When Pall Life Sciences launched its Vivid line of gene arrays in September 2002 as a nylon membrane-based alternative to coated glass self-spotting slides, the US market was already saturated with microarray offerings.
But in Japan it was apparently a different story. At the annual meeting of the country’s Molecular Biology Society in Yokohama last December, representatives from the Port Washington, NY-based filtration and separation company said they presented on the product to a standing-room-only audience of 200 scientists. Over 50 of these scientists attended a two-day follow-up workshop to learn how to use the slides, according to company executives, and the technology took hold among microarray users.
“I think in some ways we hit the Asian market at a very good time, a time when they were still very open to looking at new platforms, whereas here in the states, many of the larger core facilities at research centers have already spent a lot of money and locked their systems into working with glass slides,” said Kara Cannon, senior strategic marketing manager for drug discovery for the firm.
The company initially partnered with Genomic Solutions in Japan to launch the arrays, and a customer, GeneticLab of Sapporo, agreed to present on the technology and train other customers.
Norihiro Nishimura, of GeneticLab, said the company chose Pall’s chips because of their ability to retain DNA on the surface during the post-hybridization wash.
“As we tested several materials, such as plastics or glass slide[s], the nylon membrane overwhelmed other materials by its binding strength between detection DNAs and base surface,” Nishimura wrote in an e-mail to BioArray News. Also, he said, the company was looking for a chip that “has a stable shape,” and can be used in an automatic hybridization instrument.
Pall representatives said that biopharmaceutical companies in Japan are using the arrays for second-pass, high-throughput gene expression screens.
Nishimura confirmed this, in the case of GeneticLab, and also said the company uses the chips for “gene detection analysis.” In gene expression analysis, we “array [a] maximum 100 to 500 different genes sequences on a Vivid,” he wrote. “In gene detection analysis, we try to detect 100 to 200 viruses or bacteria by one DNA chip.”
At the core of Pall’s array technology is the nylon membrane. This membrane is one of the key technologies in a filtration business that draws in over $1.3 billion yearly revenues in at least seven different markets. The biopharmaceutical and biosciences area, a $372 million business, includes nylon membranes for Northern blot analyses, which are distributed mostly through OEM deals and claim a 90 percent share of the market. Some other membrane technologies in life sciences include 96-well microplates with membranes sealed on the bottom to prevent “crosstalk and solution weeping,” as well as GHP membranes for sample prep, combinatorial chemistry library screening, bead assays, and oligonucleotide synthesis.
The company has encountered some resistance in a market that is bound to glass slides.
“One of the things that people had claimed as a disadvantage is that you get higher background [with nylon],” Cannon said.
Although the company says this is true, “our signal is so much higher that our overall signal-to-noise ratio is better than that with glass,” said Cannon.
The company’s partners supported this claim with data: At a poster presented by Genomic Solutions at several conferences last year, researchers reported that when glass slides and Pall’s Vivid slides were each spotted with Cy3- and Cy5-labelled cDNA and imaged with the company’s GeneTac 2000 scanner, the signal was not only greater with the Vivid slides, but that signal-to-noise ratio was 5.6 to 1 with nylon, vs. 3 to 1 with glass. (The poster did not specify which glass slides were used for comparison.)
The reason for this greater signal-to-noise ratio is simple, Cannon said. “DNA wants to bind to nylon: it doesn’t necessarily want to bind to glass.” Additionally, she added in a follow-up email to BioArray News, “the 3-D membrane structure provides reproducible spot geometry without concentration of the source DNA at the edges of the spot (the donut-like appearance that sometimes occurs with glass slides).”
The company also lists as advantages the fact that the slides can be used with chemiluminescent and radioactive detection systems, as well as piezoelectric, pin and ring, solid pin and quill pin printing systems; and that users report CV’s of less than 10 percent and a higher dynamic range for radioactive quantification.
Next Stop, Diagnostics
While these arguments may seem irrelevant to core lab users with well-established protocols on glass slides, the company now has its eyes on the diagnostics market — especially in Japan.
“The Asian market seems to be moving very quickly into looking for diagnostic alternatives,” Cannon said. GeneticLab has in fact partnered with Pall to manufacture genetic diagnostics based on its nylon membrane slides, as has an unnamed company in Europe, according to Pall.
GeneticLab, Nishimura said, in April merged with a company that conducts surgical pathology services, and is planning to combine surgical pathology and gene analysis in its services.
“We will conduct the preventive diagnostic services by combining the analysis-by-pathogen-DNA-detection-and-typing DNA chip, and the traditional pathological diagnostics,” he said in an e-mail. “We are also developing several diagnostic chips for the detection and typing of infected pathogen[s] and planning to introduce them” as a service.