Manganese-iron layered double hydroxide: a theranostic nanoplatform with pH-responsive MRI contrast enhancement and drug release.

Stimuli-responsive theranostic platforms are highly desirable for efficient cancer treatment because of their improved specificity and sensitivity. In this work, we report a manganese-iron layered double hydroxide (MnFe-LDH) for the first time and demonstrate that it can serve as a pH-responsive nanoplatform for cancer theranostics. The MnFe-LDH can respond to the acidic microenvironment of solid tumors to release paramagnetic Mn2+ and Fe3+ ions, resulting in great enhancement of the T1 MRI contrast of the tumor area. In addition, the layered structure enables MnFe-LDH to effectively deliver chemotherapeutic drugs in a pH-controlled manner, and therefore it can simultaneously inhibit the growth of solid tumors. We believe that this novel MnFe-LDH with pH-responsive property holds great promise in cancer theranostic applications.