Time dependence of oligonucleotide immobilization. Dependence of averaged mean fluorescence intensity on immobilization time for aACG (black squares) and ACG (blue circles) at 20 μM spotting concentration (left scale). Averaged mean fluorescence intensity after 2 hours hybridization with 200 nM complementary Cy5 labeled oligonucleotide for aACG (black triangles) and ACG (blue triangles) under low-stringency conditions at 23°C (right scale, for experimental details see Methods section). (a) On 2D epoxy slides and (b) on 3D NHS hydrogel slide. Error bars that are not visible are hidden behind the symbols.