Effect of the Preparation Conditions on the Magnetic Coercivity of CoPt Alloy Nanowires

In this paper, 3 µm length and 200 nm diameter CoPt nanowire arrays (NWs) with different Co contents were prepared by electrodeposition at a controlled potential from an aqueous hexachloroplatinate solution. The synthesis occurred at two different solution pH values (2.5 and 5.5) in an electrochemical bath free of additives, as well as with saccharin as an organic additive. A complete morphological, compositional, structural and magnetic characterization of the as-prepared nanowires has been carried out. The results show that, by controlling the electrodeposition conditions, the Co content of the alloy can be tuned from 16% to 92%. The crystalline structure of the as-deposited compounds can also be controlled, with the obtained data showing that the face-centered cubic (fcc) crystalline structure changes into a hexagonal close-packed (hcp) structure when saccharin is used as an organic additive during the electrodeposition. The changes in the alloy’s composition and crystalline structure strongly influence the magnetic properties of the NW’s arrays

Tunnel Magnetoresistance-Based Sensor for Biomedical Application: Proof-of-Concept

The aim of this work was to investigate and prove the possibility of the real-time detection of magnetic nanoparticles (MNPs) distributed in solid material by using a tunnel magnetoresistance-based (TMR) sensor. Following the detection tests of FeCrNbB magnetic nanoparticles distributed in transparent epoxy resin (EPON 812) and measuring the sensor output voltage changes at different particle concentrations, the detection ability of the sensor was demonstrated. For the proposed TMR sensor, we measured a maximum magnetoresistance ratio of about 53% and a sensitivity of 1.24%/Oe. This type of sensor could facilitate a new path of research in the field of magnetic hyperthermia by locating cancer cells

Enhanced Multimodal Effect of Chemotherapy, Hyperthermia and Magneto-Mechanic Actuation of Silver-Coated Magnetite on Cancer Cells

Currently, various methods based on magnetic nanoparticles are being considered for the treatment of cancer. Among these, magnetic hyperthermia and magneto-mechanical actuation are the most tested physical methods that have shown promising results when applied both separately and in combination. However, combining them with specific drugs can further improve antitumor efficiency. In this study, we performed a systematic analysis to determine the best combination of hyperthermia, magneto-mechanical actuation of silver-coated magnetite nanoparticles (MNP@Ag) and chemotherapy (mitoxantrone) capable of destroying tumor cells in vitro while maintaining normal cells in their state of increased viability. The results showed that of the nine treatment configurations, the only one that satisfied the safety condition for normal cells (fibroblasts) and the highly cytotoxic condition for tumor cells (HeLa) was the combination of all three triggers. This combination led to the decrease in HeLa viability to about 32%, while the decrease in fibroblast viability reached 80%. It was observed that the cytotoxic effect was not a sum of the separate effects of each trigger involved, but the result of a nonlinear conjugation of the triggers in a dynamic regime imposed by the magneto-mechanical actuation of the nanoparticles. We conclude that by using such a treatment approach, the need for chemotherapeutic drugs can be substantially reduced while maintaining their therapeutic performance