Barcodes have been used to track many things, from airline luggage to parcels. Now they are being used to label and track samples in microfluidic, high-throughput systems.

Jong-Ryul Jeong's group at the University of Cambridge, UK, is working towards one of the big goals in biological science: a DNA sequencing technology that can sequence the human genome in one day. But to achieve this they need to create new microfluidic systems and realised they required a labelling technique to track samples through the small devices. Their solution was tiny magnetic barcodes that can be attached to the samples and tracked.

Barcoded DNA samples can be scanned much like food at the supermarket checkout

The magnetic barcodes consist of a small strip of plastic, smaller than the average human cell, onto which strips of cobalt are attached. The cobalt can be magnetised in two different directions, to give either a plus one or minus one signal, much like the black and white strips of a conventional barcode. These barcodes can then be read quickly as labelled samples pass a detector, just like being swiped at the checkout.

Jeong explains that the main advantages of this technology are that the tags can be coded after they have been applied to a sample, reducing the likelihood of mislabelling. They can also be coded remotely and even rewritten if needed, he adds. 

Samuel Sia of Columbia University, New York, US, works on creating low cost lab-on-a-chip diagnostic devices. He says that the technique is a 'potentially useful concept' that could be used in high-throughput biological assays.

Jeong has recently set up a spin-out company to explore the opportunities that the technology presents and to develop it further. He admits that there are challenges ahead, both in improving the barcode detection speed and in developing high-throughput assays to exploit the technique. Nevertheless, he points out, the concept 'is generic enough to be applied to a variety of biological assays.'

Laura Howes