LOS ANGELES, CA- According to ongoing research from Strategic Directions International, the market for microarray technology reached nearly $1 billion in 2005 and looks to be on the rise again in 2006. While the majority of this market is not composed of the scanners, there are bright spots for hardware suppliers, including those manufacturing the optical systems.
The modern study of genetics has contributed incalculably to the study of human biology and the development of treatments for disease. One of the most important laboratory technologies contributing to this revolution is the DNA microarray, which came to prominence in the mid-1990s. Microarrays have helped to automate genetic analysis, increasing workflow by several orders of magnitude.
The microarray itself is a glass slide ‘printed’ with an ordered array of thousands of known DNA sequences. DNA from a sample is treated, fluorescently tagged, and introduced to the microarray, where the sample DNA attaches itself to matching sequences on the array. Microarray scanners, which incorporate lasers, are used to read the fluorescent signature. Software then interprets the fluorescence pattern and identifies the sample’s genetic composition.
Although white light sources such as xenon lamps are used in some microarray scanners, laser-based scanning is far more common. The optical system is similar to a confocal laser scanning microscope, in that a small laser spot illuminates and excites the sample; then the fluorescent signal is detected by a photomultiplier tube. The confocal geometry prevents stray light from affecting the measurements. Depending on the fluorescent tags chosen by the researcher, different laser frequencies may be required. A typical commercial system has both a red and green laser; for instance, the Agilent G2565Bs has a 532 nm SHG-YAG laser and a 633 nm He-Ne laser. The Genechip Scanner 3000 7G of Affymetrix, far and away the overall leader in the microarray market, has a single 532 nm diode-pumped frequency doubled YAG laser. On the other hand, Molecular Devices offers up to four lasers on its Genepix 4200A microarray scanner, with frequencies of 488 nm, 532 nm, 594 nm, and 635 nm.
However, at this point the microarrays still form the bulk of this market, with vendors supplying various combinations of human and non-human DNA sequences on their respective microarray platforms. Although some researchers continue to spot their own microarrays, the increasing availability and variety of standard commercial microarrays has made do-it-yourself methods much less prevalent in the laboratory.
Looking at the hardware side of this market, sales of microarray scanners amounted to roughly 1750 units in 2005. This is a slight decrease from 2004 sales, as market saturation is beginning to exert a retarding effect on this market. Nevertheless, the current market is still twice the size it was just five years ago.
Another positive indication of growth in microarray technology is the development of protein microarrays. As life science research moves beyond the genome and into the proteome, analogous microarray systems for protein analysis are being developed. Though the protein microarray business is less than one-tenth the size of the DNA business, it is growing at about 15% per year and will soon become a more significant source of demand for laser-based microarray scanners. -MT
Michael Tice is Vice President of Consulting Services at Strategic Directions International, http://www.strategic-directions.com/.