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 Molecular Spies Sabotage a Protein's Activities in Specific Cellular Compartments
20.04.2015 | Johns Hopkins Medicine

nachricht Evolution puts checks on virgin births
20.04.2015 | Okinawa Institute of Science and Technology (OIST) Graduate University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Advances in Molecular Electronics: Lights On – Molecule On

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the University of Konstanz are working on storing and processing information on the level of single molecules to create the smallest possible components that will combine autonomously to form a circuit. As recently reported in the academic journal Advanced Science, the researchers can switch on the current flow through a single molecule for the first time with the help of light.

Dr. Artur Erbe, physicist at the HZDR, is convinced that in the future molecular electronics will open the door for novel and increasingly smaller – while also...

Im Focus: Pruning of Blood Vessels: Cells Can Fuse With Themselves

Cells of the vascular system of vertebrates can fuse with themselves. This process, which occurs when a blood vessel is no longer necessary and pruned, has now been described on the cellular level by Prof. Markus Affolter from the Biozentrum of the University of Basel. The findings of this study have been published in the journal “PLoS Biology”.

The vascular system is the supply network of the human organism and delivers oxygen and nutrients to the last corners of the body. So far, research on the...

Im Focus: Astronomers reveal supermassive black hole's intense magnetic field

Astronomers from Chalmers University of Technology have used the giant telescope Alma to reveal an extremely powerful magnetic field very close to a supermassive black hole in a distant galaxy

Astronomers from Chalmers University of Technology have used the giant telescope Alma to reveal an extremely powerful magnetic field very close to a...

Im Focus: A “pin ball machine” for atoms and photons

A team of physicists from MPQ, Caltech, and ICFO proposes the combination of nano-photonics with ultracold atoms for simulating quantum many-body systems and creating new states of matter.

Ultracold atoms in the so-called optical lattices, that are generated by crosswise superposition of laser beams, have been proven to be one of the most...

Im Focus: UV light robot to clean hospital rooms could help stop spread of 'superbugs'

Can a robot clean a hospital room just as well as a person?

According to new research out of the Texas A&M Health Science Center College of Medicine, that is indeed the case. Chetan Jinadatha, M.D., M.P.H., assistant...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

HHL's Entrepreneurship Conference on FinTech

13.04.2015 | Event News

World Conference On Regenerative Medicine 2015: Registration And Abstract Submission Now Open

25.03.2015 | Event News

University presidents from all over the world meet in Hamburg

19.03.2015 | Event News

 
Latest News

High-Power Laser Spinoff Proves Versatility Is Strength

20.04.2015 | Physics and Astronomy

New “Cool Roof Time Machine” Will Accelerate Cool Roof Deployment

20.04.2015 | Architecture and Construction

STAR Heavy Flavor Tracker Detects Signs of Charm at RHIC

20.04.2015 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>