Enzymatic digestion and peptide separation are basic steps for preparation of protein samples prior to their analysis by mass spectrometry. Micro-pillar reactors for digestion and reverse phase liquid chromatography were designed and constructed using semiconductor technologies. The performances of the micro-machined reactors were evaluated: complete Cytochrome C digestion was achieved in 6 min for a concentration up to 25 pmol.μl-1 and the separation micro-column was seen to exhibit separation capabilities and capacity close to those obtained with a commercial column. Furthermore, a comparative study between hydrodynamic and electroosmotic driven flows was performed for each peptide of a Cytochrome C digest. It was demonstrated that parasitic electrophoretic phenomena disturbed peptide mobility but not protein identification.
During the last decade, world-wide developments in micro-fabrication technologies have led to numerous Lab-On-a-Chip (LOC) micro-systems covering a wide spectrum of biotechnological applications. Although early LOC developments were driven by glass and silicon micro-fabrication techniques, in recent years polymeric-based LOC have been intensively developed. Taking advantage of each material, a hybrid device associating an active silicon chip with a passive polymeric micro-part has been developed to produce an addressable Cell-chip for individual cell manipulation and sorting. The complete hybrid micro-fluidic device fabrication is described here, including polymer structuring, hermetical sealing, biocompatibility studies, and fluidic interconnections with the sample as well as detection aspects. The cell manipulation is based on dielectrophoresis, which allows cell motion without fluid flow. First biological results will be presented.
The lab-on-a-chip approach has been increasingly present in biological research over the last ten years, high-throughput analyses being one of the promising utilization.
The work presented here has consisted in developing an automated genotyping system based on a continuous flow analysis which integrates all the steps of the genotyping process (PCR, purification and sequencing).
The genotyping device consists of a disposable hybrid silicon-plastic microfluidic chip, equipped with a permanent external, heating/cooling system, syringe-pumps based injection systems and on-line fluorescence detection. High throughput is obtained by performing the reaction in a continuous flow (1 reaction every 6min per channel) and in parallel (48 channels).
We are presenting here the technical solutions developed to fabricate the hybrid silicon-plastic microfluidic device. It includes a polycarbonate substrate having 48 parallel grooves sealed by film lamination techniques to create the channels. Two different solutions for the sealing of the channels are compared in relation to their biocompatibility, fluidic behavior and fabrication process yield. Surface roughness of the surface of the channels is the key point of this step. Silicon fluidic chips are used for thermo-cycled reactions. A specific bonding technique has been developed to bond silicon chips onto the plastic part which ensures alignment and hermetic fluidic connexion. Surface coatings are studied to enhance the PCR biocompatibility and fluidic behavior of the two-phase liquid flow. We then demonstrate continuous operation over more than 20 hours of the component and validate PCR protocol on microliter samples in a continuous flow reaction.