On-Chip Liquid Degassing With Low Water Loss

We present a novel approach for actively degassing liquid and removing trapped air bubbles in microfluidic devices. In our approach, an integrated gas permeable membrane, consisting of a structurally supporting PDMS layer that is covered with a thin Teflon® AF 1600 film, separates the on-chip liquid from an on-chip low-vacuum chamber. Since the Teflon AF permeability is near zero for liquid water and low for vapour, air bubbles and dissolved air are removed through the membrane whilst the loss of water, ions and biomolecules in the system remains low. The system has been demonstrated at elevated temperatures and could be suitable for e.g. degassing during on-chip PCR.