When most people think of the array market, they might think of the whole-genome genotyping chips sold by firms like Affymetrix and Illumina. But for providers of array slides, printers, and scanners, the market increasingly is in protein chips, and business is good.
According to firms interviewed at Select Biosciences' Advances in Microarray Technology conference, held in Dublin, Ireland, last week, protein arrays have in recent years come to compose the bulk of their business. Vendors attribute at least some of the trend to the availability of new technologies as well as disenchantment with the results of genomic approaches.
"The self-spotted DNA array market is just about dead; it's so easy to order custom printed oligo arrays from Roche NimbleGen and Agilent," said Alistair Rees, a product manager for German surface provider Schott Nexterion.
In the protein array market, though, Rees said that Schott has been taking market share from competitors like Whatman and Gentel Biosciences ever since it launched its Slide NC nitrocellulose slides at the end of 2007.
"We are converting customers to our platform," Rees said. "In two years, we have gone from having virtually no sales [to protein array users], to it being one of our best-selling products," he said of Slide NC.
Camilo Canel, Tecan's microarray product manager, had a similar assessment of the market. "I am seeing tremendous growth in the protein array market," said Canel, whose firm sells high-resolution scanners. "Last year, it was our largest customer segment," he said. Tecan also manufactures Roche NimbleGen's MS 200 Microarray Scanner, but does not factor those sales into its sales evaluations, Canel noted.
"It's just like DNA arrays were 10 years ago," Canel said. "The market is decentralized; there are small companies with spread-out operations, but everyone wants to get in to create new diagnostic tools."
Joe Blanchard, chief operating officer at Billerica, Mass.-based Aushon Biosystems, said that the company, which sells an array spotter as well as catalog and custom protein array kits, is also being buoyed by sales to protein array users. In particular, Aushon is seeing demand for reverse-phase arrays, a type of protein array pioneered by George Mason University researchers Lance Liotta and Emanuel Petricoin where lysates are arrayed in a micro dot-blot format.
"RPA users are largely academic," he said, "but we are seeing more and more interest from big pharma and biotechs in adopting that technology," he said. "Certain applications are growing, like RPAs and multiplex diagnostic assays, and like allergy panels sold by [companies like Uppsala, Sweden-based] Phadia," Blanchard said.
He also said the "success" of Luminex, which supports protein-profiling assays on its bead-based xMAP platform, is a "good gauge of how the market is growing."
A number of other vendors said that some researchers are disillusioned with genomic arrays, and are adopting protein-based approaches instead.
"There has always been the promise of proteomics, but now it is being realized," said Bruce Dudzik, senior director for business development at Skokie, Ill.-based NanoInk, which sells instruments for producing nanoarrays, catalog and custom nanoarray kits and contract research services.
"The market is growing [because] people think that the results they are getting from genomics are not matching what they hoped to achieve in the past," he added.
Marisa Gonzalez, sales and marketing executive for Roslin, UK-based Arrayjet, said the firm, which sells instruments for printing arrays, has seen growth in the protein array market. According to Gonzalez, Arrayjet has placed 32 systems since it launched its first inkjet microarrayer in 2005.
"There definitely are more and more scientists interested in looking at protein microarrays with our technology," Gonzalez told BioArray News.
According to Tecan's Canel, the uptick in the protein array market is being driven by a number of factors. One is that more tools are available to create custom arrays, but another contributor is that more antibodies are being produced.
He cited the availability of antibodies from the Swedish Human Protein Atlas project, hosted by the KTH Royal Institute of Technology in Stockholm, as an example of a resource that is supporting market growth.
Peter Nilsson, an associate professor of gene technology and proteomics at KTH, agreed that the availability of antibodies is contributing to the increased adoption of protein arrays. "We started to produce protein arrays in 1998 but spent 10 years in the DNA array side, and then the last five years also in protein arrays and now I have completely converted to using protein arrays," Nilsson told BioArray News.
"I think the main issue in the early days was the lack of content, molecules, and people needed something to put on their arrays," said Nilsson, who helps to coordinate the Human Protein Atlas project. "DNA was easy; you could buy thousands of oligos," he said. "The technical challenges of moving from DNA arrays to protein arrays were not enormous, so I think the content was the main issue," he added.
According to Nilsson, KTH is currently using a Luminex platform to do plasma profiling. The institute is also looking into acquiring an Arrayjet system for printing its own arrays. "We have, after 10 years now, more or less finished producing our own DNA arrays, but we are producing a lot of protein arrays," Nilsson said.
Bertrand Jordan, founder and coordinator of France's Marseille-Nice Genopole genomics consortium, said that, in addition to being adopted in research, protein arrays might also have a future in molecular diagnostics.
Jordan said that DNA array-based diagnostics are "on a narrow path between PCR, which is looking at between 10 and 50 genes, and next-generation sequencing: its niche is intermediate." Protein arrays, though, "may have a brighter future, as there is no competition at the high end, and no competition at the low end," Jordan said.
In the near term, Nilsson said that protein chips will more likely be used in biomarker discovery and validation. "It is hard to see that there will be diagnostics based on thousands of proteins; it will be handfuls of proteins, and many other methods are suitable for the end user," Nilsson said. "But, absolutely, they will be used in screening and validation."