A facile fabrication route for binary transition metal oxide-based Janus nanoparticles for cancer theranostic applications

Janus nanoparticles （JNPs） have multiple configurations for molecular imaging, targeting, and therapeutic effects on cancers; these properties have made these particles attractive for biomedical applications. Nonetheless, smart strategies for the controlled synthesis in a liquid phase and exploration of the appropriate applications of JNPs remain a challenge. In this study, a unique liquid-phase method was applied to fabricate Mn3O4-TiO2/ZnO/Fe3O4 multifunctional binary transition metal oxide-based JNPs, using the concept of epitaxial growth and lattice mismatch among synthesized materials. Transmission electron microscopy and scanning transmission electron microscopy results revealed that the created materials are embedded in the form of dimers with good dispersion and homogeneous growth in a nonpolar solvent. Pluronic F-127-coated MnBO4- TiO2 JNPs were utilized as a contrast agent in T1-weighted magnetic resonance imaging （MRI） and in photodynamic therapy （PDT） for cancers in vitro and in vivo. In vivo T1-weighted MRI of the heart, liver, and kidneys in mice after intravenous injection of the nanoparticles revealed high sensitivity and biocompatibility of as-synthesized Mn3O4--TiO2 JNPs. Results of synchrotron X-ray fluorescence microscopy mapping showed the stability of the nanocomposites and efficiency of penetration into the cytoplasm and perinuclear area. Inorganic TiO2 photosensitizers showed promising tumor ablation performance in PDT in vitro and in vivo at low intensity of UV irradiation （5.6 mW.cm-2） because of their ultrasmall size and photodegradable stability. These results reveal that multifunctional Mn3O4-TiO2 JNPs enhance a T1-weighted MRI contrast and have excellent properties for PDT and therefore, may be a novel agent for cancer theranostics.

Gold nanorods with a hematoporphyrin-loaded silica shell for dual-modality photodynamic and photothermal treatment of tumors in vivo

Nanocomposites （NCs） consisting of a gold nanorod core and a mesoporous silica shell doped with hematoporphyrin （HP） have been fabricated in order to improve the efficiency of cancer treatment by combining photothermal and photodynamic therapies （PDT ＋ PTT） in vivo. In addition to the long-wavelength plasmon resonance near 810-830 nm, the fabricated NCs exhibited a 400-nm absorbance peak corresponding to bound HP, generated singlet oxygen under 633-nm excitation near the 632.5-nm Q-band, and produced heat under a 808-nm near-infrared （NIR） laser irradiation. These modalities were used for a combined PDT ＋ PTT treatment of large （about 3 cm3） solid tumors in vivo with a xenorafted tumor rat model. NCs were directly injected into tumors and irradiated simultaneously with 633-nm and 808-nm lasers to stimulate the combined photodynamic and photothermal activities of NCs. The efficiency of the combined therapy was evaluated by optical coherence tomography, histological analysis, and by measurements of the tumor volume growth during a 21-day period. The NC-mediated PDT led to weak changes in tissue histology and to a moderate 20% decrease in the tumor volume. In contrast, the combined PDT ＋ PTT treatment resulted in the large-area tumor necrosis and led to dramatic decrease in the tumor volume.