Rational Design of a Theranostic Agent Triggered by Endogenous Nitric Oxide in a Cellular Model of Alzheimer's Disease.

Oxidative damage caused by upregulated nitric oxide (NO) plays an important role in the pathogenesis of Alzheimer's disease (AD). Currently, stimulus-triggered theranostic agents have received much attention due to benefits on disease imaging and targeted therapeutic effects. However, the development of a theranostic agent triggered by NO for AD remains unexplored. Herein, through the mechanism analysis of the reaction between a fluorophore of 9,14-diphenyl-9,14-dihydrodibenzo[]phenazine () and NO, which we occasionally found and thereafter structure optimization of , a theranostic agent was fabricated. In an AD cellular model, exhibits NO sensing ability for AD imaging. Meanwhile, shows improved therapeutic by targeted drug release triggered by NO and sustained therapeutic effects owing to the synergetic antioxidative abilities via the anti-AD drug and NO scavenging. This work provides an unprecedented avenue for the studies on not only AD but also other diseases with NO upregulation.