Chiung-Wen Kuo1

Nanofluidic system for the studies of single DNA molecules Here, we describe a simple and low-cost lithographic technique to fabricate size-con-trollable nanopillar arrays inside the microfluidic channels for the studies of single DNA molecules. In this approach, nanosphere lithography has been employed to grow a single layer of well-ordered close-packed colloidal crystals inside the microfluidic channels. The size of the polymeric colloidal nanoparticles could be trimmed by oxygen plasma treatment. These size-trimmed colloidal nanoparticles were then used as the etching mask in a deep etching process. As a result, well-ordered size-controllable nanopillar arrays could be fabri-cated inside the microfluidic channels. The gap distance between the nanopillars could be tuned between 20 and 80 nm allowing the formation of nanofluidic system where the be-havior of a single l-phage DNA molecule has been investigated. It was found that the l-phage DNA molecule could be fully stretched in the nanofluidic system formed by nano-pillars with 50 nm gap distance at a field of 50 V/cm. Keywords