Tiny magnets will escort ions out of rare material from a shipwreck

In 1545, freshly refitted to carry a greater number of heavy cannon, the warship Mary Rose sailed into battle against a French fleet north of the Isle of Wight. The debate over what happened next is still heated, but the most accepted version is that the added weight of the cannons made the Mary Rose sit almost a meter lower in the water than before. When the ship made a sharp turn—or perhaps when a sudden gust of wind caught the sails—water poured into open gunports, flooding the ship. Nets in place over the deck, meant to repel enemy boarders, ended up trapping more than 500 sailors aboard as the ship went down.

Some of the marine bacteria that move in when a ship sinks munch on sulfur and release a compound called hydrogen sulfide. And when iron fittings, cannons, and other artifacts corrode, they release ions that react with the hydrogen sulfide to produce iron sulfides. That doesn’t matter much in an environment without much oxygen—and there's not much in several meters of silt at the bottom of the Solent, for instance. But when exposed to air again, the iron sulfides react with oxygen to produce sulfate salts and sulfuric acid, which eat away at the already fragile timbers and artifacts where wood is in contact with iron.

And to now save the old wood, they used magnetic particles. Read on to find out how here.

Electrostatic vs. Electro-Steric Stabilization of Ferrofluids

Ever thought about which stabilization makes the better ferrofluids, electrostatic or electrosteric stabilization? If you are like me and don't know, then go and read the new paper by Ladislau Vekas et al. which is an in depth analysis of these two types of ferrofluids. 

The results of volume fraction dependent structure analyses over a large concentration range by small-angle X-ray and neutron scattering, correlated with magneto-rheological investigations for the electrostatically stabilized MFs, demonstrate formation of short chains of magnetic nanoparticles which are relatively stable against coagulation with increasing concentration, while for MFs with electro-steric stabilization, magnetic field and shear rate dependent loosely bound structures are observed. These particle structures in MF/OA samples manifest themselves already at low volume fraction values, which can be attributed mainly to magnetic interactions of larger size particles, besides non-magnetic interactions mediated by excess surfactant.

For more information, check it out here.

UCLA Bioengineers Use Magnetic Force to Manage Pain

UCLA bioengineers have demonstrated that a gel-like material containing tiny magnetic particles could be used to manage chronic pain from disease or injury. Broadly, the study demonstrates the promising use of biomechanical forces that push and pull on cells to treat disease.

"Much of mainstream modern medicine centers on using pharmaceuticals to make chemical or molecular changes inside the body to treat disease," said Dino Di Carlo, UCLA professor of bioengineering and the principal investigator of the study. "However, recent breakthroughs in the control of forces at small scales have opened up a new treatment idea -- using physical force to kick-start helpful changes inside cells. There's a long way to go, but this early work shows this path toward so-called 'mechanoceuticals' is a promising one."

The researchers used small magnetic particles inside a gel to control cell proteins that respond to mechanical stimulation, and which control the flow of certain ions. These proteins are on the cell's membrane and play a role in the sensations of touch and pain. The study was published in Advanced Materials. For more information, check it out here.

Magnetic Nanoparticles Leap from Lab Bench to Breast Cancer Clinical Trials

Longstanding Sandia, industry collaboration produces precise particles

Sandia National Laboratories materials chemist Dale Huber has been working on the challenge of making iron-based nanoparticles the exact same size for 15 years. Now, he and his long-term collaborators at lmagion Biosystems will use these magnetic nanoparticles for their first breast cancer clinical trial later this year. The nanoparticles stick to breast cancer cells, allowing the detection and removal of even small metastases.

lmagion Biosystems and Huber have been working together synthesizing nanoparticles since the opening of the Center for Integrated Nanotechnologies in 2006. "Having access to the talent pool at CINT with experts like Dale Huber has been helpful," said Bob Proulx, CEO of I mag ion Biosystems. "Additionally, the fact that CINT has a user program that allows industry to access the facilities and equipment that, otherwise, would be too expensive for a small company like ours was valuable. The initial work we did with CINT to develop a method to give precise control over the size of the nanoparticle was key for our Mag Sense magnetic relaxometry technology for the detection of cancer."

To read the whole story, click here.

Microprinting Is Cool - Magnetic Items Also Supported

The magnetic helical micromachines shown to the right have been invented in the lab of Bradley Nelson at the Federal Institute of Technology in Zurich. They can be precisely controlled by an external field. The speed can reach up to several hundred micrometers per second. The magnetic helical micromachine with a "micro-hand" is capable of pick-and-place micromanipulation. These micromachines are made in a kind of simple way by using one of the two-photon 3D printers from nanoscribe. Excellent method that seems to work very nicely, though slowly.

Please check out the movie at this link: https://youtu.be/sJP4rL57Dq8.

And more information about the high precision 3D printing is available on this website: https://www.nanoscribe.de/en/.

Magnet's Tune a Surface's Friction

Harvard University’s Joanna Aizenberg and coworkers created the surfaces by infusing a ferrofluid—a suspension of magnetic particles in a variety of liquids—into a microstructured, porous epoxy surface. The team previously had made slippery liquid-infused porous surfaces, or SLIPS, by adding lubricants to similar porous solids. What’s different about these new surfaces—called ferrofluid-containing liquid-infused porous surfaces (FLIPS)—is that they allow researchers to control the distribution of the fluid within the structure with a magnetic field.

A FLIPS surface is flat and slippery until researchers place a magnet nearby. The magnetic field pulls the ferrofluid and makes it form a variety of different configurations, depending on the underlying pattern on the microstructured surface and other factors.

As a result, the magnetic field depletes the ferrofluid in one area of the surface, exposing the roughness of the epoxy solid underneath and effectively “turning on” the surface’s friction. The team used this tunable friction to temporarily pin a water droplet in place; when the researchers released the magnetic field, the droplet slid away.

The team demonstrated several other functions for the FLIPS, ranging from those on a very small scale to some on a larger scale. For example, they transported nonmagnetic colloidal particles, pumped a dyed ethanol solution, and removed a biofilm of green algae that had accumulated on a FLIPS surface.

The study transforms a simple concept into “a versatile technique for manipulating various objects and phenomena,” says Liming Dai of Case Western Reserve University, who designs materials with functional structures and smart features.

Aizenberg says her team continues to work to better understand the underlying physical phenomena of how these fluids interact with microscructures and develop dynamic materials for various applications. In particular, the group is interested in exploring whether FLIPS surfaces could enable self-cleaning pipes that prevent the buildup of algae.

Nanocrystals Give Hematite Rainbow Colors

Naturally iridescent materials such as opal or a butterfly’s wing have long fascinated onlookers for their ability to produce spectacular rainbow colors. Now, researchers have uncovered the cause of the vibrant display in another naturally iridescent material, the iron oxide mineral known as rainbow hematite. Pennsylvania State University geochemist Peter J. Heaney and his student Xiayang Lin used a variety of imaging and spectroscopy techniques to investigate the chemical makeup and surface structure of a rainbow hematite sample from Brazil (Gems & Gemol. 2018, DOI: 10.5741/GEMS.54.1.28). They found that the mineral contains stacked sheets of spindle-shaped nanocrystals that are arranged at 120-degree angles.

The nanocrystal array acts as a diffraction grating, splitting and scattering beams of light to produce the rainbow effect. The researchers also calculated a chemical formula (Fe_1.81Al_0.23P_0.03O₃) for the mineral, which contains aluminum and phosphorus impurities in addition to its major iron and oxygen components. The presence of those impurities within the crystal structure may have prompted the nanoparticles to grow into spindle shapes rather than into more symmetrical rhombohedrons, Heaney says. He thinks the findings could inspire new nanocrystal-based iridescent coatings.

Scientists Discover New Magnetic Element

A new experimental discovery, led by researchers at the University of Minnesota, demonstrates that the chemical element ruthenium (Ru) is the fourth single element to have unique magnetic properties at room temperature. The discovery could be used to improve sensors, devices in the computer memory and logic industry, or other devices using magnetic materials.  

The use of ferromagnetism, or the basic mechanism by which certain materials (such as iron) form permanent magnets or are attracted to magnets, reaches back as far as ancient times when lodestone was used for navigation. Since then only three elements on the periodic table have been found to be ferromagnetic at room temperature—iron (Fe), cobalt (Co), and nickel (Ni). The rare earth element gadolinium (Gd) nearly misses by only 8 degrees Celsius.

Magnetic materials are very important in industry and modern technology and have been used for fundamental studies and in many everyday applications such as sensors, electric motors, generators, hard disk media, and most recently spintronic memories.

As thin film growth has improved over the past few decades, so has the ability to control the structure of crystal lattices—or even force structures that are impossible in nature. This new study demonstrates that Ru can be the fourth single element ferromagnetic material by using ultra-thin films to force the ferromagnetic phase.

The details of their work are published in the most recent issue of Nature Communications. The lead author of the paper is a recent University of Minnesota Ph.D. graduate Patrick Quarterman, who is a National Research Council (NRC) postdoctoral fellow at the National Institute of Standards and Technology (NIST).

“Magnetism is always amazing. It proves itself again. We are excited and grateful to be the first group to experimentally demonstrate and add the fourth ferromagnetic element at room temperature to the periodic table,” said University of Minnesota Robert F. Hartmann professor of electrical and computer engineering Jian-Ping Wang, the corresponding author for the paper and Quarterman’s advisor.

“This is an exciting but hard problem. It took us about two years to find a right way to grow this material and validate it. This work will trigger the magnetic research community to look into fundamental aspects of magnetism for many well-known elements,” Wang added.