Researchers at MIT are working on a means for creating tattoos made of bioinks that can react to varying chemicals. As a result, they created a structure that contains living cells and adheres to the human skin. The tattoo has the ability to detect certain chemicals and light up in response.
As part of a demonstration, the researchers 3D printed a multicolored tree-shaped tattoo made of live bacteria cells mixed in with a hydrogel. Each of the different branches of the tree contains a different type of cell that each react to different chemicals. As a response to chemical stimuli, they light up to indicate the presence of whatever material they detect. To achieve this effect the researchers had to invent a new bioprinting technique that allowd them to print bio-engineered living cells.
Such a tattoo could have multiple applications. Particularly, if adapted to work with wearable sensors in hazardous environments. Another application is in engineering the cells within. If future research could allow for varying the cell types, then doctors could use the tattoos as a drug delivery method. The researchers have also noted that complex enough arrangements of these types of structures could be an integral part of creating living computers, i.e. intricate networks of cells that can communicate with each other and pass information.
Producing Wearable Responsive Technology
One of the hurdles of producing this sort of technology is finding cells that can survive the printing process. Mammalian cells are very fragile and perish quickly, so the researchers instead used bacterial ones. This was also due to how bacterial cells are easier to preserve in hydro gel.
The researchers then decided on a pluronic hydrogel mixture because of its ideal viscosity and flow through a printer nozzle. Another problem is that the tattoos require a 3D printer especially for bioprinting. The print process uses UV to cure the tattoo onto a base and then placed on the human skin.
Though this is novel research, MIT aren’t the only ones working with wearable, flexible electronics. Harvard has a project of their own, producing stretchable conductive inks. Similarly, textile producers are also making wearable, intricate and functional 3D printed products. All these products use 3D printing to create reactive technology that can in the creation of wearable tech and smart, flexible devices. Although, this project by MIT is one of the most sophisticated due to how it uses bioinks and microorganisms. It’s a leap forward for this application of additive manufacturing.