Figure 3. Computer-controlled custom-built (A) and commercially available (B) robotic microarrayers (UCLA microarray core). The entire device is surrounded by a clear plastic case so that the appropriate environment can be maintained. (C) A magnified picture showing a printing tip with a slot which can achieve passive dispensing of target genes by capillary reaction and direct contact to the solid surface. (D) A cluster of printing tips reduces the time of printing. (E) A magnified picture showing a cDNA microarray.