First particle measurements with an integrated Coulter counter based on 2-dimensional aperture control

In this paper we present first-time measurement results for an integrated Coulter counter device with a liquid aperture. A non-conductive sheath liquid that partially surrounds the sample liquid defines the Coulter aperture. The dimensions of the aperture can be dynamically adapted by changing the flow-rates of the sample liquid and the sheath liquid. An advantage of this approach is that it prevents channel blocking, since the channel's physical dimensions can be much larger than the Coulter aperture. The measurement results show that a high sensitivity can be obtained in a channel with relatively large physical dimensions.