MicroRNAs (miRNAs) represent a new market opportunity for microarray companies (see Nature 435, 991–996; 200510.1038/435991a). “MicroRNA is as hot as it could possibly be right now,” says Scott Cole, head of genomics marketing at Agilent Technologies of Palo Alto, California, which expects to launch specific miRNA array-based products in 2006.

Exiqon of Vedbaek, Denmark, is now focused on developing miRNA detection products based on its locked nucleic acid (LNA) technology. “An LNA oligo will bind tighter to a DNA than a DNA itself will, and even more so to an RNA,” says Mikkel Nørholm, senior research scientist at Exiqon. “Because the affinity is higher you can use a shorter probe,” he says. The company offers ready-to-spot oligonucleotide capture probes based on the latest information from the miRBASE sequence database (http://microrna.sanger.ac.uk). A pre-spotted array for microRNA detection in human and mouse will be available soon.

Last month, Ambion of Austin, Texas, inked a deal with Rosetta Genomics of Rehovot, Israel, to access Rosetta's proprietary miRNA sequence database, which will add to its current range of microarrays targeting human, mouse and rat miRNAs from miRBASE. Ambion's mirVana miRNA Bioarrays are manufactured by GE Healthcare on its CodeLink platform, which uses a three-dimensional (3D) gel matrix to lift the probes off the slide surface. This is designed to maximize interaction between probe and target and enable the detection of low-abundance miRNAs.

Scott Cole: “miRNA is as hot as it possibly could be”. Credit: AGILENT

miRNA arrays from LC Sciences of Houston, Texas, are currently available on a service basis. The addressable microfluidics chip contains almost 4,000 picolitre-volume 3D chambers and stems from work at the University of Houston and the University of Michigan. At the heart of the system is the µ Paraflo microfluidic technology, which enables fast in situ parallel synthesis of large numbers of different oligos at high yield. In addition to probes based on sequences in miRBASE, researchers can add up to 100 custom sequences at no extra charge. miRNA arrays and services are also available from GenoSensor of Tempe, Arizona, and Paradigm Array Labs of Research Triangle Park, North Carolina, a service unit of Icoria.

Kreatech Biotechnology of Amsterdam, The Netherlands, plans to extend its Universal Linkage System (ULS) direct labelling technology to miRNA research by offering a labelling kit optimized for small RNAs. According to Brent Keller, Kreatech's vice-president of commercial applications, ULS provides a fast and simple alternative to enzymatic labelling methods, which can be subject to 3′-end bias. “Our chemistry is independent of fragment length,” says Keller, “making it ideal for miRNA applications.”

D.G.