Hasta La Gadget!

Video: Stanford University News Service

Making artificial limbs that can perform gross motor functions is relatively easy. Fine motor actions are harder, and wiring the limbs into the nervous system is harder still. But researchers at Berkeley and Stanford are crossing the real frontier: making artificial skin that can touch and feel.

Research teams at Berkeley and Stanford recently announced breakthroughs in producing highly touch-sensitive artificial skin. In both cases, an extremely thin layer of plastic or rubber is bonded to electronic elements arranged in micropatterns, so the skin can retain flexibility and elasticity while still transmitting a strong signal. The papers appear in an forthcoming issue of the journal Nature Materials.

At Berkeley, the team used germanium-silicon nanowires, which they compare to microscopic “hairs” on the filmy plastic skin. The Stanford team paired electrodes in a pyramid pattern, which communicate through a thin rubber film (total thickness of the artificial skin, including the rubber layer and both electrodes: less than one millimeter). They also created a flexible transistor, again to retain elasticity.

The density and sensitivity of the electrical transmitters allows the skin to detect and transmit extremely precise patterns and delicate pressure — essential for activities such as typing, handling coins, cracking an egg, loading and unloading dishes, or anything that requires a gentle touch rather than sheer mechanical force.

The sensors could also be used in nonprosthetic applications. Benjamin Tee, a Stanford graduate student, notes that an automobile’s steering wheel could be fitted with pressure-sensitive sensors that could detect whether or not a drunk or sleeping driver’s hands had slipped from the wheel.

It’s difficult to tell at this point which team’s approach might be better suited to particular applications. The Berkeley teams touts its skin’s low energy use, the Stanford team its skin’s extreme sensitivity.

There’s also a sobering link between the two projects. Both Berkeley’s and Stanford’s research were indirectly supported by the Department of Defense — Berkeley’s by Darpa, and Stanford’s by the Office of Naval Research. The past decade has seen tremendous advances in artificial limb technology, due in no small part to the number of veterans returning from Iraq or Afghanistan after losing arms or legs, or with major burns.

This in turn is partly a function of the previous decade’s advances in body armor, which have saved lives at the costs of limbs. Let’s hope that as these wars finally end, our desire to continue to improve the lives of everyone with limb differences continues.

Sources:

• “Engineers make artificial skin out of nanowires,” Berkeley News
• “Stanford researchers’ new high-sensitivity electronic skin can feel a fly’s footsteps,” Stanford Report

See Also:

• New Bionic Arms Are Strong, Sensitive, Human-Friendly
• Prosthetic Limb Research Could Lead To Bionic Athletes, Gadgets
• Pentagon Plan to Regrow Limbs: Phase One, Complete
• Salamander Discovery Could Lead to Human Limb Regeneration
• Army Aims for New Six Million Dollar Man
• Wired 13.02: The Painful Truth
• Dean Kamen's Robot Arm Grabs More Publicity