R&D Roundup: March 2014

Cyborgs Are Already Here

Cyborgs that combine machine systems with living organisms to have extraordinary abilities are already a reality say researchers at Karlsruhe Institute of Technology (KIT). This is especially true with medical implant technology.

In recent years, medical implants based on smart materials that automatically react to changing conditions, computer-supported design and fabrication based on magnetic resonance tomography datasets, or surface modifications for improved tissue integration, allowed major progress to be achieved.

Progress in microelectronics and semiconductor technology has been the basis of electronic implants controlling, restoring, or improving the functions of the human body, such as cardiac pacemakers, retina implants, hearing implants, or implants for deep brain stimulation in pain or Parkinson therapies. Currently, bioelectronic developments are being combined with robotics systems to design highly complex neuroprostheses. Scientists are working on brainmachine interfaces (BMI) for the direct physical contacting of the brain. BMI are used among others to control prostheses and complex movements, such as gripping. Moreover, they are important tools in neurosciences, as they provide insight into the functioning of the brain.

For more information, visit www.medicaldesignbriefs.com/component/content/article/1104-mdb/news/18997 .

Silver Nanowire Sensors Hold Promise for Prosthetics, Robotics

A team of scientists at North Carolina State University, Raleigh, used silver nanowires to develop wearable, multifunctional sensors that, they say, could be used in biomedical applications, including new prosthetics or robotic systems. The sensors can measure strain, pressure, human touch, and bioelectronic signals such as electrocardiograms.

They explained that the technology is similar to the mechanism used in smartphone touch screens, but the sensors they developed are stretchable and can be mounted on a variety of curvilinear surfaces, such as human skin.

The researchers sandwiched an insulating material between two layers of stretchable conductors. Pushing, pulling, or touching the stretchable conductors changes the capacitance, or the ability to store electric charges. The sensors work by measuring that change in capacitance.

The researchers used these sensors to monitor thumb movement, which can be useful in controlling robotic or prosthetic devices. They also demonstrated an application to monitor knee movements while a test subject is running, walking, and jumping. And, they developed an array of sensors that can map pressure distribution, which is important for use in robotics and prosthetics applications.

For more information, visit www.medicaldesignbriefs.com/component/content/article/1104-mdb/news/19001 .

Bio-Inspired Robotic Rehabilitation Device

A soft, wearable device that mimics the muscles, tendons, and ligaments of the lower leg could aid in the rehabilitation of patients with foot-ankle disorders such as drop foot, said Yong-Lae Park, an assistant professor of robotics at Carnegie Mellon University, Pittsburgh, PA.

He developed an active orthotic device using soft plastics and composite materials, instead of a rigid exoskeleton. The soft materials, combined with pneumatic artificial muscles (PAMs), lightweight sensors, and advanced control software, made it possible for the robotic device to achieve natural ankle motion.

The device’s artificial tendons were attached to four PAMs, which correspond with three muscles in the foreleg and one in the back that control ankle motion.

Among the innovations in the device are sensors made of a touch-sensitive artificial skin, thin rubber sheets that contain long microchannels filled with a liquid metal alloy. When these rubber sheets are stretched or pressed, the shapes of the microchannels change, which in turn causes changes in the electrical resistance of the alloy. These sensors were positioned on the top and at the side of the ankle. To view a video of the technology, visit www.techbriefs.com/tv/soft-orthotic.

For more information, visit www.medicaldesignbriefs.com/component/content/article/1104-mdb/news/19012 .

Monitoring Cerebral Pressure in Hydrocephalus

Researchers at the Fraunhofer Institute for Microelectronic Circuits and Systems IMS in Duisburg, Germany, have developed a sensor that can measure and individually adjust brain pressure if the pressure is too high in the brain of a patient with hydrocephalus, or “water on the brain.”

In hydrocephalus, the brain produces either too much cerebral fluid, or cannot drain off sufficient fluid, which increases pressure in the brain, resulting in damage. A shunt system implanted into the patient’s brain draws off superfluous fluid.

The new sensor implanted along with the shunt system, allows physicians to read brain pressure using a hand-held meter within seconds. If the patient experiences discomfort, the physician can place a hand-held meter on the outside of the patient’s head. The device sends magnetic radio waves and supplies the sensor in the shunt with power, which then measures temperature and pressure in the cerebral fluid, and transmits these data back to the hand-held device.

For more information, visit www.medicaldesignbriefs.com/component/content/article/1104mdb/news/19013 .

Sensitive Electronic Whiskers for Robotics

Researchers with Lawrence Berkeley National Laboratory and the University of California, Berkeley, say that they have created tactile sensors from composite films of carbon nanotubes and silver nanoparticles similar to the highly sensitive whiskers of cats and rats. These new e-whiskers respond to the slightest pressure. Among their many potential applications is giving robots new abilities to “see” and “feel” their surrounding environment.

To create the whiskers, they used a carbon nanotube paste to form an electrically conductive network matrix with excellent bendability. Then they loaded a thin film of silver nanoparticles that endowed the matrix with high sensitivity to mechanical strain. The composite can then be painted or printed onto high-aspect-ratio elastic fibers to form e-whiskers that can be integrated with different user-interactive systems. In tests, the whiskers were 10 times more sensitive to pressure than all previously reported capacitive or resistive pressure sensors, they reported.

They say that e-whiskers could lead to wearable sensors for measuring heartbeat and pulse rate, and should have a wide range of applications for advanced robotics, human-machine user interfaces, and biological applications.

For more information, visit www.medicaldesignbriefs.com/component/content/article/1104-mdb/news/19014 .

Portable Diagnostics Using Holograms

Researchers from the University of Cambridge, UK, are working to develop portable medical devices, which could be used to monitor medical conditions like diabetes, cardiac function, or infections easily and inexpensively using color-changing holograms that react in the presence of certain compounds.

The “smart” holograms can be used to test a variety of bodily fluids, including blood, urine, saliva, or tears for a wide range of compounds, such as glucose, alcohol, hormones, drugs, or bacteria. When one of these compounds is present, the hologram changes color, potentially making the monitoring of various conditions as simple as checking the color of the hologram against a color gradient chart.

The project uses hydrogels impregnated with tiny particles of silver. Using a single laser pulse, the silver nanoparticles are formed into three-dimensional holograms of predetermined shapes within seconds.

When in the presence of certain compounds, the hydrogels either shrink or swell, causing the color of the hologram to change to any other color in the entire visible spectrum, the first time that this has been achieved in any hydrogel-based sensor, they say.

For more information, visit www.medicaldesignbriefs.com/component/content/article/1104-mdb/news/19017 .

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