Fabrication of fluidic chips with 1-D nanochannels on PMMA substrates by photoresist-free UV-lithography and UV-assisted low-temperature bonding

A novel method for fabricating nano- or submicro-fluidic PMMA chips using photoresist-free UV-lithography and UV-assisted low-temperature bonding was developed. The nano- or submicro-channels were fabricated by exposing the PMMA substrate to the UV-light through a mask for a certain time. The PMMA substrate with channels and another flat PMMA cover sheet were pretreated with the UV-light for 2 h before they were brought together in running water. The bonding was carried out under a pressure of (1.19 ± 0.12) × 105 Pa and at a temperature of 45°C for 35 min. The chips bonded in this way could bear a tensile of 6.71 ± 2.50 MPa, and the deformation of the bonded channel was about 13%. A hybrid micro- and nano-fluidic PMMA chip fabricated with the developed method was demonstrated for the test of the electrokinetically driven ion enrichment and ion depletion.