In court papers filed last week, Illumina's lawyers claim that two devices offered by Oxford – MinION, first available in 2014, and the forthcoming PromethION – infringe upon two nanopore-sequencing patents to which the US giant has exclusive licence.
Illumina has also requested that the US International Trade Commission temporarily ban the importation of Oxford's products to the US while further investigation takes place.
The technology in question centres around nanopores – tiny holes within proteins through which DNA molecules can pass. Each of the four DNA bases (A, C, G and T) creates a distinct change in electrical current as it passes through the pore, allowing the genetic code to be read. Oxford's MinION device, which uses this technology, is less reliable than Illumina's refrigerator-sized machines (which use a different type of genome sequencing), but it has the advantage of being small (roughly three inches long), is easily accessible and can generate results in real time.
Since 2013, Illumina has licensed patents from researchers at the Universities of Washington and Alabama who, in 2010, showed that use of a particular pore known as MspA significantly improves the technology. Illumina claims that it is this pore that is now used by Oxford's devices, arguing that the UK firm has long been interested in the research related to the patents.
The two companies had previously attempted to collaborate on new nanopore technologies. But in 2013 Illumina sold its 13.5 percent share in Oxford, and now claims that its investments and patent rights are under threat from the start-up.
'Illumina has made substantial investments to obtain licenses and develop the nanopore-sequencing technology invented by researchers at the University of Alabama at Birmingham and University of Washington. Illumina filed the lawsuits to protect its investment and patent rights in this technology,' they stated in a press release.
Speculation mounts as to Illumina's motives, and some are of the view that the US firm is trying to stifle its smaller rival or else launch a new nanopore-sequencing tool of its own.
Mick Watson, a researcher at the University of Edinburgh, has pointed to the timing of this legal action, with Oxford planning to float on the stock market later this year. He has also questioned the applicability of Illumina's patents, given the significant modifications Oxford Nanopore have likely made to the pores over the past few years.
Oxford have remained unwilling to explain precisely how its nanopore technology works. However, in a press release on the company's website, CEO Dr Gordon Sanghera remarked: 'It is gratifying to have the commercial relevance of Oxford Nanopore products so publicly acknowledged by the market monopolist for NGS [next generation sequencing].'
According to MIT Technology Review, the outcome of the legal action could have ramifications on scientific research, as nanopore-sequencing is being used by researchers in increasingly diverse ways. For example, the device has recently been used by researchers in Guinea to sequence the Ebola virus.
Illumina have not announced any plans to launch their own nanopore-sequencing device, but their lawyers claim that they could 'fill any void' created by blocking imports of Oxford's products.
Oxford said it did not expect disruption to its 'commercial progress' from Illumina's legal action.