A DNA-detection platform with integrated photodiodes on a silicon chip

In this paper, we had proposed a silicon integrated circuit (IC) compatible DNA-detection platform using photodiode and ordinary optical illumination to detect DNA hybridization events occurred on the chip surface. The method utilizes gold nanoparticle labeling and silver enhancement to generate opaque surface at area with target DNA hybridization. A photodiode fabricated underneath the supporting surface can then be used to detect the light intensity changes, before and after the silver enhancement. With this technique, we have successfully discriminated single base-mismatched DNA from matched DNA sequence, and the detection limit could be as low as 10 pM. By exploiting the advanced modern IC manufacturing technology and the well-established electrochemical immobilization of DNA, this approach has the potential to be used to construct a portable high-density DNA nanoarray system with fully electronic readout.