The Synergistic Effects of Gold Particles and Dexamethasone on the Electrochemical and Biological Performance of PEDOT Neural Interfaces.

Although neural devices have shown efficacy in the treatment of neurodegenerative diseases, their functionality is limited by the inflammatory state and glial scar formation associated with chronic implantation. The aim of this study was to investigate neural electrode performance following functionalization with an anti-inflammatory coating derived from a conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) matrix doped with dexamethasone (Dex) and decorated with Au particles. Pristine PEDOT, PEDOT-Dex and their gold-decorated analogues (PEDOT/Au and PEDOT-Dex/Au) were formulated by electrochemical deposition and characterized with respect to electrode electrochemical properties, surface morphology and biocompatibility towards primary neural cells. Through a process of gold deposition, it was possible to eliminate the initial burst release observed in PEDOT-Dex and maintain a stable, stepwise increase in Dex elution over 7 days. The released amounts of Dex exceeded the concentrations considered as therapeutic for both PEDOT-Dex and PEDOT-Dex/Au. The results clearly indicated that the presence of either Dex or Au particles facilitated the outgrowth of neurites. Finally, it was shown that the application of composite materials, such as PEDOT-Dex/Au, is an efficient way to improve the efficacy of neural interfaces in vitro.

Fractal form PEDOT/Au assemblies as thin-film neural interface materials.

Electrically conducting polymer formulations have emerged as promising approaches for the development of interfaces and scaffolds in neural engineering, facilitating the development of physicochemically modified constructs capable of cell stimulation through electrical and ionic charge transfer. In particular, topographically functionalized or neuromorphic materials are able to guide the growth of axons and promote enhanced interfacing with neuroelectrodes in vitro. In this study, we present a novel method for the formation of conducting polymer/gold assemblies via a combinational sputter and spin coating technique. The resulting multilayered PEDOT/Au substrates possessed enhanced electrochemical properties as a function of the number of deposited organic/inorganic layers. It was observed that through subsequent electrochemical conditioning it was possible to form neuromorphic fractal-like assemblies of gold particles, which significantly impacted on the electrochemical characteristics of the PEDOT/Au films. PEDOT/Au assemblies were observed to possess unique topographical features, advantageous charge storage capacity (34.9 ± 2.6 mC cm-2) and low electrical impedance (30 ± 2 Ω at 1 kHz). Furthermore, PEDOT/Au assemblies were observed to facilitate the outgrowth of neurites in a mixed ventral mesencephalon cell population and promotean increase in the neurons/astrocytes ratio relative to all experimental groups, indicating PEDOT/Au biomimetic neuromorphic assemblies as promising materials in engineering electrically conductive neural interface systems.

Aligning a new reference genetic map of Lupinus angustifolius with the genome sequence of the model legume, Lotus japonicus.

We have developed a dense reference genetic map of Lupinus angustifolius (2n = 40) based on a set of 106 publicly available recombinant inbred lines derived from a cross between domesticated and wild parental lines. The map comprised 1090 loci in 20 linkage groups and three small clusters, drawing together data from several previous mapping publications plus almost 200 new markers, of which 63 were gene-based markers. A total of 171 mainly gene-based, sequence-tagged site loci served as bridging points for comparing the Lu. angustifolius genome with the genome sequence of the model legume, Lotus japonicus via BLASTn homology searching. Comparative analysis indicated that the genomes of Lu. angustifolius and Lo. japonicus are highly diverged structurally but with significant regions of conserved synteny including the region of the Lu. angustifolius genome containing the pod-shatter resistance gene, lentus. We discuss the potential of synteny analysis for identifying candidate genes for domestication traits in Lu. angustifolius and in improving our understanding of Fabaceae genome evolution.