INNOVATION
BUSINESS
GADGETRY
BRIGHT IDEAS
M
ind-controlledprostheticsmay seem like somethingout of
sciencefiction,butthey’verecentlybecomeagroundbreaking,
game-changingreality.Whilebionichandshaveallowedamputees
to,say,playchessorholdacupof tea,theyhaven’tmanagedtoclear
onemajorhurdle:restoring thesenseof touch.But lastDecember,
Dae-HyeongKim,oftheSchoolofChemicalandBiologicalEngi-
neering at SeoulNationalUniversity,andhis colleagues unveiled
a new “smart”artificial skin for prosthetics in the journal
Nature
Communications
.Equippedwith integratedheatingelements that
emitwarmth likea real hand (and thuskeep it from feeling likea
cold slab of rubber), the ultra-flexible,ultra-sensitivematerial is
composedofhundredsofmicroscopicsensors thatwill eventually
allow theuser to“feel”temperature,moistureandpressure.Here’s
how itwillwork.
—
NICHOLASDERENZO
DesigningaSmart
SkinThatLets
AmputeesFeelAgain
how it’s done
Thesyntheticskin ismadeupofacomplexweb
ofultrathinsiliconandgold ribbonsembedded
instretchy transparent silicone rubber. The ribbons
actassensorsandarearranged inwavy, serpentine
patterns thatallow it tostretchandbend tobetter
mimic theelasticityof real humanskin. Inpartsof the
hand that requiremoreflexibility, like thewrist, the
ribbonsarearranged ina looserpattern,whileareas
that requiremoresensation, like thefingertips, are
denselypackedwithsensors.
Inaddition todetecting temperature, the
sensorsgenerateelectricitywhenphysically
manipulated—poked,prodded, caressed, smooshed—
registeringstimuli likerealnerveendings. Theyalso
includehumiditysensors in the formofcapacitors.
Whenmetwithmoisture, thecapacitors’ ability to
storeachargechanges, and thisshift isregisteredasa
quantifiablemeasureofwetness. (Scientists tested this
featurebyhaving thehand touchwetanddrydiapers.)
Thefinal step involvesfiguringoutexactlyhow to
link theskin to thenervoussystem. Inearly tests
onrats, researchersshowed thatwhenpressurewas
applied to theskin, anelectricsignal couldsuccessfully
besent to thebrainviaelectrodes, though theycan’tbe
surepreciselywhichsensations theratsexperienced.
Nextup:much larger testsubjects.
HEMISPHERESMAGAZINE.COM
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MARCH2015
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ILLUSTRATIONBYJAMESONSIMPSON
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