posted on 2020-03-31, 19:06authored byYusuke Kikuchi, Abdon Pena-Francesch, Mert Vural, Melik C. Demirel
Composites
of conducting polymers offer a broad spectrum of materials
for interfacing electronic devices with biological systems. Particularly,
material systems based on poly(styrenesulfonate) doped poly(3,4-ethylenedioxythiophene)
(PEDOT:PSS) have found applications in many bioelectronic devices
as biosensitive transistors, controlled drug delivery media, and strain,
temperature, and humidity sensors. The biocompatibility, intercoupled
electronic and ionic conductivity, and air stable electrical properties
render PEDOT:PSS based material systems indispensable for bioelectronics.
However, these materials are commonly used in thin film form since
freestanding films of pristine PEDOT:PSS are considered mechanically
brittle compared to biological tissues, and unlike biological systems
these conductive films cannot restore/heal their physical properties
after excessive mechanical deformation. Here we report conductive
biocomposites of PEDOT:PSS and tandem repeat proteins with the ability
to self-heal once plasticized via water. The tandem repeat proteins
acquired from squid ring teeth (SRT) induce structural effects on
PEDOT:PSS including improved crystallinity and formation of fibrous
network structures. These structural effects lead to electrical conductivity
values reaching 120 S/cm for biocomposites with SRT protein concentrations
below 20 wt %, which exceeds the conductivity of pristine PEDOT:PSS
(∼100 S/cm). More importantly, tandem proteins facilitate consistent
self-healing of freestanding biocomposites with SRT protein concentrations
beyond 40 wt %. These robust biocomposites with high electrical conductivity
and the ability to self-heal can find applications in numerous soft
electronic systems spanning from implantable, transient, and epidermal
electronics to electronic textiles.