Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Caught Red-Handed

12.04.2011
Detection of latent fingerprints through release of fluorescein from a nanofiber mat

When a forensic agent dusts a surface with powder or exposes it to the vapors of an iodine chamber, mystery fans know what is going on: This is how latent fingerprints are made visible so that they can be compared to those of a suspect. Su Chen and a team at Nanjing University of Technology have now developed a new process for especially rapid and simple detection of fingerprints.

As the Chinese researchers report in the journal Angewandte Chemie, all it takes is a special nanofiber mat that is pressed onto the suspect surface and briefly treated with hot air—the fingerprints appear as red ridge patterns.

When we touch a surface, tiny traces of perspiration and oils stay behind, mirroring the ridge patterns on our fingertips. There are now a number of different methods to make these latent fingerprints visible. The new method is significantly faster than the classic technique of dusting with powder. Unlike spectroscopic methods, it does not require complex technical instruments, and problematic chemicals like ninydrin are not needed either. In addition, it is suitable for all types of surfaces: by lightly pressing the mat onto the surface, the researchers were able to reliably transfer fingerprints from a wide variety of materials, including steel, quartz, glass, plastic, marble, and wood.

The secret of their success is the special mat, a fleece made from nanofibers of thermoplastic polyurethane and fluorescein, a dye. The mat is made in a process called electrospinning. When the mat comes into contact with a fingerprint, components of the perspiration react with the polyurethane, causing cross-linking of the polymer chains. The hot air accelerates the reaction.

In the cross-linked regions, the fluorescein cannot remain within the fibers so it comes out as a powdery solid. However, the dye only fluoresces when it is very finely dispersed in the nanofibers, not when it is in small solid clumps. This causes the color of the mat to change from straw yellow to red, making the fingerprint visible within 30 seconds in daylight. The method only works with nanofibers, because only they have enough surface area to produce a visible reaction.

The mat can identify more than mere fingerprints. The researchers were able to “print” an image of a small dragon onto the mat by using an ink-jet printer. Their ink was simply water, which can also cause the cross-linking reaction. The combination of ink-jet printing and the release of a chemical from a nanofiber mat could also be used to produce miniaturized systems such as sensors, microreactors, and diagnostic chips.

Author: Su Chen, Nanjing University of Technology (P.R. China), mailto:chensu@njut.edu.cn
Title: A Release-Induced Response for the Rapid Recognition of Latent Fingerprints and Formation of Inkjet-Printed Patterns

Angewandte Chemie International Edition 2011, 50, No. 16, 3706–3709, Permalink to the article: http://dx.doi.org/10.1002/anie.201006537

Su Chen | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>