LAUSR

Numerous microfluidic separation applications have been shown in the past years providing a fast analysis of biological samples like DNA or proteins. Microfluidic separation based on dielectrophoresis (DEP), i.e., migration of a polarizable object in an inhomogeneous electric field, provides numerous advantages. However, the main drawback of DEP separation devices is that they are not sufficient for large scale sample purification due to the lack of high sample throughput. In this work, we present for the first time a microfluidic device with two parallelized dielectrophoretic separations of (biological) samples smaller than 1 μm. The separation is carried out by means of insulator based DEP, i.e., an insulating ridge reduced the flow through height and thus created a nanoslit at which the selective DEP forces occur. The device consists of a cross injector, two parallel operation regions, and separate harvesting reservoirs where the samples are collected. Each DEP operation region contains an insulating ridge. We successfully demonstrate separation of 100 nm and 40 nm beads and 10 kbp and 5 kbp DNA with a separation purity of more than 80%. This states the proof of concept for up-scaling of dielectrophoretic separation by parallelization. Since the present technique is virtually label-free, it offers a fast purification, for example in the production of gene vaccines. This article is protected by copyright. All rights reserved.