Mn-doped maghemite (γ-Fe₂O₃) particles were generated from a binary metal (Fe,Mn)-based metal–organic framework (MOF) via thermal decomposition under air. The X-ray photoelectron spectroscopy analysis revealed that the synthesis of Fe/Mn-MOF accompanied the reduction of the metal ions. The existence of Mn ions in this synthetic process leads to thermally stable maghemite particles under air. A temperature-induced structural phase transition from γ-Fe₂O₃ to α-Fe₂O₃ was observed through a mixed phase with another structure. Mn-doped γ-Fe₂O₃ and α-Fe₂O₃ exhibit superparamagnetic behavior. The sample annealed at 600 °C showed a mixed magnetic hysteresis loop indicating the existence of an intermediate structural phase between γ-Fe₂O₃ and α-Fe₂O₃ during the phase conversion from FeMn-MOF. The constructed Mn-doped iron oxides are active toward reducing nitric oxide with NH₃. The NO conversion is 97% over Mn-doped γ-Fe₂O₃ calcined at 320 °C.

Among many nanostructural shapes, filamentous shapes can have unique advantages over the others, including longer persistence in the bloodstream. With the advent of nanotechnology in recent years, a variety of shape-controlled nanostructures has been fabricated. As a wide variety of building blocks can self-assemble into filamentous nanostructures, there are many options available for biomaterial developments with filamentous nanostructures. Similarly to conventional spherical micelles, most filamentous nanostructures have hydrophobic cores where hydrophobic guest molecules can be encapsulated, which enable them to be used in drug delivery applications. Moreover, on suitable molecular design and self-assembly process control, filamentous nanostructures can also be made to deliver nucleic acids or even both drugs and nucleic acids simultaneously. This review describes the self-assembly process, current developments, and prospects of filamentous nanostructures in drug and gene delivery applications. This review should be helpful in gaining insight into the self-assembly process and nanostructural shape control, the advantages of constructing filamentous nanostructures, and the design of more advanced nanobiomaterials. At present, the development of multifunctional nanostructures is one of the main focuses in nanobiomaterial developments. In this regard, filamentous nanostructures can be good initial targets for tailor-made nanostructure developments because they have more structural variables, as compared with spherical micelles.

Mechanochemical processes allow the 1D chain of [Ag(dmotz)(CF₃SO₃)]_n to easily convert to a 2D grid network of {[Ag(dmotz)₂](ClO₄)}_n in the presence of [ClO₄]⁻.