Guided growth of neurons and glia using microfabricated patterns of parylene-C on a SiO2 background.

This paper describes a simple technique for the patterning of glia and neurons. The integration of neuronal patterning to Multi-Electrode Arrays (MEAs), planar patch clamp and silicon based 'lab on a chip' technologies necessitates the development of a microfabrication-compatible method, which will be reliable and easy to implement. In this study a highly consistent, straightforward and cost effective cell patterning scheme has been developed. It is based on two common ingredients: the polymer parylene-C and horse serum. Parylene-C is deposited and photo-lithographically patterned on silicon oxide (SiO(2)) surfaces. Subsequently, the patterns are activated via immersion in horse serum. Compared to non-activated controls, cells on the treated samples exhibited a significantly higher conformity to underlying parylene stripes. The immersion time of the patterns was reduced from 24 to 3h without compromising the technique. X-ray photoelectron spectroscopy (XPS) analysis of parylene and SiO(2) surfaces before and after immersion in horse serum and gel based eluant analysis suggests that the quantity and conformation of proteins on the parylene and SiO(2) substrates might be responsible for inducing glial and neuronal patterning.

Complex I specific increase in superoxide formation and respiration rate by PrP-null mouse brain mitochondria.

An imbalance in free radical production and removal is considered by many to be an important factor in the etiology of many degenerative diseases. Since mitochondria are a major source of free radicals, we have examined mitochondrial free radical production in relation to oxidative phosphorylation in PrP-null mice. Quantitative electron paramagnetic resonance spectroscopy revealed up to a 70% increase in superoxide production from Complex I of submitochondrial particles prepared from PrP-null mice. This was accompanied by elevated respiratory capacity through Complex I without any discernible alteration in respiratory efficiency. These differences are associated with changes in superoxide dismutase levels and defects in mitochondrial morphology, confirming previously reported results. Our results demonstrate a clear difference in free radical production and oxygen consumption by mitochondrial Complex I between PrP-null mice and wild-type controls, pointing to Complex I as a potential target for pathological change, suggesting similarities between prion-related and other neurodegenerative diseases.