Amine functionalized ZrO₂ nanoparticles as biocompatible and luminescent probes for ligand specific cellular imaging

Surface functionalized ZrO₂ nanoparticles show strong photoluminescence and are a versatile tool for cellular targeting due to their chemical functionality. They are highly photostable, biocompatible and amenable to coupling with bioligands (e.g. secondary goat anti-rabbit antibody (GAR) and tri-phenyl phosphine (TPP)) via carbodiimide chemistry. Antibody (GAR) functionalized ZrO₂ nanoparticles were used to image the nuclear protein Sirt6, whereas triphenyl phosphonium ion (TPP) functionalized ZrO₂ nanoparticles specifically targeted the mitochondria. The versatility and easiness of the ZrO₂ surface modification opens up new possibilities for designing non-toxic water dispersible and photostable photoluminescent NPs.