Heterogeneous nanocrystals For Near-infrared BioImaging – NanoFBI

The proposed project stems from the need to increase the depth of exploration in photonic imaging of biological tissues. As a solution to this problem, we propose to use infrared techniques for a wavelength located at the minimum of absorption of the biological medium. Nanocrystals with a precise composition in lanthanides will luminesce under pulsed laser excitation at virtually the same wavelength as the excitation. We will develop a family of core@(shell)n nanomaterials excitable at the wavelength of 808 nm and emitting at 802 nm with a lifetime of 100's of µs. On the basis of a first-generation imager, we will build a new imager that allows for pulsed excitation and time-gated luminescence detection. Besides, we will take advantage of the non-radiative decay of the nanoparticles for photoacoustic imaging. The final objective will be to confirm the persistence, innocuousness and detection potential of the nanoparticles by the time-gated imager in the context of murine cardiology.

The NanoFBI project is broken down into 4 tasks:
1) Synthesis and characterisation of the nanoparticles. This task incorporates the synthesis of multiple batches of nanoparticles with complex core@shell1@shell2 architectures, as well as various studies concerning the surface coatings of these crystals.
2) Photophysical measurements (quantum yield, brightness and lifetime) of the nanoparticles prepared in task 1; detailed study of the core@shell interface.
3) Mutation and optimisation of a small animal imager to enable asynchronous detection with respect to excitation.
4) In vivo application with murine cardiology as a main focus, as well as investigation of our nanoparticles as contrast agents in photoacoustic imaging.

Several key points make the NanoFBI project original and extremely promising. First of all, the nanostructures presented have complex and highly tunable architectures and bring great novelty, as they have never been described before. Second, NanoFBI will give the first proof of concept of a small animal imager operating entirely in the 800 nm range, which is the optimal wavelength in Vis-NIR. Finally, the in vivo study in NanoFBI will be very meticulous and thorough, resting on solid in vitro foundation.