Fabrication of SU-8 photoresist micro-nanofluidic chips by thermal imprinting and thermal bonding

Micro-nanofluidic chips have been widely applied in biological and medical fields. In this paper, a simple and low-cost fabrication method for micro-nano fluidic chips is proposed. The nano-channels are fabricated by thermal nano-imprinting on an SU-8 photoresist layer followed by thermal bonding with a second SU-8 photoresist layer. The micro-channels are produced on the second layer by UV exposure and then thermal bonded by a third layer of SU-8 photoresist. The final micro-nano fluidic chip consists of micro-channels (width of 200.0 +/- 0.1 mu m and, depth of 8.0 +/- 0.1 mu m) connected by nano-channels (width of 533 +/- 6 nm and, depth of 372 +/- 6 nm), which has great potential in molecular filtering and detection.