It may seem like the height of bling, but a new technique for tattooing gold on living tissue is a step toward integrating human cells with electronic devices.
Using a manufacturing technique called nanoimprint lithography, scientists printed living mouse embryo fibroblast cells with patterns of gold nanodots and nanowires. According to them, this is an important first step towards adding more complex circuits.
And it’s not even just because cyborgs are cool. According to the scientists who developed it, led by engineer David Gracias of Johns Hopkins University, the technique could have incredible health applications.
“If you imagine where all this will take us in the future, we would like to have sensors that can remotely monitor and control the state of individual cells and the environment surrounding those cells in real time,” says Gracias.
“If we had technologies to track the health of single cells, we might be able to diagnose and treat diseases much earlier and not wait for the whole organ to be damaged.”
Engineers have been looking for a way to integrate electronics into human biology for some time, but there are significant hurdles. One of the biggest obstacles is the incompatibility of living tissue with the manufacturing techniques used to build electronics.
While there are ways to make objects small and flexible, they often use harsh chemicals, high temperatures, or vacuums that destroy living tissue or soft water-based materials.
Gracias and his team based their technique on nano-imprint lithography, which is pretty much what it sounds like: using a stamp to imprint nanoscale patterns into a material. The material here is gold, but that’s only the first step in the process. Once the pattern has been created, it must be transferred and adhered to living tissue.
The researchers first printed their nanoscale gold on a polymer-coated silicon wafer. Then the polymer was dissolved so that the pattern could be transferred to thin films of glass, where it was treated with a biological compound called cysteamine and covered with a hydrogel.
Then the pattern was removed from the glass and treated with gelatin, before being transferred to a fibroblast cell. Eventually the hydrogel was dissolved. The cysteamine and gelatin helped the gold bind to the cell, where it stayed and moved with the cell for the next 16 hours.
They used the same technique to attach networks of gold nanowires to ex-vivo rat brains. But the fibroblasts, they say, represent the most interesting result.
“We have shown that we can attach complex nanopatterns to living cells, while ensuring that the cell does not die,” says Gracias.
“The fact that cells can live and move with tattoos is a very important finding, because there is often significant incompatibility between living cells and the methods engineers use to make electronic components.”
Since nanoscale lithography is relatively simple and inexpensive, this work represents a way forward for developing more complex electronic components such as electrodes, antennas and circuits, to be integrated not only with living tissue, but also with hydrogels and other soft materials incompatible with harder manufacturing methods.
“We hope that this nanostructuring process, combined with various classes of materials and standard microfabrication techniques such as photolithography and electron beam lithography,” the researchers write, “will open up opportunities for the development of novel culture substrates cells, biohybrid materials, bionic devices and biosensors.”
The research has been published in nano letters.
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