Technologies for nanofluidic systems:: top-down vs. bottom-up -: a review

This paper gives an overview of the most commonly used techniques for nanostructuring and nanochannel fabrication employed in nanofluidics. They are divided into two large categories: top-down and bottom-up methods. Top-down methods are based on patterning on large scale while reducing the lateral dimensions to the nanoscale. Bottom-up methods arrange atoms and molecules in nanostructures. Here, we review the advantages and disadvantages of those methods and give some future perspectives. It is concluded that technology in the region of 1 - 10 nm is lacking and potentially can be covered by using the pulsed-laser deposition method as a controlled way for thin film deposition ( thickness of a few nanometers) and further structuring by the top-down method.