Figure 4.

DNA immobilization by GOPS-modification. (a) Scheme for obtaining structured layers of capture DNA C1 on the chip surface using an elastomeric mask, prior to probing with fluorescently labeled target-DNA TF. (b) The result of the procedure described in (a) is shown in fluorescence contrast. The last step of the scheme describes the structure along the dashed line in the micrograph. (c) Control experiment, demonstrating the low unspecific binding of gold-labeled DNA TG to GOPS-surfaces without capture DNA. (d) The incubation of surfaces of complementary capture DNA C1 with gold-labeled TG results in a surface coverage with gold colloids due to specific DNA–DNA interactions.