Graphene is a wonder material, with a wide array of dazzling properties, and according to a new report in the journal Open Physics, researchers have now developed graphene that is capable of healing itself. The discovery could be a massive breakthrough for medical technology, robotics and countless other fields.
Graphene is a sheet of pure carbon atoms so thin, many consider it to be two-dimensional. The world’s strongest material and capable of conducting electricity, graphene has rapidly become one of the most promising nanomaterials among researchers.
The new report described the incredible and previously-undocumented ability of graphene to heal itself, an ability which could result in the advancement of flexible sensors that imitate the self-healing qualities of our skin.
The biggest organ in the human body, skin's ability to heal has fascinated scientists who, until now, have been unable to copy this ability. As a result of manipulation and incidental scratches, artificial skin found in robots is very vulnerable to breaks and fissures. The study provides a unique solution in which a sub-nano sensor uses graphene to detect a crack once it starts, and even after it has spread a certain distance. This technology could rapidly become practical in a range of applications, the study team said.
The scientists, from Hyderabad, India, said they were able to record the self-healing of breaks in graphene without any outside stimulus and at room temperature. The outcomes showed that self-healing took place by impromptu recombination of the hanging atomic bonds whenever it occurred, within a certain crack width.
In the study, scientists put graphene with various flaws like pre-existing gaps and obtuse cracks under pressure until they fractured. Oddly enough, as soon as the load was pulled back, the graphene began to heal and the self-healing prolonged, no matter the nature of pre-existing defects in the graphene sheet. Regardless of what length of the crack, they all healed, given that the crack opening distance was within 0.3 to 0.5 nanometres for both a flawless sheet and a sheet with flaws.
This tantalizing new discovery comes after researchers showed in November that artificial skin could be engineered to deliver the sense of touch. The scientists behind that discovery said they could transmit a touching sensation as an electric pulse to sensory brain cells in mice.
The elastic, flexible skin developed by the team is manufactured from a man-made rubber that has been created to have tiny pyramid-like structures that make it particularly responsive to pressure, like springs on a tiny mattress. The researchers added carbon nanotubes to their pressure-sensitive rubber, which allowed the device to generate a series of electrical pulses. The pulses were then shipped to mouse brain tissue in a way that replicated how human receptors send sensations to the brain.
To evaluate if the skin could produce useful electric pulses, the researchers connected the man-made skin to a blue LED light. When the skin was contacted, the sensor sent electricity to the LED, which then lit up. The greater the stress on the skin, the quicker the LED flashed.
Researchers then added channelrhodopsin, a unique protein that makes brain cells respond to blue light, to the mouse brain cells responsible for sensation. This made the LED work like receptor cells in the skin: When the light lit up, it delivered a signal to the brain cells that the synthetic skin had been contacted.
The experiment revealed that the synthetic skin, when contacted, was capable of sending signals to the brain in the same manner as genuine skin signalling the brain when being touched.