Self-integration of ion transport tunable nanoporous microplugs in a microfluidic chip for electrokinetic bio-sample concentration

We describe simple and robust methods that can be used for microfabricating nanoporous materials as leakage-tight membranes in a microfluidic channel network. The methods consist of a common self-integration process and individual solidification processes such as solvent evaporation, UV-curing, and temperature treatment. We demonstrate that the fabricated membranes can be used for electrokinetic, nanofluidic pre-concentration of bio-samples such as proteins, cells, and nanobeads on either the anodic or cathodic side of the membranes. In addition, we not only compare the physicochemical properties of the membranes but also characterize biocompatibility and robustness of the membranes. The methods are versatile for many nanoporous precursor materials, and it is easy to control the location and dimension of the membranes. Hence, the methods developed in this work and the characterized properties of the membranes could be widely employed for further applications of nanoporous membranes in microfluidic systems