Figure 3.

Effect of the concentration of oligonucleotides. A mix of two primers, 5′-SH up₁ and 5′-SH up₂, was applied to a glass surface derivatised with ATS and functionalised with cross-linker s-MBS. Concentration of the mixed primer solution ranged from 1 to 100 µM. Glass slides were submitted to solid phase PCR with 1 nM template E1-2 (square) or I8 (circle) in solution or with no template in solution (triangle). Radioactively-labelled nucleotides were incorporated during PCR to the solid phase amplified DNA. Glass slides were exposed for phosphor imaging (A, top left) and density of the radioactive signal analysed (A). The loading density of up₁, after PCR, at different concentrations was analysed by hybridisation using radioactively-labelled Rup₁ complementary oligonucleotide (B).