A low-cost highly sensitive DNA microarray scanner for fluorescent detection is developed based on the pick-Lip head of a commercially available optical storage device, DVD. A laser beam of 650 nm, generated by a DVD laser diode, is used for dynamic auto-focusing as well as the excitation of Cy5 fluorescent dye. The fluorescence intensity emitted from Cy5 dye is measured by a pholomultiplier tube (PMT). In contrast to other microarray scanners, the DVD-based scanner offers the auto-focusing function Using the focus error signal (FES) and a voice coil motor (VCM), and this enables fast response, high accuracy and compact size. The fluorescence-detecting performance of the scanner is inspected by using a commercial BAC (bacterial artificial chromosome) oligonucleotide Chip and a scanner evaluation microarray (DS01). Experiments have shown that the DVD-based scanner meets the limit of detection, ensuring the feasibility of a low-cost, highly sensitive DNA rnicroarray scanner. (C) 2007 Elsevier B.V. All rights reserved.