By Julia Karow
Life Technologies officials last week provided additional information about improvements the company has made to the emulsion PCR process that underlies the Ion OneTouch System, an automated template preparation device for the Ion Torrent Personal Genome Machine that it plans to start shipping in late June.
While the new sample-prep system will still use emulsion PCR, the company said that it will be an improved version that involves a microfluidic disposable and is vastly different from the emPCR process used with the SOLiD system and 454 Life Sciences' sequencers.
The Ion OneTouch will cost $5,000 and reduce the template prep time to about three hours, including five minutes of hands-on time. In an earlier interview with In Sequence, an Ion Torrent representative had erroneously stated that the amplification process involves no emulsion (IS 4/19/2011).
According to Andy Felton, Life Tech's senior director for product marketing, company scientists have automated the process of creating the droplets, or microreactors, that contain the Ion Sphere microbeads on which the DNA is amplified. "The droplets are created continuously in a membrane and then fed into a PCR disposable," he said.
The droplets then travel inside the disposable and undergo PCR thermal cycling along the way to amplify the DNA. Finally, the droplets are fed into a microcentrifuge to recover the beads.
"With traditional emPCR, everything was done manually," requiring separate pieces of equipment and numerous manual steps for creating and breaking the emulsion, and for thermal cycling, Felton explained. Life Tech has already improved that older process for the PGM with its Ion Xpress kit, launched last week, which cuts the protocol time to five hours, including 90 minutes of hands-on time. "Now we've gone one step further and taken it down to three [hours] with almost no hands-on," he said.
The OneTouch System will require a PCR mastermix, Ion Spheres, and a library of DNA fragments. Users will "put that together in a little consumable that we've developed that attaches to the PCR plate disposable, and then once they've done that, they'll literally press 'go' on the instrument," he said.
Users of both Life Tech's SOLiD and 454's Genome Sequencers have often complained about the emulsion PCR process involved in these systems, saying it is laborious and complex. Both companies have launched ancillary equipment to automate one or several steps of the process, but some users maintain this has not solved the problem. Life Tech, for example, last year introduced the $50,000 three-module SOLiD EZ Bead System, which consists of an emulsifier, an amplifier, and an enricher (IS 2/2/2010). For the GS FLX, 454 last year launched the $19,000 REM e System (IS 1/26/2010), an accessory for a standard liquid handling system that automates the emPCR enrichment and sequencing primer hybridization steps.
Some PGM users are hopeful about the OneTouch. Chad Nusbaum, co-director of the Broad Institute's genome sequencing and analysis program and an early collaborator of Ion Torrent, said that even though the system still uses emulsion PCR, "it appears that it will be elegant and easy to use, and thus would solve the vast majority of the hassles of the previous emPCR process."
— Bernadette Toner contributed reporting for this article.
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