Tag Archives: tattoos

Tattoos that detect glucose levels

Temporary tattoos with a biomedical function are a popular topic and one of the latest detects glucose levels without subjecting a person with diabetes to pin pricks. From a Jan. 14, 2015 news item on ScienceDaily,

Scientists have developed the first ultra-thin, flexible device that sticks to skin like a rub-on tattoo and can detect a person’s glucose levels. The sensor, reported in a proof-of-concept study in the ACS [American Chemical Society] journal Analytical Chemistry, has the potential to eliminate finger-pricking for many people with diabetes.

A Jan. 14, 2015 ACS news release on EurekAlert, which originated the news item, describes the current approaches to testing glucose and the new painless technique,

Joseph Wang and colleagues in San Diego note that diabetes affects hundreds of millions of people worldwide. Many of these patients are instructed to monitor closely their blood glucose levels to manage the disease. But the standard way of checking glucose requires a prick to the finger to draw blood for testing. The pain associated with this technique can discourage people from keeping tabs on their glucose regularly. A glucose sensing wristband had been introduced to patients, but it caused skin irritation and was discontinued. Wang’s team wanted to find a better approach.

The researchers made a wearable, non-irritating platform that can detect glucose in the fluid just under the skin based on integrating glucose extraction and electrochemical biosensing. Preliminary testing on seven healthy volunteers showed it was able to accurately determine glucose levels. The researchers conclude that the device could potentially be used for diabetes management and for other conditions such as kidney disease.

There is a Jan. 14, 2015 University of California at San Diego news release (also on EurekAlert) describing the work in more detail,

Nanoengineers at the University of California, San Diego have tested a temporary tattoo that both extracts and measures the level of glucose in the fluid in between skin cells. …

The sensor was developed and tested by graduate student Amay Bandodkar and colleagues in Professor Joseph Wang’s laboratory at the NanoEngineering Department and the Center for Wearable Sensors at the Jacobs School of Engineering at UC San Diego. Bandodkar said this “proof-of-concept” tattoo could pave the way for the Center to explore other uses of the device, such as detecting other important metabolites in the body or delivering medicines through the skin.

At the moment, the tattoo doesn’t provide the kind of numerical readout that a patient would need to monitor his or her own glucose. But this type of readout is being developed by electrical and computer engineering researchers in the Center for Wearable Sensors. “The readout instrument will also eventually have Bluetooth capabilities to send this information directly to the patient’s doctor in real-time or store data in the cloud,” said Bandodkar.

The research team is also working on ways to make the tattoo last longer while keeping its overall cost down, he noted. “Presently the tattoo sensor can easily survive for a day. These are extremely inexpensive—a few cents—and hence can be replaced without much financial burden on the patient.”

The Center “envisions using these glucose tattoo sensors to continuously monitor glucose levels of large populations as a function of their dietary habits,” Bandodkar said. Data from this wider population could help researchers learn more about the causes and potential prevention of diabetes, which affects hundreds of millions of people and is one of the leading causes of death and disability worldwide.

People with diabetes often must test their glucose levels multiple times per day, using devices that use a tiny needle to extract a small blood sample from a fingertip. Patients who avoid this testing because they find it unpleasant or difficult to perform are at a higher risk for poor health, so researchers have been searching for less invasive ways to monitor glucose.

In their report in the journal Analytical Chemistry, Wang and his co-workers describe their flexible device, which consists of carefully patterned electrodes printed on temporary tattoo paper. A very mild electrical current applied to the skin for 10 minutes forces sodium ions in the fluid between skin cells to migrate toward the tattoo’s electrodes. These ions carry glucose molecules that are also found in the fluid. A sensor built into the tattoo then measures the strength of the electrical charge produced by the glucose to determine a person’s overall glucose levels.

“The concentration of glucose extracted by the non-invasive tattoo device is almost hundred times lower than the corresponding level in the human blood,” Bandodkar explained. “Thus we had to develop a highly sensitive glucose sensor that could detect such low levels of glucose with high selectivity.”

A similar device called GlucoWatch from Cygnus Inc. was marketed in 2002, but the device was discontinued because it caused skin irritation, the UC San Diego researchers note. Their proof-of-concept tattoo sensor avoids this irritation by using a lower electrical current to extract the glucose.

Wang and colleagues applied the tattoo to seven men and women between the ages of 20 and 40 with no history of diabetes. None of the volunteers reported feeling discomfort during the tattoo test, and only a few people reported feeling a mild tingling in the first 10 seconds of the test.

To test how well the tattoo picked up the spike in glucose levels after a meal, the volunteers ate a carb-rich meal of a sandwich and soda in the lab. The device performed just as well at detecting this glucose spike as a traditional finger-stick monitor.

The researchers say the device could be used to measure other important chemicals such as lactate, a metabolite analyzed in athletes to monitor their fitness. The tattoo might also someday be used to test how well a medication is working by monitoring certain protein products in the intercellular fluid, or to detect alcohol or illegal drug consumption.

This reminds me a little of the Google moonshot project concerning health diagnostics. Announced in Oct. 2014, that project involved swallowing a pill containing nanoparticles that would circulate through your body monitoring your health and recongregating at your wrist so a band worn there could display your health status (Oct. 30, 2014 article by Signe Brewster for GigaOm). Experts welcomed the funding while warning the expectations seemed unrealistic given the current state of research and technology. This temporary tattoo seems much better grounded in terms of the technology used and achievable results.

Here’s a link to and a citation for the paper,

Tattoo-Based Noninvasive Glucose Monitoring: A Proof-of-Concept Study by Amay J. Bandodkar, Wenzhao Jia, Ceren Yardımcı, Xuan Wang, Julian Ramirez, and Joseph Wang. Anal. Chem., 2015, 87 (1), pp 394–398 DOI: 10.1021/ac504300n Publication Date (Web): December 12, 2014

Copyright © 2014 American Chemical Society

This appears to be an open access paper.

My latest posting posting on medical tattoos (prior to this) is an Aug. 13, 2014 post about a wearable biobattery.

University of Toronto’s (Canada) smiley face tattoo/sensor

Researchers at the University of Toronto have created a medical sensor that can be applied to the skin like a temporary tattoo.

University of Toronto Scarborough student Vinci Hung helped create the smiley face sensor shown here in the box at upper right (photo by Ken Jones)

The Dec. 3, 2012 news item on ScienceDaily notes,

A medical sensor that attaches to the skin like a temporary tattoo could make it easier for doctors to detect metabolic problems in patients and for coaches to fine-tune athletes’ training routines. And the entire sensor comes in a thin, flexible package shaped like a smiley face.

“We wanted a design that could conceal the electrodes,” says Vinci Hung, a PhD candidate in the Department of Physical & Environmental Sciences at UTSC [University of Toronto Scarborough], who helped create the new sensor. “We also wanted to showcase the variety of designs that can be accomplished with this fabrication technique.”

The Dec. 3, 2012 University of Toronto news release by Kurt Kleiner, which originated the news item, provides details about how the sensor/tattoo is fabricated and how it functions on the skin,

The new tattoo-based solid-contact ion-selective electrode (ISE) is made using standard screen printing techniques and commercially available transfer tattoo paper, the same kind of paper that usually carries tattoos of Spiderman or Disney princesses. In the case of the smiley face sensor, the “eyes” function as the working and reference electrodes, and the “ears” are contacts to which a measurement device can connect.

The sensor Hung helped make can detect changes in the skin’s pH levels in response to metabolic stress from exertion. Similar devices, called ion-selective electrodes (ISEs), are already used by medical researchers and athletic trainers. They can give clues to underlying metabolic diseases such as Addison’s disease, or simply signal whether an athlete is fatigued or dehydrated during training. The devices are also useful in the cosmetics industry for monitoring skin secretions.

But existing devices can be bulky, or hard to keep adhered to sweating skin. The new tattoo-based sensor stayed in place during tests, and continued to work even when the people wearing them were exercising and sweating extensively. The tattoos were applied in a similar way to regular transfer tattoos, right down to using a paper towel soaked in warm water to remove the base paper.

To make the sensors, Hung and her colleagues used a standard screen printer to lay down consecutive layers of silver, carbon fibre-modified carbon and insulator inks, followed by electropolymerization of aniline to complete the sensing surface.

By using different sensing materials, the tattoos can also be modified to detect other components of sweat, such as sodium, potassium or magnesium, all of which are of potential interest to researchers in medicine and cosmetology.

You can find the reserchers’ article in the Royal Society’s Analyst journal,

Tattoo-based potentiometric ion-selective sensors for epidermal pH monitoring
Amay J. Bandodkar ,  Vinci W. S. Hung ,  Wenzhao Jia ,  Gabriela Valdés-Ramírez ,  Joshua R. Windmiller ,  Alexandra G. Martinez ,  Julian Ramírez ,  Garrett Chan ,  Kagan Kerman and Joseph Wang in Analyst, 2013,138, 123-128 DOI: 10.1039/C2AN36422K

The article is open access but you do need to register for a free account with the Royal Society’s RSC [ublishing platform.

Skin as art and as haptic device

I stumbled across an essay, Nano-Bio-Info-Cogno Skin by Natasha Vita-More on the IEET (Institute for Ethics & Emerging Technologies) website newly republished on Mar. 19, 2012. (The essay was originally published Jan. 19, 2009 on the Nanotechnology Now website.) No matter the date, it has proved quite timely in light of Nokia’s (Finnish telephone company) application to patent magnetic tattoos. From the Vibrating tattoo alerts patent filed by Nokia in US  March 20, 2012 story on the BBC News online,

Vibrating magnetic tattoos may one day be used to alert mobile phone users to phone calls and text messages if Nokia follows up a patent application.

The Finnish company has described the idea in a filing to the US Patent and Trademark Office.

It describes tattooing, stamping or spraying “ferromagnetic” material onto a user’s skin and then pairing it with a mobile device.

It suggests different vibrations could be used to create a range of alerts.

The application is dated March 15, 2012. From United States Patent Application no. 20120062371 (abstract),

1. An apparatus comprising: a material attachable to skin, the material capable of detecting a magnetic field and transferring a perceivable stimulus to the skin, wherein the perceivable stimulus relates to the magnetic field.

2. An apparatus according to claim 1, wherein the material comprises at least one of a visible image, invisible image, invisible tattoo, visible tattoo, visible marking, invisible marking, visible marker, visible sign, invisible sign, visible label, invisible label, visible symbol, invisible symbol, visible badge and invisible badge.

3. An apparatus according to claim 1, wherein the perceivable stimulus comprises vibration.

4. An apparatus according to claim 1, wherein the magnetic field originates from an electronic device and relates to digital content stored in the electronic device.

5. An apparatus according to claim 1, wherein the perceivable stimulus is related to the magnetic field.

6. An apparatus according to claim 1, wherein the perceivable stimulus relates to a time variation of at least one of a magnetic field pulse, height, width and period.

7. An apparatus according to claim 1, wherein the magnetic field originates from a remote source.

8. An apparatus according to claim 7, wherein the perceivable stimulus relates to digital content of the remote source.

If you want the full listing, there are 13 more claims for a total of 21 listed in the abstract. Nokia’s initial plans are to create a material that you’d wear, the notion of tattoos arises later in the application according to Vlad Bobleanta in his March 15, 2012 article for unwiredview.com. He describes the potential tattoos is some detail,

The tattoo would be applied using ferromagnetic inks. The ink material would first be exposed to high temperatures to demagnetize it. Then the tattoo would be applied. You’ll apparently be able to choose the actual image you want as the tattoo. The procedure is identical to that of getting a ‘normal’ tattoo – only the ink is special.

After the tattoo has been applied, you’ll need to magnetize it. That means bringing the tattooed area in the close proximity of an external magnet, and going “several times over this magnet to magnetize the image material again”. The tattoo will then have enhanced sensitivity towards external alternating magnet fields, and will basically function the same way the aforementioned material attached to your skin did. Only in a more permanent fashion, so to speak.

I suggest reading Bobleanta’s article as he includes diagrams of the proposed tattoo, fabric, and fingernail applications. Yes, this could be attached to your fingernails.

Getting back to Vita-More’s essay, she was exploring the integration of nanotechnology, biotechnology, cognitive and neuro sciences (nano-bio-info-cogno- or NBIC) as applied to skin (from the essay),

NBIC is a far cry from the biological touch, taste and smell of our skin because it suggests a cold, mechanical and invasive integration. While the cognitive and neuro sciences are a bit more familiar from a biological viewpoint, they too suggest tampering with our thoughts and probing our privacy. Nonetheless, the enhancement of our human skin is not only lifesaving; it offers new textures, sensations and smells which will have their own sensorial capabilities. [emphasis mine]

New sensorial capabilities certainly evokes Nokia’s proposed magnetic tattoo. She also comments from an artist’s perspective,

What does this mean for designers and media artists? From the perspective of my own artistic practice, it means that it is natural that humans integrate with other types of organisms, that we will evolve with other types of systems, and that this evolution is essential for our future.

The idea of fusing skin with technology is not new as you can see from Vita-More’s essay and countless science fiction stories, as well, there’s research of this kind being done globally. For example, there’s research on electronic tattoos as I noted in my Aug. 12, 2011 posting (and you can find more references elsewhere online). However, these magnetic tattoos represent the first time I’ve seen interest from a commercial enterprise.