Polypyrrole-based conducting polymers and interactions with biological tissues

IRC in Biomedical Materials, Queen Mary University of London, London E14NS, UK.
Journal of The Royal Society Interface (Impact Factor: 3.92). 01/2007; 3(11):741-52. DOI: 10.1098/rsif.2006.0141
Source: PubMed


Polypyrrole (PPy) is a conjugated polymer that displays particular electronic properties including conductivity. In biomedical applications, it is usually electrochemically generated with the incorporation of any anionic species including also negatively charged biological macromolecules such as proteins and polysaccharides to give composite materials. In biomedical research, it has mainly been assessed for its role as a reporting interface in biosensors. However, there is an increasing literature on the application of PPy as a potentially electrically addressable tissue/cell support substrate. Here, we review studies that have considered such PPy based conducting polymers in direct contact with biological tissues and conclude that due to its versatile functional properties, it could contribute to a new generation of biomaterials.

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    • "The higher values of the electrical conductivity observed in such organic polymers have led to the name ''synthetic metals'' [1]. CPs have numerous practical applications such as battery electrodes [2], sensors [3] and biosensors [4] [5], various biomedical devices [6], e-Textiles [7], artificial muscles [8] and enzyme immobilization matrices [9]. "
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    ABSTRACT: Conjugated polymer - polypyrrole (PPy) - particles were synthesized by chemical oxidative polymerization of pyrrole (Py) monomers using H2O2 as an oxidant. No surfactants were added to the polymerization solution, therefore pure PPy particles were formed. UV–vis molecular absorption spectroscopy (UV–vis MAS) was used to monitor the Py polymerization process. The spectral properties and morphology of formed PPy particles were studied using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The influence of H2O2 and Py concentration, temperature and pH of media on the PPy particles formation rate was investigated. It was found that the polymerization solutions were unstable colloidal suspensions consisting of the PPy particles. SEM analysis revealed that PPy particles were 50 – 100 nm in diameter, which aggregated into larger structures of 600 – 1000 nm in diameter with irregular granular morphology. FTIR data showed that the molecular structure of the synthesized particles was identical to that of PPy produced by conventional methods.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 05/2015; 483. DOI:10.1016/j.colsurfa.2015.05.008 · 2.75 Impact Factor
    • "Substrate conductivity can be achieved through polypyrrole (PPy), which is a conductive polymer, not only easy to synthesize but also easy to incorporate anionic biomolecules (dopants) to enhance biocompatibility and target cellular function (Ateh et al., 2006). Several recent studies have demonstrated that PPy doped with bioactive molecules can influence cell survival and differentiation (Ateh et al., 2006; Zhang et al., 2010). Our group also demonstrated that PPy-coated polyester fabrics retained sufficient long-term electrical stability/conductivity when ES was used, thus providing an opportunity to directly apply a conductive textile matrix as a scaffold for ES delivery (Jiang et al., 2002). "
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    ABSTRACT: The aim of this study was to investigate the healing characteristics and the underlying signalling pathway of human dermal fibroblasts under the influence of pulsed electrical stimulation (PES). Primary human dermal fibroblasts were seeded on polypyrrole-coated polyester fabrics and subjected to four different PES protocols. The parameters of the rectangular pulse included potential intensity (50 and 100 mV/mm) and stimulation time (pulse width 300 s within a period of 600 s, and pulse width 10 s within a period of 1200 s). Our study revealed that PES moderately improved the ability of the cells to migrate in association with a statistically significant (p < 0.05) increase of FGF2 secretion by the PES-exposed fibroblasts. These exposed fibroblasts were able to contract collagen gel matrix up to 48 h and this collagen gel contraction paralleled an increase in α-SMA mRNA expression and protein production from the PES-exposed fibroblasts. Interestingly, the effect of PES on the human fibroblasts involved the Smad signalling pathway, as we observed higher levels of phosphorylated Smad2 and Smad3 in the stimulated groups compared to the control groups. Overall, this study demonstrated that PES modulates fibroblast activities through the Smad signalling pathway, thus providing new mechanistic insights related to the use of PES to promote wound healing in humans. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
    Journal of Tissue Engineering and Regenerative Medicine 02/2015; DOI:10.1002/term.2014 · 5.20 Impact Factor
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    • "In this way, intensive studies have been carried out to evaluate this interesting aspect of polypyrrole, the biocompatibility. In previous studies it has been shown that PPy is compatible with a wide range of cell types in vitro [18] [19] and in vivo [20] [21]. PPy has been also used as a polymeric matrix for hybrid coatings which provide antibacterial activity by incorporating different materials such as silver nanoparticles [22] [23], fluoroquinolone [24] or PEG [25]. "
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    ABSTRACT: This study aims to address an issue to a subject that is still less present in literature: the adherence of polypyrrole (PPy) films on bioinert substrate. The poly(dopamine) (PDA) assisted deposition of PPy film on titanium substrate was performed in two steps. The chemical self-polymerization of dopamine was performed as a preliminary step from dopamine in Tris buffer solution on titanium substrate. Then, the resulted poly(dopamine) layer consisting of anchors with strong interactions with Ti surface was a new suitable substrate for polypyrrole film electrochemical deposition. The new PDA-PPy films were characterized in terms of interest properties for the desired biomedical applications: adherence, electrochemical stability of PDA-PPy film, wettability, topography, morphology and antibacterial effect. The poly(dopamine) assisted deposition of PPy film has been shown to be a facile and efficient route to improve the adhesion of PPy film on titanium maintaining or improving the properties of polymeric film.
    Progress in Organic Coatings 11/2014; 77(11). DOI:10.1016/j.porgcoat.2014.06.023 · 2.36 Impact Factor
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