CHICAGO (GenomeWeb) — Bio-Rad has developed an automated droplet generator for its droplet digital PCR platform and plans to begin shipping the add-on in September.
Unlike the current manual droplet generator, the automated system, called AutoDG, does not require a hood or clean room, and, after about five minutes of set-up time, generates 20,000 droplets per well in a 96-well plate format.
Company representatives spoke to PCR Insider from the Bio-Rad booth on the floor of the American Association of Clinical Chemistry annual meeting and lab expo, held here this week.
Viresh Patel, senior marketing manager at Bio-Rad's digital biology center, said he believes that the AutoDG is the first automated droplet generating system on any digital PCR platform.
The instrument may help reduce user-to-user variability seen with the current manual droplet generator. "Droplet digital PCR is sensitive enough to detect differences in people's pipetting habits," Patel said. "This instrument will basically eliminate those differences."
With digital PCR, each droplet contains a PCR reaction. Droplet generation is performed in a separate, smaller device. A plate full of droplets is sealed and transferred to a thermocycler. Then the plate is loaded into Bio-Rad's droplet reader, the second generation of which is called the QX200. This detects fluorescence in droplets where amplification occurred, and provides absolute quantification of nucleic acid in a starting sample.
The company displayed photographs and video of the AutoDG at AACC. Carolyn Reifsnyder, a marketing manager at the digital biology center, said, "We're planning to start shipping at the end of September, so we'll take orders just before that. We're taking pre-orders now."
The AutoDG has a HEPA filter and maintains positive pressure, Reifsnyder explained. "The droplets are generated in this clean environment, so the risk of contamination is reduced. This means that the AutoDG can be placed in a standard lab," she said.
The device may also make larger runs more efficient, and help users start maximizing the throughput of ddPCR. Compared to the manual droplet generator, "Instead of preparing up to 96 reactions, eight at a time, you simply load your plate of up to 96 reactions into the AutoDG," Reifsnyder said.
The device has a color, touch-screen interface, and users can choose droplet generation oil for fluorescent probes or EvaGreen intercalating fluorescent dye, loading only the consumables needed for a particular run.
"With a five-minute setup, you're able to walk away and return to a full plate of droplets ready for thermal cycling and analysis," said Reifsnyder.
The AutoDG generates droplets for both the QX200 and the company's first-generation QX100, "so if you have a QX100, the AutoDG is still a good option," she added.
The company has sold a number of ddPCR platforms since 2011, when it gained the technology from the acquisition of QuantaLife for $162M, although it declined to disclose specific sales figures. Since then, it has also focused on deeper applications, providing scientific data and validated assays on the platform, such as ones for cancer mutations and copy number variation, Patel said.
For the AutoDG, "We're seeing interest from both existing users who want to upgrade, as well as new users who understand the value that this brings," he said.
The AutoDG will be more expensive than the manual system, "but not exorbitantly," Patel said.
Reifsnyder added that the running cost "is not going to be that much different," remaining in the $3-per-well range.
So far, the ddPCR platform is for research use only. "That being said, very early on, translational and clinical researchers saw the value of this technology and what it could do in several areas of medicine, and have taken it and developed their own process around the system to move it into the clinic," Patel said.
For example, one recently described assay uses ddPCR to report methylation status of cell-free DNA to quantify beta cell death in diabetes. This assay was licensed by Yale University to Islet Sciences, a company that hopes to develop it into a commercially available test in 2015.
Patel noted that because of the publication cycle for researchers, many of the assays now described in the scientific literature use the QX100. The QX200 has been commercially available for less than a year, so he expects more research using that platform to be published in the future.
Patel also commented on the development of the droplet-based sequencing platform acquired from GnuBio, saying that while it is still too soon to comment on a timeline for product availability, the early results are promising.
Patel said he expects the platform – a hybridization-based droplet sequencing technology that uses a picoinjector – to be synergistic with ddPCR, and that the workflow will eliminate sample prep and shorten turn-around time to four hours.