Did You Know ...

… that H.C. Ørsted was awarded the pharmaceutical master's degree in 1797, and that he was strongly involved in the development of the pharmaceutical degree programme? His lectures were the first at the University of Copenhagen that women were allowed to attend. This is the reason why an Ørsted bust on a travertine pedestal adorns the main entrance to the PharmaSchool, Universitesparken 2. Remember, this is also not far where we had our 12th Magnetic Carrier meeting!

Next year is the 200th anniversary of Ørsted's discovery of electromagnetism. On 21 April 1820, during a lecture, Ørsted noticed a compass needle deflected from magnetic north when an electric current from a battery was switched on and off, confirming a direct relationship between electricity and magnetism.

His initial interpretation was that magnetic effects radiate from all sides of a wire carrying an electric current, as do light and heat. Three months later he began more intensive investigations and soon thereafter published his findings, showing that an electric current produces a circular magnetic field as it flows through a wire. For his discovery, the Royal Society of London awarded Ørsted the Copley Medal in 1820 and the French Academy granted him 3,000 francs.

Ørsted's findings stirred much research into electrodynamics throughout the scientific community, influencing French physicist André-Marie Ampère's developments of a single mathematical formula to represent the magnetic forces between current-carrying conductors. Ørsted's work also represented a major step toward a unified concept of energy.

Best Practices for Characterization of Magnetic Nanoparticles for Biomedical Applications

The use of magnetic nanoparticles in biomedical applications provides a wealth of opportunities. Nonetheless, to truly understand the interactions of these materials in biological media, detailed characterization is necessary with these complex systems. Prof. Thompson Mefford together with Sarah E. Sandler and Benjamin Fellows just published an article that might be very helpful to many of our colleagues.

The article highlights some “best practices” in the analytical techniques and challenges in the measurement of the properties of these materials.

Check it out here, it is worth reading!

Complete JMMM Special Issue After the 2018 Meeting Is Now Available

It is our great pleasure to announce the official publication of the special JMMM issue after our 2018 meeting in Copenhagen.

At the end, we have now 75 interesting publications in our special issue. We hope you will all take the time to download, browse through the articles, and enjoy the new and interesting magnetic particle themes that all of your colleagues wrote about.

We make it easy for you - go to this website, and check them all out!

And then start planning for the next meeting in London, UK. Next June 2-5, 2020!

Watch Liquid-Based Magnet Droplets Twirl and Morph

Researchers at Lawrence Berkeley National Laboratory (LBNL) have created a more malleable tool: a miniscule liquid-based magnet made from nanoparticles.

Such flexible magnets could be useful in places where rigid ones cannot go, including soft robots or flexible electronics. And although they are not yet ready for practical applications, the liquid-based magnets reveal a new facet of nanoparticle behavior, which could pave the way for a novel range of magnetic materials, the researchers say.

To create the liquid-based magnets, researchers led by Thomas P. Russell, a polymer scientist at the University of Massachusetts Amherst and a visiting researcher at LBNL, started with a modified 3-D printer. First, they printed millimeter-sized droplets of liquid filled with magnetic nanoparticles. This liquid-particle mix is superparamagnetic—it is strongly attracted to a magnetic field, but as soon as the field disappears, so does the magnetism. In plain language, it is magnetic but not a magnet—a characteristic typical of fluids that can be magnetized, called ferrofluids.

Bubble Magnetometry Highlights Nanoparticle Heterogeneity and Interaction

Several authors from NIST (Andrew Balk, Ian Gilbert, John Unguris, Samuel Stavis) and also Robert Ivkov from Johns Hopkins published recently in Physical Review Applied an interesting article that highlights heterogeneity of hysteresis behavior in nanorods and nanoparticles using magneto-optical Kerr effect (MOKE) microscopy. It is relevant when considering mechanisms of hysteresis heating and other time-dependent properties of magnetic nanoscale structures exposed to magnetic fields.

Check it out here.

Magnetic Nanoparticles Can Fix Broken Electric Wires

Inspired by armies of ants that link together to form living structures such as bridges and rafts, researchers have directed millions of nanoparticles to span the gap between two electrodes, forming an electrical wire (ACS Nano 2019, DOI: 10.1021/acsnano.9b02139). The technology could provide a new way to repair broken microcircuits and make tiny programmable microswitches, the researchers say.

Roboticists dream of emulating the natural swarming behavior of insects and birds to make robots that work together on construction tasks or search-and-rescue missions. Scientists have also been engineering swarming particles that could have applications on the microscopic scale, such as tracking down tumors and delivering drugs.

Li Zhang, a mechanical and automation engineer at the Chinese University of Hong Kong, and his colleagues are designing microswarms for electronic applications. In 2018, they reported using oscillating magnetic fields to control millions of magnetic iron oxide nanoparticles in an ethanol suspension (Nat. Commun. 2018, DOI: 10.1038/s41467-018-05749-6). Changing the field’s strength relative to the fluid’s resistance made the particles line up into ribbon-like chains. By programming other parameters of the magnetic field, such as the oscillation frequency and angle, the researchers could elongate and shorten the ribbons, and make the nanoparticles split up and regroup. They could also make the swarms move through a maze.

Magnetic Bacteria Cause a Stir

Using bacteria as tiny stirring bars could be a new way to accelerate chemical reactions in droplets. Researchers in China have shown that they can significantly speed up an epoxidation reaction within a Pickering emulsion droplet by using naturally magnetic bacteria to mix the catalysts and reactants.

Carrying out chemical reactions in Pickering emulsions avoids the large temperature and concentration gradients associated with traditional reaction systems. ‘But still, we need to find a way to stir the solution inside these micro-droplets. And this is the reason why we carried out this study to develop nano-sized stirrers,’ explains Weiguo Song from the Chinese Academy of Sciences.

For more information, check out https://www.chemistryworld.com/news/magnetic-bacteria-stir-reaction-in-droplet-microreactor/3008713.article.

Toyota Promises Cheaper Magnets for Electric Cars

Japanese carmaker Toyota says it can cut the cost of rare earth element-containing magnets within the motors of electric vehicles by replacing up to half the neodymium in them with the more abundant, lower-cost rare earths lanthanum and cerium.

Toyota expects these magnets to be used in motors for electrified vehicles within 10 years. They could also be used in electric power steering and other applications including robots and various household appliances by the first half of the 2020s.

For more information, check here.