Silane-modified lanthanide complexes for integration into hybrid coatings and nanoparticles: thermal sensing applications and live cell labeling

Temperature sensing at the micro- and nanoscale remains a significant challenge due to the limitations of conventional techniques in spatial resolution and invasiveness. Here, we report the development of luminescent, temperature-sensitive coatings and nanoparticles based on a newly synthesized europium (Eu) complex integrated into a composite poly(methyl methacrylate)-siloxane-silica (PMMA-siloxane silica) matrix. The Eu complex, identified as the most promising candidate among three lanthanide complexes, was functionalized with silyl ethers via copper-catalyzed azide-alkyne cycloaddition and successfully incorporated into thin PMMA-siloxane silica films on glass surfaces and within silica nanoparticles. These materials exhibited strong thermal responsiveness, chemical stability, and suitability for high-resolution temperature sensing. Furthermore, Eu-loaded silica nanoparticles showed a distinct fluorescent signal and multiplexing capability in live-cell confocal microscopy and were internalized by lung epithelial cells (LA-4 cell line), highlighting their potential as bioimaging probes for localized intracellular temperature sensing. Although some photobleaching was observed under prolonged excitation, the materials demonstrated sufficient chemical and mechanical stability, making them promising for luminescent temperature sensing and live-cell imaging. These results establish the developed Eu-based hybrid materials as robust, non-invasive luminescent probes for high-resolution thermal sensing and cellular imaging.