Integrated plastic microfluidic device for ssDNA separation

An integrated microfluidic device with on-chip photodiode is fabricated for single strand DNA (ssDNA) separation and detection. The microfluidic component is fabricated by parylene thin-wall technology. In order to achieve oxygen free environment for acrylamide gel polymerization in microfluidic channel, alumina inner coating is introduced to decrease parylene thin film permeability. On-chip high sensitivity photodiode successfully detected ssDNA fluorescence at the end of separation. Results show alumina is a good oxygen barrier which secures excellent cross-linking of the sieving matrix. Single base pair resolution for ssDNA separation in this device has been achieved.