Label-free DNA detection based on silicon nanowires

Based on silicon nanowires (SiNWs) fabricated by MEMS technology, highly sensitive, sequence-specific and label-free DNA sensors were demonstrated in this paper. Optical lithography and anisotropic self-stop etching were employed to guarantee low cost batch production for SiNWs. Amine-functionalized SiNWs exhibit pH-dependent linear current over a wide range. SiNWs with chemically functionalized single-stranded DNA can recognize the complementary DNA at pM range. In contrast, there is no current change for non-complementary DNA even at a high concentration. With small size and potential for mass production, SiNWs can be potentially developed to become a portable biosensor.