LabAutomation 2006 - SLAS

Where Laboratory Technologies Emerge and Merge
9:30 am Wednesday, January 25, 2006 Track 1: Detection & Separation Room: Catalina
Wyndham Palm Springs Hotel
Holger Bartos
Co-Author
Boehringer Ingelheim microParts GmbH
Dortmund,
Germany
holger.bartos@microparts.de
Ralf-Peter Peters
Emerging Trends in Microfluidics
Recent developments in fluidics, microelectronics and detection techniques have matured the use of BioMEMS in medical diagnostics and
drug discovery. Microfluidic chips, for example, now compete in routine applications with macroscale test devices. It has become obvious
that miniaturisation alone is not the key factor for success. The recent trend in microfluidics has been the development of integrated
devices which incorporate multiple fluidic assay functions like blood separation, metering, resuspension, fluid transport and detection. By
the use of these devices the instrumentation for sample handling, incubation and detection can be simplified considerably. However, the
acceptance of such biochips strongly correlates with important features like low cost, easy handling, high reliability and a consistent and
mature fabrication technology. In this presentation microfluidic design elements for typical assay steps are demonstrated and it is discussed
how design, function, fabrication and application have an impact on the technical and commercial success of BioMEMS.
10:00 am Wednesday, January 25, 2006 Track 1: Detection & Separation Room: Catalina
Wyndham Palm Springs Hotel
Norbert Gottschlich
Co-Author(s)
Greiner Bio-One, Inc.
G. Knebel
Longwood, Florida
norbert.gottschlich@gbo.com
Greiner-Bio-One GmbH
T. Brenner, C. Mueller, H. Reinecke, R. Zengerle, J. Ducrée
IMTEK - University of Freiburg; Germany
Epoxy-Based Master Tools for the Production of Plastic Microchips by Injection Molding
The trend to use polymer chips for lab-on-a-chip applications is strongly driven by cost-efficient mass production techniques such as
injection molding. However, expensive and time-consuming fabrication of conventional metal masters limits its use for prototyping.
We present a technique for low-cost fabrication of epoxy-based mold inserts to injection-mold plastic microchips. In our novel approach,
SU-8 lithography was applied to generate high-precision structures which were then cast into epoxy masters. Low-viscosity resins (25000
mPa s) containing aluminium powder (10% by weight) provided excellent filling of microcavities together with adequate mechanical and
thermal stability after curing (Tmax= 220°C). The versatile master could be used both in hot embossing and injection molding. A smooth
removal of molded polymer parts from the epoxy master required tapered structures with sloped sidewalls. In our fabrication method,
we exposed the resist from bottom to top through a transparent Pyrex wafer, forming structures which were tapered towards the top,
facilitating the critical demolding step. The optimum taper angle of could be adjusted by the exposure dosage. We replicated microfluidic
structures of typical geometries (channel height=160 µm, width=150 µm) into various polymers. By optimizing the injection protocol,
excellent dimensional conformance was achieved between the epoxy master and the replicated part. Additionally, low surface roughness
(