Fabrication of nanofluidic devices utilizing proton beam writing and thermal bonding techniques

The fabrication of polymer lab-on-a-chip systems for applications in Chemistry and Biology is one of the envisaged niche areas for the Proton Beam Writing (PBW) technique developed at the Centre for Ion Beam Applications (CIBA). Utilizing a highly focused beam of MeV protons, well-defined nanostructures with smooth and straight side walls have been directly written in a 500 nm to 10 μm thick PMMA layer spin coated onto a Kapton substrate. By subsequently thermally bonding the fabricated structures to bulk PMMA and carefully peeling off the Kapton, nanostructures can be attached to bulk PMMA. Finally, by bonding a PMMA sheet to the bottom side of the structure, an integrated PMMA device with enclosed multiple high aspect ratio nanochannels can be realized. Preliminary experiments conducted in order to test this polymeric device indicate good fluidic properties. The nanochannels can be easily filled with dye solution using both pressure and capillary action in the case of hydrophilic solutions.