This is one in a series presenting news on technology and innovation, made possible with generous support from the Lemelson Foundation.
One day, bandages could speed healing by zapping wounds with gentle bursts of electricity. They wouldn’t even need a battery pack. A patient’s own body movements would power the device. And such a system may not be that far off. Researchers have already produced a working prototype.
“We thought it might work, but we didn’t know how good it would be,” says Xudong Wang. “Then we saw the result and thought, ‘Wow! That’s really fascinating.” Wang is a materials scientist at the University of Wisconsin–Madison. He leads the group working on this new bandage.
His team has been developing a nanogenerator for many years. It uses body movements to generate electricity. These engineers were hoping to use the device to power wearable electronics. Then they realized it might be even more useful as medicine.
Scientists have known for decades that electricity can stimulate wounds to heal. For instance, electricity fosters cells on the skin’s surface to grow. This “electrotherapy” has relied on bulky devices that need a power source. That’s why it’s usually used only in hospitals for treating serious injuries.
The Wisconsin engineers have now created a bandage with small electrodes. “Our device is very simple,” Wang says. “It’s a flexible, wearable device.” Its electrodes connect to nanogenerators inside the bandage. Those nanogenerators turn movement into electricity. That power then travels through the electrodes into the skin as mild electrical pulses.
Wang’s group tested the bandage on more than 10 injured rats. As these “patients” breathed in and out, their wounds received tiny electrical shocks. Another group of injured rats served as controls. That means they received no treatment.
The wounds of rats in the control group took about two weeks to heal. Those on rats treated with the electrified bandages healed in just three days.
Wang’s team described its new findings online November 29, 2018 in the journal ACS Nano.
No pain, big gain
The new bandage not only is simple, flexible and wearable, but also gentle. Compared to the electrical stimulation delivered by hospital machines, these bandage gives a much smaller electrical pulse. That should help protect healthy tissue from being damaged by the zaps. In fact, Wang says: “Usually, you don’t even feel it.”
This is “a good first step toward an interesting and potentially promising approach to wound care,” says Tyler Ray. He says you might think of it as a “smart Band-Aid.” Ray is a mechanical engineer at the University of Hawaii at Manoa who had no role in creating the new system. He said he’d like to see the bandage tested on larger animals or people, and lots of them.
Wearable technology has been around for several years. Usually these are fairly stiff devices, like a Fitbit, Ray notes. Researchers across many fields are now working on building soft, flexible devices for people to wear on their skin.
Wang next wants to design a nanogenerator that’s even more sensitive. His goal is to build one that can generate electricity from the tiniest movements — like blood moving under your skin. That way, the bandage could be powered by something as small as someone’s pulse.
battery A device that can convert chemical energy into electrical energy.
cell The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall.
control A part of an experiment where there is no change from normal conditions. The control is essential to scientific experiments. It shows that any new effect is likely due only to the part of the test that a researcher has altered. For example, if scientists were testing different types of fertilizer in a garden, they would want one section of it to remain unfertilized, as the control. Its area would show how plants in this garden grow under normal conditions. And that gives scientists something against which they can compare their experimental data.
electricity A flow of charge, usually from the movement of negatively charged particles, called electrons.
electrical stimulation A type of medical or therapeutic treatment provided by the deliberate and precisely placed delivery of electrical shocks to the body. This treatment is most often used on the skin or parts of the brain.
electrode A device that conducts electricity and is used to make contact with non-metal part of an electrical circuit, or that contacts something through which an electrical signal moves. (in electronics) Part of a semiconductor device (such as a transistor) that either releases or collects electrons or holes, or that can control their movement.
electronics Devices that are powered by electricity but whose properties are controlled by the semiconductors or other circuitry that channel or gate the movement of electric charges.
electrotherapy The delivery of small electrical pulses with the aim of healing or strengthening parts of the body.
engineer A person who uses science to solve problems. As a verb, to engineer means to design a device, material or process that will solve some problem or unmet need.
field An area of study, as in: Her field of research was biology.
journal (in science) A publication in which scientists share their research findings with experts (and sometimes even the public). Some journals publish papers from all fields of science, technology, engineering and math, while others are specific to a single subject. The best journals are peer-reviewed: They send all submitted articles to outside experts to be read and critiqued. The goal, here, is to prevent the publication of mistakes, fraud or sloppy work.
materials science The study of how the atomic and molecular structure of a material is related to its overall properties. Materials scientists can design new materials or analyze existing ones. Their analyses of a material’s overall properties (such as density, strength and melting point) can help engineers and other researchers select materials that are best suited to a new application. A scientist who works in this field is known as a materials scientist.
mechanical engineer Someone trained in a research field that uses physics to study motion and the properties of materials to design, build and/or test devices.
nano A prefix indicating a billionth. In the metric system of measurements, it’s often used as an abbreviation to refer to objects that are a billionth of a meter long or in diameter.
prototype A first or early model of some device, system or product that still needs to be perfected.
shock (in biology and medicine) A potentially fatal bodily reaction to a variety of conditions, including illness, injury, blood loss and lack of adequate water, usually characterized by marked loss of blood pressure, decreased blood circulation and inadequate blood flow to the tissues.
technology The application of scientific knowledge for practical purposes, especially in industry — or the devices, processes and systems that result from those efforts.
tissue Made of cells, it is any of the distinct types of materials that make up animals, plants or fungi. Cells within a tissue work as a unit to perform a particular function in living organisms. Different organs of the human body, for instance, often are made from many different types of tissues.