CodeLink Enters the Fray

Northbrook, Ill.-based Motorola Life Sciences has tossed its hat into the microarray ring. The company's CodeLink™ platform includes arrays, reagent kits, tools, and software, but the core technology is a proprietary three-dimensional polyacrylamide-based matrix, which Motorola acquired from SurModics of Eden Prairie, Minn. Unlike Santa Clara, Calif.-based Affymetrix, which synthesizes oligonucleotides directly on its biochips using a photolithographic process, Motorola synthesizes its 30-nucleotide oligos offline, tests them by mass spectrometry, deposits them on the array, and then assays them for quality control. The final step in the array production process is the addition of a Flex Chamber™—a disposable hybridization chamber already attached to the slide, which resembles a piece of cellophane with adhesive around the edges. In this case, however, the "cellophane" consists of seven layers of material designed in-house at Motorola. Because the arrays come with the Flex Chamber attached, researchers need not purchase special hybridization chambers; they simply apply their target through the holes at the corners of the Flex Chamber, and then seal them to prevent leakage. Motorola offers several premade, catalog arrays, as well as a custom array synthesis service. The UniSet™ arrays, useful for expression analysis experiments, contain 10,000 unique sequences from rats or humans. A mouse UniSet array is due for release shortly. The ADME-Rat, with approximately 1,200 spots triple-deposited on a single slide, is an array that measures expression of genes involved in adsorption, distribution, metabolism, elimination, and toxicology for drug discovery. Another biochip, used for genotyping 72 different SNPs in the P450 gene family, contains four identical arrays on one slide in a four-up configuration. Unlike many contemporary array systems for two-color fluorescent analysis, Motorola's CodeLink protocol is for one-color analysis. "The reason people do two-color is to have control over a whole lot of the variability from slide to slide to slide," explains Nancy Schmelkin, Motorola's marketing director. "If you control the variability in your manufacturing process, you shouldn't need to have a control in your sample process." In a typical two-color analysis of normal versus diseased tissue, for example, researchers compare ratios of expression levels within an experiment. In a one-color experiment, however, scientists can compare actual raw intensity values across experiments. "You can compare as many samples as you'd like. You are no longer limited to single-slide ratios for those comparisons," says Schmelkin. "Statistically, it's very doable. It's not complicated, but it's a different methodology." And, she adds, a proven one. Besides the array, the CodeLink platform includes reagent kits; parallel processing tools, such as a device to process multiple slides and reduce slide handling; and software for image acquisition and analysis. Presently, this software is optimized for use with Axon® scanners, but the company is working to expand compatibility to other microarray readers as well. The UniSet expression arrays cost $580 (US), while the P450 SNP array lists for $150 per array ($600 for the four-up configuration). According to Schmelkin, Motorola is working to double the capacity of its UniSet arrays, to 20,000 elements per slide. It also is working with The SNP Consortium to produce a high-density, genomic SNP map array, containing around 1,200 SNPs; this array will facilitate disease linkage analyses. Schmelkin anticipates both these products being released near the end of the year. Only time will tell whether Motorola's move into the crowded microarray field is successful, but Schmelkin says her company has something new to offer. "If you just came out with another microarray, and don't move the performance hurdle up a notch, then this isn't really that exciting to enter into," she says. But according to Schmelkin, early customer feedback suggests that CodeLink arrays enable researchers to do things they couldn't do before. "If we can really accomplish that," she says, "I think there's good reason then for another player in the microarray business." —Jeffrey M. Perkel For More Information Motorola Life Sciences +1 (800) 220-4187 www.motorola.com/lifesciences

CodeLink Enters the Fray

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