Deprivation of O 2 in most solid tumors greatly limits the effectiveness of photodynamic therapy. Prussian blue nanozyme (PBzyme) are reported to possess catalase-like (CAT) activity to alleviate tumor hypoxia . However, the low catalytic activity is far from satisfactory. Metal doping may improve the catalytic activity of PBzyme, but there are few reports in this regard. Herein, by a screening of metal dopants , Gd-doped PB with enhanced CAT activity is constructed on the basis of small-sized hollow mesoporous silica nanoparticles . Theoretical calculation demonstrates that Gd regulates the state density population of Fe in PBzyme and reduces the Gibbs free energy of CAT catalytic cycle, thus improving its CAT activity (approximately 4 times higher than that of pure PBzyme). After conjugated with photosensitizer Ce6 and tumor-targeted molecule folic acid and loaded with chemotherapy drug doxorubicin , the nanoplatform displays dual-enhanced T 1 and T 2 imaging capacity simultaneously. Upon high accumulation in tumors, the nanoplatform demonstrates augmented antitumor effects by combining enhanced photodynamic therapy and doxorubicin-mediated chemotherapy both in vitro and in vivo . This work demonstrates that the integration of Gd into PBzyme is an effective strategy to improve the catalytic activity of PBzyme and further potentiate the effectiveness of tumor theranostics.
Triple-negative breast cancer is a highly aggressive and metastatic tumor; diagnosing it in the early stages is still difficult, and the prognosis for conventional radio-chemotherapy and immunotreatment is not promising due to cancer’s immunosuppressive microenvironment. The utilization of protein-based nanosystem has proven to be effective in delivering agents with limited adverse effects, yet the combination of diagnosis and treatment remains a difficult challenge. This research took advantage of natural albumin and organic molecules to construct a self-assemble core-shell nanostructure combining with superparamagnetic iron oxide nanocrystals and heptamethine cyanine dye IR780 through non-covalent interactions. This nanocomposite successfully decreased the transverse relaxation time of the magnetic resonance hydrogen nucleus, resulting in outstanding T2 imaging, as well as emitting near-infrared II fluorescence, thereby the resulting dual-modality imaging tool was applied to improve diagnostic competency. It is noteworthy that the nanocomposites exhibited impressive enzyme-like catalytic and photothermal capabilities, resulting in a successful activation of the immune system to efficiently suppress distant metastatic lesions in vivo. Consequently, this nanodrug-based therapy could be an advantageous asset in reinforcing the immune system and hindering the growth and reappearance of the immune-cold breast cancer.
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