A simple approach for an optically transparent nanochannel device prototype.

Compared with microfluidic devices, the fabrication of structure-controllable and designable nanochannel devices has been considered to have high costs and complex procedures, which require expensive equipment and high-quality raw materials. Exploring fast, simple and inexpensive approaches in nanochannel fabrication will be greatly helpful to speed up laboratory studies of nanofluidics. Here we developed a simple and inexpensive approach to fabricate a nanochannel device with a glass/epoxy resin/glass structure. The grooves were engraved using a UV laser on an aluminum sacrificial layer on the substrate glass, and epoxy resin was coated on the substrate and stuffed fully into the grooves. Another glass plate with holes for fluidic inlets and outlets was bonded on the top of the resin layer. The nanochannels were formed by etching thin sacrificial layers electrochemically. Meanwhile, the microstructures of the fluidic outlets and inlets could be fabricated simultaneously to the nanochannel formation. The total processing time for the simple nanochannel device took less than 10 hours. Optically transparent nanochannels with a depth of up to 20 nm were achieved. Nanofluidic behaviors in the nanochannels were observed under both optical and fluorescence microscopes.