The 6100 is a small, bench top instrument comprised of a programmable vacuum manifold, key pad control and LCD display screen. The system uses 96-well filtration plates as the extraction format and facilitates the extraction of DNA or RNA from a range of sample types including whole blood, buffy coat and cell cultures.
The instrument uses solid phase extraction chemistry. The dimensions of the instrument are 53 x 48 x 27 cm (bench top) and it weighs about 20 kg. It takes at least 2 hours to process samples; user intervention is required about every 15 minutes. Reagents tracking is done manually (i.e. not by bar coders as by other, fully-automated instruments). Maintenance involves minimal cleaning.
We use the 6100 mainly for the extraction of genomic DNA and viral RNA mainly from blood as well as serum/plasma. It generates very good yields both in terms of amount of the amount of nucleic acid and in terms of quality. The yield of extracted DNA is at least 19 – 20 µg/ml and the purity of the OD260/OD280 ratio is usually 1.9.
Obtaining total RNA from blood requires several steps. In the initial step, we add lysis solution which lyses red blood cells. The lysis occurs almost immediately after the reagent is added to the blood sample. The reagent also inactivates cellular RNases, preventing degradation of the isolated nucleic acid while RNA is selectively precipitated; genomic DNA and protein remain in the solution. This allows a separation of total RNA from genomic DNA and other cellular debris. The blood lysate is then transferred to the total RNA purification tray, where it is passed through the tray under precisely controlled vacuum conditions. The total RNA purification tray consists of: 96 wells (650 µL/well), a membrane to physically capture the precipitated RNA, a low retention volume dripper and an aerosol guard to prevent well-to-well cross contamination. After performing all these exercises, the system enables purification of 96 samples of total RNA from whole blood in about 2 hours, start to finish. Set-up requires about 40 minutes and the actual run time of the instrument is about an hour, plus time for the manual interventions. In addition to increasing the overall processing time, these interventions make the process a little difficult.
Overall, the instrument performed very well in the terms of quality and yield of DNA and RNA and I would recommend it for purification from large numbers of samples, but not for small batches. Although manual preparation for each run took about 40 minutes, the process is simple and easy to manage.