In this contribution, we present a system for efficient preconcentration of pathogens without affecting their viability. Development of miniaturized molecular diagnostic kits requires concentration of the sample, molecule extraction, amplification, and detection. In consequence of low analyte concentrations in real-world samples, preconcentration is a critical step within this workflow. Bacteria and viruses exhibit a negative surface charge and thus can be electrophoretically captured from a continuous flow. The concept of phaseguides was applied to define gel membranes, which enable effective and reversible collection of the target species. E. coli of the strains XL1-blue and K12 were used to evaluate the performance of the device. By suppression of the electroosmotic flow both strains were captured with efficiencies of up to 99%. At a continuous flow of 15 ll/min concentration factors of 50.17 6 2.23 and 47.36 6 1.72 were achieved in less than 27 min for XL1-blue and K12, respectively. These results indicate that free flow electrophoresis enables efficient concentration of bacteria and the presented device can contribute to rapid analyses of swab-derived samples.

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For the first time we demonstrate a microfluidic platform for the preparation of biosensing hydrogels by in situ polymerization of polyethyleneglycol diacrylate (PEG-DA) in a single step. Capillary pressure barriers enable the precise formation of gel microstructures for fast molecule diffusion. Parallel arrangement of these finger structures allows for macroscopic and standard equipment readout methods. The analyte automatically fills the space in between the gel fingers by the hydrophilic nature of the gel. Introducing the functional structures in the chip fabrication allows for rapid assay customization by making surface treatment, gel curing mask alignment and washing steps obsolete. Simple handling and functionality are illustrated by assays for matrix metalloproteinase, an important factor in chronic wound healing. Assays for total protein concentration and cell counts are presented, demonstrating the possibilities for a wide range of fast and simple diagnostics.