Painting circuits on skin

Chemistry World ^ | 22 March 2013 | Melissae Fellet

[neverdem]

A-ok. Yang Yu models the new liquid metal electrodes holding two batteries to power LEDs connected by a circuit © Jing Liu

Painting a patient’s skin with a liquid metal ink could make heart monitoring much less painful and even let doctors keep an eye on a whole range of vital signs. Scientists used the ink to draw electrodes on to the skin, which could also be used to monitor muscle or brain activity.¹

Currently, doctors monitor a patient’s heartbeat by detecting the muscle’s electrical signals using electrocardiography (ECG). Disposable electrodes attach to a patient’s chest using a sticky paper backing. A conductive gel between the skin and the electrode helps transmit the electrical signals to a rigid metal button that connects to the monitor. But these electrodes are so sticky that pulling them off can be painful.

Flexible electrodes that conform to the body like a tattoo² are more comfortable than traditional ECG electrodes. Jing Liu, at Tsinghua University in China, and colleagues thought that another way to make flexible, comfortable electrodes would be to paint the electrodes directly on to the skin using a metal ink.

The researchers tinkered with the formulation of a gallium-based liquid metal ink, adding 0.3% gallium oxide. This made the ink stick to skin like wet paint, instead of rolling around like a drop of water.

The researchers used the ink to paint electrodes for an ECG on a student volunteer, Yang Yu. They connected the electrodes to a wireless module that detected the electrical signals from Yu’s heart and transmitted the information to a mobile phone for display. The heartbeat recorded by the liquid metal electrodes was comparable to that recorded using standard rigid button electrodes.

These liquid metal electrodes can be easily removed by washing with medical alcohol, Liu says. The ink solidifies as the alcohol evaporates, making it easy to peel off electrodes or circuits.

Liu envisions using liquid metal electrodes for easy point-of-care biomedical monitoring, perhaps detecting weak signals from the brain or muscles. The ink might even be useful to draw a circuit over the whole body for monitoring, he adds.

Chemical engineer Michael Dickey, of North Carolina State University, US, says the direct contact between the skin and the liquid metal electrodes is ideal for electrical performance. However, he wonders about the potential toxicity of the metal ink.

Liu agrees that more long-term tests are needed to ensure the safety and efficacy of the liquid metal ink. However, there are some indications that gallium-based materials could be safe for biomedical applications. A gallium alloy has been used in dentistry, and radioactive gallium-67 is used for medical imaging.

References

1 Y Yu et al, PLoS One, 2013, DOI: 10.1371/journal.pone.0058771

2 D-H Kim et al, Science , 2011, 333, 6044 (DOI: 10.1126/science.1206157)

[neverdem]

The PLoS One article discusses using these electrodes with mobile phones for doing a electrocardiogram. With enough memory you could obviate Holter monitors when abnormal rhythms are suspected.

[WCH]

Like these painted circuits on Ms. Upton?

[al baby]

Seems to have excellent amount of mammeries

[LibWhacker]

Feeling is believing.

[Boiling point]

Hmmm, counter measure against taser?

[EEGator]

Excellent way to work that in...kudos.

[neverdem]

LOL!

[Vince Ferrer]

Something tells me you have had that for a while, waiting for an opportunity to work that in.

These will be more than just medical devices, it would be easy to print an antennae onto skin, RFID chip type devices, sensory circuits. Since we can now store information in DNA, we can probably use our own bloodstream as a disk drive, with an interface tattooed onto our skin.

[WCH]

THX

She’s my new favorite hottie.

[WCH]

After all, we are the ‘blueprint’ from which the modern computer came.

[EEGator]

You’ve made a good choice.

[WCH]

Sorry for the off-topic. :~) 3