A reducer was used to construct Au nanowires (AuNWs) by the conjugation of 2-aminoethanthiol-capped gold nanoparticles (AET-AuNPs) and the immobilized DNA molecules on 3-aminopropyltriethoxysilane-coated Si wafer. The AuNPs coated with AET monolayer seem to be electrostatically assembled along DNA molecules by careful control of the relative molar quantities of AuNPs and AET. A variety of AuNP sizes (2, 5, and 10 nm) was used and also the ratio of AET to AuNP solution was varied to control the interparticle spacing and finally to form the nanowire based on DNA template. The formation of long-range AuNWs and the interparticle spacing were observed with atomic force microscopy. (c) 2006 American Vacuum Society.