A DNA micro-array (DMA) for DNA detection is reported. The DMA combines a standard CMOS active pixel image sensor with a DNA detection protocol utilizing the binding of DNA targets and probes functionalized with gold nano-particles that can modify the opaqueness at the detection site. The DMA has been fabricated using a 0.5 mu m CMOS process together with on-chip timing control and correlated double sampling. Experimental results show that the system can detect DNA samples with extremely low concentration down to 10 pM using ordinary light source. (C) 2005 Elsevier Ltd. All rights reserved.