Featured Research

from universities, journals, and other organizations

New method developed to capture fingerprints on difficult surfaces

Date:
May 11, 2010
Source:
Penn State
Summary:
CSI notwithstanding, forensics experts cannot always retrieve fingerprints from objects, but a new conformal coating process can reveal hard-to-develop fingerprints on nonporous surfaces without altering the chemistry of the print.

Researchers have developed a new method that can reveal hard-to-develop fingerprints on nonporous surfaces without altering the chemistry of the print.
Credit: iStockphoto/Ryan Lane

CSI notwithstanding, forensics experts cannot always retrieve fingerprints from objects, but a conformal coating process developed by Penn State professors can reveal hard-to-develop fingerprints on nonporous surfaces without altering the chemistry of the print.

"As prints dry or age, the common techniques used to develop latent fingerprints, such as dusting or cyanoacrylate -- SuperGlue -- fuming often fail," said Robert Shaler, professor of biochemistry and molecular biology and director of Penn State's forensic sciences program.

This happens because most of the techniques currently used for developing fingerprints rely on the chemistry of the print. Fingerprints are made up of a mixture of secretions from the body that reacts with different chemicals to form a visible or fluorescent product. Infrared and x-ray imaging also target specific chemicals left behind by the ridges and valleys in the skin.

"Lots and lots of processes take advantage of the chemistry of fingerprints," said Shaler. "This approach looks at the geometry of the fingerprints."

The conformal coating applications suggested by Shaler and Ahklesh Lakhtakia, Charles Godfrey Binder Professor in engineering science and mechanics, use the physical properties of the fingerprint, not the chemistry of the substances left behind. In fact, the researchers believe that even after the fingerprints are developed using the coating, forensics experts could sample the fingerprint material to determine specifics about the person who left the prints.

"The body chemistry of the person who left the fingerprint can tell us some things," said Shaler. "If the suspect is older or younger or a lactating mother, for example."

The researchers used a form of physical vapor deposition -- a method that uses a vacuum and allows vaporized materials to condense on a surface creating a thin film. Normally, the deposition process requires exceptionally clean surfaces because any speck of dust or grease on the coated surface shows up as a deformity. However, with fingerprints, the point is to have the surface material's ridges and valleys -- topography -- show up on the new surface so analysts can read them using an optical device without the necessity of chemical development or microscopy.

"This approach allows us to look at the topography better and to look at the chemistry later," said Shaler. "We wouldn't have thought of this by ourselves, but we could do it together."

One benefit of this approach would be the ability to retrieve fingerprints off fragments from incendiary or explosive devices and still be able to analyze the chemicals used in the device.

The specific method used is a conformal-evaporated-film-by-rotation technique developed to create highly accurate copies of biological templates such as insect eyes or butterfly wings. Both are surfaces that have nanoscale variations.

"It is a very simple process," said Lakhtakia. "And fingerprints are not nanoscale objects, so the conformal coating is applied to something big by nanotechnology standards."

The researchers tested two materials for coating, magnesium flouride and chalcogenide glass -- a combination of germanium, antimony and selenium. The coating material is heated in a vacuum, while the artifact to be coated is rotated fairly quickly to allow deposition over the entire surface.

"We need to have a coating that is uniform as far as we can see," said Lakhtakia. "But we do not need much of a coating -- in the range of only a micron."

The researchers tried coating a variety of fingerprints on glass and even on tape. They coated pristine fingerprints and those that had been fumed with SuperGlue. In all cases, the coated fingerprints were usable.

Of course, like all approaches, this one can only be used on non-porous surfaces, surfaces that do not de-gas. The equipment used to deposit the coating is a laboratory device, but it can produce the coating in about 15 minutes. The researchers would like to design a portable device that could be brought to a crime scene and produce readable fingerprints on site.

"We are in the process of redesigning the chamber and looking not just at fingerprints, but at other objects," said Lakhtakia. "These would include bullets, cartridges, footprints, bite marks and lip impressions." Shaler and Lakhtakia have filed a provisional patent application on this application.


Story Source:

The above story is based on materials provided by Penn State. Note: Materials may be edited for content and length.


Cite This Page:

Penn State. "New method developed to capture fingerprints on difficult surfaces." ScienceDaily. ScienceDaily, 11 May 2010. <www.sciencedaily.com/releases/2010/05/100511102121.htm>.
Penn State. (2010, May 11). New method developed to capture fingerprints on difficult surfaces. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2010/05/100511102121.htm
Penn State. "New method developed to capture fingerprints on difficult surfaces." ScienceDaily. www.sciencedaily.com/releases/2010/05/100511102121.htm (accessed July 29, 2014).

Share This




More Matter & Energy News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Lithium Battery 'Holy Grail' Could Provide 4 Times The Power

Lithium Battery 'Holy Grail' Could Provide 4 Times The Power

Newsy (July 28, 2014) — Stanford University published its findings for a "pure" lithium ion battery that could have our everyday devices and electric cars running longer. Video provided by Newsy
Powered by NewsLook.com
The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) — AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Shipping Crates Get New 'lease' On Life

Shipping Crates Get New 'lease' On Life

Reuters - Business Video Online (July 25, 2014) — Shipping containers have been piling up as America imports more than it exports. Some university students in Washington D.C. are set to get a first-hand lesson in recycling. Their housing is being built using refashioned shipping containers. Lily Jamali reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) — Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins