In situ growth of luminescent lanthanide coordination nanoparticles inside living plants

Lanthanide coordination nanoparticles have drawn considerable attention owing to their outstanding luminescence properties. However, biosynthesis of lanthanide coordination nanoparticles is a relatively new and poorly explored area. Plants possess complex passive fluid transport systems and are potential green nanofactories for the synthesis of nanomaterials. In this study, luminescent lanthanide coordination nanoparticles with various morphologies were synthesized from various living plants. The two-step process involved incubating plant clippings or intact plants in p-phthalic acid (PTA) solution, followed by washing and subsequent incubation in lanthanide ion (Eu³⁺ and Tb³⁺) solution. Different types of plants and lanthanide ions led to the formation of lanthanide coordination nanoparticles of different shapes and sizes. Specifically, the Eu/PTA and Tb/PTA coordination nanoparticles inside shamrock and epipremnum aureum revealed spherical, rod-shaped, octahedral, cubic, and rectangular crystals with sizes in the nanometer and micrometer ranges. Moreover, luminescent shamrocks with red, green, and even yellow emissions were obtained using Eu³⁺, Tb³⁺, and a mixture. Finally, the intact shamrocks with luminescent Eu/PTA and Tb/PTA coordination nanoparticles were used for the in situ detection of Cu²⁺ in water. The integration of functional lanthanide coordination nanoparticles into living plants is a promising innovation in nanobionics that could open the door to advanced sensors and other applications.