Chemist contributes to development of novel method for recovering old fingerprints

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Latent fingermarks from a male donor developed on aluminum foil. Credit: Xanthe Spindler

A Northern Illinois University chemist is part of an international team of scientists whose work might someday crack open cold-case files.

The scientists are developing a new fingerprinting method that could make it possible to recover previously unusable or undetected prints from old evidence and from surfaces long considered too difficult by crime scene investigators.

Results of a preliminary study on the development of the novel immunogenic method were published this past spring in Chemical Communications, a journal of the Royal Society of Chemistry.

Despite fingerprinting being a foundational technique of modern forensic science, only a fraction of all the fingermarks at a crime scene are actually detected.

The new method uses unique antibodies developed by NIU Chemistry and Biochemistry Professor Oliver Hofstetter. The antibodies are immobilized onto gold nanoparticles and applied to a surface, where they bind to amino acids contained in any fingerprints that are present. A fluorescent dye is then used to improve the visualization and capture of the fingerprint.

While not seen as a replacement for current techniques of recovering fresh prints, the new method is particularly effective for enhancing aged or dried fingermarks on non-porous surfaces.

“Our new fingerprint detection method enables the visualization of weak fingerprints that are difficult to develop with other current techniques,” Hofstetter said. “This is the first antibody-based technique that specifically targets amino acids, which are ubiquitous components of human sweat and are present in invisible fingerprints on non-porous surfaces, such as glass and ceramics.”

Hofstetter is working to develop the fingerprinting method with a team of researchers led by Xanthe Spindler, a forensic science researcher at the University of Technology Sydney (UTS) in Australia. Chief investigators and key personnel also include Director of the UTS Center for Forensic Science Professor Claude Roux, Professor Chris Lennard from the University of Canberra in Australia and Andrew McDonagh from UTS.

“The targeting of amino acids in fingerprint detection has been around since the mid-’50s, but its use has been limited largely to porous surfaces like paper because of the fragility of amino acid secretions on non-porous surfaces,” Spindler said.

“We’ve been able to successfully target amino acids on non-porous surfaces for the first time, with promising results in enhancing aged and degraded fingermarks that typically give poor results with traditional powdering and cyanoacrylate fuming,” Spindler said. “The potential is there to go back to old cases to see what might now be recovered.”

Hofstetter said the researchers have tested fingerprints that have been stored for as long as a year. Unlike conventional techniques, the effectiveness of the antibody-based system did not decrease with fingerprint age. Because amino acids are relatively stable, there is the potential to detect even much older fingerprints, the scientists said.

The research is also a step in pursuit of what Spindler calls the “Holy Grail”—a reliable method for recovering fingerprints from human skin.

“The work we have done so far enables us to pursue several intriguing research directions and to test the method under a variety of experimental conditions,” Hofstetter said. “It’s possible to work on fingerprints of any age or composition and to expand this work further to include other surfaces, possibly even skin.”

Hofstetter’s research expertise is in the production, characterization and application of antibodies that recognize small molecules.

“The Australian team originally contacted me,” he said. “They had the idea of trying to detect amino acids in fingerprints using an immunological approach and knew that I had antibodies directed against amino acids. After discussing their planned approach with them, I selected a batch of antibodies I thought might work and advised them on how to apply them and use them in their test.”

Provided by Northern Illinois University

Israeli scientists develop date-rape drug detector

The days of having to cart your cocktail to the ladies room may be over: two Israeli scientists say they have developed a sensor that can accurately detect date-rape drugs in drinks 100 percent of the time.

Professor Fernando Patolsky and Doctor Michael Ioffe of Tel Aviv University's school of chemistry say the sensor can tell you in real time whether your martini or your mocktail has been spiked with either of the two most common date-rape drugs.

"You just dip it into your drink, it might actually look like a stirrer in the final production, it's tiny, very tiny," Ioffe told AFP.

"And you don't even have to hold it up to the light and the system will let you know whether there are drugs dissolved in your drink."

The device sucks up a tiny drop of the suspect beverage and puts it in contact with the patented chemical formula devised by Patolsky and Ioffe.

"The drug itself is reacting with this chemical formulation and the previously clear formula becomes dirty and when the light shines it you can detect it," Ioffe said. "You don't have to do anything but dip it in your drink."

The two scientists tested their device on a range of popular cocktails as well as soft drinks and other beverages and found it was able to correctly tell which had been spiked 100 percent of the time.

"What's amazing is that there is no false positives until now," Ioffe said.

At present, the device can accurately detect the presence of the two of the most-commonly used date-rape drugs: GHB (gamma-hydroxybutyric acid) and ketamine.

The scientists are also working to expand the device's detection capacity to include Rohypnol, another drug commonly used to sedate the victims of date rape.

"We have some very, very optimistic preliminary results," Ioffe said. "All we need is money."

The pair expect the first batch of sensors could be commercially available within a year and a half.

The chemical formula that the device uses is cheap to produce and is not poisonous, meaning companies should be able to produce the sensor without requiring government approval.

All that remains is for the producers to decide how the device will let its users know whether their drink is safe for consumption, and a range of options are being considered, Ioffe said.

"We haven't decided how it will let you know. Maybe it will just light up or a part of it will rotate or maybe it will send a signal to your cell phone because you want to be discreet about it."

(c) 2011 AFP

Curry spice could offer treatment hope for tendinitis

A derivative of a common culinary spice found in Indian curries could offer a new treatment hope for sufferers of the painful condition tendinitis, an international team of researchers has shown.

In a paper due to be published in the Journal of Biological Chemistry, the researchers at The University of Nottingham and Ludwig Maximilians University in Munich have shown that curcumin, which also gives the spice turmeric its trademark bright yellow colouring, can be used to suppress biological mechanisms that spark inflammation in tendon diseases.

Dr Ali Mobasheri of the University's School of Veterinary Medicine and Science, who co-led the research, said: "Our research is not suggesting that curry, turmeric or curcumin are cures for inflammatory conditions such as tendinitis and arthritis. "However, we believe that it could offer scientists an important new lead in the treatment of these painful conditions through nutrition. Further research into curcumin, and chemically-modified versions of it, should be the subject of future investigations and complementary therapies aimed at reducing the use of non-steroidal anti-inflammatory drugs, the only drugs currently available for the treatment of tendinitis and various forms of arthritis."

Tendons, the tough cords of fibrous connective tissue that join muscles to bones, are essential for movement because they transfer the force of muscle contraction to bones. However, they are prone to injury, particularly in athletes who may overstretch themselves and overuse their joints. Tendinitis (or tendonitis) is a form of tendon inflammation, which causes pain and tenderness near to joints and is particularly common in shoulders, elbows, knees, hips, heels or wrists. Other examples of common tendon disease include tennis and golfer's elbow and Achilles tendinitis.

The global incidence of tendinitis is on the increase in line with the rise in ageing and inflammatory diseases. It is also linked to other arthritic and rheumatic diseases such as rheumatoid arthritis or metabolic diseases such as diabetes.

The only treatment is to relieve pain and reduce inflammation and the only medicines which are effective in treating tendinitis are non-steroidal anti-inflammatory drugs (NSAIDS), such as aspirin or ibuprofen. In more serious cases of tendon injury, steroid injections can be given directly into the tendon sheath to control pain and enable physical therapy to start.

However, NSAIDS and steroids are associated with undesired side effects including stomach ulcers, nausea, vomiting, heartburn, headache, diarrhoea, constipation, drowsiness and fatigue. Consequently, there is an acute need for new treatments with fewer debilitating side effects.

This latest research centres on curcumin, a key ingredient of the spice turmeric, which has been used for centuries in traditional Indian or 'Ayurvedic' medicine as an anti-inflammatory agent and remedy for symptoms related to irritable bowel syndrome and other disorders.

More recently, studies have linked curcumin to potential uses in treating arthritis and a range of rheumatic diseases and, potentially, even as an agent to kill cancer cells directly or make them more sensitive to killing by chemotherapy and radiotherapy.

The Nottingham-Munich study used a culture model of human tendon inflammation to study the anti-inflammatory effects of curcumin on tendon cells. The main objective of the study was to observe the effects that curcumin had on the inflammatory and degenerative properties induced by signalling molecules called interleukins. Interleukins are a type of small cell-signalling protein molecules called cytokines that can activate a whole series of inflammatory genes by triggering a dangerous 'switch' called NF-kB.

The results showed that introducing curcumin in the culture system inhibits NF-kB and prevents it from switching on and promoting further inflammation.

The results follow on from another study by the Nottingham-Munich collaboration, published in the Journal of Biological Chemistry earlier this year, demonstrating that a compound found in red wine could have therapeutic potential for osteoporosis related bone loss in elderly patients, post-menopausal women and patients with rheumatoid arthritis.

The research found that resveratrol, a naturally occurring phytoestrogen found in the skin of red grapes, vines and various other fruits and nuts, inhibits inflammation in bone cells. Its effects extended to inhibiting the formation of osteoclasts, giant congregations of blood-derived cells responsible for bone degeneration, especially in osteoporosis in later life. Resveratrol prevented NF-kB from switching on to trigger inflammation.

The results suggest that resveratrol plays a pivotal role in regulating the balance between the formation of new bone and bone loss, which can lead to weak or brittle bones.

The findings are an important step in the search for new drugs to treat conditions such as osteoporosis, which are currently treated using medications including calcium and vitamin D supplements and a class of drugs known as bisphosphonates. Post-menopausal women can also benefit from hormone replacement therapy (HRT), however, it is associated with a large number of side-effects ranging from headaches to behavioural changes and acne and long-term use can increase the risk of developing uterine cancer.

Provided by University of Nottingham (news : web)

Polymer's hunt for nicotine

Newly synthesized polymer, fitted with molecular pincers of carefully tailored structure, effectively captures nicotine molecules and its analogues. The polymer can be used for fabrication of sensitive and selective chemical sensors to determine nicotine in solutions, and in the near future also in gases. Moreover, the polymer is suitable for slow, controlled release of nicotine, e.g., for therapeutic purposes.

The collaboration of researchers of the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) and of the Department of Chemistry, Wichita State University, Wichita, KS, has resulted in fabrication of a polymer trap for nicotine. Bearing molecular pincers, the polymer effectively captures nicotine molecules and its analogues, and can also release them in a controlled way. The compound will be used in reusable chemical sensors for determination of nicotine for industrial and biomedical purposes as well as in patches for smokers to evenly release nicotine to the body for a prolong time.

"The first nicotine trap has been synthesized by our US partner, Prof. Francis D'Souza, several years ago. It was a sort of molecular pincers, molecules that freely move in solution and form complexes with nicotine therein. Recently, our US-Polish team has been able to fix the pincers inside a polymer. The substance is solid, and that's why we could use it to construct chemosensors", says Prof. Włodzimierz Kutner from IPC PAS.

The core of the polymer nicotine trap, which has been recently filed for a patent, is a metalloporphyrin derivative, a substance present, i.a., in human blood. The molecule contains a ring (a macrocycle) with a centrally located zinc atom and amide pincers attached to this ring. Nicotine binds to this polymer with its two nitrogen atoms: one binds to the zinc atom, whereas the other to the pincers. "It is due to the specific two-point binding that we are surer that the captured molecule is nicotine", stresses Dr. Krzysztof Noworyta from IPC PAS, adding that in one of the devised polymers the pincers are located on both sides of the zinc containing-ring plane. "Such a design clearly increases the efficiency of nicotine trapping", says Dr. Noworyta.

Beside nicotine, the polymer captures also a cotinine alkaloid produced in the metabolism of nicotine and other alkaloids often accompanying nicotine, e.g., myosmine. Polymer binding to nicotine is durable but reversible. It is the property why the new chemosensors for determination of nicotine and its analogues can be used repeatedly.

Nicotine is detected by means of a piezoelectric resonator coated by electropolymerization with a submicrometer thick polymer film. The captured nicotine increases the mass of the film resulting in a decrease in the resonant frequency of the resonator that is easy to measure. "It can be said that we are weighing a film of our polymer all throughout the experiment. Because we know the initial polymer mass and we know that the polymer selectively captures nicotine and its analogues, an increased mass of the film means that these compounds are present in solution", explains Dr. Noworyta.

Quartz acoustic bulk wave resonators used in experiments with the new polymer allow determining nicotine in solutions. In the near future, the researchers from IPC PAS plan to establish collaboration with manufacturers of surface acoustic wave resonators. These resonators oscillate at significantly higher frequencies, thus being more sensitive, and after coating with the nicotine capturing polymer film could detect nicotine also in gases.

In the method described herein, the detection and determination of nicotine do not need to be confined to weighing. Because nicotine is electroactive, the researchers from IPC PAS are going to measure oxidation current of nicotine trapped in the polymer in parallel with the resonant frequency measurement. Simultaneous measurement with these two methods will increase the detection reliability.

The polymer with pincers for nicotine can be used, among others, in chemosensors devised to analyze nicotine content in tobacco leaves and in biomedical studies to determine nicotine metabolites in patients' body fluids. Another potential application is nicotine patches to help quit smoking. The new polymer could be used for prolong and smooth release of nicotine.

On the Polish side, the research described herein has been performed within the project "Quantum semiconductor nanostructures for applications in biology and medicine". The project, funded in 85% from the European Regional Development Fund, has been awarded to seven Polish research institutions for construction of prototype diagnostic devices on semiconductor substrates, designed for applications in biology, medicine, and environment protection as well as for the development of fundamentals of materials technologies for sensor applications and molecular diagnostics devices. Almost 50 researchers from IPC PAS participate in the project implementation.

Provided by Institute of Physical Chemistry of the Polish Academy of Sciences

A bit of boron, a pinch of palladium: One-stop shop for the Suzuki reaction

Carbon-containing compounds are at the heart of organic chemistry, and carbon is the basis of all living matter. However, the so-called Suzuki reaction provides a simple means of creating carbon-carbon bonds to form compounds that can serve as the starting points for the synthesis of an infinite variety of organic molecules.

A team of researchers led by chemist Professor Paul Knochel from Ludwig-Maximilians-Universitaet (LMU) in Munich has recently developed a practical and general method for the synthesis of a class of intermediates that readily undergo the Suzuki reaction. "The new method is broadly applicable to diverse starting compounds and is very economical because it produces very few unwanted byproducts," says Knochel. "It should also be of great interest in an industrial setting, where Suzuki reactions are used in the development of medicinal compounds and novel materials such as liquid crystals for display screens."

The Suzuki reaction – which involves the use of palladium to catalyze the cross-coupling of organoboron compounds with organic halogen-containing molecules – makes it possible to link carbon atoms together in a very straightforward way. The products of the reaction can then be utilized for the construction of a virtually unlimited number of organic substances. The Suzuki reaction thus forms the basis for the synthesis of novel drugs and innovative materials. Akira Suzuki was awarded the Nobel Prize in Chemistry for his discovery of the reaction that bears his name.

Knochel and his team were hoping to extend the applicability of the reaction by finding an easy, economical and general way to synthesize the necessary organoboron compounds so that they could be used in Suzuki reactions without further purification. "We were able to optimize the process in such a way that the boronates can be made in a one-pot reaction", says Christoph Sämann, who made a major contribution to the study. "The method works well under very mild conditions, is compatible with many different functional groups and can therefore be applied to a wide range of compounds."

In contrast to the organoboronates that have been used so far, the products generated via the new synthetic route have two organic groups attached to the boron atom, and both can be transferred, without loss, in the course of the subsequent Suzuki reaction. "This significantly improves overall yields, making the reaction much more economical," says Knochel. "The new reaction also produces less waste, which is an especially important consideration in industrial applications." (suwe)

More information: Angewandte Chemie International Edition, 1. August 2011

Provided by Ludwig-Maximilians-Universität M?nchen