Nugen’s amplification products are based on a set of related inventions by its co-founder, Nurith Kurn, who was formerly a research director at Dade-Behring Diagnostics. Nugen has so far published ten US patent applications and received one patent for these inventions. The patent and the applications describe in detail the company's single primer isothermal amplification, or SPIA, method, and related mechanisms for amplification of DNA.
The granted patent, US Patent No. 6,251,639, "Methods and compositions for linear isothermal amplification of polynucleotide sequences, using a RNA-DNA composite primer," decribes broadly the SPIA method and kits that use this method. This method involves a composite primer, primer extension, strand displacement, and an optional termination sequence to amplify cDNA, as well as a similar method for amplifying sense RNA using strand displacement, template switching, and a propromoter oligonucleotide, as well as a composite primer and primer extension.
The company has also applied for patents on methods for the production of partially double-stranded nucleic acids comprising a 3' overhang from an RNA target and use in methods of recombining polynucleotides (20030215926); additional methods for amplifying RNA (20030087251, 20020164628); methods for amplifying and detecting nucleic acid sequences generally (20030186234, 20030175785, 20020115088 20030017591, 20020058270), and specifically, methods for linear isothermal amplification of polynucleotide sequences (20010034048).