Nanofluidic interfaces in microfluidic networks

The integration of nano- and microfluidic technologies enables the construction of tunable interfaces to physical and biological systems across relevant length scales. The ability to perform chemical manipulations of miniscule sample volumes is greatly enhanced through these technologies and extends the ability to manipulate and sample local fluidic environments at subcellular, cellular, and community or tissue scales. Here, the authors describe the development of a flexible surface micromachining process for the creation of nanofluidic channel arrays integrated within SU-8 microfluidic networks. The use of a semiporous, silicon rich, silicon nitride structural layer allows for a rapid removal of the sacrificial silicon dioxide during the nanochannel fabrication. Nanochannel openings that form the interface to biological samples are customized using focused ion beam milling. The compatibility of these interfaces with on-chip microbial culture is demonstrated.