Intelligent Nanoprobe: Acid-Responsive Drug Release and In Situ Evaluation of Its Own Therapeutic Effect.

The design of an intelligent nanoprobe capable of intracellular controlled release of apoptosis inducers and subsequent high-fidelity imaging of the drug-induced apoptosis is highly desirable for precise cancer treatment. Herein, we report an intelligent nanoprobe that combined therapeutic and imaging functions in one agent. Briefly, a gold nanoparticle is designed to be conjugated with acid-responsive DNA duplexes (Dox intercalates in this region) and caspase-3-specific cleavable peptides (labeled with fluorophore). We demonstrated that the nanoprobe could efficiently deliver an anticancer drug (Dox) into cancer cells and achieve acid-responsive drug release. Furthermore, the apoptotic process was in situ-monitored by detection of fluorescence through the cleavage of the peptide linker by caspase-3, which is one of the executioner caspases involved in apoptosis. This newly developed nanoprobe could serve as a theranostic agent for targeted responsive chemotherapy and also provide feedback apoptosis imaging of the self-therapeutic effect.