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German Engineering Firm Bosch Developing Microfluidics Platform for PCR

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NEW YORK (GenomeWeb) — A series of papers published in the past three months has demonstrated a novel microfluidics platform for PCR assay automation being developed in part by Bosch, a Stuttgart, Germany-based engineering company known primarily for manufacturing automotive parts and consumer products.

According to the recent publications — co-authored by scientists from Bosch, the Massachusetts Institute of Technology, and Germany's Institut für Mikro- und Informationstechnik — the platform uses basic lab supplies and equipment – a 50-ml tube and a standard centrifuge – to pass sample through disposable cartridges containing reagents. The PCR and readout are then performed in a separate device, designed to employ integrated loop-mediated isothermal DNA amplification or quantitative real-time PCR.

Bosch and collaborators are developing the platform for food safety applications as an entry into the PCR space. However, in the most recent study, published last month in Analyst, the authors hinted at future uses for the platform, including medical diagnostics. They contrasted the new platform with a market standard, the GeneXpert from Cepheid, anticipating a comparative cost benefit, stating that their platform is "ultimately expected to be an order of magnitude lower in cost ... whilst having a similar throughput."

The sample prep device, termed LabTube, is the core component of the platform. It is combined with an amplification and analysis device, called LabReader, to form the complete platform, called LabSystem.

In February, a Biomedical Microdevices study demonstrated LAMP amplification using the LabTube device and a 3V battery. That paper showed fully automated DNA purification of as few as 100 cell-equivalents of verotoxin-producing Escherichia coli, or VTEC, in water, milk, and apple juice. It used integrated and automated LAMP amplification, and demonstrated a reduction of hands-on time from 45 minutes to one minute, according to the published results.

Next, a Lab on Chip paper published in March described LabTube as a device intended to "close the gap" for PCR in low-throughput labs and point-of-care testing, where use of larger, fully automated systems is impractical.

According to this paper, the LabTube platform is based on assay-specific disposable cartridges for processing using laboratory centrifuges.

These "comprise interfaces for sample loading and downstream applications, and fluidic unit operations for release of pre-stored reagents, mixing, and solid phase extraction." The study also stated that "process control is achieved by a centrifugally actuated ballpen mechanism," using thorns to pierce reagent-containing foil blisters.

Now, the most recent study in Analyst debuted the combined platform of the centrifugally-driven LabTube with the amplification and analysis component, LabReader. In the study, the researchers used LabSystem to quantify pathogens and contaminants in food. Specifically, they assessed VTEC in milk, and a less toxic pathogen in fruit juices, Alicyclobacillus acidoterrestris, which causes product spoilage without telltale signs like color change or production of gasses.

A researcher at Bosch, Melanie Hoehl, was first author on two of the three recent studies. She did her dissertation work at MIT in the mechanical engineering lab of Alexander Slocum. This included developing a method using DNA intercalating dyes coupled with a UV and visual light-based reader to detect microbial contamination, as described in The Journal of Agricultural and Food Chemistry.

A patent application was filed for this reader in 2013, specifically for use in detecting the contaminant ethylene glycol via enzyme assays. This application lists Hoehl and Slocum as inventors, and Bosch as the assignee.

Bosch recorded sales of €46.4 billion ($64.2 billion) in 2013, according to a press statement. Its department of corporate research also includes a number of researchers with expertise in PCR, according to the networking site ResearchGate. For example, Jochen Hoffmann, whose recent publications include a 2012 Lab on Chip paper on solid-phase PCR on picowell arrays, is in Bosch's Corporate Research division. He also co-authored two studies in Lab on Chip in 2010; one on pre-storage of liquid reagents in glass ampoules for DNA extraction on a fully integrated lab-on-a-chip cartridge, and another on a microfluidic lab-on-a-foil device for nucleic acid analysis based on isothermal recombinase polymerase amplification.

In the most recent study, the advantages of LabSystem are further described as compared to market standard platforms, such as Cepheid's GeneXpert:

"The semi-automated LabSystem workflow substantially reduces pipetting steps and hence cross-contamination risk," the researchers wrote. "Compared with manual methods, the hands-on time for the LabSystem is reduced from 50 to 3 min by only requiring two instead of 13 manual steps."

They added that compared with fully automated commercial systems such as GeneXpert, the LabSystem currently has four instead of six optical channels, although the researchers have yet to demonstrate multiplexing.

"Compared with fully automated systems, the semi-automated LabSystem has a higher contamination risk," the researchers noted in their paper. "However, the here introduced removable PCR tube limits this risk inside the LabSystem and it makes it more flexible than fully automated systems, like the GeneXpert: the semi-automation affords the separation of the used DNA extraction and amplification systems or the storage of the purified DNA prior to further processing. The LabReader is also more flexible than the GeneXpert, as … PCR, LAMP, and other biochemical reactions can be used without being restricted to specialized kits. The LabSystem performs appropriate DNA purification (which the GeneXpert does not), hence making it less susceptible to PCR-inhibitors from difficult-to-extract matrices."

Representatives at Bosch were unavailable to comment on the platform's development in time for this publication.

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