Biotoxin E.coli Detection Device

Innovative magnetic detection technology brings quicker assays to the laboratory bench.

Our entire Electronics and Advanced Services departments were involved in the software development, circuitry design, troubleshooting, and the problem-solving challenges that occurred during development. For this article we interviewed Paul Gleason, a member of that group.

Projects that are a technical challenge, and solve real-world problems are a great fit for us. Do you recall the news about illness arising because of eating undercooked hamburger, and raw milk? E. coli 0157, a bacterium that normally lives in the intestines of mammals is the microbe responsible for most of these recalls. In 2002 a major U.S. supplier had to recall 19 million pounds of beef because of E. coli contamination!

Companies that process food need a rapid and accurate method to test their products before they are sold to the public. We have developed such a testing device for Centrus International, a subsidiary of Eastman Chemical. It is a desktop instrument and assay test cassette that uses para-magnetic microparticles, which bind to the target microbes during the test. The results are displayed and printed. Until now the food industry has not had access to a system with this combination of accuracy, speed, and sensitivity.

The system has its own built-in CPU and printer, and calibrates itself each time it is turned on.

But how does it work? 1) The sample in question is mixed in enrichment broth, a growth media for E. coli. 2) After an incubation period the broth is filtered. Magnetic particles that later attach to the target bacteria are added. 3) A small amount is placed in the assay cassette. 4) Capillary action pulls the magnetic particles, with or without their E. coli hitchhikers, along the assay membrane strip to a detection zone, and then into a control zone. 5) A magnetic detector module reads the strip and identifies minute concentrations of the magnetic-bound bacteria. Results of the test are displayed on the instrument, and printed with its internal printer.

Development of the Envisio® instrument (shown at right) was an example of an integrated team effort.

Paul Gleason, Omnica’s Vice President, was chosen to head the development team because the system requirements were similar to those found in the clinical diagnostics market, his field of expertise. “There’s an assay consumable, a detection methodology, software, user interface, and instrument hardware. It’s a different market, but it is laboratory instrumentation,” explains Paul. “Originally we worked for MagnaBioSciences® to develop the technology of their assay cassette (shown below left) and the magnetic detector module. Eastman® licensed the patented magnetic detection technology, and we were hired to implement it in their new instrument.”
The Envisio device is aimed toward high-volume test sites, so it was designed to be easy to operate. The assay results are interpreted in less than 30 seconds. There are only two buttons, one for the printer paper feed and the other to cancel the process. “Basically the user opens the door and inserts the cassette, and that’s all they have to do,” states Paul.

The instrument incorporates the cutting edge of electronics and software design. “There’s a lot going on in that box. In most lateral-flow assays, concentrations of the target molecules are high, as is true with a pregnancy test.” comments Paul, “To achieve the sensitivity our client wanted, we had to develop special algorithms to detect very low concentrations in test samples. This part of the software and firmware development was particularly intense and rigorous.”

They said “develop the product, and get the appropriate approvals for marketing on three continents.”

The Omnica team faced significant challenges combining just-perfected technology from one company with reagent chemistries from another into an innovative, sleek, and distinctive package. Our client made it clear that the instrument development should not be a hold-up to production (not a unique circumstance for us). Paul describes other unique requirements, which could have slowed the process. “We had to develop a custom miniature barcode reader, which may be the world’s tiniest, and we had to design, tool and mold the cassette. The production processes and components we chose were tailored specifically to their projected production volumes. From Eastman’s point-of-view, the process was turnkey. They said ‘develop the product, and get the appropriate approvals for marketing on three continents’, and we did that.” Transfer to the contract manufacturer was another big part of the process. Paul clarifies by saying, “Eastman chose the manufacturer, and we tailored elements like the documentation, control drawings, preliminary release prints, and inspection according to that manufacturer’s quality system.”

Near the end of the program, one ranking member of the client’s development team commented that the large medical OEM he previously worked for could not have done this job in the short amount of time Omnica completed it. Later, another member added that Omnica has successfully pushed the envelope to the state-of-the-art limit for this parallel project effort.