Microfluidics & Consumables
Liquid Reagent Storage
Customer Requirement
Lab-on-a-Chip consumables often require storage of liquid reagents on the consumable itself to provide a fully self-contained cartridge which runs without liquid interfaces to the instrument. Hence a reliable, cost effective, and mass manufacturable solution for the storage of liquid reagents is needed. In addition, the storage concept must fulfill the following requirements:
- Protection and preservation of reagent stability during manufacturing and assembly as well as long-term storage
- Chemical and/or biological compatibility with different reagent types to be stored, no leaching of substances which could affect the assay
- Application of a reproducible mechanism to open the storage container for reagent release and dispense
Solution
Liquid reagents have been stored on both blister packs and in cavities on the chip. For the blister storage concept, the blister pack is formed of a composite-layer film, assembled to the cartridge backbone, filled with the liquid reagent. A small channel connects the blister to the rest of the fluidic network of the cartridge. This channel provides a frangible seal. Once the blister is pressed by the instrument (or manually), this seal opens. With such a concept, a controlled release of the liquid reagent is achieved. The materials used offer protection against environmental conditions (gas exchange, etc.) and the reagent is stored without residual air in the blister. Depending on the number of reagents and the volume to be stored, the concept of storing liquid reagents in cavities on the chip can be advantageous. Since most Lab-on-a-Chip platforms are made of polymers, it is essential to use polymers with sufficient barrier properties to allow storage of volatile reagents. Again, the cavities are closed with frangible seals or frangible seal film valves which are opened by the instrument.
