Combinatorial DNA barcoding for security applications

2019-11-08T15:20:17Z (GMT) by Maria Pakendorf
Forensic tagging has been widely used in recent years – from the use in large companies or institutions, to preventing large scale cable theft to private home owners who want to protect their property. Such tagging can be done by applying a solution containing a unique DNA code to devices, doors or valuable objects. Another method for forensic tagging is a spraying device which also deploys a unique code onto intruders. This code can then be decoded and used to create a link between criminal and the house/institution where the device was deployed or the solution applied to property. The market for such forensic applications within the UK is largely dominated by SmartWater® and SelectaDNA®. However, both companies base their decoding method on the time-consuming and expensive technique of sequencing. In collaboration with the security company Spyral®, we have developed a combinatorial system which exploits the advantages of Real-Time PCR (qPCR). Synthetic oligonucleotide constructs were designed, consisting of primer pair amplification sites and a target site, the latter to which a fluorescent probe can bind. The original approach for the target site detection involved HyBeacons® which are already extensively used in forensic science. After encountering many difficulties using these probes, the experimental approach was changed and TaqMan® probes were used which are already well-established for qPCR experiments. Having established a stable detection system using TaqMan®, it was shown that, despite limitations, mixtures containing several oligonucleotides could be decoded. The final series of experiments showed a positive outcome for deployment and subsequent recovery of the oligonucleotides.

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