Stabilizing electrode-host interfaces: a tissue engineering approach.

Y Zhong; X Yu; R Gilbert; R V Bellamkonda

PubMed · 11767970

Stabilizing electrode-host interfaces: a tissue engineering approach.

Abstract

The stability of implanted electrodes is a significant problem affecting their long-term use in vivo. Problems include mechanical failure and inflammation at the implantation site. The engineering of bioactive electrode coatings has been investigated for its potential to promote in-growth of neural tissue and reduce sheer at the electrode-host interface. Preliminary results indicate that hydrogel coatings with either collagen I or polylysine-laminin-1 can promote cortical nerve cell attachment and differentiation on silicon substrates. Additionally, slow-release microtubules can also be implanted in these gels to release agents that either provide trophic support to neurons or prevent inflammation locally. When silicon discs are coated with collagen type I, the coating remains stable for 55 days. Further testing is underway, but initial results indicate that tissue-engineering approaches provide useful insights to help address the problem of host-electrode instability in the brain.

Explore related subjects

Cells, Cultured Coated Materials, Biocompatible Electrodes, Implanted Humans Microtubules Motor Neurons Nerve Regeneration Tissue Engineering Journal Article Research Support, U.S. Gov't, Non-P.H.S.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Y Zhong, X Yu, R Gilbert, R V Bellamkonda. Stabilizing electrode-host interfaces: a tissue engineering approach.. https://pubmed.ncbi.nlm.nih.gov/11767970/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2004

Robust phosphoproteomic profiling of tyrosine phosphorylation sites from human T cells using immobilized metal affinity chromatography and tandem mass spectrometry.

Protein tyrosine phosphorylation cascades are difficult to analyze and are critical for cell signaling in higher eukaryotes. Methodology for profiling tyrosine phosphorylation, considered herein as the assignment of multiple protein tyrosine phosphorylation sites in single analyses, was reported recently (Salomon, A. R.; Ficarro, S. B.; Brill, L. M.; Brinker, A.; Phung, Q. T.; Ericson, C.; Sauer, K.; Brock, A.; Horn, D. M.; Schultz, P. G.; Peters, E. C. Proc. Natl. Acad. Sci. U.S.A. 2003, 100, 443-448). The technology platform included the use of immunoprecipitation, immobilized metal affinity chromatography (IMAC), liquid chromatography, and tandem mass spectrometry. In the present report, we show that when using complex mixtures of peptides from human cells, methylation improved the selectivity of IMAC for phosphopeptides and eliminated the acidic bias that occurred with unmethylated peptides. The IMAC procedure was significantly improved by desalting methylated peptides, followed by gradient elution of the peptides to a larger IMAC column. These improvements resulted in assignment of approximately 3-fold more tyrosine phosphorylation sites, from human cell lysates, than the previous methodology. Nearly 70 tyrosine-phosphorylated peptides from proteins in human T cells were assigned in single analyses. These proteins had unknown functions or were associated with a plethora of fundamental cellular processes. This robust technology platform should be broadly applicable to profiling the dynamics of tyrosine phosphorylation.

Cells, Cultured↗

PubMed2002

Fabrication and surface modification of macroporous poly(L-lactic acid) and poly(L-lactic-co-glycolic acid) (70/30) cell scaffolds for human skin fibroblast cell culture.

The fabrication and surface modification of a porous cell scaffold are very important in tissue engineering. Of most concern are high-density cell seeding, nutrient and oxygen supply, and cell affinity. In the present study, poly(L-lactic acid) and poly(L-lactic-co-glycolic acid) (70/30) cell scaffolds with different pore structures were fabricated. An improved method based on Archimedes' Principle for measuring the porosity of scaffolds, using a density bottle, was developed. Anhydrous ammonia plasma treatment was used to modify surface properties to improve the cell affinity of the scaffolds. The results show that hydrophilicity and surface energy were improved. The polar N-containing groups and positive charged groups also were incorporated into the sample surface. A low-temperature treatment was used to maintain the plasma-modified surface properties effectively. It would do help to the further application of plasma treatment technique. Cell culture results showed that pores smaller than 160 microm are suitable for human skin fibroblast cell growth. Cell seeding efficiency was maintained at above 99%, which is better than the efficiency achieved with the common method of prewetting by ethanol. The plasma-treatment method also helped to resolve the problem of cell loss during cell seeding, and the negative effects of the ethanol trace on cell culture were avoided. The results suggest that anhydrous ammonia plasma treatment enhances the cell affinity of porous scaffolds. Mass transport issues also have been considered.

Cells, Cultured↗

PubMed2002

Wnt-7a is upregulated by norethisterone in human endometrial epithelial cells: a possible mechanism by which progestogens reduce the risk of estrogen-induced endometrial neoplasia.

Progestogens are added to oestrogen in hormone replacement therapy regimens to reduce the risk of endometrial cancer. We have performed in vitro studies analysing gene expression of isolated normal endometrial epithelia cells (NEE) treated with estradiol and the progestogen norethisterone acetate (NETA). We report here for the first time upregulation of the Wnt-7a gene by NETA in estrogen treated NEE. Wnt genes are a large family of developmental genes associated with cellular responses such as oncogenesis. We therefore suggest that upregulation of Wnt-7a may be associated with the antineoplastic effects of progestogens on the endometrium.

Cells, Cultured↗