Carbon Nanotube Thread Could Generate Electricity From The Bloodstream

Researchers have reported an idea to implant nanotube yarns that could draw electricity from flowing blood

2 min read
Image: Fudan University/Wiley
Image: Fudan University/Wiley

To power wearable electronics, engineers have for years been tinkering with ways to generate electricity from our bodies. They’ve cooked up schemes to convert heartbeats, footsteps, and muscle motions into electricity.

Now a team from Fudan University in China has come up with a method for generating electricity from blood flow using a tiny fiber spun from carbon nanotubes. The idea is that the fiber could be implanted in a blood vessel to harvest the energy from flowing blood. They’ve presented the rudimentary concept in Angewandte Chemie, and haven’t tested the device in animals yet.

To make the 0.8-millimeter-diameter fibers, they either wrap a plastic fiber with an ordered array of carbon nanotubes, or simply twist a carbon nanotube sheet to make a yarn-like thread.

The researchers call the system a mini version of hydropower, but the principle is different. When the fiber comes in contact with salt solution, an electrical double layer builds up on the interface between immersed nanotubes and the solution, with the nanotube surface becoming negatively charged and a thin layer of the solution becoming positively charged.

As the solution flows past, negative ions in the solution and electrons drawn from the nanotubes try to balance out the electric double layer. But they don’t quite succeed: more charge builds up at the front of the flow. And this leads to a potential difference between the two ends of the fiber, generating voltage and electric current. Other teams have made nanotube-based yarns that generate electricity when twisted and stretched.

When the fiber is put in a tube that is connected on each end with a copper wire and has salty fluid flowing through it, it generates power with an efficiency of over 23 percent. This is higher than previously reported fiber-shaped energy harvesting devices, the researchers say. The electrical output is higher with longer fibers, faster-flowing liquid, and more concentrated salt solution.

A 30-centimeter-long device generates 0.04 milliwatts of power. That might be enough to power very small sensors and implants. To demonstrate an application in the body, the researchers connected three 10-cm-long fibers to a frog’s sciatic nerve. When they immersed the fiber in flowing salt solution, it generated a slight muscle contraction.

The fiber could also be woven into textiles to make power-generating clothes, the researchers say.

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This CAD Program Can Design New Organisms

Genetic engineers have a powerful new tool to write and edit DNA code

11 min read
A photo showing machinery in a lab

Foundries such as the Edinburgh Genome Foundry assemble fragments of synthetic DNA and send them to labs for testing in cells.

Edinburgh Genome Foundry, University of Edinburgh

In the next decade, medical science may finally advance cures for some of the most complex diseases that plague humanity. Many diseases are caused by mutations in the human genome, which can either be inherited from our parents (such as in cystic fibrosis), or acquired during life, such as most types of cancer. For some of these conditions, medical researchers have identified the exact mutations that lead to disease; but in many more, they're still seeking answers. And without understanding the cause of a problem, it's pretty tough to find a cure.

We believe that a key enabling technology in this quest is a computer-aided design (CAD) program for genome editing, which our organization is launching this week at the Genome Project-write (GP-write) conference.

With this CAD program, medical researchers will be able to quickly design hundreds of different genomes with any combination of mutations and send the genetic code to a company that manufactures strings of DNA. Those fragments of synthesized DNA can then be sent to a foundry for assembly, and finally to a lab where the designed genomes can be tested in cells. Based on how the cells grow, researchers can use the CAD program to iterate with a new batch of redesigned genomes, sharing data for collaborative efforts. Enabling fast redesign of thousands of variants can only be achieved through automation; at that scale, researchers just might identify the combinations of mutations that are causing genetic diseases. This is the first critical R&D step toward finding cures.

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