Smart Tattoos: A Deep Dive

I recently wrote an article titled “The “Next Big Thing” in Technology : 20 Inventions That Will Change the World”, which was read more than 21,000 times in August. Interestingly, out of the 20 innovations described, “Smart Tattoos” is the one that generated the most excitement. 

As such, I’ve gone more in depth on the technology, identifying use cases and drawbacks to see if there really are opportunities for this idea to be truly transformative. It might otherwise be one of those technologies quickly abandoned for lack of technical breakthroughs or customer needs. During my research, I had the chance to speak to Jonathan Lester, Principal Electrical Engineer at Microsoft Research (and all-around dream-boat). His quotes are peppered throughout this article.

What’s a Smart Tattoo?

In short, “Smart Tattoos” (aka “epidermal electronic systems”, but that’s less sexy) are personalized circuits, adhesives, conductors and microprocessors that can be “glued” onto the skin. They can then send signals to devices via touch, and allow its users to interact with the world around them. They can also be used to monitor vitals, or react to external stimuli such as temperature. If that sounds cyberpunk AF, trust your instincts.

Put simply, it is a logical extension of the personalisation trend, the wearables trend, and the healthtech trend.

In their current form, Smart Tattoos would be temporary on the skin. They can however last much longer on prosthetics or clothes, and have the benefit of being cheap compared to a lot of the hardware available out there.

Why is it a “Next Big Thing”?

In 2011, Nature published a paper which discussed epidermal electronic systems / electronic skin. It required no power, could fit to the skin without any adhesive, and lasted up to 24 hours. The authors highlighted the many uses of such a technology, especially when it came to monitoring the brain, the heart and/or muscles, which can be hard to get to with “normal” hardware.

Though concrete medical use cases have been sparse since then due to technical and material challenges, research is very much ongoing, and has even produced some (small) initial commercial successes. In 2018, for example, L’Oréal introduced a wearable sensor named My UV Patch, which tracks UV exposure on the skin (one might assume that the end goal was to sell more La Roche Posay sunscreen).

If you’re thinking that this does not really sound like a tattoo, you’d be right. It’s not. The technology may remain the same, but the major difference between a (health)tech “wearable” and a tattoo is that a tattoo is personalised and fulfills an aesthetic purpose. According to Jonathan, a smart tattoo should allow anyone with access to a craft store, easy-to-master graphic design software and inexpensive electronics to create temporary tattoos with a wide variety of functions (skipping songs, turning on the coffee machine, ordering a drone strike…) :

“This is about getting people interested in controlling their technologies. The smart tattoos project is framed around giving people the tools to do cool things on their bodies and be able to personalise their electronics, make them reflect their own personalities.”

This concept is revolutionary in many ways. Most people are merely consumers of technology, and have no control over its design. When Apple designs a smart watch, AirPods or an iPhone, customers have no choice but to buy and use it as it is presented to them (that’s how business works, after all). But Smart Tattoos can give customers a sense of control over technology : not only do they allow the design of the “product” to be personalised, but the same can also be said about its functionalities ! 

Though the technology is still looking for its killer application, it is only a matter of time before it is found: making a concept widely available and easily usable means that it is possible to crowd-source innovation. This democratisation is a brilliant move by Microsoft : deploying an MVP (minimum viable product) and getting the public or partners to experiment and play with it multiplies the chances of a breakthrough that can then be commercialised at scale. 

Are Smart Tattoos dangerous ?

It’s really hard to make Smart Tattoos that are safe, robust and that can last for more than a couple of days. 

The main challenge comes from the fact that putting anything on the body means that it has to be bio-compatible. That rules out many materials that people are allergic to, as well as anything that could cause irritation over a long period of time. Microsoft Research originally started the Smart Tattoo project with the idea of patterning gold leaves onto adhesives and then sticking it onto people’s skin, and graphene tests have also been done. It is however difficult to highlight the democratising features of a technology when it is composed of rare metals. 

Skin also experiences a lot of different forces throughout the day. Depending on where the tattoo is located, it could stay there and be fine, or will be gone 3 hours later because you put your jacket on, taking part of your skin with it in the process (ouch). As such, putting the tattoo on any surface that you can get caught on the edge of something is out of the question. Ay, there’s the rub: we’re trying to keep something on the skin so that it stays there for a long period of time, but can’t stick it so hard that it essentially becomes impossible to remove.

Additional issues include the fact that skin stretches in many different dimensions, that humans sweat A LOT, that we like to put creams on ourselves, that skin changes dramatically with age (older people can’t put on band-aids without running the risk of their skin ripping when taking it off)… As Jonathan mentioned, one of the bigger challenges might also be the fact that skin regenerates : 

You have this fundamental issue where you’re trying to bond to a surface that every two weeks is regenerated.

The list of challenges really does go on. Researchers must ask themselves: what skin are we designing for, who is going to be wearing it, how long are they going to be wearing it… those issues get pretty complex pretty quickly.

This is why fashion has also seen some use for this technology : it’s easier to work fabric than skin. Fabrics don’t stretch nearly as much as skin does, so the conductors don’t break as easily. It’s also a little bit more forgiving in terms of application : it is possible to take a bit of fabric, push really hard and get that tattoo onto the material. Furthermore, researchers can use certain adhesives on fabric that they would not be able to use on skin.

On fabric you can be a little bit more industrial in your choice of materials.

Some issues nevertheless stay the same : After some number of re-uses, the circuits are going to degrade or start peeling, one way or another. We’re still far from iron-on stickers that will last for years. Real uses are nevertheless flourishing. At New York’s 2017 Fashion Week, for example, models donned DuoSkin tattoos that transmitted information about the garments to audience members’ smart phones. 

Why am I not wearing a Smart Tattoo right now ?

There is a design aspect and a fabrication aspect in addition to the materials aspect. Beyond purely technical issues, it’s difficult to give the public the tools to do Smart Tattoos something themselves (which is the ultimate goal). There is a reason people don’t tattoo themselves.

The smarty-pants over at Microsoft can make something with a multi-layer structure, with various technologies and patterns to make really small lines that are really compact, making a wide variety of functionalities possibles. But the average Joe is not a Microsoft smarty-pant and does not have a lab at their disposal. The average Joe can draw lines and cut out large shapes, but that’s pretty much it, which limits the number of traces, and by extension the number of possible functionalities created. 

You have got to work with the skill sets that people have today…

That should not deter us : Jonathan and his team organised workshops that showed how far we can go even with comparatively primitive tools.

In theory, you just need some glue, and something that conducts electricity and does whatever sensing you want, and you need a way to protect that.

They had users take a few sheets material and had them cut it by hand. They then took some tattoo paper and printed the desired patterns onto it. They then put this tattoo layer on top of another electrical layer with some LEDs, ending up with a dragon that has light-up eyes, its spine lights up… Those are things that people seem to really enjoy. 

As mentioned above, it is also possible to make even basic tattoos interactive by incorporating some buttons (you press this and it does that), and interact with the world around us. Buttons are really easy, so Jonathan and his team did some demos involving keyboards, for example. By pressing a smart tattoo button, I could also answer the phone, turn up the volume, skip tracks... There are even some simple musical applications, that are really easy for people to pick up. This may not mean much for someone without a disability, but anyone with ALS will tell you that being able to play the drums (for example) could be a transformative experience. 

The technology is about you being able to say “I don’t know you but I saw this thing and I want to try it”, taking it and then doing something on your own and being able to own it and do it from start to finish.

What’s the next step to democratise Smart Tattoos ?

Microsoft Research is working on new materials with a handful of partners, and is in the process of testing and refining them. The aim is to find partners who could work with the labs and advise on the best materials over the long term.

The smart tattoo concept is indeed still leading to a lot of learning and discoveries, pushing it forward and making the technology more democratised. Yet, only when the basic components are widely available will it draw material scientists, chemists, physical designers and mechanical engineers who will make that one breakthrough that unlocks the whole ecosystem. As of today, we’re still nowhere close to where it needs to be for a consumer device.

Jonathan is hoping to soon get to a point where we can get the material made, come up with some simple use cases, see if there is a market, and build on user feedback. “Getting it out to the world and letting people play around with it and come up with the next amazing ideas”, as he says. 

Indeed, given the current state tech, Smart Tattoos might just be what we need to escape the clutch of technological monopolies, and give some power of innovation back to the masses. In many ways, this is a technology born out of necessity, as many things are nowadays. 

Who knows where it will take us next ? 

This article was originally posted on my blog, The Pourquoi Pas. Come say hi!