Magnetic DNA nanoparticles and their use in the olive oil trade

Have you heard about the crisis in the world of extra virgin olive oil? Of course you have, this is important stuff. There's even a book about it. In short, most of the olive oils labelled "Extra Virgin" for sale in the States are in fact not. They have been diluted with soy bean or other inexpensive oils and given additives or artificial colours to keep up appearances. Their countries of origin are equally suspect. Consumers are being duped. But don't worry — science is on the case!

To prevent fraud along the supply chain, producers want to be able to tag batches of oil with unique markers. The markers need to be inert, safe, invisible, cheap to manufacture and read, and easily removable from the product. Enter nanoscience.

In a new paper soon to be published in ACS Nano, researchers report creating encapsulated magnetic DNA nanoparticles for use in oil tagging. There is a whole lot of cleverness happening here. For example:

  • DNA is a perfect choice for nanoscale labelling. It has already been used for many millenia (billenia?) as Nature's information-storage platform of choice.
  • By adsorbing the DNA on the surface of magnetic iron oxide nanoparticles, the nano-tags are easily removable from the oils at the end of the chain using magnets.
  • Finally, the DNA-iron oxide particles are encapsulated in a silica outer shell making them inert to both chemical reactions and changes in temperature.

All-in-all, the process was pretty successful. The particles were found to be shelf stable in oil for up to two years at room temperature. Recovering the DNA at the end of the line was relatively easy and required only a sacrificial millilitre of oil. The particles worked in a variety of oils, including gasoline and bergamot oil, so they may have several industrial applications. And both silica and iron oxide are approved as food additives.

But let's get to the real elephant in the room here: what are people going to think about DNA being added to their food? DNA in this context is just a big molecule, not a lifeform, but given the outcry about GMOs (for example), I expect that the average consumer will be highly suspicious. What do you think?

For all the details, you can read "Magnetically Recoverable, Thermostable, Hydrophobic DNA/Silica Encapsulates and Their Application as Invisible Oil Tags" here.