New nanomaterial to be used at crime scenes without lab, can transform forensics

Researchers have created a fluorescent nanoparticle that could revolutionise forensic science, particularly in the detection of latent (non-visible) fingermarks.

Research conducted at Diamond’s labSAXS used a combination of materials (MCM-41, chitosan and dansylglycine) to examine latent fingermarks.

These nanoparticles have special properties that make them adhere well to fingerprint residues, even old ones.

Capable of working on various surfaces, including metal, plastic, glass, and complex objects such as polymer banknotes, the nanoparticles have the potential to be used directly at crime scenes without lab facilities, which is a significant advantage over some previous reagents.

New nanoparticles are capable of producing high-quality fingerprint images

The particles are capable of producing high-quality fingerprint images, with the vast majority of those tested meeting the UK Home Office standards for a successful identification. This new method captures the finer details of a fingermark, making it easier to identify individuals and is expected greatly to aid in forensic investigations .

Published in a Royal Society of Chemistry paper , the study underlines that the new nanomaterial has proven to be a versatile and effective tool for visualizing fingermark evidence.

Small angle X-ray scattering (SAXS) techniques at Diamond provided useful data to validate these results, according to researchers.

Researchers exploited the MCM’s desirable characteristics

“There are few studies employing chitosan for detection and enhancement of latent fingerprints and, to the best of our knowledge, no reports of the use of hierarchically structured MSNs modified with chitosan (MSN@Ch) for such applications – which was our strategy in this research,” said Prof. Adriana Ribeiro, Federal University of Alagoas.

“We exploited the MCM’s desirable characteristics – notably high surface area and surface modification – for the case of MCM-41 to enhance the interaction between the development reagent and fingerprint residue.”

The international collaboration of researchers developed the new nanostructured hybrid material, MCM-41@chitosan@dansylglycine, to visualise latent fingermarks. This material combines mesoporous silica nanoparticles with a fluorescent dye (dansylglycine) and chitosan, a polysaccharide derived from the exoskeletons of shrimps, crabs and lobsters, according to researchers .

Traditional methods have limitations in recovering high-quality results

Latent fingermarks require physicochemical development techniques to enhance their visibility and make them interpretable for forensic purposes. Traditional methods for developing fingerprints include optical, physical, and chemical processes that involve interaction between the developing agent (often a coloured or fluorescent reagent) and the fingermark residue, according to the study.

These methods have limitations in recovering high-quality results in certain conditions.

“The overarching aim of this study was to create a versatile and effective latent fingermark visualisation material based on MSNs, chitosan and dansyl derivatives. These nanoparticles were applied as latent fingermark developers for marks on surfaces of diverse chemical composition, topography, optical characteristics and spatially variant nature, typical of forensically challenging evidence,” said Professor of Physical Chemistry, Robert Hillman, University of Leicester.

Hillman maintained that for quality assessment of the enhanced fingermarks, researchers analyzed the developed images using the UK Home Office scale, forensic protocols and, in terms of their constituent features, (minutiae), specialist forensic software.

Across a substantive collection of marks deposited on chemically diverse surfaces and subject to complex environmental and temporal histories, the overwhelming majority of the enhanced images presented sufficient minutiae for comparison with model dactyloscopy images, according to Hillman.

“It is pleasing to see that Diamond’s unique analytical tools once again have delivered outstanding science,” said Diamond Light Source CEO Prof. Gianluigi Botton.

“Our network of international users is key to making sure our science delivers results. This advance in nanomaterials could be a step change in how forensics may be applied in the future.”