Mapping nanoparticles injected into a biological tissue using laser-induced breakdown spectroscopy

• We describe the protocol for the optimization of tissue measurements by LIBS.
• LIBS multi-elemental mapping is performed on kidney tissue with 100 μm resolution.
• The distribution of Gd inside the tissue is quantified.
• Nanoparticle distribution inside the tissue is realized without any labeling.

We describe a setup for LIBS mapping of nanoparticles and trace metallic elements in biological organ as well as the followed experimental procedure. Mapping was performed for metallic elements such as Gd, Si, Ca and Fe, with a resolution of 100 μm on kidney slices sampled from a mouse 24 h after intravenous injection of a solution of gadolinium-based nanoparticles. An approach for quantifying Gd in the tissue is also presented with a good agreement with measurement performed by ICP-OES. We demonstrate that LIBS offers a simple and robust method to study the distribution of gadolinium-based nanoparticles in biological samples, without any labeling of the nanoparticles. The used bench-top instrumentation is fully compatible with the standard optical microscopy, which shows its large potential use in Biology and Medicine as a tool for complementary observation of trace metallic elements with respect to the classical optical observations which are generally based on the responses of biomolecules or cells.