A synthetic material made from a protein in spider silk and laced with graphene can rapidly repair itself and form healable electrical circuits.
at the National Taiwan University and his colleagues collected silk from giant golden orb-weaver spiders (Nephila pilipes) and dissolved it in a chemical called hexafluoroisopropanol.
They dried the solution to create a thin film and used a razor blade to make a small cut in it, about 30 micrometres wide. When they added a few drops of water to the site of damage, the cut started to heal. After 20 minutes, the scar width had reduced to just 2.4 micrometres.
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鈥淭his is the first time silk materials from this spider have been shown to have self-healing ability,鈥� says Wu. 鈥淲e think adding water may make the proteins more flexible at the cut site, which helps them form networks to heal the material more quickly.鈥�
The team identified a protein called R2 as the source of this self-healing ability. The researchers modified聽E. coli bacterial cells to produce the protein, then connected the ends of thin strips of it so that they self-healed to form a ring.
Next, the researchers laced some more of the silk with graphene, allowing it to conduct electricity. They fused a layer of this modified silk inside the ring using water and connected the ring to a small circuit board with a display screen using copper wires. The system could distinguish whether it was being worn on a finger, on top of nitrile gloves or in contact with aluminium foil based on the flow of electrical current.
鈥淭he discovery of self-healing properties in [golden orb-weaver spider silk] represents a significant breakthrough in the field of self-healing biomaterials,鈥� says at Johns Hopkins University in Maryland. 鈥淭he researchers have created a new class of materials that could have a wide range of applications in fields such as biomedicine, electronics and textiles.鈥�
鈥淥ur spider silk material is easy to make, soft and flexible with a self-healing ability that could make it very useful in wearable biosensors that, for example, could monitor your health in real-time,鈥� says Wu.
bioRxiv
