During the first year of the project, efforts have been made in the design of scintillating nanoparticles, surface modification to ensure their biocompatibility and in vitro evaluation of their internalization/toxicity.
- Inorganic nanoparticles doped with various mount of Terbium were prepared and the optimized composition was set based on emission properties of the probes. The particles have a diameter below 10 nm evaluated by TEM and show highly crystalline orthorhombic structure.
- Thorough study of the scintillation (ie emission of light upon excitation by X-rays) properties was performed with mircoCT device. The nanoparticles show intense emission in the green, corresponding to the emission of Terbium.
- The functionalization of the particle was conducted with a series of molecules and macromolecules such as polyethylene glycol derivatives or albumin. Also, core-shell systems were considered with a layer of silica surrounding the nanoparticles. The obtained hybrid systems were analyzed with several techniques (Dynamic Light Scattering, Infrared, Thermogravimetric analysis, ICP…etc) to prove the efficient surface modification. All prepared probes are stable in saline media such as PBS buffer making them suitable for further in vitro studies.
- The kinetics of intracellular diffusion of the probes was studied on healthy and cancer cell lines. Synchrotron X-rays fluorescence microscopy was used to study the internalization of the probes. Several concentrations of nanoparticles suspensions were incubated with cells during 24 hours before imaging. Results first show no toxicity of the probes whatever the concentration considered. Imaging clearly evidenced the colocalization of endosomes and main elements of the probes.