Adhesion of cultured mammalian central nervous system neurons to flame-modified hydrophobic surfaces.

Surface wettability is an excellent indicator of the ability of cells to adhere to a culture substrate. We have determined that brief exposure of a hydrophobic culture surface to a propane flame may increase wettability more than 1200% via the deposition of ionic combustion products. Previously nonadherent mouse spinal cord cells will adhere to and differentiate morphologically on a hydrophobic surface after flaming. Central nervous system cells remain adhered to flamed surfaces for periods of 2 mo. or longer and demonstrate spontaneous electrical activity during that time. Secondary modification of a flamed surface with polylysine further enhances the strength of single cell adhesion, thereby retarding mobility and promoting neurite extension. Flaming also enhances the wettability of common culture materials such as glass and polystyrene, as well as metal. Flaming of hydrophobic substrates through masks permits creation of discrete adhesion islands and patterns which may be used for a variety of investigations requiring maintenance of different cell types in separate regions of a culture surface.