biothiols in aqueous solution. The limit of detection for Cu2+ and GSH can reach 1.2 nM and 92 nM, respectively. Furthermore, the proposed system was successfully used in the detection of Cu2+ in real water samples and biothiols in food samples, and successfully applied for the visualization of intracellular Cu2+ and biothiols in Hela cells.