Tiny technology can target the gunmen

These microscopic tags – ‘nanotags’ – recently developed could help to solve and deter gun crime by providing hands-on evidence, literally.

Nanotechnology involves manipulating materials on a very small scale. The nanotags – just 30 microns in size (one micron is a millionth of a metre in diameter) and invisible to the naked eye – are designed to be coated on to bullets and cartridges. They then attach themselves to the hands or gloves of anyone handling the casing and are very difficult to wash off completely.

Nanotags make the link

Crucially, some of these nanotags also remain on the shell case even after it has been fired. This should make it possible to establish a robust forensic link between a bullet or shotgun cartridge fired during a crime and whoever handled it.

Up to now, it has been extremely hard to establish such a link because of the difficulty in retrieving fingerprints or significant amounts of DNA from cartridge surfaces that are shiny and smooth. The nanotags – quite unlike anything previously used in the fight against gun crime – could therefore lead to a significant increase in successful convictions.

This breakthrough has been achieved by a team of chemists, engineers, management scientists, sociologists and nanotechnologists from the UK universities of Brighton, Brunel, Cranfield, Surrey, and York (all in England), with funding from the Engineering & Physical Sciences Research Council (EPSRC).

… our work clearly could make a valuable contribution not only to solving gun crime but also to deterring criminals from resorting to the use of firearms in the first place

Professor Paul Sermon

University of Surry

“The tags primarily consist of naturally occurring pollen, a substance that evolution has provided with extraordinary adhesive properties,” said Professor Paul Sermon, from the University of Surrey, who has led the research.

“It has been given a unique chemical signature by coating it with titanium oxide, zirconia, silica or a mixture of other oxides. The precise composition of this coating can be varied subtly from one batch of cartridges to another, enabling a firm connection to be made between a particular fired cartridge and its user,” he added.

Trapping DNA

In addition to this breakthrough, the team has also developed a method of trapping forensically useful amounts of human DNA on gun cartridges. It involves increasing the abrasive character of the cartridge with micro-patterned pyramid textures or adding an abrasive grit held in place by a thin layer of resin to the cartridge base.

This rough surface is able to retain dead skin cells from a finger or thumb as it loads a cartridge into a firearm. A key benefit is also the affordability, a cost-effective way of reliably capturing sufficient DNA from a cartridge has never been available before.

The technology has been designed to avoid damage to the DNA captured that is caused by temperatures generated as the gun is fired – when heat is rapidly transferred from the burning propellant into the cartridge case – and when copper is extracted from the shell case by lactic acid in sweat.

The nanotag and DNA capture technologies could potentially be available for use within 12 months. There may also be scope to apply them in other fields, such as knife crime, in future.

“We are currently focusing on understanding the precise requirements of the police and cartridge manufacturers,” added Professor Sermon. “But our work clearly could make a valuable contribution not only to solving gun crime but also to deterring criminals from resorting to the use of firearms in the first place.”

The 18-month initiative – called DNA Receptors With Nanotags On Cartridges – has consisted of two parallel projects receiving total EPSRC funding of nearly £379,000. Project partners are the Forensic Science Service, BAE Systems and coatings manufacturer Andura.

The concept for the initiative was identified through the EPSRC ideas factory ‘sandpit’ process. A sandpit is a five-day interactive workshop involving a multidisciplinary mix of participants, some being active researchers and some being potential users of research outcomes, to drive lateral thinking and radical approaches to addressing particular research challenges.

EPSRC invest £800m annually

Government statistics indicate that 21,521 offences involving firearms were committed in England and Wales in 2005/06. Current success rates for DNA profiling using evidence from gun cartridges are only about 10 per cent.

Pollen from two types of lily, Lilium orientale and Lilium longiflorum, were used in this research. The nanotags are applied to gun cartridges by being embedded in cartridge coatings made from polylactic acid, sucrose ester and tetrahydrofuran.

The Engineering & Physical Sciences Research Council is the UK’s main agency for funding research in its title’s fields. The EPSRC invests about £800 million a year in research and postgraduate training, to help the nation handle the next generation of technological change.

The areas covered range from information technology to structural engineering, and mathematics to materials science. This research forms the basis for future economic development in the UK and improvements for everyone’s health, lifestyle and culture.

The EPSRC also actively promotes public awareness of science and engineering. It works alongside other research councils with responsibility for other areas of research.