Innovative nanomaterials have the potential to revolutionise forensic science, particularly in the detection of latent (non-visible) fingermarks, following research conducted at Diamond’s labSAXS instrument (P38).

Researchers created a fluorescent nanoparticle using 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. The nanoparticles work on various surfaces, including metal, plastic, glass and complex objects such as polymer banknotes. They have the potential to be used directly at crime scenes without lab facilities, which is a significant advantage over some previous reagents. They produce 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.

The research was published in a Royal Society of Chemistry paper, highlighting that the new nanomaterial has proven to be a versatile and effective tool for visualising fingermark evidence. Small angle X-ray scattering (SAXS) techniques at Diamond provided useful data to validate these results.
The research team includes scientists from the Technical and Scientific Section of Alagoas, Federal Police, Brazil; the National Institute of Criminalistics of the Federal Police, Brazil; the University of Leicester’s School of Chemistry; the Federal University of Alagoas, Brazil; and the UK’s national synchrotron, Diamond Light Source.

Ridge patterns on fingertips remain unchanged during and beyond a person’s life. They provide the primary method of personal identification in criminal investigations. When an object’s surface is touched by a finger, sweat and oily substances are transferred and deposited onto the surface, resulting in the formation of a mark. Most fingermarks are invisible to the naked eye and are referred to as latent fingermarks.

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.

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. These methods have limitations in recovering high-quality results in certain conditions.
Recently, new methods using mass spectrometry, spectroscopy, electrochemistry, and nanoparticles have improved the development of latent fingermarks. These techniques offer better contrast, sensitivity, and selectivity, with low toxicity. The ability to adjust nanomaterial properties further enhances the detection of both fresh and aged fingermarks.

Mesoporous silica nanoparticles (MSNs) have attracted significant interest since the discovery of the M41S family of molecular sieves, which encompasses MCM-41, MCM-48, and SBA-15. These nanoparticles are characterised by their controlled particle size, porosity, high specific surface area, chemical stability, and ease of surface functionalisation.

Profa. Adriana Ribeiro, Federal University of Alagoas comments: “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. 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 team added dansyl fluorophores which exhibit intense absorption bands in the near UV region and emit strong fluorescence in the visible spectrum with high emission quantum yields.

Professor of Physical Chemistry, Robert Hillman, University of Leicester concludes: “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. For quality assessment of the enhanced fingermarks, we analysed 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.”

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

ENDS

Paper: https://doi.org/10.1039/D4RA03074E RSC Advances 17.07.24
“Dansyl fluorophore functionalized hierarchically structured mesoporous silica nanoparticles as novel latent fingerprint development agents”†
Authors: Lais F. A. M. Oliveira, ^a Lais V. A. T. da Silva, ^a Artur F. Sonsin, ^a Meclycia S. Alves, ^a Cristiane V. Costa, ^a Jeane C. S. Melo, ^a Nicholas Ross, ^b Paul T. Wady, ^c Thomas Zinn,^c Ticiano G. do Nascimento, ^a Eduardo J. S. Fonseca, ^a Alexandro M. L. de Assis, ^ade A. Robert Hillman *^b and Adriana S. Ribeiro *^a Author affiliations

Development of latent fingerprints. Representative images on stainless steel are shown, illuminated by and viewed under visible light (a) before development and (b) after development with MCM-41@Ch@DnsGly NPs. Corresponding images generated by illumination with UV light (λ_ex = 365 nm) after MCM-41@Ch@DnsGly NP development are shown on (c) stainless steel, (d) glass, (e) plastic and (f) unfired brass cartridge case substrates.

For further information on the research: Federal University of Alagoas, Campus A. C. Simões, Maceió, AL, Brazil E-mail: aribeiro@qui.ufal.br
or School of Chemistry, University of Leicester, Leicester LE1 7RH, UK E-mail: arh7@leicester.ac.uk

For further information: please contact Diamond Communications: Lorna Campbell +44 7836 625999 or Isabelle Boscaro-Clarke +44 1235 778130 Diamond Light Source: www.diamond.ac.uk X/Twitter: @DiamondLightSou

Diamond Light Source provides industrial and academic user communities with access to state-of-the-art analytical tools to enable world-changing science. Shaped like a huge ring, it works like a giant microscope, accelerating electrons to near light speeds, to produce a light 10 billion times brighter than the Sun, which is then directed off into 33 laboratories known as ‘beamlines’. Additionally, Diamond offers access to several integrated laboratories including the world-class Electron Bio-imaging Centre (eBIC) and the Electron Physical Science Imaging Centre (ePSIC).

Diamond serves as an agent of change, addressing 21st century challenges such as disease, clean energy, food security and more. Since operations started, more than 16,000 researchers from both academia and industry have used Diamond to conduct experiments, with the support of approximately 760 world-class staff. Almost 12,000 scientific articles have been published by its users and scientists.

Funded by the UK Government through the Science and Technology Facilities Council (STFC), and by the Wellcome Trust, Diamond is one of the most advanced scientific facilities in the world, and its pioneering capabilities are helping to keep the UK at the forefront of scientific research.
Diamond was set-up as an independent not for profit company through a joint venture, between the UKRI’s Science and Technology Facilities Council and one of the world’s largest biomedical charities, the Wellcome Trust - each respectively owning 86% and 14% of the shareholding.

The University of Leicester is led by discovery and innovation – an international centre for excellence renowned for research, teaching and broadening access to higher education. It is among the Top 30 universities in the Times Higher Education (THE)’s Research Excellence Framework (REF) 2021 rankings with 89% of research assessed as world-leading or internationally excellent, with wide-ranging impacts on society, health, culture, and the environment. In 2023, the University received an overall Gold in the Teaching Excellence Framework (TEF) 2023, making it one of a small number of institutions nationally to achieve TEF Gold alongside a top 30 REF performance. The University is home to more than 20,000 students and approximately 4,000 staff.
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Federal University of Alagoas (UFAL) Located in the city of Maceió, the Federal University of Alagoas (UFAL) is the major University in coastal state Alagoas. It is currently considered one of the main research centers in the Brazilian Northeast region. The Federal University of Alagoas (UFAL) is a national reference in teaching, research and extension activities, establishing itself as an excellent support for the demands of society. It is the largest public higher education institution in the state of Alagoas and was ranked 49th among the best universities in Brazil in the 2023 edition of the World University Rankings (CWUR). One of the reasons for reaching this level was the impact of institutional support and investment in research. All of this is the result of the prioritization of research at the University over the last four years, which is reflected in quality teaching and service. UFAL has 82.1% of its publications with national and international collaboration. And most of the citations were from works produced with researchers from other countries.
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