Transfection of cells attached to selected cell based biosensor surfaces

Mammalian cell attachment studies were conducted on a variety of common microchip surfaces for potential use in cell based biosensors. COS-7 cell attachment to Au, Pt or ITO, per unit area was greater than to SiO(2) surfaces. The number of cells that would attach was essentially maximized 3 h after cell seeding. HL-1 cells attached more readily to surfaces precoated with fibronectin, but by 3 h equivalent number of cells had attached independent of fibronectin precoating. Inclusion of serum in media during the initial period of attachment decreased the number of COS-7 cells attached to SiO(2) surfaces, but no dependence on serum was seen for ITO surfaces. The number of cells attached per unit area varied with the composition of the surface. However, no differences were observed in the percentage of cells transfected with a green fluorescent protein gene, or in the level of reporter gene expression over the population of transfected cells on ITO, SiO(2), Pt, Ag, or Au surfaces. Similar FACS analysis of transfected Hep G2 cells revealed lower levels of both transfection efficiency and levels of GFP fluorescence. Hep G2 cells plated on Ag did not remain attached for analysis, but there were no significant differences between tissue culture plastic and the other biosensor surfaces in the percentage of cells transfected. This suggests that, in general, cells will attach to the various conducting and nonconducting biosensor surfaces studied and will provide comparable data in reporter gene expression assays.