tFirst Thought-Controlled Bionic Leg Revealed

A team of researchers at the Rehabilitation Institute of Chicago has revealed clinical applications for the world’s first thought-controlled bionic vleg—a significant milestone for lower limb amputees in the rapidly growing field of bionics. Neural signals were used to safely improve limb control of the leg, which features intelligent engineering, meaning that it can learn and perform activities including seamless transitions between sitting, walking, ascending, and descending stairs and ramps and repositioning the leg while seated.

The bionic leg allows users thought-controlled movement of their prosthetic.
The study focuses on a lower-limb amputee who underwent targeted muscle reinnervation surgery to redirect nerves from damaged muscle in his amputated limb to healthy hamstring muscle above his knee. When the redirected nerves instruct the muscles to contract, sensors on the patient’s leg detect tiny electrical signals from the muscles. A specially-designed computer program analyzes the signals and data from sensors in the leg, instantly decodes the type of movement being attempted, and sends commands to the robotic leg. Using muscle signals, instead of robotic sensors, makes the system safer and more intuitive, the scientists say.

For more information, visit http://www.medicaldesignbriefs.com/component/content/article/17567. To see a video of this device in action, visit http://www.techbriefs.com/tv/bionic-leg.

Bendable Ceramics with Shape Memory

Ceramics are brittle and tend to crack under stress. But, researchers from Massachusetts Institute of Technology, Cambridge, along with colleagues in Singapore, say that they have found a way around that problem, at least for tiny objects.

They have made minuscule ceramic objects that are not only flexible, but also have “shape memory.” When bent and then heated, they return to their original shapes. Shape-memory materials, usually polymers or metals, but not ceramics, can bend and return to original configurations in response to temperature change. The key, they found, to shape-memory ceramics, was thinking small.

When subjected to a load, the molecular structure of the ceramic material deforms instead of cracking. When heated, it returns to original shape. (Credit: Alan Lai)
First, they created tiny ceramic objects made of zirconia, which were invisible to the naked eye. Then, they made the individual crystal grains span the entire small-scale structure, removing the crystal-grain boundaries where cracks are most likely to occur, which resulted in tiny samples of ceramic material with deformability equivalent to about 7 percent of their size. These materials could be used to develop micro- and nanodevices for biomedical applications, such as actuators on a chip, and self-deploying medical devices.

For more information, visit http://www.medicaldesignbriefs.com/component/content/article/17568.

Using Light to Restart Hearts

The “optrode” (left) delivers blue light to the heart via fiber optics, while (right) a red heart cell contains an implanted light-sensitive blue opsin protein that works with (yellow) heart proteins. (Credit: Patrick M. Boyle)
When heartbeats slip into an irregular rhythm, a pacemaker or defibrillator can jolt the heart back into rhythm. But because electricity can cause tissue damage, a team scientists at Johns Hopkins University, Balti more, MD, say there is a gentler option—light.

The engineers are working with optogenetics, inserting light-responsive proteins called opsins into cells. When exposed to light, these proteins become tiny portals, allowing an electric charge in the form of a stream of ions to pass through.

They tested this technique on a heart computer model, incorporating data on techniques to make heart tissue lightsensitive by inserting opsins into cells. Then, they will test how the cells respond when illuminated.

The team plans to conduct virtual experiments to determine how to position and control the light-sensitive cells to help maintain a healthy heart rhythm. They say that the technology could be incorporated into future light-based pacemakers and defibrillators.

For more information, visit http://www.medicaldesignbriefs.com/component/content/article/17166.