Label free CMOS DNA image sensor based on the charge transfer technique.

This paper describes a label free and fully electronic 32x32 CMOS DNA image sensor fabricated in a 1-poly 1-metal CMOS technology, suitable for inexpensive and highly integrated applications. The pixel operates using the charge transfer technique. DNA immobilization and hybridization on the silane-coated surface are detected, as well as variations in the silane coating. Significant output voltages of 76.4+/-16.5 mV and 64.5+/-15.7 mV were measured after immobilization and hybridization of DNA molecules containing 22 bases. From these results, the immobilized and hybridized DNA densities were estimated. These were 6.3+/-1.4x10(8) cm(-2) and 5.3+/-1.3x10(8) cm(-2), respectively. The DNA detection limit was calculated to be approximately 2.7x10(7) cm(-2) molecules (22 bases). Thanks to its potentiometric detectability, the DNA immobilization and hybridization was successfully verified.