Won-seok Chung

Label-Free CMOS DNA Quantification with On-Chip Noise Reduction Schemes

We present a label-free CMOS DNA sensor with a new sensing-pixel architecture and background noise reduction scheme. The proposed sensor generates a differential signal between bio-samples and reference buffer solution with significant reduction in offset and gain fixed pattern noise by employing on-chip correlated double sampling circuits. Non-surface-binding detection technique allows to quantify DNA molecules continuously and sequentially and to reuse the sensor by simple washing protocol. By directly reading the negative charges of DNA molecules, DNA concentrations from 1 muM to 10 muM have been successfully discriminated.

Real-time label-free quantitative monitoring of biomolecules without surface binding by floating-gate complementary metal-oxide semiconductor sensor array integrated with readout circuitry

We report a label-free field-effect sensing array integrated with complementary metal-oxide semiconductor (CMOS) readout circuitry to detect the surface potential determined by the negative charge in DNA molecules. For real-time DNA quantification, we have demonstrated the measurements of DNA molecules without immobilizing them on the sensing surface which is composed of an array of floating-gate CMOS transistors. This nonimmobilizing technique allows the continuous monitoring of the amount of charged molecules by injecting DNA solutions sequentially. We have carried out the real-time quantitative measurement of 19bp oligonucleotides and analyzed its sensitivity as a function of pH in buffer solutions.