Spatially controlling neuronal adhesion and inflammatory reactions on implantable diamond

The mechanical and chemical properties of diamond and diamond-like carbon (DLC) coatings make them very suitable materials for improving the long-term performance of invasive electrode systems used in brain-computer interfaces (BCIs). We have performed in vitro testing to demonstrate methods for spatially directing neural cell growth and limiting the detrimental attachment of cells involved in the foreign body response on boron-doped diamond and DLC. Inkjet-printing, laser micro-machining, and stencil-assisted patterning techniques were used to control neuronal adhesion and modify inflammatory cell attachment. This work presents micro-tailored materials that could be used to improve the long-term quality of recorded signals from neural-electronic interfaces. © 2011 IEEE

Arteriolar genesis and angiogenesis induced by endothelial nitric oxide synthase overexpression results in a mature vasculature

Background - Generation of physiologically active vascular beds by delivery of combinations of growth factors offers promise for vascular gene therapy. Methods and Results - In a mesenteric model of physiological angiogenesis, combining endothelial nitric oxide synthase ( eNOS) ( and hence NO production) with VEGF and angiopoietin-1 overexpression resulted in a more functional vascular phenotype than growth factor administration alone. eNOS gene delivery upregulated eNOS, VEGF, and Ang-1 to similar levels as gene transfer with VEGF or Ang-1. eNOS overexpression resulted in neovascularization to a similar extent as VEGF and Ang-1 combined, but not by sprouting angiogenesis. Whereas combining Ang-1 and VEGF increased both exchange vessels and conduit vessels, neither growth factor nor eNOS alone resulted in vessels with smooth muscle cell (SMC) coverage. In contrast, combining all three generated microvessels with SMCs (arteriolar genesis) and further increased functional vessels. Use of a vasodilator, prazosin, in combination with Ang1 and VEGF, but not alone, also generated SMC-positive vessels. Conclusion - Coexpression of eNOS, VEGF, and Ang-1 results in a more mature vascularization of connective tissue, and generates new arterioles as well as new capillaries, and provides a more physiological therapeutic approach than single growth factor administration, by combining hemodynamic forces with growth factors

Differential patterning of neuronal, glial and neural progenitor cells on phosphorus-doped and UV irradiated diamond-like carbon

Diamond-like carbon (DLC) is an attractive biomaterial for coating human implantable devices. Our particular research interest is in developing DLC as a coating material for implants and electrical devices for the nervous system. We previously reported that DLC is not toxic to N2a neuroblastoma cells or primary cortical neurons and showed that phosphorus-doped DLC (P:DLC) could be used to produce patterned neuron networks. In the present study we complement and extend these findings by exploring patterning of dorsal root ganglion (DRG) explants, human neural progenitor cells (hNPC) and U-87 astroglioma cells on P:DLC. Further P:DLC data is provided to highlight that P:DLC can be used as an effective coating material for in vitro multi-electrode arrays (MEAs) with potential for patterning groups of neurons on selected electrodes. We also introduce ultraviolet (UV) irradiation as a simple treatment to render DLC neurocompatible. We show that UV:DLC can be used to support patterned and unpatterned cortical neuron growth. These findings strongly support the use of DLC as tailorable and tuneable substrate to study neural cell biology in vitro and in vivo. We conclude that DLC is a well-suited candidate material for coating implantable devices in the human nervous system. (C) 2009 Elsevier Ltd. All rights reserved