A CMOS Image Sensor Utilizing Opacity of Nanometallic Particles for DNA Detection

This paper reports a DNA detection protocol utilizing the opacity of self-assembled nanometallic particles and the optical response of a CMOS image sensor. Due to the complementary nature of the DNA hybridization process, the DNA fragments attached to the nanoparticles precipitate them only at locations where complementary DNA strands exist. The opacity of the chip surface change due to the accumulation of nanometallic particles can be used to detect the existence of some targeted DNA fragments. Ordinary light sources can be used in this approach rather than special ultraviolet light sources in the most popular fluorescence-based detection method. DNA detection has been carried out on a CMOS image sensor chip fabricated using a standard 0.5-mum CMOS process. It has been demonstrated that the approach is very sensitive, detecting even single-base mismatched DNA targets with extremely low concentration DNA samples down to 10 pM