Vital signs second skin technology

Nicky Phillips TECHNOLOGY August 12, 2011

Second skin … the ultra-thin electronic device that can be applied to skin like a temporary tattoo. Photo: John A. Rogers.  THE days of connecting patients to medical monitoring machines with bulky electrodes and intrusive wires may soon be over thanks to an ultra-thin electronic device that can be applied to skin like a temporary tattoo.

The stick-on device can measure a person’s heart beat, brain waves and muscle activity and, in future, could also be used for wound healing and muscle rehabilitation. An engineer and co-inventor of the device, John Rogers, said the aim was to develop an electronic technology that could integrate with the skin and was almost unnoticeable to the user. ”[We wanted to] blur the distinction between electronics and biological tissues in ways that can provide new functionality in health-care and non-health-care-related applications,” said Dr Rogers , an engineering professor at the University of Illinois.

The device can power a range of electronic components, including miniature sensors, such as EEG and EMG monitors that measure brain waves and muscle activity, and LED indicator lights and semi-conductors. The “spider’s web” of micro-electronics is then embedded into a transparent film that can be laminated on the skin with water. The patch was thin and compliant enough to conform to the surface of the skin without requiring an adhesive, Dr Rogers said. The membrane was non-invasive, so the researchers hoped it could be used to monitor premature babies and people with sleep apnoea.

Existing technologies measured a person’s vital signs using bulky electrodes that might require adhesive tapes and conducting gels or needles, connected to circuit boards and power supplies. Studies on animals had also shown the device could stimulate muscle contractions, which may allow the device to be used in rehabilitation. ”The key thing about the device is it doesn’t constrain the movement of the muscle,” Dr Rogers said. His findings were published in the journal Science .

The gadget’s negligible width also overcame the rigidity often associated with traditional electronics. “If you make anything thin enough, it becomes flexible,” he said.  It can be powered by wireless energy transfer or silicon solar cells and it may be integrated with batteries in the future.  The patch can be applied to most areas of the skin and can remain attached to the skin for one to two weeks.  ”The devices we have now – we envision them as things you stick on your skin, wear them for a week, peel it off and reapply a new one,” Dr Rogers said.


Electronic skin tattoo has medical, gaming, spy uses

(AFP) 12 August 2011

WASHINGTON — A hair-thin electronic patch that adheres to the skin like a temporary tattoo could transform medical sensing, computer gaming and even spy operations, according to a US study published Thursday. The micro-electronics technology, called an epidermal electronic system (EES), was developed by an international team of researchers from the United States, China and Singapore, and is described in the journal Science. “It’s a technology that blurs the distinction between electronics and biology,” said co-author John Rogers, a professor in materials science and engineering at the University of Illinois at Urbana-Champaign.

“Our goal was to develop an electronic technology that could integrate with the skin in a way that is mechanically and physiologically invisible to the user.” The patch could be used instead of bulky electrodes to monitor brain, heart and muscle tissue activity and when placed on the throat it allowed users to operate a voice-activated video game with better than 90 percent accuracy. “This type of device might provide utility for those who suffer from certain diseases of the larynx,” said Rogers. “It could also form the basis of a sub-vocal communication capability, suitable for covert or other uses.” The wireless device is nearly weightless and requires so little power it can fuel itself with miniature solar collectors or by picking up stray or transmitted electromagnetic radiation, the study said.

Less than 50-microns thick — slightly thinner than a human hair — the devices are able to adhere to the skin without glue or sticky material. “Forces called van der Waals interactions dominate the adhesion at the molecular level, so the electronic tattoos adhere to the skin without any glues and stay in place for hours,” said the study. Northwestern University engineer Yonggang Huang said the patch was “as soft as the human skin.” Rogers and Huang have been working together on the technology for the past six years. They have already designed flexible electronics for hemispherical camera sensors and are now focused on adding battery power and other energy options.

The devices might find future uses in patients with sleep apnea, babies who need neonatal care and for making electronic bandages to help skin heal from wounds and burns.


Electronic tattoo ‘could revolutionise patient monitoring’

By James GallagherHealth reporter, BBC News 12 August 2011

The sensor can be built into a temporary tattoo

An “electronic tattoo” could herald a revolution in the way patients are monitored and provide a breakthrough in computer gaming, say US scientists.  They used the device, which is thinner than a human hair, to monitor the heart and brain, according to a study in the journal Science.  The sensor attaches to human skin just like a temporary tattoo and can move, wrinkle and stretch without breaking.

Researchers hope it could replace bulky equipment currently used in hospitals. A mass of cables, wires, gel-coated sticky pads and monitors are currently needed to keep track of a patient’s vital signs. Scientists say this can be “distressing”, such as when a patient with heart problems has to wear a bulky monitor for a month “in order to capture abnormal but rare cardiac events”.

Solar cells

With the tattoo, all the electronic parts are built out of wavy, snake-like components, which mean they can cope with being stretched and squeezed. There are also tiny solar cells which can generate power or get energy from electromagnetic radiation. The device is small, less than 50 micrometres thick — less than the diameter of a human hair. The sensor is mounted on to a water-soluble sheet of plastic, so is attached to the body by brushing with water, just like a temporary tattoo. It sticks on due to weak forces of attraction between the skin and a polyester layer at the base of the sensor, which is the same force which sticks geckos to walls.

In the study, the tattoo was used to measure electrical activity in the leg, heart and brain. It found that the “measurements agree remarkably well” with those taken by traditional methods.  The sensor moves with the skin. Researchers believe the technology could be used to replace traditional wires and cables. Smaller, less invasive, sensors could be especially useful for monitoring premature babies or for studying patients with sleep apnoea without them wearing wires through the night, researchers say.

Prof Todd Coleman, from the University of Illinois, said: “If we want to understand brain function in a natural environment, that’s completely incompatible with studies in a laboratory. “The best way to do this is to record neural signals in natural settings, with devices that are invisible to the user.” The device was worn for up to 24 hours without loss of function or skin irritation. However, there are problems with longer-term use, as the skin constantly produces new cells, while those at the surface die and are brushed off, meaning a new sensor would need to be attached at least every fortnight.

‘Electronic skin’

When the tattoo was attached to the throat, it was able to detect differences in words such as up, down, left, right, go and stop. The researchers managed to use this to control a simple computer game. John Rogers, professor in material science and engineering at the University of Illinois, said: “Our goal was to develop an electronic technology that could integrate with the skin in a way that is invisible to the user. “It’s a technology that blurs the distinction between electronics and biology.”

Prof Zhenqiang Ma, an electrical and computer engineer at the University of Wisconsin, argued that the technology could overcome issues with bulky sensors. “An electronic skin will help solve these problems and allow monitoring to be simpler, more reliable and uninterrupted. “It has proved to be viable and low-cost in this demonstration which will greatly facilitate the practical clinical use of the electronic skin.”


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