Artificial Skin

Indian Researcher Makes Touch Sensitive Prosthetic Arm That Could Give New Life To Amputees.

Posted by

0


Though prosthetics have come a long way towards enabling people who have lost their limbs to fully function, they still lack in certain areas like fine motor skills and the sense of touch. Now, researchers at the University of Glasgow have developed new technology that could remedy the latter.

Touch Sensitive Prosthetic Arms Could Give New Life To Amputees, And Even Contribute To Nanny Robots

A team from the Glasgow School of Engineering has developed artificial skin that would allow amputees to regain their sense of touch when using a prosthetic. The prototype involves using a polymeric protective layer over the prosthetic’s surface, that sends back pressure and temperature signals to the wearer. For example, someone wearing this prosthetic could pick up a cup of coffee, and would be able to feel the grain of the ceramic as well as how hot the mug is.

 The problem these researchers, headed by Dr Ravinder Dahiya, faced is that such a device needed its own power source, making it necessary to also attach a battery pack to the robotic arm. Of course, this made the prosthetic bulky and unwieldy. The solution then, was to develop a version of the touch-sensitive layer that could power itself.

As such, the team began experimenting with graphene, a material that remains transparent and flexible while also being incredibly durable. Using this, the researchers were able to make a new protective layer that was also capable of converting solar energy, 98 percent of the light hitting it to be exact. They did this by layering the graphene over a set of solar cells underneath the “skin”, which would generate energy while in the sun and power the wearer’s sense of touch.

Touch Sensitive Prosthetic Arms Could Give New Life To Amputees, And Even Contribute To Nanny Robots

RAVINDER DAHIYA WITH HIS PROTOTYPE PROSTHETIC

However, the researchers believe they still have a lot of improvements to make to the prototype. The device is still too bulky, so the next step is to miniaturise the technology further, in order to bring the prosthetic’s weight closer to that of a real human hand. The team is also researching a way to store the solar energy converted in a light-weight battery pack within the device. Doing that would give the wearer the full experience of a mobile, sensitive hand, without worrying about when it will run out of power.

Watch the video. URL:

While the technology has been designed with amputees in mind, it could also eventually find its way to applications in robotics. A touch-sensitive skin could give a huge boost to the development of caregiver robots. With a sense of touch feeding back data, these bots could exercise restraint when dealing with infants, the old, or infirm, while still allowing them utilise more strength when say, picking up and moving household objects.

Source:indiatimes.com

Artificial Skin Sends Touching Signals to Nerve Cells

Posted by

0


Sensors transmit pressure changes to neurons and could help prosthetic limbs truly feel

Model robotic hand with artificial mechanoreceptors touching a human hand.
Prosthetic limbs can restore an amputee’s ability to walk or grip objects, but they haven’t yet been able to restore a person’s sense of touch. Researchers at Stanford University have taken a step closer to this type of prosthetic by creating an electronic skin that responds to pressure changes and transmits signals via nerve cells, much as human skin does.

Zhenan Bao and coworkers made the artificial skin by connecting three components: microstructured resistive pressure sensors, flexible printed organic electronic circuits, and nerve cells containing light-activated ion channels (Science 2015, DOI: 10.1126/science.aaa9306).

The pressure sensors are made of a carbon nanotube-elastomer composite shaped into tiny pyramidal structures that are coated onto a surface. The sensor changes conductance in response to applied pressure. Bao previously made similar capacitive sensors, but the new resistive sensors better detect the range of pressures sensed by human skin.

Each sensor is connected to an organic circuit printed with the help of researchers at Xerox’s Palo Alto Research Center (PARC). The circuit converts the pressure signal into a series of electrical pulses and increases pulse frequency in response to increasing pressure. “This circuit is relatively simple to build,” Bao says. “It serves as the perfect electrical readout for our sensors.”

The researchers used the electrical pulses to modulate the frequency of a light-emitting diode. In their proof-of-concept study, they sent light from the LED through an optical fiber to stimulate neurons in mouse brain slices. The nerve cells in these samples were decorated with engineered channelrhodopsins that open in response to light, triggering nerve cells to fire.

The work represents “an important advance in the development of skinlike materials that mimic the functionality of human skin at an unprecedented level,” says Ali Javey, who is developing electronic skin at the University of California, Berkeley. “It could have important implications for the development of smarter prosthetics.”

“This is just the beginning of the path toward building fully integrated artificial skin,” Bao says. Next, she says, her team hopes to mimic other sensing functions of human skin, such as the ability to feel heat, and integrate them into the new platform.

This Fake Skin Allows Prosthetic Hands To Feel Heat, Humidity, And Pressure

Posted by

0


Prosthetic hand

In a new study, researchers used a flexible material made of nanoribbons to create fake skin, which is able to decipher between hot and cold, wet and dry, and levels of pressure. 

Amputees may soon be able to feel and touch things again even without their limb: scientists have developed artificial skin that is able to detect pressure, temperature, and humidity, making prosthetic limbs far more realistic than in the past.

Currently, certain prosthetic limbs are able to be controlled by an amputee’s thoughts, which is quite remarkable in itself. But the artificial skin may be the next step in making a prosthetic truly an extension of the body. The stretchy material the researchers created, which acts as the “skin,” even has a built-in heater to make it feel like real flesh. Ultimately, the researchers hope, the fake skin will be able to interlock with the patient’s nerves so they can feel what it touches.

“The prosthetic hand and laminated electronic skin could encounter many complex operations such as hand shaking, keyboard tapping, ball grasping, holding a cup of hot or cold drink, touching dry or wet surfaces and human to human contact,” the authors wrote in theirstudy, which was published in Nature Communications.

The artificial skin was developed using a silicone material that is stretchy and transparent. It’s called polydimethylsilozane (PDMS), and it contains silicon nanoribbons that are able to generate electricity when they’re touched or stretched — and are able to detect whether something is warm or cold. In order to test the humidity sensors in the skin, which were able to distinguish between wet and dry, the researchers had the prosthetic hand touch a variety of wet and dry diapers. It was able to successfully sense whether they were wet or dry — something that might prove useful in the future for busy parents.

The researchers were smart in the way they designed the skin and how it wraps around the prosthetic hand. For smaller areas that should be highly sensitive, such as the fingertips, they packed the nanoribbons tightly to increase the amount of sensitivity to touch. Around the wrist, which requires more flexibility in movement, the researchers allowed the nanoribbons to loop around and give room for expansion.

Recreating sense of touch for amputees is, in essence, a notion that involves cheating the brain. Dustin Tyler, a bioengineer at Case Western Reserve University and the author of a previous study that examined creating fake touch through prosthetics, led a study that was able to create sensations artificially. “If we get it correct, the brain interprets it that it’s coming from the hand in the first place,” Tyler said. “The brain doesn’t know we cheated it.”

Though researchers like Tyler have developed “feeling” hands in the past, this is the first time using the stretchy material. “Recent efforts to develop smart prosthetics, which exploit rigid and/or semi-flexible pressure, strain and temperature sensors, provide promising routes for sensor-laden bionic systems, but with limited stretchability, detection range and spatio-temporal resolution,” the authors write in the Abstract. “Here we demonstrate smart prosthetic skin instrumented with ultrathin, single crystalline silicon nanoribbon strain, pressure and temperature sensory arrays as well as associated humidity sensors, electroresistive heaters and stretchable multi-electrode arrays for nerve stimulation.”

It will be some time before the researchers are able to create a connection between the prosthetic skin and the brain in order to let amputees themselves feel its sensations. But it provides hope for those who previously could only have a robotic extension as a prosthetic, rather than a sensitive, feeling, and touching one. “This collection of stretchable sensors and actuators facilitate highly localized mechanical and thermal skin-like perception in response to external stimuli, thus providing unique opportunities for emerging classes of prostheses and peripheral nervous system interface technologies,” the authors write.

Source: Kim J, Lee M, Shim H, Ghaffari R, Cho Hye, Son D. “Stretchable silicon nanoribbon electronics for skin prosthesis.” Nature Communications, 2014.

Medical breakthrough could lead to functional artificial skin.

Posted by

0


Medical breakthrough could lead to functional artificial skin

Swiss researchers have achieved a major breakthrough in the development of bioengineered skin. The new grafts, which are about to undergo clinical trials, work a lot like the real thing — because they actually contain functioning blood vessels and lymph capillaries.

The breakthrough was made by Daniela Marino and her team from the Tissue Biology Research Unit at University Children’s Hospital Zurich. It’s another amazing advance in the field of tissue engineering — one that’s poised to help patients with severe burns who don’t have enough of their own healthy skin available for grafts. The same technology could also be applied to cosmetic surgery.

Like the Real Thing

What’s remarkable about these new skin grafts — which have only been tested on rats — is how much they work like human skin. They’re equipped with not just blood vessels — which transport nutrients, oxygen, and other essential factors that keep organs alive and functioning — but lymphatic capillaries as well. These are necessary to prevent the build-up of fluids that can kill the graft before it has time to become part of the patient’s own skin. Lymph vessels remove fluid from the tissue and return it to the bloodstream.

The researchers say their findings strongly suggest that if an engineered skin graft containing both blood and lymph vessels would be transplanted on humans, fluid formation would be thwarted, wound healing improved — and it would result in an enhanced ability to grow skin that looks, feels, and functions like the real thing.

To this point, bioengineered skin grafts have not contained the components of real skin, including blood and lymphatic vessels. Looking ahead, researchers will also have to figure out a way to add pigmentation, sweat glands, nerves, and hair follicles. Other unrelated research projects are striving to give artificial skin the capacity for sensitivetouch.

Growing Skin

To create the skin grafts, the researchers used human cells from blood and lymph vessels. They were placed in a solution that scattered the cells onto a skin-like gel. After spending some time in an incubator, the mixture grew into skin grafts.

These grafts were then tested successfully on rats. The transplanted skin morphed into near-normal skin. Then, after connecting the grafts to the rats’ own lymph system, it collected and drew fluid away from the tissue.

Not Ideal?

But not everyone’s enthused about the prospect. HealthDay science reporter Steven Reinberg explains:

Dr. Alfred Culliford, director of plastic, reconstructive and hand surgery at Staten Island University Hospital in New York City, called the bioengineered tissue “a technology in search of a purpose.”

“I don’t think it will be broadly applicable to many people who need skin grafts,” Culliford said. “It may be helpful in burn patients who have had a large portion of their body surface burned and don’t have enough healthy skin to transplant.”

Culliford said the best grafts for most patients still come from the patient’s own skin. In addition, he said he doesn’t believe adding lymph vessels to a graft is a great advance, since fluid drainage is now done by methods such as compressing the graft.

Unswayed, Marino says the new tissue is a true advance. Human trials are next.

Breakthrough Could Lead to ‘Artificial Skin’ That Senses Touch, Humidity and Temperature.

Posted by

0


touchUsing tiny gold particles and a kind of resin, a team of scientists at the Technion-Israel Institute of Technology has discovered how to make a new kind of flexible sensor that one day could be integrated into electronic skin, or e-skin. If scientists learn how to attach e-skin to prosthetic limbs, people with amputations might once again be able to feel changes in their environments.

The findings appear in the June issue ofACS Applied Materials & Interfaces.

The secret lies in the sensor’s ability to detect three kinds of data simultaneously. While current kinds of e-skin detect only touch, the Technion team’s invention “can simultaneously sense touch, humidity, and temperature, as real skin can do,” says research team leader Professor Hossam Haick. Additionally, the new system “is at least 10 times more sensitive in touch than the currently existing touch-based e-skin systems.”

Researchers have long been interested in flexible sensors, but have had trouble adapting them for real-world use. To make its way into mainstream society, a flexible sensor would have to run on low voltage (so it would be compatible with the batteries in today’s portable devices), measure a wide range of pressures, and make more than one measurement at a time, including humidity, temperature, pressure, and the presence of chemicals. In addition, these sensors would also have to be able to be made quickly, easily, and cheaply.

The Technion team’s sensor has all of these qualities. The secret is the use of monolayer-capped nanoparticles that are only 5-8 nanometers in diameter. They are made of gold and surrounded by connector molecules called ligands. In fact, “monolayer-capped nanoparticles can be thought of as flowers, where the center of the flower is the gold or metal nanoparticle and the petals are the monolayer of organic ligands that generally protect it,” says Haick.

The team discovered that when these nanoparticles are laid on top of a substrate — in this case, made of PET (flexible polyethylene terephthalate), the same plastic found in soda bottles — the resulting compound conducted electricity differently depending on how the substrate was bent. (The bending motion brings some particles closer to others, increasing how quickly electrons can pass between them.) This electrical property means that the sensor can detect a large range of pressures, from tens of milligrams to tens of grams. “The sensor is very stable and can be attached to any surface shape while keeping the function stable,” says Dr. Nir Peled, Head of the Thoracic Cancer Research and Detection Center at Israel’s Sheba Medical Center, who was not involved in the research.

And by varying how thick the substrate is, as well as what it is made of, scientists can modify how sensitive the sensor is. Because these sensors can be customized, they could in the future perform a variety of other tasks, including monitoring strain on bridges and detecting cracks in engines.

“Indeed,” says Dr. Peled, “the development of the artificial skin as biosensor by Professor Haick and his team is another breakthrough that puts nanotechnology at the front of the diagnostic era.”

The research team also included Meital Segev-Bar and Gregory Shuster, graduate students in the Technion’s Russell Berrie Nanotechnology Institute, as well as Avigail Landman and Maayan Nir-Shapira, undergraduate students in the Technion’s Chemical Engineering Department.

Source: http://www.sciencedaily.com