Direct Attachment of Double-stranded DNA to Gold Surface for Preparation of Nano-structured Devices

To the 5ʹ-ends of two complementary oligonucleotides, 5ʹ-mercapto-5ʹ-deoxythymidine was introduced and reacted with the surface of either gold plate or colloidal gold particle. Well-defined Au(nanoparticle)/DNA-duplex/Au(plate) composite was fabricated in self-assembled monolayer (SAM) of 11-hydroxy-1-undecanethiol. The current through this composite was measured by conductive probe atomic force microscopy (CP-AFM).