Characterization of cortical astrocytes on materials of differing surface chemistry.

The behavior of cortical astrocytes was evaluated on a number of medically relevant materials of differing physicochemical properties. This study describes cell attachment, DNA synthesis, production of extracellular matrix (ECM) proteins, and neuronal interactions of perinatal rat astrocytes in vitro. The number of attached astrocytes initially differed among the materials, decreasing with increasing material hydrophobicity. In contrast, the rate of DNA synthesis increased with increasing material hydrophobicity. With the exception of only one material, astrocytes reached confluence by 12 days in culture on all the materials tested. Furthermore, the expression of characteristic ECM proteins and the fundamental ability of astrocytes to support neuronal attachment and growth was qualitatively identical between populations of astrocytes on different materials. The ability of astrocytes to colonize different surfaces initially was mediated via adsorbed serum proteins, as reducing the capacity of a model surface to adsorb proteins inhibited astrocyte colonization for up to 2 weeks in culture. We propose that astrocytes are relatively insensitive to differences in surface chemistries so long as the proteins necessary for cellular attachment are capable of adsorbing to the material to some extent. It seems likely that the ability of astrocytes to produce and remodel a matrix creates a surface environment that eventually becomes similar regardless of the surface chemistry of the underlying material.