Tag Archives: cochlear implants

Solar-powered graphene skin for more feeling in your prosthetics

A March 23, 2017 news item on Nanowerk highlights research that could put feeling into a prosthetic limb,

A new way of harnessing the sun’s rays to power ‘synthetic skin’ could help to create advanced prosthetic limbs capable of returning the sense of touch to amputees.

Engineers from the University of Glasgow, who have previously developed an ‘electronic skin’ covering for prosthetic hands made from graphene, have found a way to use some of graphene’s remarkable physical properties to use energy from the sun to power the skin.

Graphene is a highly flexible form of graphite which, despite being just a single atom thick, is stronger than steel, electrically conductive, and transparent. It is graphene’s optical transparency, which allows around 98% of the light which strikes its surface to pass directly through it, which makes it ideal for gathering energy from the sun to generate power.

A March 23, 2017 University of Glasgow press release, which originated the news item, details more about the research,

Ravinder Dahiya

Dr Ravinder Dahiya

A new research paper, published today in the journal Advanced Functional Materials, describes how Dr Dahiya and colleagues from his Bendable Electronics and Sensing Technologies (BEST) group have integrated power-generating photovoltaic cells into their electronic skin for the first time.

Dr Dahiya, from the University of Glasgow’s School of Engineering, said: “Human skin is an incredibly complex system capable of detecting pressure, temperature and texture through an array of neural sensors which carry signals from the skin to the brain.

“My colleagues and I have already made significant steps in creating prosthetic prototypes which integrate synthetic skin and are capable of making very sensitive pressure measurements. Those measurements mean the prosthetic hand is capable of performing challenging tasks like properly gripping soft materials, which other prosthetics can struggle with. We are also using innovative 3D printing strategies to build more affordable sensitive prosthetic limbs, including the formation of a very active student club called ‘Helping Hands’.

“Skin capable of touch sensitivity also opens the possibility of creating robots capable of making better decisions about human safety. A robot working on a construction line, for example, is much less likely to accidentally injure a human if it can feel that a person has unexpectedly entered their area of movement and stop before an injury can occur.”

The new skin requires just 20 nanowatts of power per square centimetre, which is easily met even by the poorest-quality photovoltaic cells currently available on the market. And although currently energy generated by the skin’s photovoltaic cells cannot be stored, the team are already looking into ways to divert unused energy into batteries, allowing the energy to be used as and when it is required.

Dr Dahiya added: “The other next step for us is to further develop the power-generation technology which underpins this research and use it to power the motors which drive the prosthetic hand itself. This could allow the creation of an entirely energy-autonomous prosthetic limb.

“We’ve already made some encouraging progress in this direction and we’re looking forward to presenting those results soon. We are also exploring the possibility of building on these exciting results to develop wearable systems for affordable healthcare. In this direction, recently we also got small funds from Scottish Funding Council.”

For more information about this advance and others in the field of prosthetics you may want to check out Megan Scudellari’s March 30, 2017 article for the IEEE’s (Institute of Electrical and Electronics Engineers) Spectrum (Note: Links have been removed),

Cochlear implants can restore hearing to individuals with some types of hearing loss. Retinal implants are now on the market to restore sight to the blind. But there are no commercially available prosthetics that restore a sense of touch to those who have lost a limb.

Several products are in development, including this haptic system at Case Western Reserve University, which would enable upper-limb prosthetic users to, say, pluck a grape off a stem or pull a potato chip out of a bag. It sounds simple, but such tasks are virtually impossible without a sense of touch and pressure.

Now, a team at the University of Glasgow that previously developed a flexible ‘electronic skin’ capable of making sensitive pressure measurements, has figured out how to power their skin with sunlight. …

Here’s a link to and a citation for the paper,

Energy-Autonomous, Flexible, and Transparent Tactile Skin by Carlos García Núñez, William Taube Navaraj, Emre O. Polat and Ravinder Dahiya. Advanced Functional Materials DOI: 10.1002/adfm.201606287 Version of Record online: 22 MAR 2017

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Are we becoming machines?

According to the advertisement (being broadcast in January 2013 on US television channels) for HTC’s Droid smartphone, we’ve already become machines,

This advertisement isn’t the only instance, look at this from a Jan. 17, 2013 news release on EurekAlert,

A nano-gear in a nano-motor inside you

To live is to move. You strike to swat that irritable mosquito, which skilfully evades the hand of death. How did that happen? Who moved your hand, and what saved the mosquito? Enter the Molecular Motors, nanoscale protein-machines in the muscles of your hand and wings of the mosquito. You need these motors to swat mosquitoes, blink your eyes, walk, eat, drink… just name it. Millions of motors tug as a team within your muscles, and you swat the mosquito. This is teamwork at its exquisite best.

It’s not unusual to have bodily processes described in terms that one uses for machines (particularly in science-related publications), what’s different here (for me at least) is the intimacy in the ad. The phone is plugged into your chest and the upgrade is to your brain.

This ad is part of a continuum in the popular culture conversation (e.g. Deux Ex game featuring human enhancement and augmentation as  mentioned in my Aug. 30, 2011 posting and in my Aug. 18, 2011 posting) and the prosthetic in the ear seems to be a reference to cochlear implants but now they are for anyone who might care to augment their hearing past the limits of what has been possible for humans. Congratulations, you’ve been upgraded.

Ear-powered batteries

According to the Nov. 7, 2012 news item on phys.org, the idea of powering batteries with vibrations from the inner ear is not new (Note: I have removed a link),

“In the past, people have thought that the space where the high potential is located is inaccessible for implantable devices, because potentially it’s very dangerous if you encroach on it,” Stankovic [Konstantina Stankovic, an otologic surgeon at MEEI {Massachusetts Eye and Ear Infirmary}]] says. “We have known for 60 years that this battery exists and that it’s really important for normal hearing, but nobody has attempted to use this battery to power useful electronics.”

Larry Hardesty’s Nov. 7, 2012 news release for the Massachusetts Institute of Technology (MIT), which originated the news item, provides more technical detail about how the researchers have reduced the risk associated with this type of  implant,

In experiments, Konstantina Stankovic, an otologic surgeon at MEEI, and HST [Harvard-MIT Division of Health Sciences and Technology] graduate student Andrew Lysaght implanted electrodes in the biological batteries in guinea pigs’ ears. Attached to the electrodes were low-power electronic devices developed by MIT’s Microsystems Technology Laboratories (MTL). After the implantation, the guinea pigs responded normally to hearing tests, and the devices were able to wirelessly transmit data about the chemical conditions of the ear to an external receiver.

The ear converts a mechanical force — the vibration of the eardrum — into an electrochemical signal that can be processed by the brain; the biological battery is the source of that signal’s current. Located in the part of the ear called the cochlea, the battery chamber is divided by a membrane, some of whose cells are specialized to pump ions. An imbalance of potassium and sodium ions on opposite sides of the membrane, together with the particular arrangement of the pumps, creates an electrical voltage.

Although the voltage is the highest in the body (outside of individual cells, at least), it’s still very low. Moreover, in order not to disrupt hearing, a device powered by the biological battery can harvest only a small fraction of its power. Low-power chips, however, are precisely the area of expertise of Anantha Chandrakasan’s group at MTL.

The MTL researchers — Chandrakasan, who heads MIT’s Department of Electrical Engineering and Computer Science; his former graduate student Patrick Mercier, who’s now an assistant professor at the University of California at San Diego; and Saurav Bandyopadhyay, a graduate student in Chandrakasan’s group — equipped their chip with an ultralow-power radio transmitter: After all, an implantable medical monitor wouldn’t be much use if there were no way to retrieve its measurements.

But while the radio is much more efficient than those found in cellphones, it still couldn’t run directly on the biological battery. So the MTL chip also includes power-conversion circuitry — like that in the boxy converters at the ends of many electronic devices’ power cables — that gradually builds up charge in a capacitor. The voltage of the biological battery fluctuates, but it would take the control circuit somewhere between 40 seconds and four minutes to amass enough charge to power the radio. The frequency of the signal was thus itself an indication of the electrochemical properties of the inner ear.

To reduce its power consumption, the control circuit had to be drastically simplified, but like the radio, it still required a higher voltage than the biological battery could provide. Once the control circuit was up and running, it could drive itself; the problem was getting it up and running.

The MTL researchers solve that problem with a one-time burst of radio waves. “In the very beginning, we need to kick-start it,” Chandrakasan says. “Once we do that, we can be self-sustaining. The control runs off the output.”

Stankovic, who still maintains an affiliation with HST, and Lysaght implanted electrodes attached to the MTL chip on both sides of the membrane in the biological battery of each guinea pig’s ear. In the experiments, the chip itself remained outside the guinea pig’s body, but it’s small enough to nestle in the cavity of the middle ear.

The researchers seem to think that this kind of device might be used as a monitor for people with hearing difficulties or balance problems or, even, to deliver therapies. Regardless of any possible future uses, we are still a long way from human clinical trials.