Magnetoelectrically driven catalytic degradation of organics

Here, we report the catalytic degradation of organic compounds by exploiting the magnetoelectric (ME) nature of cobalt ferrite-bismuth ferrite (CFO-BFO) core-shell nanoparticles. The combination of magnetostrictive CFO with the multiferroic BFO gives rise to a magnetoelectric engine that purifies water under wireless magnetic fields via advanced oxidation processes, without involvement of any sacrificial molecules or co-catalysts. Magnetostrictive CoFe2O4 nanoparticles are fabricated using hydrothermal synthesis, followed by sol-gel synthesis to create the multiferroic BiFeO3 shell. We perform theoretical modeling to study the magnetic field induced polarization on the surface of magnetoelectric nanoparticles. The results obtained from these simulations are consistent with the experimental findings of the piezo-force microscopy analysis, where we observe changes in the piezoresponse of the nanoparticles under magnetic fields. Next, we investigate the magnetoelectric effect induced catalytic degradation of organic pollutants under AC magnetic fields and obtained 97% removal efficiency for synthetic dyes and over 85% removal efficiency for routinely used pharmaceuticals. Additionally, we perform trapping experiments to elucidate the mechanism behind the magnetic field induced catalytic degradation of organic pollutants by using scavengers for each of the reactive species. Our results indicate that hydroxyl and superoxide radicals are the main reactive species in the magnetoelectrically induced catalytic degradation of organic compounds

Magnetoelectric 3D scaffolds for enhanced bone cell proliferation

Regulation of cellular functions by an exogenous and non-invasive approach has the means of revolutionizing the field of tissue engineering. In this direction, use of electric fields has garnered significant interest due to its positive influence on cell adhesion, proliferation, and differentiation. Recently, this has been achieved by placing electrodes in direct contact with cells, or through a non-contact approach by inducing deformation of piezoelectric membranes. In this work, we have developed 3D magnetoelectric inverse opal scaffolds that can generate localized electric fields upon the application of magnetic fields. These scaffolds were composed of biodegradable poly(l-lactic acid), and cobalt ferrite@bismuth ferrite magnetoelectric nanoparticles and were designed to mimic the natural micro-environment of cancellous bone by endowing them with piezoelectric properties and porosity. The effect of magnetic field induced electric stimulation on the proliferation of human-derived MG63 osteoblast cells, a model for primary osteoblast cells, was investigated on 2D membranes and 3D scaffolds by applying a magnetic field of 13 mT at 1.1 kHz. During this study, a 134% increase in cell proliferation was achieved on stimulated 3D scaffolds in comparison to non-stimulated ones, and in case of 2D membranes, we have obtained an increase of 43% of stimulated 2D membranes in comparison to non-stimulated ones. These findings showcase the importance of designing scaffolds with 3D characteristics that provide a suitable micro-environment for host cells. The results obtained from this work further demonstrate the beneficial influence that the magnetoelectric effect has on regulating cellular functions and draws light on the possibility of exploiting this effect for tissue engineering and regenerative medicine in the future