Pre-storage of liquid reagents in glass ampoules for DNA extraction on a fully integrated lab-on-a-chip cartridge

Self-containing, ready-to-use cartridges are essential for mobile Lab-on-a-Chip (LoaC) systems intended for Point-of-Care (POC) use. Up to now, a common weak point in many LoaC developments is the need to dispense liquid reagents into the test cartridge before or during processing of the assay. To address this issue we have developed an efficient method for fusing liquid reagents into glass ampoules, which are then sealed into a centrifugally operated cartridge. For on-demand reagent release, the ampoules are disrupted through the flexible lid of the cartridge. Upon centrifugation, 98.7 mu L out of 100 mu L (CV = 2.5%) of the pre-stored contents are released into the microfluidic system. No liquid loss is observed for ethanol and H2O stored for 300 days at room temperature. Frozen storage is possible without damage to the ampoules. Applicability of this concept is demonstrated by performing a LoaC integrated DNA extraction after 140 days of reagent pre-storage. DNA yield from 32 mu L of whole blood was up to 199 ng, which is 77% of an off-chip reference extraction. The presented approach allows the improvement of existing LoaC cartridges where pre-storage of liquid reagents was not implemented yet.