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GWC Tech Nabs $100K NSF Grant to Develop Carbon-on-Metal SPR Array for Protein Studies

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By Justin Petrone

GWC Technologies, a Madison, Wis.-based company specializing in protein-analysis tools, said last week that it received a $100,000 Small Business Innovation Research grant from the National Science Foundation to continue developing its carbon-on-metal protein array platform.

CEO Tim Burland told BioArray News this week that the 12-year-old company hopes to make its carbon-coated-on-gold surfaces available by year end, with an eye on expanding the firm's business into applied markets, such as bioengineering and environmental and agricultural testing.

According to Burland, the NSF grant, funded under the American Recovery and Reinvestment Act of 2009, is part of an effort to diversify the surfaces GWC offers to its customers. The firm currently sells three different gold surfaces for use with its surface plasmon resonance-based SPRimager II label-free array reader, a platform that is "popular with bioengineers who are developing new surface assays, and with life scientists who want to understand in-depth how their protein molecules function," he said.

Though gold-coated slides enable label-free array analysis, bypassing fluorescent labels that some scientists believe interfere in measuring the real-life behavior of proteins, the bond of proteins to gold-coated surfaces is not durable enough for routine testing, such as in point-of-care diagnostics, or field experiments, such as in environmental surveillance.

"Our products target analysis of protein function, because the value of label-free analysis in this sector is compelling," Burland said. "Researchers interested in protein function would rather not modify a protein with a major chemical change such as a fluorescent label in order to study it," he said. Since GWC's SPR imaging technology detects any type of molecule, it can be used to study interactions of proteins with other molecules, he said.

The CoM surface was initially developed in a project between GWC and a research team at Lloyd Smith's lab at the University of Wisconsin led by postdoc Matthew Lockett, Burland said. While label-free technology required gold surfaces for array fabrication, the CoM project showed that coating the gold with a protective layer of carbon created an "extraordinarily robust surface for label-free analysis" as probes bond more strongly to carbon than metal.

"The key is the first step. Instead of being a gold bond, it will be a carbon bond," Burland said. "That is what makes it a more stable molecular array," he said. "Gold can get washed off in certain conditions but probe arrays made with carbon will stay there indefinitely."

Burland also said that gold is highly "surface active," meaning that the coating may complicate protein-interaction analysis, while such nonbinding specific issues do not occur on carbon-coated surfaces. The CoM researchers have also showed that it is possible to fabricate arrays via in situ synthesis on the carbon-coated substrates. Burland said that in situ synthesis protocols "would destroy a gold surface," but CoM surfaces "resist the procedure."

GWC's current goal is to demonstrate the performance of CoM for protein arrays and to make them available to its customers for use in custom applications. The company does not offer catalog arrays, though it is considering making them available in the future, Burland said.

The NSF grant will also fund "commercial-scale" CoM chip manufacturing, spectroscopic characterization of CoM surfaces to identify parameters for optimization, and development of methods for fabrication of protein arrays on CoM substrates, according to Burland.

"We think this platform will have big impact on the attractiveness of our array reader," Burland said. "It will be the first new label free surface in over 20 years and it will enable some applications that people weren’t able to do label free previously."

GWC has seen "significant interest" in CoM from bioengineering customers that use its SPRimager system to study absorption of underlying surface chemistry areas. He said that life scientists would like to use the platform to take advantages of SPR detection on a higher-throughput platform.

The SPRimager II is an "extremely versatile tool," Burland noted. "All our customers are doing something different with it and there is no single surface that satisfies everybody." GWC will also continue to sell gold surfaces as there are "quite a few scientists who are happy to put proteins directly on gold." As provider of tools, GWC is "agnostic," he said. "We'll help people do experiment whatever way they want to."

Burland said he believes the CoM array technology could be useful for products manufactured by other companies. In order to bring the technology to market, the company is seeking corporate partners, he said.

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From Spectrometers to SPR

GWC Technologies was established in 1997 by University of Wisconsin researchers Mike Green, Stephen Weibel, and Robert Corn. Initially the firm, then called GWC Instruments, manufactured synchronous sampling demodulators, accessories that improve the performance of spectrometers.

Later, the company moved into SPR imaging, which uses a Fourier transform infrared light source to elicit the SPR response over a broad infrared spectrum. The development of imaging products prompted the company to sell products that could be used with biomolecular arrays, Burland said.

The first version of the SPRimager was launched in 2001. In February, the company launched the SPRimager II-D, which enables users to run experiments in a dual-channel flow cell. The new system allows users to measure multiple molecular interactions for two different analytes in parallel, multiple molecular interactions for two concentrations of the same analyte simultaneously, and adsorption of surface layers from organic or aqueous solutions, using the second channel as a control for the unmodified surface, according to the company.

"Some customers requested a second channel, to split the array in two and flow different solutions over the samples," Burland said of the new instrument. "This is used by people who are developing biosensors. They don’t just want to monitor protein interactions but development of surface chemistry," he said. "They can see how chemistry is working well with dual channel flow cell. They can basically do an array in two halves and do two separate experiments at the same time."

According to Burland, GWC derives most of its revenues from sales of its imager, associated substrates, and other products, such as its spectrometry accessories, which it manufactures for other companies.