Effect of the amount of adenoviral vectors on in situ transduction of target cells on a solid surface. Ad5.CMV-LacZ was treated with 15 μg/ml sulfo-NHS-LC-biotin, followed by the removal of non-virion-associated biotinylation reagent. Varying numbers of the resulting biotinylated adenoviral vectors (2.5 × 105 – 2.5 × 108 viral particles per well) were added to streptavidin-coated wells (well diameter, 0.64 cm; Reacti-Bind Streptavidin Coated Polystyrene Wells) for immobilization, followed by the removal of unbound viral particles. Then, D-17 cells (8 × 102 cells per well) were placed on the wells and cultured at 37°C for 48 h. Cells were fixed with glutaraldehyde and stained for the expression of the lacZ gene (●). Unmodified Ad5.CMV-LacZ was used free in solution as a control (○). Data shown are representative of five independent experiments.