Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Inverse Fingerprints on Paper

05.11.2012
Visualization of Latent Fingermarks by Nanotechnology: Reversed Development on Paper: A Possible Remedy to the Variation in Sweat Composition

Paper is one of the surfaces most commonly tested for fingerprints in forensics. Unfortunately, it is particularly difficult to make fingerprints on paper visible. In the journal Angewandte Chemie, Israeli scientists have now introduced a new method developed specifically for use on paper.



It produces a “negative” of the fingerprint and is, in contrast to conventional methods, independent of the composition of the sweat residue left behind.

In many criminal cases, paper evidence plays an important role and it would be useful to know through whose hands checks, documents, or paper currency have passed. Studies have shown that only about half of the fingerprints present on paper can be made sufficiently visible. The main reason that this does not work consistently seems to be the highly variable composition of the sweat left behind on the paper.

A team led by Daniel Mandler and Joseph Almog at the Hebrew University of Jerusalem has now developed a procedure that avoids these problems. It involves a sort of inversion of an established method in which gold nanoparticles are first deposited onto the invisible fingerprints, followed by elemental silver, similar to the development of a black and white photograph.

In the conventional technique, the gold particles get stuck to components of the sweat in fingerprints. In contrast, the gold nanoparticles in the new method stick directly to the paper, not the sweat. This technique uses the sebum from the fingerprints, which effectively shields the paper beneath it from the gold nanoparticles. Treatment with a developer containing silver, which turns the areas with gold on them black, results in a negative image of the fingerprint.

The secret to the success of these researchers is a special bifunctional reagent. The head of this molecule is an acylpyridazine group, which can bind to cellulose. The tail is made of hydrocarbon chains with a sulfur-containing group at the end, which binds to gold and attaches the molecule to the surface of the gold nanoparticles. When gold particles coated with these molecules are deposited onto paper with a fingerprint on it, the heads bind to the cellulose in the paper, avoiding the fat-containing lines.

Because only the fatty components of the fingerprints are used, the possibly unfavorable composition of the sweat in the fingerprint plays no role in this method. This technique also promises to alleviate another problem: if paper has become wet, it has previously been nearly impossible to detect fingerprints because the amino acids in the sweat, which are the primary substrate for current chemical enhancement reactions, are dissolved and washed away by water. The fatty components are barely effected.

About the Author
Joseph Almog is a Professor of forensic chemistry at the Casali Institute of Applied Chemistry, The Hebrew University of Jerusalem, and formerly the director of the Division of Identification and Forensic Science (DIFS) of the Israel Police. His main research topics are development of crime-scene techniques, explosives detection and identification and enhancement of latent fingermarks. He is the 2005 laureate of the American Academy of Forensic Sciences' Lucas Medal "for outstanding achievements.
Author: Joseph Almog, Hebrew University of Jerusalem (Israel), http://www.huji.ac.il/dataj/controller/ihoker/MOP-STAFF_LINK?sno=208470

Title: Visualization of Latent Fingermarks by Using Nanotechnology for Reversed Development on Paper: A Remedy to the Variation in Sweat Composition

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201205259

Joseph Almog | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht New Technique Maps Elusive Chemical Markers on Proteins
03.07.2015 | Salk Institute for Biological Studies

nachricht New approach to targeted cancer therapy
03.07.2015 | CECAD - Cluster of Excellence at the University of Cologne

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Viaducts with wind turbines, the new renewable energy source

Wind turbines could be installed under some of the biggest bridges on the road network to produce electricity. So it is confirmed by calculations carried out by a European researchers team, that have taken a viaduct in the Canary Islands as a reference. This concept could be applied in heavily built-up territories or natural areas with new constructions limitations.

The Juncal Viaduct, in Gran Canaria, has served as a reference for Spanish and British researchers to verify that the wind blowing between the pillars on this...

Im Focus: X-rays and electrons join forces to map catalytic reactions in real-time

New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions

A new technique pioneered at the U.S. Department of Energy's Brookhaven National Laboratory reveals atomic-scale changes during catalytic reactions in real...

Im Focus: Iron: A biological element?

Think of an object made of iron: An I-beam, a car frame, a nail. Now imagine that half of the iron in that object owes its existence to bacteria living two and a half billion years ago.

Think of an object made of iron: An I-beam, a car frame, a nail. Now imagine that half of the iron in that object owes its existence to bacteria living two and...

Im Focus: Thousands of Droplets for Diagnostics

Researchers develop new method enabling DNA molecules to be counted in just 30 minutes

A team of scientists including PhD student Friedrich Schuler from the Laboratory of MEMS Applications at the Department of Microsystems Engineering (IMTEK) of...

Im Focus: Bionic eye clinical trial results show long-term safety, efficacy vision-restoring implant

Patients using Argus II experienced significant improvement in visual function and quality of life

The three-year clinical trial results of the retinal implant popularly known as the "bionic eye," have proven the long-term efficacy, safety and reliability of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

World Conference on Regenerative Medicine in Leipzig: Last chance to submit abstracts until 2 July

25.06.2015 | Event News

World Conference on Regenerative Medicine: Abstract Submission has been extended to 24 June

16.06.2015 | Event News

MUSE hosting Europe’s largest science communication conference

11.06.2015 | Event News

 
Latest News

Siemens receives order for offshore wind power plant in Great Britain

03.07.2015 | Press release

'Déjà vu all over again:' Research shows 'mulch fungus' causes turfgrass disease

03.07.2015 | Agricultural and Forestry Science

Discovery points to a new path toward a universal flu vaccine

03.07.2015 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>