title: Mechanisms of Reduced Astrocyte Surface Coverage in Cortical Neuron-Glia Co-cultures on Nanoporous Gold Surfaces.
abstract: Nanoporous gold (np-Au) is a promising multifunctional material for neural electrodes. We have previously shown that np-Au nanotopography reduces astrocyte surface coverage (linked to undesirable gliosis) while maintaining high neuronal coverage in a cortical primary neuron-glia co-culture model as long as two weeksin vitro. Here, we investigate the potential influence of secreted soluble factors from cells grown on np-Au on the cell type-specific surface coverage of cells grown on conventional tissue culture plastic and test the hypothesis that secretion of factors is responsible for inhibiting astrocyte coverage on np-Au. In order to assess whether factors secreted from cells grown on np-Au surfaces reduced surface coverage by astrocytes, we seeded fresh primary rat neuron-glia co-cultures on conventional polystyrene culture dishes, but maintained the cells in conditioned media from co-cultures grown on np-Au surfaces. After one weekin vitro, a preferential reduction in astrocyte surface coverage was not observed, suggesting that soluble factors are not playing a role. In contrast, four hours after cell seeding there were a significant number of non-adhered, yet still viable, cells for the cultures on np-Au surfaces. We hypothesize that the non-adherent cells are mainly astrocytes, because: (i) there was no difference in neuronal cell coverage between np-Au and pl-Au for long culture durations and (ii) neurons are post-mitotic and not expected to increase in number upon attaching to the surface. Overall, the results suggest that the np-Au topography leads to preferential neuronal attachment shortly after cell seeding and limits astrocyte-specific np-Au surface coverage at longer culture durations.
authors: Department of Biomedical Engineering, University of California - Davis, Davis, California 95616, United States.
authors: Christopher A R
authors: CA
authors: Chapman
authors: Department of Molecular Biosciences, University of California - Davis, Davis, California 95616, United States.
authors: Hao
authors: H
authors: Chen
authors: Department of Molecular Biosciences, University of California - Davis, Davis, California 95616, United States.
authors: Marianna
authors: M
authors: Stamou
authors: Department of Molecular Biosciences, University of California - Davis, Davis, California 95616, United States.
authors: Pamela J
authors: PJ
authors: Lein
authors: Department of Electrical and Computer Engineering, University of California - Davis, Davis, California 95616, United States.
authors: Erkin
authors: E
authors: Seker
keywords: cell attachment; cell-material interaction; gliosis; nanoporous gold; nanostructure; neuroengineering; neuron-glia co-culture; soluble factors