Poly(3,4-ethylenedioxythiophene) (PEDOT) is an organic conducting polymer that has been the focus of significant research over the last decade, in both energy and biological applications. Most commonly, PEDOT is doped by the artificial polymer polystyrene sulfonate due to the excellent electrical characteristics yielded by this pairing. The biopolymer dextran sulphate (DS) has been recently reported as a promising alternative to PEDOT:PSS for biological application, having electrical properties rivaling PEDOT:PSS, complimented by the potential bioactivity of the polysaccharide. In this work we compared chemical and electrochemical polymerisations of PEDOT:DS in terms of their impact on the electrical, morphological and biological properties of the resultant PEDOT:DS films. Post-growth cyclic voltammograms and UV-Vis analyses revealed comparable redox behaviour and absorbance profiles for the two synthesis approaches. Despite good intrinsic conductivity of particles, the addition of chemically produced PEDOT:DS did not markedly enhance the bulk conductivity of aqueous solutions due to the lack of interconnectivity between adjacent PEDOT:DS particles at achievable concentrations. Scanning electron microscopy revealed significantly greater roughness in films cast from chemically produced PEDOT:DS compared to electropolymerised samples, attributable to the formation of solution phase nanoparticles prior to casting. In cell studies with the L929 cell line, electrochemical polymerisation of PEDOT:DS afforded better integrity of resultant films for surface seeding, whilst chemically polymerised PEDOT:DS appeared to localised at the proliferating cells, suggesting possible applications in drug delivery.

The electrical and mechanical characteristics of ionic-covalent entanglement hydrogels consisting of combinations of the edible biopolymers gellan gum and gelatin were investigated. Impedance analysis and compression testing showed that these hydrogels (with water content = 97%) exhibited conductivity values of up to 13 mS/cm and compressive stress at failure values of up to 1.0 MPa. These are suitable characteristics for printed and mechanically robust wet device components.

Designers and engineers have been dreaming for decades with motors sensing, by themselves, working and surrounding conditions, as biological muscles do originating proprioception. The evolution of the working potential, or that of the consumed electrical energy, of electrochemical artificial muscles based on electroactive materials (intrinsically conducting polymers, redox polymers, carbon nanotubes, fullerene derivatives, grapheme derivatives, porphyrines, phtalocyanines, among others) and driven by constant currents senses, while working, any variation of the mechanical (trailed mass, obstacles, pressure, strain or stress) thermal or chemical conditions. They are linear faradaic polymeric motors: applied currents control movement rates and applied charges control displacements. One physically uniform artificial muscle includes one motor and several sensors working simultaneously under the same driving chemical reaction. Actuating (current and charge) and sensing (potential and energy) magnitudes are present, simultaneously, in the only two connecting wires and can be read by the computer at any time. From basic polymeric, mechanical and electrochemical principles a basic equation is attained for the muscle working potential evolution. It includes and describes, simultaneously, the polymeric motor characteristics (rate of the muscle movement and muscle position) and the working variables (temperature, electrolyte concentration and mechanical conditions). By changing working conditions experimental results overlap theoretical predictions. The ensemble computer-generator-muscle-theoretical equation constitutes and describes artificial mechanical, thermal and chemical proprioception of the system. Proprioceptive tools, zoomorphic or anthropomorphic soft robots can be envisaged.

Covalent functionalization of reduced graphene oxide (rGO) with the photosynthetic reaction center (RC) from Rhodobacter sphaeroides R26 via click chemistry reaction has been performed. The hybrid system was characterized by flash photolysis and infrared spectroscopy and the RC was found to retain its photoactivity and structural integrity. The strategy is applicable for the fabrication of hybrid bio-electronic devices capable of absorbing and converting solar energy.

In nerve and muscle regeneration applications, the incorporation of conducting elements into biocompatible materials has gained interest over the last few years, as it has been shown that electrical stimulation of some regenerating cells has a positive effect on their development. A variety of different materials, ranging from graphene to conducting polymers, have been incorporated into hydrogels and increased conductivities have been reported. However, the majority of conductivity measurements are performed in a dry state, even though material blends are designed for applications in a wet state, in vivo environment. The focus of this work is to use polypyrrole nanoparticles to increase the wet–state conductivity of alginate to produce a conducting, easily processable, cell–supporting composite material. Characterization and purification of the conducting polymer nanoparticle dispersions, as well as electrochemical measurements, have been performed to assess conductivity of the nanoparticles and hydrogel composites in the wet state, in order to determine whether filling an ionically conducting hydrogel with electrically conductive nanoparticles will enhance the conductivity. It was determined that the introduction of spherical nanoparticles into alginate gel does not increase, but rather slightly reduces conductivity of the hydrogel in the wet state.