Figure 6
Illustration of most important sensor preparation procedures. Top: Reference measurement spots are covered either in water or buffer solution in the first and third step. In the second step they are treated with a MCH solution and Urea solution (not shown) resulting in a SAM which shields the gold surface thus preventing unspecific binding of nucleus proteins in these areas in the final step. Center: Sample measurement spots are treated with a dsDNA solution first and subsequently with MCH solution and Urea solution (not shown). The resulting biofilm consists of tssDNA and MCH. The immobilized tssDNA can be hybridized by treatment with the complementary ssDNA oligomer to form a dsDNA film or left denatured (not shown). If EGR2 transcription factors are present in the protein mixture, they can selectively bind to the immobilized DNA oligomers. Bottom: Blind sample measurement spots are prepared in the same manner as sample measurement spots are. The only difference is that the protein mixture is treated with a dsDNA solution \(ex-situ\) beforehand, which inhibits the selective EGR2 immobilization on the sensor surface.
