Each oligonucleotide probe was diluited in a spotting buffer (Corning, Schiphol-rijk, The Netherlands) at a final concentration of 50 pmoli/ul. After this, oliigonucleotide probes were mechanically “spotted” onto UltraGAPS glass slides (Corning, Schiphol-rijk, The Netherlands) using The RoboArrayer™ (Microgrid Compact Plus, BioRobotics ). Each oligonucleotide probe was represented in triplicate per array. Printing conditions were humidity among 50-55% and temperature 25°C. Printed slides were dried overnight and cross-linked with UV light at 600 mJ using a Strata-linker 2400 (Stratagene, Glenville, VA) and stored in a desiccator at room temperature.