Microfluidic chip made of COP (cyclo-olefin polymer) and comparion to PMMA (polymethylmethacrylate) microfluidic chip

Hot embossing method was studied for the fabrication of microfluidic microchannels on COP (cyclo-olefin polymer) chip. The ending temperature of heating stage, i.e. embossing reference temperature (Tr), was determined by the viscoelastic property of the COP, according to variable temperature quasi-creep experiments. Taguchi method was used to decide the processing parameters in cooling and demolding stage. The optimized parameters of hot embossing are: embossing reference temperature 143 °C, temperature and pressure holding time 2 min, pressure at cooling and demolding stage 1.6 MPa, the demolding temperature in the lower heating plate 80 °C and temperature difference between the upper and lower heating plate 10 °C. Experiment shows that microchannel fabricated with the above parameters has high repeatability and low substrate deformation, average repeatability is 97.6% in width and 94.3% in depth. Experiments on background fluorescence, electrophoresis, and DNA separation and detection were carried out on COP and PMMA (polymethylmethacrylate) chips, respectively. Compared to the PMMA chip, the COP chip has higher signal to noise ratio, higher electrophoresis efficiency, and lower peak area relative standard deviation (R.S.D.). In separation 6 μg/ml ϕ X174 RF DNA Hinc II, 11 DNA fragments have been identified in less than 2 min on the COP chip, thus it has large application potential in biochemical analysis.