2 research outputs found
Physical and Electrochemical Properties of PEDOT:PSS as a Tool for Controlling Cell Growth
Conducting polymers are promising
materials for tissue engineering applications, since they can both
provide a biocompatible scaffold for physical support of living cells,
and transmit electrical and mechanical stimuli thanks to their electrical
conductivity and reversible doping. In this work, thin films of one
of the most promising materials for bioelectronics applications, poly(3,4-ethylenedioxythiophene)
poly(styrenesulfonate) (PEDOT:PSS), are prepared using two different
techniques, spin coating and electrochemical polymerization, and their
oxidation state is subsequently changed electrochemically with the
application of an external bias. The electrochemical properties of
these different types of PEDOT:PSS are studied through cyclic voltammetry
and spectrophotometry to assess the effectiveness of the oxidation
process and its stability over time. Their surface physical properties
and their dependence on the redox state of PEDOT:PSS are investigated
using atomic force microscopy (AFM), water contact angle goniometry
and sheet resistance measurements. Finally, human glioblastoma multiforme
cells (T98G) and primary human dermal fibroblasts (hDF) are cultured
on PEDOT:PSS films with different oxidation states, finding that the
effect of the substrate on the cell growth rate is strongly cell-dependent:
T98G growth is enhanced by the reduced samples, while hDF growth is
more effective only on the oxidized substrates that show a strong
chemical interaction with the cell culture medium
Electrically Controlled “Sponge Effect” of PEDOT:PSS Governs Membrane Potential and Cellular Growth
PEDOT:PSS
is a highly conductive material with good thermal and
chemical stability and enhanced biocompatibility that make it suitable
for bioengineering applications. The electrical control of the oxidation
state of PEDOT:PSS films allows modulation of peculiar physical and
chemical properties of the material, such as topography, wettability,
and conductivity, and thus offers a possible route for controlling
cellular behavior. Through the use of (i) the electrophysiological
response of the plasma membrane as a biosensor of the ionic availability;
(ii) relative abundance around the cells via X-ray spectroscopy; and
(iii) atomic force microscopy to monitor PEDOT:PSS film thickness
relative to its oxidation state, we demonstrate that redox processes
confer to PEDOT:PSS the property to modify the ionic environment at
the film–liquid interface through a “sponge-like”
effect on ions. Finally, we show how this property offers the capability
to electrically control central cellular properties such as viability,
substrate adhesion, and growth, paving the way for novel bioelectronics
and biotechnological applications