Heartbeats tapped to generate power for implant

May 21, 2010 By Leave a Comment

London, May 21 (ANI): A minuscule electricity generator implanted in the body could tap heartbeats to power an early-warning system for hypoglycaemia, or other medical conditions, according to a study.

A “nanogenerator” has been implanted in a live rat and has generated electricity from the animal”s beating heart.

And researchers led by Zhong Lin Wang at the Georgia Institute of Technology in Atlanta believe that it could run in-vivo sensors.

Wang knew that at the nanoscale carefully constructed wires of zinc oxide could act as piezoelectric materials – materials that convert mechanical energy into electricity.

Thus, he collaborated with colleagues to create a flexible generator that could harvest energy from natural actions such as breathing or heartbeats.

The team deposited zinc-oxide nanowires on a flexible polymer substrate that allows the nanowires to bend in a variety of ways.

They sealed the device in a polymer to shield it from body fluids and to ensure that any electricity they measured was generated by the device, not background interference.

This 2 millimetre by 5 millimetre rectangular device was then attached to a rat”s diaphragm muscle using tissue adhesive.

“The device is so tiny, you can barely see it by eye,” New Scientist quoted Wang as saying.

With each breath, the rat”s implant stretched and twisted, deforming the nanowires and generating up to 4 picoamps of current at a potential of 2 millivolts.

Then, the researchers implanted a similar device on a different rat”s heart, generating around 30 picoamps at 3 millivolts.

While the amount of energy generated is small, researchers are hopeful that they can scale up its output enough to power simple implantable nanosensors – blood pressure or glucose sensors, for instance – that have modest power requirements and don”t need a continuous supply.

Wang said that the device can capture motion in any direction, so it does not have to be fixed in a particular alignment.

“Any deformation can drive the device,” he added.

The study has been published in the journal Advanced Materials. (ANI)

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Charging your iPod by running

April 26, 2010 By Leave a Comment

Washington, April 26 (ANI): If you””ve forgotten to charge your iPod and a power plug is nowhere in sight, a simple run could help you get out of the trouble – if new technology being developed is successful.

Every step you take can generate electricity. By packing 20,000 nanowires into three square centimeters, Georgia Tech scientists have developed the world””s first gadget powered solely by piezoelectric materials.

A piezoelectric material when pushed or pulled creates a mild electrical charge.

Within three to five years piezoeleectric nanowires, woven into a cotton shirt or placed in a shoe heel, could charge a cell phone or laptop battery after even a short walk.

“This is a key step to designing technology that will be useful in the near future,” Discovery News quoted Z.L. Wang, a professor at Georgia Tech and co-author of two new papers in Nature Nanotechnology and Advanced Materials, as saying.

Wang””s group says piezoelectrics can generate voltages up to 1.26 volts, and can produce even higher voltages.

The team used plentiful and easy-to-manipulate zinc oxide nanowires to come up with their nanogenerator.

An individual zinc oxide nanowire is invisible to the human eye, measuring anywhere between 50 and 200 nanometers across and about five microns in length.

Twenty thousand nanowires, placed side-by-side and end-to-end, cover three square centimeters, with two thin electrodes hanging off either end.

The arrangement maximizes the electricity the piezoelectric nanowires can generate.

The wires work in sync, amplifying the electrical charge to record levels as the single layer is pushed back and forth with the slightest nudge.

Pushing the arranged nanowires harder or faster would enhance the power output up to 30 times without damaging the device.

And if gallium nitride replaced the cheap zinc oxide nanowires the power output could increase almost 10 times.

Piezoelectric-powered devices could also help detect fires and collect weather data in areas that are not within the reach of traditional power grids. (ANI)

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Charging your iPod by running

April 24, 2010 By Leave a Comment

Washington, April 24 (ANI): If you”ve forgotten to charge your iPod and a power plug is nowhere in sight, a simple run could help you get out of the trouble – if new technology being developed is successful.

Every step you take can generate electricity. By packing 20,000 nanowires into three square centimeters, Georgia Tech scientists have developed the world”s first gadget powered solely by piezoelectric materials.

A piezoelectric material when pushed or pulled creates a mild electrical charge.

Within three to five years piezoeleectric nanowires, woven into a cotton shirt or placed in a shoe heel, could charge a cell phone or laptop battery after even a short walk.

“This is a key step to designing technology that will be useful in the near future,” Discovery News quoted Z.L. Wang, a professor at Georgia Tech and co-author of two new papers in Nature Nanotechnology and Advanced Materials, as saying.

Wang”s group says piezoelectrics can generate voltages up to 1.26 volts, and can produce even higher voltages.

The team used plentiful and easy-to-manipulate zinc oxide nanowires to come up with their nanogenerator.

An individual zinc oxide nanowire is invisible to the human eye, measuring anywhere between 50 and 200 nanometers across and about five microns in length.

Twenty thousand nanowires, placed side-by-side and end-to-end, cover three square centimeters, with two thin electrodes hanging off either end.

The arrangement maximizes the electricity the piezoelectric nanowires can generate.

The wires work in sync, amplifying the electrical charge to record levels as the single layer is pushed back and forth with the slightest nudge.

Pushing the arranged nanowires harder or faster would enhance the power output up to 30 times without damaging the device.

And if gallium nitride replaced the cheap zinc oxide nanowires the power output could increase almost 10 times.

Piezoelectric-powered devices could also help detect fires and collect weather data in areas that are not within the reach of traditional power grids. (ANI)

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Improved nanogenerators used to power sensors based on zinc oxide nanowires

March 29, 2010 By Leave a Comment

Washington, March 29 (ANI): In latest research work, scientists have used improved nanogenerators with two types of zinc oxide nanowire sensors to develop the first self-powered nanometer-scale sensing devices that draw power from the conversion of mechanical energy.

The new devices can measure the pH of liquids or detect the presence of ultraviolet light using electrical current produced from mechanical energy in the environment.

Based on arrays containing as many as 20,000 zinc oxide nanowires in each nanogenerator, the devices can produce up to 1.2 volts of output voltage, and are fabricated with a chemical process designed to facilitate low-cost manufacture on flexible substrates.

Tests done with nearly one thousand nanogenerators, which have no mechanical moving parts, showed that they can be operated over time without loss of generating capacity.

“We have demonstrated a robust way to harvest energy and use it for powering nanometer-scale sensors,” said Zhong Lin Wang, a Regents professor in the School of Materials Science and Engineering at the Georgia Institute of Technology.

“We now have a technology roadmap for scaling these nanogenerators up to make truly practical applications,” he added.

For the past five years, Wang’s research team has been developing nanoscale generators that use the piezoelectric effect that produces electrical charges when wires made from zinc oxide are subjected to strain.

The strain can be produced by simply flexing the wires, and current from many wires can be constructively combined to power small devices.

The research effort has recently focused on increasing the amount of current and voltage generated and on making the devices more robust.

In the research paper, Wang and collaborators report on a new configuration for the nanowires that embeds both ends of the tiny structures in a polymer substrate.

The wires can then generate current as they are compressed in a flexible nanogenerator enclosure, eliminating the contact with a metallic electrode that was required in earlier devices.

Because the generators are completely enclosed, they can be used in a variety of environments.

“We can now grow the wires chemically on substrates that are foldable and flexible and the processing can now be done at substrate temperatures of less than 100 degrees Celsius – about the temperature of coffee,” explained Wang.

“That will allow lower cost fabrication and growth on just about any substrate,” he added.

Wang’s team has so far produced two tiny sensors that are based on zinc oxide nanowires and powered by the nanogenerators.

By measuring the amplitude of voltage changes across the device when exposed to different liquids, the pH sensor can measure the acidity of liquids. (ANI)

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