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Friedhelm Schönfeld

Publications and source records attributed to Friedhelm Schönfeld.

2 recordsLinked to original sources

Sinusoidal crossflow microfiltration device--experimental and computational flowfield analysis.

We present an analysis of the flowfield inside a novel crossflow microfiltration device. The filter performance relies on shear focusing by means of a corrugated channel. The flow and shear stress characteristics inside the filter are studied by means of both micro Particle Image Velocimetry (micro-PIV) measurements and Computational Fluid Dynamics (CFD) analysis. We show that an increase of the shear rate by 55-85% as compared to a straight channel geometry is achieved for crossflow velocities ranging from 0.05 m s(-1)-0.8 m s(-1)(Re 5-70). This substantial increase in the local wall shear may improve filter performance in terms of reduced clogging and cell cake formation as compared to conventional crossflow filtration devices. Our current investigation, along with the fact that the filter employs no complex, three dimensional geometrical patterns, advanced pumping schemes, nor has a need for costly assembly and sealing procedures, indicates that the sinusoidal crossflow microfiltration module may serve as a technically and economically feasible solution for integrated lab-on-a-chip devices. Furthermore, the presented approach of shear-focusing may be beneficial in other bio-chemical contexts, such as cell lysis and surface chemistry.

Journal Article↗

Integrated polymer chip for two-dimensional capillary gel electrophoresis.

Two-dimensional (2D) gel electrophoresis (GE) is one of the most powerful methods for nucleic acid and protein separation, but generally suffers from high laboratory efforts connected with high analysis costs. Therefore, we herein present the development of a miniaturized 2D capillary GE (CGE) device which allows for an efficient protein separation in analysis times of about 1.5 h. This integrated 2D-CGE chip comprises a first channel for isoelectric focussing (IEF), a second specially designed transfer channel, 300 parallel micro channels, each having a cross section of 50 microm x 50 microm, and buffer reservoirs. The present work discusses fabrication aspects, in particular the combination of different microfabrication technologies, experimental separation performances of isoelectric focussing (IEF) and CGE, and presents computer simulations and first experimental results of protein transfer from the first to the second dimension.

Animals↗