Surface Plasmon Resonance has been around for a while, enabling researchers to study how two molecules interact over time. But recent developments have opened the technology to proteomics and its need for higher throughput and detailed analysis of binding proteins.
This week, Applied Biosystems sold its first 8500 Affinity Chip Analyzer, an SPR instrument, to a large biotechnology company. The instrument was first introduced in September (see PM 9-19-2003) but was only made available for sale last week.
The 8500 Affinity Chip Analyzer, developed in collaboration with HTS Biosystems (see PM 5-6-2002), comes with disposable chips allowing users to address up to 400 binding interactions simultaneously. Since research-ers can now do a large number of experiments on a single chip, run-to-run variability is eliminated, according to Tony Chiulli, product manager for applications and market development for the 8500.
The instrument uses grating-coupled SPR developed by HTS and reads the chips from the top. The basic technology, though, is similar to SPR instruments from Biacore, and the 8500 is priced similarly to a “middle-of-the-road Biacore system,” said Chiulli, who declined to reveal the price of the instrument or that of the chips. “The main difference is throughput,” he said.
Applied Biosystems launched the instrument initially for three applications: characterizing antibodies, mapping peptide epitopes, and finding sandwich pairs of antibodies or of antibodies and receptors. The company is currently working on protocols for three further applications, said Chiulli: protein-peptide interactions, protein-nucleic acid interactions, and protein-protein interactions. No specific changes to the technology are planned for this year, he said, and Applied Biosystems will not offer content for the chips this year either, though “we are doing some research on that,” he added.
ABI’s competitors, meanwhile, are planning to ramp up their own SPR offerings soon — and in different ways.
For example Biacore, which has so far only been offering low-throughput SPR chips with four spots per chip, has been working on its own version of a high-throughput interaction array, and is planning to announce it at the end of this year, according to a company spokesperson. The array will enable researchers to use multiple targets and samples. Its throughput, she said, “will be an order of magnitude higher than existing systems.”
Another company, Intrinsic Bioprobes, of Tempe, Ariz., is working on a system that would couple SPR chips directly to a MALDI mass spectrometer by applying the MALDI matrix to the SPR chip, without the need to elute the proteins and transfer them to a MALDI chip. However, a novel chip from Instrinsic Bioprobes that could do this is still “two to three years away,” said Dobrin Nedelkov, Intrinsic’s director of research and technology development. In the meantime, Nedelkov said he would be interested in seeing how ABI’s product could link up with mass spectrometry.
With regard to coupling SPR and mass spectrometry, Applied Biosystems “will look into potenti-ally something like that,” said Chiulli, but added that there is no concrete plan yet.
Bruker and Biacore have also been collaborating on a way to link SPR and MALDI mass spectrometry (see PM 11/5/2001), and the two companies already offer some combined services, a Bruker employee told ProteoMonitor. Last spring, Biacore said it had developed a MALDI plate holder and surface prep unit that can automatically transfer samples from Biacore chips onto Bruker MALDI plates (see PM 3-17-2003).
According to Nedelkov, several other companies are also developing or manufacturing SPR arrays, among them GWC Technologies, Graffinity Pharmaceuticals, Zyomyx, Cambridge Consultants, and Proterion.