is strongly dependent on the dopant type [22]. This study can be exploited to build up

new platforms for label-free bacterial differentiation, as well as for monitoring the bac­

terial population. The electroactivity of PPys has been exploited to achieve mechano-

transduction in mesenchymal stem cells. In particular, Jiang and collaborators showed

that the nano-morphology of a Ppy array can be switched between highly adhesive hy­

drophobic nanotubes and poorly adhesive hydrophilic nanotips via electrochemical

oxidation/reduction (Figure 4.3) [23].

4.3.3 Poly(3,4-Ethylene Dioxythiophene): Polystyrene Sulfonate

PEDOT:PSS is perhaps the most employed conductive polymer in bioelectronics, owing

to its conductivity, stability, biocompatibility, and excellent mixed electronic and ionic

conduction. Specifically, PEDOT is conductive but virtually insoluble in water, while the

addition of the negatively charged sulfonate groups of PSS increases PEDOT solubility

and dispersibility via Coulomb interactions. In this ionomer mixture form, PEDOT:PSS

is thus highly processable and biocompatible, allowing the formation of biocompatible

and stable hydrogels, whose conductivity can be largely tuned by using a variety of

FIGURE 4.3

(a) Illustration of switching between the nanotube/nanotip on a PPy array upon redox switching. (b) Scanning

electron microscopy images of the nano-morphology switching scale bars, 100 nm. The insets show magnified

nanostructures. Scale bars, 20 nm. Adapted with permission [ 23]. Copyright (2017) American Chemical Society.

Materials for Organic Bioelectronics

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