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AsianScientist (Jan. 14, 2021) – In a hair-raising development, scientists from Japan have come up with a new strategy to identify criminals from just a single strand of hair. Their findings were published in Analytical Sciences.
Avid fans of classic shows like Crime Scene Investigation would be familiar with the arduous process of searching a crime scene for clues. From dusting for fingerprints to analyzing minute amounts of blood, even the smallest piece of evidence could mean all the difference in a case or trial. Should investigators chance upon a strand of hair with attached root cells, a DNA test can easily reveal the culprit’s identity. Unfortunately, such an ideal scenario rarely happens.
Inspired by the ubiquity of dyed hair in the 21st century, researchers led by Associate Professor Shinsuke Kunimura developed a two-in-one technique to identify criminals based on their hair dyes. The technique employs two common analytical methods, namely: surface-enhanced Raman spectroscopy (SERS) and X-ray fluorescence (XRF) analysis.
In SERS, scattered light is used to reveal insights into a substance’s chemical makeup even with just a few molecules. Meanwhile, XRF analysis focuses on the distinctive photons emitted by molecules exposed to X-rays. By closely examining these emitted photons, elements present in the sample can be identified and quantified. Using portable devices, Kunimura and his colleagues then conducted SERS and XRF analyses to differentiate between single strands of dyed hog hairs based on their composition.
“SERS can easily detect the overall differences in composition between different types of hair dyes, such as permanent, semi-permanent, or natural dyes. However, it is not enough to distinguish between hair coloring products that contain or produce similar dyes,” he explained. “To do this, we also relied on XRF analysis, which can detect the presence of metallic elements used in the ingredients of hair dye products.”
With both techniques at hand, the team managed to easily distinguish between five different dyes applied to individual strands of hog hair. Because SERS and XRF are both non-destructive methods, the strategy proposed by Kunimura’s team could be used to analyze hairs found in crime scenes on-site before they are sent for further DNA analysis.
“Our approach provides supportive information for more reliably identifying whose hair was found in a crime scene,” remarked first author Dr. Momona Horiguchi. “This could help us clarify if someone is a criminal, meaning that our methodology could greatly contribute to forensic investigations.”
The article can be found at: Horiguchi & Kunimura (2020) Surface-enhanced Raman Scattering and X-ray Fluorescence Analyses of a Single Hair Colored with a Hair Dye Product.
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Source: Tokyo University of Science; Photo: Shutterstock.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.
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