When we touch something our skin feels the pressure exerted by the object, thus giving us perception of the hardness and texture of the object. Reporting in Science, a team of researchers led by Prof. Zhenan Bao from Stanford University has developed a tactile sensing system which could replicate the human sensation of touch. This artificial skin could one day allow people with prostheses to feel the sense of touch with their artificial limbs.
The system consists of a two-ply printed plastic construct, with the upper layer serving as a sensing platform, while the lower layer being a circuit for translating touch into digital signals. To enable the sensory system to feel as sensitively as the human skin, the scientists aligned carbon nanotubes of pyramidal formations throughout the surface of the upper layer plastic. Applying pressure on the plastic construct forces the nanotubes to come closer together, allowing electricity to pass through. The circuit on the lower layer subsequently translates the electrical signals into digital signals –as the pressure increases, the electrical force also increases, leading to a greater signal.
In addition, the researchers demonstrated that the digital signals could be recognized by live neuronal cells in mouse brains. Using an optogenetic approach, they translated the digital signals from the artificial skin into LED light pulses. This triggered the genetically modified brain cells to respond in correspondence to the frequencies of pulses received, indicating that the digital output generated by the artificial skin is biologically functional. In the future, Bao’s team aimed to incorporate more sensing abilities, for instance, to feel temperature and pain sensations, into the artificial electronic skin for highly functional prostheses. With these new findings, making a prosthetic limb come ‘alive’ seems closer to reality.
Study in Science: A skin-inspired organic digital mechanoreceptor…
