CeO$_{2}$-calcein nanoconjugate protective action against H$_2$O$_2$-induced oxidative stress in vitro

We studied cerium oxide-calcein nanoconjugate, which is capable of providing intracellular detection and simultaneous inactivation of reactive oxygen species (ROS). The synthesized nanoconjugate is easily uptaken by human mesenchymal stem cells (MSCs) and demonstrates antioxidant properties, protecting cells from H$_{2}$O$_{2}$-induced oxidative stress in vitro. Cerium oxide-calcein nanoconjugate neutralizes hydrogen peroxide, meanwhile releasing brightly fluorescent calcein from its surface, which is easily detected by fluorimeter or fluorescent microscope. This nanoconjugate is biocompatible and non-toxic to MSCs in concentrations below 2 mM. Such a theranostic agent can be considered as a promising tool for tracking the redox status of human MSCs in vitro.