Multilevel Nanoarchitecture Exhibiting Biosensing for Cancer Diagnostics by Dual-Modal Switching of Optical and Magnetic Resonance Signals.

In this research, the fabrication and application of a multifunctional core-shell nanoarchitecture are proposed. NaYF4:Yb,Er@NaYF4:Yb,Nd exhibits upconversion luminescence (UCL) of erbium ions but has quenched UCL emission when it is coated with MnO2 nanosheets. This hierarchical multilevel UCNP-MnO2 exhibits restoration of UCL and generation of a magnetic resonance imaging (MRI) signal when it is exposed to a microenvironment containing glutathione (GSH)/H2O2, which strips the MnO2 sheets by converting them to paramagnetic Mn2+ ions. This dual-modal switching feature of the optical emission and MRI signals provides a platform for stimuli-responsive biosensing of GSH/H2O2. Our new formulation as a dual-modal biosensor for detecting aberrant levels of intracellular GSH/H2O2 associated in cancer cells could be a potential diagnostic probe to distinguish tumor cells from normal cells.