Synthesis of hetero-bifunctional, end-capped oligo-EDOT derivatives

Conjugated oligomers of 3,4-ethylenedioxythiophene (EDOT) are attractive materials for tissue engineering applications, and as model systems for studying the properties of the widely used polymer PEDOT. We report here the facile synthesis of a series of keto-acid end-capped oligo-EDOT derivatives (n = 2-7) through a combination of a glyoxylation end capping strategy and iterative direct arylation chain extension. Importantly, these structures not only represent the longest oligo-EDOTs reported, but are also bench stable in contrast to previous reports on such oligomers. The constructs reported here can undergo subsequent derivatization for integration into higher order architectures, such as those required for tissue engineering applications. The synthesis of hetero-bifunctional constructs, as well as those containing mixed monomer units is also reported, allowing further complexity to be installed in a controlled manner. Finally, we describe the optical and electrochemical properties of these oligomers and demonstrate the importance of the keto-acid in determining their characteristics

Highly porous scaffolds of PEDOT:PSS for bone tissue engineering.

UNLABELLED: Conjugated polymers have been increasingly considered for the design of conductive materials in the field of regenerative medicine. However, optimal scaffold properties addressing the complexity of the desired tissue still need to be developed. The focus of this study lies in the development and evaluation of a conductive scaffold for bone tissue engineering. In this study PEDOT:PSS scaffolds were designed and evaluated in vitro using MC3T3-E1 osteogenic precursor cells, and the cells were assessed for distinct differentiation stages and the expression of an osteogenic phenotype. Ice-templated PEDOT:PSS scaffolds presented high pore interconnectivity with a median pore diameter of 53.6±5.9µm and a total pore surface area of 7.72±1.7m2·g-1. The electrical conductivity, based on I-V curves, was measured to be 140µS·cm-1 with a reduced, but stable conductivity of 6.1µS·cm-1 after 28days in cell culture media. MC3T3-E1 gene expression levels of ALPL, COL1A1 and RUNX2 were significantly enhanced after 4weeks, in line with increased extracellular matrix mineralisation, and osteocalcin deposition. These results demonstrate that a porous material, based purely on PEDOT:PSS, is suitable as a scaffold for bone tissue engineering and thus represents a promising candidate for regenerative medicine. STATEMENT OF SIGNIFICANCE: Tissue engineering approaches have been increasingly considered for the repair of non-union fractions, craniofacial reconstruction or large bone defect replacements. The design of complex biomaterials and successful engineering of 3-dimensional tissue constructs is of paramount importance to meet this clinical need. Conductive scaffolds, based on conjugated polymers, present interesting candidates to address the piezoelectric properties of bone tissue and to induce enhanced osteogenesis upon implantation. However, conductive scaffolds have not been investigated in vitro in great measure. To this end, we have developed a highly porous, electrically conductive scaffold based on PEDOT:PSS, and provide evidence that this purely synthetic material is a promising candidate for bone tissue engineering

Electrospun aniline-tetramer-co-polycaprolactone fibers for conductive, biodegradable scaffolds

Conjugated polymers have been proposed as promising materials for scaffolds in tissue engineering applications. However, the restricted processability and biodegradability of conjugated polymers limit their use for biomedical applications. Here we synthesized a block-co-polymer of aniline tetramer and PCL (AT-PCL), and processed it into fibrous non-woven scaffolds by electrospinning. We showed that fibronectin (Fn) adhesion was dependent on the AT-PCL oxidative state, with a reduced Fn unfolding length on doped membranes. Furthermore, we demonstrated the cytocompatibility and potential of these membranes to support the growth and osteogenic differentiation of MC3T3-E1 cells over 21 days

Solid state processing of organic semiconducting polymer blends

Organic electronics is an exciting scientific frontier that holds great promise for the manufacture of low-cost, flexible electronic devices. The advancement of these technologies relies on gaining a deeper understanding of important structure/ processing/property interrelationships in organic semiconductors. Addressing such fundamental questions enables the employment of well-defined schemes to efficiently improve device performances and optimise industrially relevant processing routes. Compression molding, a solid state process, is for example an excellent candidate for the manufacture of mechanically robust, freestanding organic semiconductor films with a high degree of molecular order and anisotropy. Regrettably, research into the use of such promising processing means are to date sorely lacking, limiting their applicability for future commercialisations. This thesis explores the solid state processing of the model semiconductor poly(3-hexylthiophene) (P3HT) and several blends with thermoplastic insulators. Studies herein address key areas in which solid state pressing has not yet been optimised and demonstrate versatile schemes that facilitate enhanced microstructure formation, molecular ordering and charge transport pathways in the freestanding films. Investigations further verify for the first time the highly anisotropic charge transport properties (as determined by time-of-flight photoconductivity measurements) that arise from solid state processing. Moreover, these flexible films, with well-defined semiconducting architectures, are envisaged as outstanding candidates for the regeneration of electroresponsive biological tissues and as regenerative platforms. The solid state processing protocols are therefore augmented with facile patterning techniques to replicate biologically relevant surface topographies, in the form of microgrooves, onto the film surfaces. Preliminary cell studies, using a cardiac-like cell line, indicate that the substrates support cell culture practices, and that the cells aligned on the groove surfaces. The results presented herein thereby demonstrate that solid state processing of neat organic semiconductors and their blends is a versatile and facile avenue to generate highly structured semiconducting architectures with potential bioelectronic applications.Open Acces

Spatiotemporal Control of Amyloid-Like A Plaque Formation Using a Multichannel Organic Electronic Device

We herein report on an iontronic device to drive and control A1-40 and A1-42 fibril formation. This system allows kinetic control of A aggregation by regulation of H+ flows. The formed aggregates show both nanometer-sized fibril structure and microscopic growth, thus mimicking senile plaques, at the H+-outlet. Mechanistically we observed initial accumulation of A1-40 likely driven by electrophoretic migration which preceded nucleation of amyloid structures in the accumulated peptide cluster.Funding Agencies|VINNOVA [2010-00507]; Swedish research council [2011-5804, 621-2011-3517]; Advanced Functional Materials Center at Linkoping University; Onnesjo foundation; ERC Starting Independent Researcher Grant (Project: MUMID) from the European Research Council</p

Research data supporting "Electrospun aniline-tetramer-co-polycaprolactone fibres for conductive, biodegradable scaffolds"

Research data supporting the publication: Guex, A.G. et al., 2017, "Electrospun aniline-tetramer-co-polycaprolactone fibres for conductive, biodegradable scaffolds", MRS Communications. https://doi.org/10.1557/mrc.2017.4

Barreiras à mobilidade : aspectos fundamentais

Mestrado em Gestã