A DNA Taggant Watermarking System

Taggants are small objects used to label things or people that need to be traced. Synthetic DNA Taggants are ideal for this, since very small amounts can be detected if the sequence is known, and can be disguised by natural DNA in the environment. Known protocols for DNA amplification (e.g. PCR) allow for very sensitive DNA detection, but suffer from disadvantages: the apparatus is not very portable, require energy, and enzymes used degrade rapidly without refrigeration. Our primary goal is to develop a prototype full-scale DNA Taggant system which includes (a) software to design the DNA strands comprising the DNA taggants, (b) means for dispersal of the DNA taggants, and (c) a detection device and associated biochemical protocols for detection of the DNA taggants. The detection device uses two novel biochemical protocols for DNA detection. Like PCR, our protocols are also exquisitely sensitive: given only few molecules of single stranded DNA to be detected, the protocols increase the concentration of the DNA to be detected at a rate increasing exponentially with time. Unlike conventional PCR, our detection protocols are isothermal (that is, they operate without thermal cycling) and so our apparatus is very portable and needs no energy source.