Micro channel systems for bio/chemical analysis

A modular concept for micro liquid handling in chemical and biochemical analysis was developed. All devices presented are based on monolithic structures manufactured with the same simple micro fabrication techniques. The devices are designed to be tolerant to particle containing samples allowing novel applications in biochemical and cellular analysis. This basic strategy has been used in the design of sorters/injectors, immobilisation reactors, Coulter counter, mixers, valves, dialysis membranes and flow sensors. All devices have been fabricated using a single silicon wafer with channels etched on both sides. A separating membrane was selectively perforated to connect the channels at over crossing regions.
Example: A micro fluidic injection valve was developed allowing a reproducible the injection of minute amount of liquids on a continuous flow stream down to 0.1 nl. For demonstration the flow switch in chemical analysis a chemilumino metric glucose assay was used. For this a simple flow injection analysis system was designed using the flow switch for both, sample injection and reagent addition. The experimental results showed excellent reproducibility (r. s. d. 0.5 - 2.5 %, n=10) in the linear range of 0.1 mM to 10 mM, reflecting the stability and reliability of the injection system. By using the flow chip simultaneously for reagent addition and sample injection the system becomes very simple.