Persistent luminescence nanoparticles used in the form of a diagnosis agent for in vivo optical imaging

Method for in vivo optical imaging of an organism comprising the steps of:

• a) providing a persistent luminescence nanoparticle, between 25 nm and 1 μm in size, emitting photons at wavelengths between 600 and 1300 nm for at least one minute to several hours, after light excitation at wavelengths between 100 and 800 nm, or after excitation by means of X-rays, wherein said nanoparticle consists of a compound selected from the group consisting of:
• silicates, aluminates, aluminosilicates, germanates, titanates, oxysulfides, phosphates and vanadates, such compounds comprising at least one metal oxide, sulfides comprising at least one metal ion selected from zinc, strontium and calcium, and metal oxides,
• said compound being doped with at least one rare earth ion, and optionally with at least one transition metal ion;
• b) exciting said persistent luminescence nanoparticle by means of light excitation at wavelengths between 100 and 800 nm or by means of X-rays;
• c) administering the excited persistent luminescence nanoparticle obtained in step b) to the organism under study;
• d) detecting said persistent luminescence nanoparticle in vivo at wavelengths between 600 and 1300 nm to obtain an in vivo optical image of said organism.