The preferred method for printing nucleic acid microarrays uses the OmniGrid by GeneMachines. This robot uses up to 48 quill-tip pins to print up to 100 slides. The pins take up about 0.5 µl when loading and print about 1nl onto each slide. Between samples, the pins can be washed with a sonicator or a water bath and dried by vacuum. The robot takes about one hour to set up and can print a 384-well plate in about 20 minutes when using 32 pins.