The interaction between magnetic and acoustic excitations has recently inspired many interdisciplinary studies ranging from fundamental physics to circuit implementation. Specifically, the ...exploration of their coherent interconversion enabled via the magnetoelastic coupling opens a new playground combining straintronics and spintronics and provides a unique platform for building up on-chip coherent information processing networks with miniaturized magnonic and acoustic devices. In this Perspective, we will focus on the recent progress of magnon–phonon coupled dynamic systems, including materials, circuits, imaging, and new physics. In particular, we highlight the unique features such as nonreciprocal acoustic wave propagation and strong coupling between magnons and phonons in magnetic thin-film systems, which provide a platform for their coherent manipulation and transduction. We will also review the frontiers of surface acoustic wave resonators in coherent quantum transduction and discuss how the novel acoustic circuit design can be applied in microwave spintronics.
Nanomagnetic materials offer exciting avenues for probing cell mechanics and activating mechanosensitive ion channels, as well as for advancing cancer therapies. Most experimental works so far have ...used superparamagnetic materials. This report describes a first approach based on interfacing cells with lithographically defined microdiscs that possess a spin-vortex ground state. When an alternating magnetic field is applied the microdisc vortices shift, creating an oscillation, which transmits a mechanical force to the cell. Because reduced sensitivity of cancer cells toward apoptosis leads to inappropriate cell survival and malignant progression, selective induction of apoptosis is of great importance for the anticancer therapeutic strategies. We show that the spin-vortex-mediated stimulus creates two dramatic effects: compromised integrity of the cellular membrane, and initiation of programmed cell death. A low-frequency field of a few tens of hertz applied for only ten minutes was sufficient to achieve approximately 90% cancer-cell destruction in vitro.
The collective behavior of geometrically frustrated magnetization in connected networks of ferromagnetic nanowires, known as artificial spin ice, leads to complex magnetotransport behavior in those ...structures. Here, we present temperature- and current-dependent magnetotransport studies on a connected square artificial spin-ice system and correlate our observations to micromagnetic simulations. We find that the field at which the lattice magnetization collectively switches increases as the temperature is lowered. Our experimental findings highlight the importance of the global and local temperatures for the onset of a collective magnetization reversal in the connected system. These studies may also provide useful insights into novel storage concepts and applications in neuromorphic computing.
In this review, we discuss the prospective medical application of magnetic carriers microfabricated by top-down techniques. Physical methods allow the fabrication of a variety of magnetic structures ...with tightly controlled magnetic properties and geometry, which makes them very attractive for a cost-efficient mass-production in the fast growing field of nanomedicine. Stand-alone fabricated particles along with integrated devices combining lithographically defined magnetic structures and synthesized magnetic tags will be considered. Applications of microfabricated multifunctional magnetic structures for future medicinal purposes range from ultrasensitive in vitro diagnostic bioassays, DNA sequencing and microfluidic cell sorting to magnetomechanical actuation, cargo delivery, contrast enhancement and heating therapy.
Abstract
Colloidal gold nanoparticles (AuNPs) are of interest as non-toxic carriers for drug delivery owing to their advanced properties, such as extensive surface-to-volume ratio and possibilities ...for tailoring their charge, hydrophilicity and functionality through surface chemistries. To date, various biocompatible polymers have been used for surface decoration of AuNPs to enhance their stability, payloads capacity and cellular uptake. This study describes a facile one-step method to synthesize stable AuNPs loaded with combination of two anticancer therapeutics, -bleomycin and doxorubicin. Anticancer activities, cytotoxicity, uptake and intracellular localization of the AuNPs were demonstrated in HeLa cells. We show that the therapeutic efficacy of the nanohybrid drug was strongly enhanced by the active targeting by the nanoscale delivery system to HeLa cells with a significant decrease of the half-maximal effective drug concentration, through blockage of HeLa cancer cell cycle. These results provide rationale for further progress of AuNPs-assisted combination chemotherapy using two drugs at optimized effective concentrations which act via different mechanisms thus decreasing possibilities of development of the cancer drug resistance, reduction of systemic drug toxicity and improvement of outcomes of chemotherapy.
To control the angle between magnetizations in two adjacent ferromagnetic layers without using a rotator, a novel spin valve was designed and fabricated. A key element of the design is a replacement ...of a pinned ferromagnetic layer by a synthetic antiferromagnet (SAF). The predefined non-collinear magnetization configurations are produced by cooling the valve in different magnetic fields. Giant magnetoresistance (GMR) measurements allowed mapping of the angle between the magnetizations in the SAF and the free layer depending on the magnitude of the cooling field.
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