Electrokinetic Transport and Fluidic Manipulation in Three Dimensional Integrated Nanofluidic Networks

Nanometre-scale fluidic structures (pores, channels) offer the possibility of accessing flow regimes and fluidic phenomena not possible in larger structures. In particular, control of the surface charge density and zeta potential enable permselective behaviour, when the product of inverse Debye length, κ and channel dimension, a, give κa ≤ 1, and the resulting structures can support electrokinetic flow over a wide range of control parameters. Combining this control paradigm with multi-level structures yields integrated structures in which the nanochannel/nanopore functions as an active element, thereby producing digital fluidic structures. In addition, the special properties of nanofluidic structures can be combined with chemical reactivity in interesting ways. For example, the space charge region at the nanofluidic-microfluidic interface can be exploited to pre-concentrate reactants for enhanced measurements and chemical processing. Furthermore, nanofluidic elements exhibit low Péclet number flow, making it possible to use diffusive transport to efficiently couple reactants in a nanofluidic channel to reactive sites on the walls.