30.10.2009Rainer Gransee , Eva Schäffer, Marion Ritzi-Lehnert, Institut für Mikrotechnik Mainz GmbH
For the transfer of biochemical assays into Lab-on-a-Chip (LOC) systems sophisticated valve concepts are needed due to the highly complex fluidic layouts. Often, these valve concepts also include fluid storage during shelf life and metering, separating and/or merging of fluids during the assay. Several micro fluidic valve concepts have been developed at IMM. These micro-valves are designed for integration into fluidic polymer chips, flexible adaptation to the fluidic layout and usage on chip and consist of biocompatible materials.
The leakage rate is the most important factor for characterizing micro-valves and to evaluate fluidic control of LOC applications. Commercial available valves are mostly characterized by their response time and the maximum pressure which can be applied. However, the maximum pressure is not sufficient for characterizing novel developed micro-valves, as a small leakage can already occur at pressures of 20 mbar (2000 Pa). Even small leakage volumes in the order of μl can strongly interfere with robust process control during micro fluidic applications.