Biomedical subjects

Oliver Geschke

Publications and source records attributed to Oliver Geschke.

5 recordsLinked to original sources

PubMed2004

Rapid prototyping of polymer microsystems via excimer laser ablation of polymeric moulds.

This study presents a novel method for rapid prototyping of polymer microsystems. The method is based on excimer laser ablation of a thermally and mechanically stable polymer, such as PEEK (poly-ether-ether-ketone). A negative of the desired microsystem is laser machined in PEEK, which can then be used directly for hot embossing or injection moulding of a series of prototypes. This approach is very rapid and considerably cheaper than more traditional approaches to toolmaking, while still performing well in terms of reproduction of tool dimensions. The reduction in time and cost for a master tool using this method opens up new possibilities for testing small series in the R&D phase of a microsystem. Finally, two particular applications of the technique are presented.

Benzophenones↗

PubMed2004

Development of a multiplex microarray microsystem.

A hybrid multiplex microarray microsystem has been developed that consists of 32 individually addressable array reaction chambers, supporting the use of multichannel pipettes for addition of up to 8 samples simultaneously. Discrimination between Campylobacter jejuni and Campylobacter coli bacteria was observed in DNA samples containing Campylobacter spp., with the same specificity and sensitivity as when compared to a full-size microarray. The spinloaded multiplex microarray microsystem described provides a novel and convenient test format for simultaneous low-density microarray analysis and is universally adaptable to other DNA, protein or small molecule microarray based applications.

Biocompatible Materials↗

PubMed2003

Microstructure fabrication with a CO2 laser system: characterization and fabrication of cavities produced by raster scanning of the laser beam.

In this paper we describe the use of a CO(2) laser for production of cavities and microstructures in poly(methyl methacrylate) (PMMA) by moving the laser beam over the PMMA surface in a raster pattern. The topography of the cavities thus produced is studied using stylus and optical profilometry and scanning electron microscopy (SEM). The microstructures display artifacts from the laser ablation process and we describe how the laser ablation parameters can be optimized in order to minimize these artifacts. Using this technique it is possible to generate structures with a depth from 50 microm and a minimum width of approximately 200 microm up to depth and widths of several mm, governed by the beam size and the laser settings.

Journal Article↗

PubMed2003

CO2 laser microfabrication of an integrated polymer microfluidic manifold for the determination of phosphorus.

A simple colorimetric technique is implemented in a polymer microfluidic manifold. The simple chemistry aids an uncomplicated microchannel design, which is fabricated by CO(2) laser ablation. Issues such as bonding of multiple layers, alignment of micro-fabricated structures and integration of optical components are addressed. A demonstration of a stopped flow regime in the microfluidic manifold is also presented.

Journal Article↗

PubMed2002

CO(2)-laser micromachining and back-end processing for rapid production of PMMA-based microfluidic systems.

In this article, we focus on the enormous potential of a CO(2)-laser system for rapidly producing polymer microfluidic structures. The dependence was assessed of the depth and width of laser-cut channels on the laser beam power and on the number of passes of the beam along the same channel. In the experiments the laser beam power was varied between 0 and 40 W and the passes were varied in the range of 1 to 7 times. Typical channel depths were between 100 and 300 microm, while the channels were typically 250 microm wide. The narrowest produced channel was 85 microm wide. Several bonding methods for microstructured PMMA [poly(methyl methacrylate)] parts were investigated, such as solvent-assisted glueing, melting, laminating and surface activation using a plasma asher. A solvent-assisted thermal bonding method proved to be the most time-efficient one. Using laser micromachining together with bonding, a three-layer polymer microstructure with included optical fibers was fabricated within two days. The use of CO(2)-laser systems to produce microfluidic systems has not been published before. These systems provide a cost effective alternative to UV-laser systems and they are especially useful in microfluidic prototyping due to the very short cycle time of production.

Journal Article↗