A better forensic test to help investigators to determine “Who Did It?” on the basis of traces of blood to detect traces of blood at a crime scene has been developed by researchers at Ben-Gurion University of the Negev (BGU) in Beersheba. The innovative chip could increase the efficiency and accuracy of the crime-scene investigation.
The new device combines the use of luminol (C8H7N3O2), a synthetic chemical that that exhibits chemiluminescence, together with nanoscale spheres of gold or silver, located in a specially designed curved device that allows for the flow of minimal quantities of liquids.
It produces a blue glow when mixed with an appropriate oxidizing agent. Luminol is a white-to-pale-yellow crystalline solid that is soluble in most polar organic solvents but insoluble in water. Luminol emits increased light in the presence of blood, as it reacts with the iron in hemoglobin.
When luminol is sprayed evenly across an area, trace amounts of an activating oxidant make the luminol emit a blue glow that can be seen in a darkened room. The glow only lasts about 30 seconds, but investigators can document the effect with a long-exposure photograph. Crime scene investigators must apply it evenly to avoid misleading results, as blood traces appear more concentrated in areas that receive more spray. The intensity of the glow does not indicate the amount of blood or other activator presents, but only shows the distribution of trace amounts in the area. The compound was first synthesized in Germany in 1902, but was named luminol only in 1934.
The spheres serve as nanoscale “antennas” that increase luminol’s light emission and simplify detection of blood traces due to integration with the chip. The technology is the result of the development of Prof. Alina Karabchevsky of the department of optoelectronics and photonics engineering at the School of Electrical and Computer Engineering and the Ilse Katz Institute of Science and Nanotechnology at Ben-Gurion University.
“Our findings open the door to the production of integrated microchips that allow us to test small quantities of liquids based on the nanocrystalline-controlled Purcell Effect (enhancement of a quantum system’s spontaneous emission rate by its environment) that is made possible by nanoparticles and changing the density of energetic states,” she explained. “The implementation of this phenomenon will lead to improved sensors based on light emission for forensics, biological and chemical research and optoelectric lasers.”
Criminologists use luminol to detect microscopic blood droplets, as well as low concentrations of hydrogen peroxide, proteins and DNA, all hidden from the human eye. They use chemical luminescence to detect these biological residues because they don’t rely on external light sources. The chip, invented by Prof. Karabchevsky and her research group, not only increases luminol’s light emission but also extends the duration of the emission and allows for the identification of much smaller blood samples at the crime scene.
“The identification of blood traces can increase the efficiency and accuracy of the crime scene investigation, but it requires more sensitive sensors than those available today,” said Neta Cohen, CEO of BGN Technologies – the university’s research and development company. “The technique developed by BGU researchers will make it possible in the future to develop sensors with improved sensitivity. We are now looking for partners to further develop this promising invention, which is protected by a patent.”
BGN Technologies commercializes the inventions of the university’s researchers and fosters cooperation and entrepreneurship among researchers and students. It has established over 100 start-up companies in a wide range of technological fields such as biopharma, cyber, cleantech, medical devices, optics and more. In addition, BGN Technologies has set up incubators and technological accelerators in cooperation with leading organizations in the Israeli market.
Over the last decade, the company has established long-term partnerships with multinational companies such as Deutsche Telekom, Bayer, Dell, EMC, PayPal, and others, thereby helping to create value and growth for BGU, as well as the entire Negev.
Source: Israel in the News