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.


Artificial Skin Opens SuperHuman Perception

A new type of sensor could lead to artificial skin that someday helps burn victimsfeel’ and safeguards the rest of us, University of Connecticut (UConn)  researchers suggest in a paper in Advanced Materials.

Our skin’s ability to perceive pressure, heat, cold, and vibration is a critical safety function that most people take for granted. But burn victims, those with prosthetic limbs, and others who have lost skin sensitivity for one reason or another, can’t take it for granted, and often injure themselves unintentionally. Chemists Islam Mosa from UConn, and James Rusling from UConn and UConn Health, along with University of Toronto engineer Abdelsalam Ahmed, wanted to create a sensor that can mimic the sensing properties of skin. Such a sensor would need to be able to detect pressure, temperature, and vibration. But perhaps it could do other things too, the researchers thought.

It would be very cool if it had abilities human skin does not; for example, the ability to detect magnetic fields, sound waves, and abnormal behaviors,” said Mosa.

Mosa and his colleagues created such a sensor with a silicone tube wrapped in a copper wire and filled with a special fluid made of tiny particles of iron oxide just one billionth of a meter long, called nanoparticles. The nanoparticles rub around the inside of the silicone tube and create an electric current. The copper wire surrounding the silicone tube picks up the current as a signal. When this tube is bumped by something experiencing pressure, the nanoparticles move and the electric signal changes. Sound waves also create waves in the nanoparticle fluid, and the electric signal changes in a different way than when the tube is bumped.

The researchers found that magnetic fields alter the signal too, in a way distinct from pressure or sound waves. Even a person moving around while carrying the sensor changes the electrical current, and the team found they could distinguish between the electrical signals caused by walking, running, jumping, and swimming.

Metal skin might sound like a superhero power, but this skin wouldn’t make the wearer Colossus from the X-men. Rather, Mosa and his colleagues hope it could help burn victimsfeelagain, and perhaps act as an early warning for workers exposed to dangerously high magnetic fields. Because the rubber exterior is completely sealed and waterproof, it could also serve as a wearable monitor to alert parents if their child fell into deep water in a pool, for example.


Strain Improves Performance of Atomically Thin Semiconductor

Researchers in UConn’s Institute of Materials Science significantly improved the performance of an atomically thin semiconductor material by stretching it, an accomplishment that could prove beneficial to engineers designing the next generation of flexible electronics, nano devices, and optical sensors.

In a study appearing in the research journal Nano Letters, Michael Pettes, assistant professor of mechanical engineering, reports that a six-atom thick bilayer of tungsten diselenide exhibited a 100-fold increase in photoluminescence when it was subjected to strain. The material had never exhibited such photoluminescence before.

The findings mark the first time scientists have been able to conclusively show that the properties of atomically thin materials can be mechanically manipulated to enhance their performance, Pettes says. Such capabilities could lead to faster computer processors and more efficient sensors.

The process the researchers used to achieve the outcome is also significant in that it offers a reliable new methodology for measuring the impact of strain on ultrathin materials, something that has been difficult to do and a hindrance to innovation.

Experiments involving strain are often criticized since the strain experienced by these atomically thin materials is difficult to determine and often speculated as being incorrect,” says Pettes. “Our study provides a new methodology for conducting strain-dependent measurements of ultrathin materials, and this is important because strain is predicted to offer orders of magnitude changes in the properties of these materials across many different scientific fields.”