Tag Archives: magnetism

How To Stimulate Broken Bone Cells To Heal Much More Quickly

It was just a couple of months ago that we heard about an implantable material that electrically stimulates bone cells, causing them to reproduce. Now, scientists have created a similar substance that utilizes magnetism. There are already a number of experimental materials that have a three-dimensional scaffolding-like microstructure, which simulates the structure of natural bone. After a piece of such a material has been implanted at a bone wound site, cells from the body’s adjacent bone tissue gradually migrate into it. Those cells reproduce over time, while the scaffolding simultaneously dissolves. Eventually, all that’s left is newly-grown bone, in the shape and location of the implant.

One of the challenges of the technology involves getting the bone cells to migrate and reproduce quickly. Although growth-boosting chemicals are often added to the material, scientists at the University of Connecticut took another approach with a scaffolding that they announced this June – it generates a weak electrical field in response to externally applied ultrasound pulses, and that field in turn prompts the bone cells to reproduce.

More recently, though, a team at Spain’s University of the Basque Country developed a material that instead incorporates magnetic nanoparticles. These are dispersed within a 3D matrix of a biocompatible silk-derived protein known as fibroin.

When we apply a magnetic field, we bring about a response by these nanoparticles, which vibrate and thus deform the structure, they stretch it and transmit the mechanical stress to the cells,” says the lead scientist, Dr. José Luis Vilas-Vilela. In in vitro lab tests, that stress stimulated bone cells to reproduce much more quickly than would have otherwise been the case. In fact, the technology could conceivably be used to regrow more than just bone.

We are developing various types of materials, stimuli and processes so that we can have the means to achieve the regeneration of different tissue,” says Vilas-Vilela. “In addition, the idea would be to use the stem cells of the patients themselves and be capable of differentiating them towards the type of cell we want to form the tissue with, be it bone, muscle, heart or whatever might be needed.”

The research – which also involved scientists from Portugal’s University of Minho and biotech firm BCMaterials – is described in a paper that was recently published in the journal Materialia.

Source: https://www.sciencedirect.com/
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Beyond Moore’s Law

A team of researchers based in Manchester, the Netherlands, Singapore, Spain, Switzerland and the USA has published a new review on a field of computer device development known as spintronics, which could use graphene as a building block for next-generation electronics. Recent theoretical and experimental advances and phenomena in studies of electronic spin transport in graphene and related two-dimensional (2D) materials have emerged as a fascinating area of research and development.

Spintronics is the combination of electronics and magnetism at nanoscale and could allow electronic development at speeds exceeding Moore’s law, which observes that computer processing power roughly doubles every two years, while the price halves. Spintronic devices may offer higher energy efficiency and lower dissipation as compared to conventional electronics, which rely on charge currents. In principle, we could have phones and tablets operating with spin-based transistors and memories, greatly improving speed and storage capacity.

Since its isolation in 2004, graphene has opened the door for other 2D materials. Researchers can then use these materials to create stacks of 2D materials called heterostructures. These can be combined with graphene to create new ‘designer materials‘ to produce applications originally limited to science fiction. As published in APS Journal Review of Modern Physics, the review focuses on the new perspectives provided by heterostructures and their emergent phenomena, including proximity-enabled spin-orbit effects, coupling spin to light, electrical tunability and 2D magnetism. The average person already encounters spintronics in laptops and PCs, which are already using spintronics in the form of the magnetic sensors in the reading heads of hard disk drives. These sensors are also used in the automotive industry.

The continuous progress in graphene spintronics, and more broadly in 2D heterostructures, has resulted in the efficient creation, transport and detection of spin information using effects previously inaccessible to graphene alone” said Dr Ivan Vera Marun, Lecturer in Condensed Matter Physics at The University of Manchester.

As efforts on both the fundamental and technological aspects continue, we believe that ballistic spin transport will be realised in 2D heterostructures, even at room temperature. Such transport would enable practical use of the quantum mechanical properties of electron wave functions, bringing spins in 2D materials to the service of future quantum computation approaches.”

Controlled spin transport in graphene and other two-dimensional materials has become increasingly promising for applications in devices. Of particular interest are custom-tailored heterostructures, known as van der Waals heterostructures, that consist of stacks of two-dimensional materials in a precisely controlled order.

Billions of spintronic devices such as sensors and memories are already being produced. Every hard disk drive has a magnetic sensor that uses a flow of spins, and magnetic random access memory (MRAM) chips are becoming increasingly popular.

Source: https://www.manchester.ac.uk/