Miniaturized DNA and RNA quantification has become a standard as it allows for the measurement of a broad concentration range and offers higher reproducibility by avoiding sample dilution steps. Trinean has further optimized this approach in terms of measurement speed, automation capability, and limiting repetitive manipulations by developing a microfluidic sample holder containing 16 or 96 sample positions.
As shown in Figure 1, each sample read-out structure consists of a pipetting inlet, capillary storage, microcuvettes, and an aspiration outlet with a waste trap. The pipetting inlets are conical recipients at a 9 mm pitch that allow easy pipetting with manual single or eight-channel pipettes as well as by liquid-handling robots.
When a two microliter sample is applied, the sample is spontaneously taken up into the storage area by capillary force. Once inside the holding pattern, the sample is protected from evaporation, without measurable change in readout for about two hours. The sample is also protected from cross-contamination and will not leave the capillary, preventing contamination.
This allows the preparation and loading of all samples at the workbench or in a liquid-handling robot and takes only the chip as sample container to the reader in a convenient and safe way. Once inside the reader, each sample will be transferred by aspiration to the microcuvette(s) with path lengths of 0.1, 0.5, or 0.7 mm depending on the selected microfluidic chip type.
The design and uniformity of the microcuvettes allows for the measurement of very precise UV/Vis spectra, which is needed for the spectral content profiling analytics. Within a single chip a large dynamic range from 0.03 OD up to 200 OD (corrected to 1 cm path length) is available. The measuring speed of both the Xpose and DropSense96 reader is approximately 4 seconds/sample, leading to a reading time of a 96-well microfluidic plate of 5 minutes.