A magnetically controlled elastically driven electroporation phenomenon, or magneto-elasto-electroporation (MEEP), is discovered while studying the interactions between core-shell magnetoelectric nanoparticles (CSMEN) and biological cells in the presence of an a.c. magnetic field. In this paper we report the effect of MEEP observed via a series of in-vitro experiments using core (CoFe2O4)-shell (BaTiO3) structured magnetoelectric nanoparticles and human epithelial cells (HEP2). The cell electroporation phenomenon and its correlation with the magnetic field modulated CSMEN are described in detail. The potential application of CSMEN in electroporation is confirmed by analyzing crystallographic phases, multiferroic properties of the fabricated CSMEN, influences of d.c. and a.c. magnetic fields on the CSMEN and cytotoxicity tests. The mathematical formalism to quantitatively describe the phenomena is also reported. The reported findings provide insights into the underlying MEEP mechanism and demonstrate the utility of CSMEN as an electric pulse-generating nano-probe in electroporation experiments with a potential application toward accurate and efficient targeted cell permeation.

We have developed a remotely controlled dynamic process of manipulating targeted biological live cells using fabricated core-shell nanocomposites, which comprises of single crystalline ferromagnetic cores (CoFe2O4) coated with crystalline ferroelectric thin film shells (BaTiO3). We demonstrate them as a unique family of inorganic magnetoelectric nanorobots (MENRs), controlled remotely by applied a.c. or d.c. magnetic fields, to perform cell targeting, permeation, and transport. Under a.c. magnetic field excitation (50 Oe, 60 Hz), the MENR acts as a localized electric periodic pulse generator and can permeate a series of misaligned cells, while aligning them to an equipotential mono-array by inducing inter-cellular signaling. Under a.c. magnetic field (40 Oe, 30 Hz) excitation, MENRs can be dynamically driven to a targeted cell, avoiding untargeted cells in the path, irrespective of cell density. D.C. magnetic field (−50 Oe) excitation causes the MENRs to act as thrust generator and exerts motion in a group of cells.

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This review provides a broad overview of the structural characteristics, compositional flexibility, and structure-property relationships of hollandite materials. Hollandites have a general formula A x B 8 O 16 , x ≤ 2, with 'A' cations located in one-dimensional tunnels formed by a framework of 'B'-O octahedra. With numerous possibilities for chemical and structural modifications, hollandite family provides many opportunities to manipulate its properties for specific applications. First, we review the chemistry, structure-property relationship, and processing techniques for various applications. The primary focus is on the cumulative effects of Aand B-cation interaction, and the resultant parameters including unit cell symmetry, cation order-disorder, electronic and/or magnetic coupling, that dictate the material's applicability. Then, selected applications, such as crystalline hosts for radioactive caesium disposal, electrode material for Li-ion batteries, and ferromagnetic materials, are outlined from a structure-property relationship perspective. Finally, processing strategies in correlation with structural evolution and applications are briefly addressed.