Joerg Nestler

Integrated point of care testing system based on low cost polymer biochips

A new diagnostic testing device is proposed for point of care (POC) applications. It consists of a microfluidic cartridge with a polymer biochip and an instrument for reading the biochip and controlling the microfluidics. This system allows a very easy determination of several parameters e.g. in patients blood automatically. The biochip is made of a thin polymer foil serving as waveguiding element and as carrier for the receptors on the biochip surface. A sensitive TIRF (total internal reflection fluorescence) readout is realised. Optical elements for incoupling and outcoupling of light are integrated into the foil. Beside the TIRF element, the disposable microfluidic cartridge integrates a sample inlet, several reservoirs for reagents, fluidic microchannels and electrochemical micropumps. Sandwich assays for the detection of clinically relevant parameters have been investigated. This hardware configuration forms the basis for a fully automated compact low cost device using cost efficient disposables.

Nanostructured polymer thin films : Application to biosensors

Damien Dresse Introduction The possibility to modify and control the surface wettability of different materials has attracted signicant scientic and technological interest. Particularly for biological systems (implantable microdevices in the body or microfluidic systems) the hydrophobic and hydrophilic nature of a surface plays a key role on the mediation of solute (e.g. protein) adsorption and cell adhesion [1,2]. Also, surface roughness may amplify hydrophobicity as observed with superhydrophobicity of self-cleaning surfaces like some plant leaves, e.g., lotus [3]. Such an effect can be desirable for channel flows since it can reduce resistance to the flow [4]. Moreover, the clinical use of so-called non-fouling surfaces requires the ability to effectively interface with the biological milieu in a non-immunogenic and stable manner [5]. So to address this twofold request of surfaces having a tuneable physical behaviour towards a liquid sample as well as a natural compatibility with biomarkers carried within the sample suitable polymer films have been developped by Plasma Enchanced Chemical Vapor Deposition (PECVD). These polymers films also have practical uses in the surface modification of all kinds of materials such as binding of biomaterials, dyeing of textiles, catalyst preparation, printability of polymers, adhesion improvement of composite, wettability improvement of materials etc. [5-9]. PECVD films provide unique advantages due to the ability to control topography and film thickness on the micro and nanoscale, and control surface chemistry in a precise manner through chemical coupling and precursors tayloring. The present article is illustrating this technology through the case of application of SEMOFS. SEMOFS is an European project whose aim is to develop technologies, demonstrators and bioprotocols for the polymer based integrated probe card. It applies a label-free optical detection based on surface plasmon resonance (SPR) [10], where biochemical interactions at the sensor surface are monitored by observing the resonant behaviour of surface waves at a thin metal film. Both active and passive optical components (light source, waveguide, detector) as well as fluidic elements for active liquid transport and immobilised biological material (e.g. antibodies) will be integrated in the card. This new type of biosensor concept will

Liquid reagent storage in self-pumping lab-on-a-chip systems for quick assay and biosensor integration

We present a novel approach for liquid reagent storage in lab-on-a-chip systems. A special normally-closed valving technology using thermal-release adhesive tapes is presented. The cartridge and experimental setup is explained. The thermal release tape is opened by attaching heating elements to the areas to be opened. Heating parameters were optimized and a newly developed cartridge containing nine liquid reservoirs is emptied completely automatically, including valve-opening steps and integrated pumping.