Surgery is the main treatment for liver cancer in clinic owing to its low sensitivity to chemotherapy and radiotherapy, but this results in high mortality, recurrence, and metastasis rates. It is a feasible strategy to construct tumor microenvironments activated by nanotheranostics agents for the diagnosis and therapy of liver cancer. This study reports on a nanotheranostic agent (MONs@PDA-ICG) with manganese oxide nanoflowers (MONs) as core and polydopamine (PDA) as shell loading, with ICG as a photosensitizer and photothermal agent. MONs@PDA-ICG can not only produce ROS to kill cancer cells but also exhibit good photothermal performance for photothermal therapy (PTT). Importantly, O 2 generated by MONs decomposition can relieve the tumor hypoxia and further enhance the treatment effects of photodynamic therapy (PDT). In addition, the released Mn 2+ ions make MONs@PDA-ICG serve as tumor microenvironments responsive to MRI contrast for highly sensitive and specific liver cancer diagnosis.

The rapid development of medical imaging has boosted the abilities of modern medicine. As single modality imaging limits complex cancer diagnostics, dual-modal imaging has come into the spotlight in clinical settings. The rare earth element Holmium (Ho) has intrinsic paramagnetism and great X-ray attenuation due to its high atomic number. These features endow Ho with good potential to be a nanoprobe in combined x-ray computed tomography (CT) and T 2 -weighted magnetic resonance imaging (MRI). Herein, we present a facile strategy for preparing HoF 3 nanoparticles (HoF 3 NPs) with modification by PEG 4000. The functional PEG-HoF 3 NPs have good water solubility, low cytotoxicity, and biocompatibility as a dual-modal contrast agent. Currently, there is limited systematic and intensive investigation of Ho-based nanomaterials for dual-modal imaging. Our PEG-HoF 3 NPs provide a new direction to realize in vitro and vivo CT/MRI imaging, as well as validation of Ho-based nanomaterials will verify their potential for biomedical applications.