Nanoparticles [Ru(dipy)$_3$]$^{2+}$ @ SiO$_2$ as thermosensors and probes for luminescence tomography of biological samples

New luminescent nanomaterials attract tremendous interest, and in this work, silicon dioxide SiO$_2$ nanoparticles of 55 nm size containing tris(2,2'-bipyridyl) ruthenium(II) complexes [Ru(dipy)$_3$]$^{2+}$ are tested as nanoprobes for biomedical applications. We have shown that calibration of the spectral parameters of the luminescent response based on the ratiometric method allows the use of nanoparticles in biological media as thermosensors with an accuracy of $\pm$2$^\circ$C in the biologically significant temperature range of 20–50$^\circ$C. In addition, a fluorescent tomography method has been proposed and implemented. As a result, a three-dimensional model of the surface of the grape snail's nervous system was obtained with a resolution of 10 $\mu$m. This allowed us to perform a demonstration experiment – remote measurement of the local temperature of a selected area on the surface of a neuron.