Focus ion beam based nanofluidic system for biomolecule characterization

A Pyrex nanochannel system with embedded transverse nanoelectrodes was designed and fabricated by MEMS based microfabrication and focused ion beam (FIB) nanolithography. The microchannels and microelectrodes in the system were patterned on a Cr/Au coated Pyrex wafer using conventional photolithography while the nanoelectrodes (100 nm wide and 50 nm thick) and the nanochannels (500 nm to 1 μm wide and 100 nm deep) were fabricated by FIB nanolithography. A Pyrex chip coated with amorphous silicon was used as the capping piece to seal off the nanochannels and nanoelectrodes through anodic bonding. Fluorescein isothiocyanate (FITC) solution was pumped through the completed nanochannel system after wetting steps to verify flow patency. The electrical conductivity of four different liquids solutions were measured in the nanochannel system and compared to their bulk values. Translocation of negatively charged nanobeads with an average diameter of 20 nm was successfully carried out and the instantaneous transverse electrical conductivity of the translocating nanobeads was measured by the embedded nanoelectrodes.