Prosthetic limbs have come a long way in the past 25 years. People who lose an arm or a leg can now be fitted with sophisticated prostheses that interface with the nervous system directly, which read the brain signals related to planning movements and translate them into commands for the device, enabling the user to control their replacement appendage by merely thinking about it.
Neurally-controlled prosthetic devices can vastly improve quality of life for amputees and paralysed patients, by helping them to move and regain at least some of their independence.
Ref: A skin-inspired organic digital mechanoreceptor. Science (16 October 2015) | DOI: 10.1126/science.aaa9306
Human skin relies on cutaneous receptors that output digital signals for tactile sensing in which the intensity of stimulation is converted to a series of voltage pulses. We present a power-efficient skin-inspired mechanoreceptor with a flexible organic transistor circuit that transduces pressure into digital frequency signals directly. The output frequency ranges between 0 and 200 hertz, with a sublinear response to increasing force stimuli that mimics slow-adapting skin mechanoreceptors. The output of the sensors was further used to stimulate optogenetically engineered mouse somatosensory neurons of mouse cortex in vitro, achieving stimulated pulses in accordance with pressure levels. This work represents a step toward the design and use of large-area organic electronic skins with neural-integrated touch feedback for replacement limbs.