On-demand degradable magnetic resonance imaging nanoprobes

Theranostic nanoprobes can potentially integrate imaging and therapeutic capabilities into a single platform, offering a new personalized cancer diagnostic tool. However, there is a growing concern that their clinical application is not safe, particularly due to metal-containing elements, such as the gadolinium used in magnetic resonance imaging (MRI). We demonstrate for the first time that the photothermal melting of the DNA duplex helix was a reliable and versatile strategy that enables the on-demand degradation of the gadolinium-containing MRI reporter gene from polydopamine (PDA)-based theranostic nanoprobes. The combination of chemotherapy (doxorubicin) and photothermal therapy, which leads to the enhanced anti-tumor effect. In vivo MRI tracking reveals that renal filtration was able to rapidly clear the free gadolinium-containing MRI reporter from the mice body. This results in a decrease in the long-term toxic effect of theranostic MRI nanoprobes. Our findings may pave the way to address toxicity issues of the theranostic nanoprobes.