Contrast agents (CAs) play a crucial role in high-quality magnetic resonance imaging (MRI) applications. At present, as a result of the Gd-based CAs which are associated with renal fibrosis as well as the inherent dark imaging characteristics of superparamagnetic iron oxide nanoparticles, Mn-based CAs which have a good biocompatibility and bright images are considered ideal for MRI. In addition, manganese oxide nanoparticles (MONs, such as MnO, MnO2, Mn3O4, and MnOx) have attracted attention as T1-weighted magnetic resonance CAs due to the short circulation time of Mn(II) ion chelate and the size-controlled circulation time of colloidal nanoparticles. In this review, recent advances in the use of MONs as MRI contrast agents for tumor detection and diagnosis are reported, as are the advances in in vivo toxicity, distribution and tumor microenvironment-responsive enhanced tumor chemotherapy and radiotherapy as well as photothermal and photodynamic therapies.
a b s t r a c tA method is addressed to prepare poly(hydroxybutyrate)/poly(ethylene-co-vinyl acetate)/starch (PHB/EVA/starch) blends with fine dispersion of starch, i.e. by an in situ compatibilization in the presence of maleic anhydride (MA) and peroxide. The starch particle size is reduced from hundreds-m to sub-m after the compatibilization accompanied by an improvement in interfacial adhesion. Meanwhile, starch-in-EVA-type morphology is observed in the blends. The EVA and starch gradually changed into a (partially) co-continuous phase with increasing MA content. Consequently, toughness of the blends was improved as evidenced by an increase in elongation at break and tensile-fracture energy (work). Cavitation, fibrillation and matrix yielding are regarded as the toughening mechanism for the compatibilized blends. In addition, the T g of the EVA phase is dependent on its phase morphology in the blends while the thermal behavior of the PHB was only slightly affected by the compatibilization.
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