Patent ID: 8426216

Claim:
A method for authenticating an article comprising the steps of: providing an optical reporter marker, the optical reporter marker having at least one light emitting upconverting phosphor particle linked by a linking group comprising an alkylene moiety, to a nucleic acid taggant, the nucleic acid taggant having a plurality of artificial polymorphic double stranded (ds) DNA fragments, said artificial polymorphic dsDNA fragments each having an artificial sequence obtained by restriction digestion and ligation of extracted DNA applying the optical reporter marker onto the article of interest, detecting the optical reporter marker associated with the article of interest with a light source, obtaining a sample of the optical reporter marker from the article of interest for analysis; analyzing the collected sample to detect the presence of the identifiable portion of the artificial polymorphic double stranded (ds)DNA fragments linked to the upconverting phosphor particle using a polymerase chain reaction-on the collected sample comprising said artificial polymorphic (ds)DNA fragments using specific primers, thereby producing specific length amplicons; and verifying that the article is genuine by detecting the specific length amplicons amplified from said artificial polymorphic dsDNA fragments on said article of interest, wherein verifying that the article is genuine by detecting said polymorphic DNA fragments in said article comprises analyzing the specific lengths of said specific length amplicons.