Rapidly clearable MnCo2O4@PAA as novel nanotheranostic agents for T1/T2 bimodal MRI imaging-guided photothermal therapy.

Integrating multi-modal imaging and therapy functions into a nanoplatform has been recognized as a promising strategy for cancer theranostics with high accuracy and efficiency. However, there are still some challenges, such as the complicated synthesis process and instability. Herein, we successfully prepared clearable MnCo2O4 nanodots modified with polyacrylic acid (MnCo2O4@PAA) as nanoagents for T1/T2 bimodal MRI imaging-guided PTT. Owing to their intrinsic magnetic properties, single MnCo2O4@PAA nanomaterials can serve as contrasts for T1/T2 bimodal MRI, providing precise diagnotic information. Moreover, excellent absorption in the NIR biowindow endows MnCo2O4@PAA with good photothermal performance, and the ultrasmall size of MnCo2O4@PAA allows them to penetrate deeply into tumors, resulting in a good anticancer effect in vitro and in vivo. What is more, MnCo2O4@PAA can almost be completely cleared from mice at 7 d postinjection, implying their negligible long-term toxicity. These findings demonstrate that MnCo2O4@PAA are promising nanoagents for cancer diagnosis and treatment, which have great potential for clinical applications.