Glowing nanoparticles help image fingerprints
doi:10.1038/nindia.2019.3 Published online 14 January 2019
Researchers have synthesised a new kind of light-emitting nanoparticle that can be used to image latent fingerprints on a wide range of surfaces. These nanoparticles will be potentially useful in identifying criminals1.
During contact between a finger and a surface, secretions from the skin surface are transferred onto the surface, which retains an impression of the finger. Known as latent fingerprints, such impressions linger on various surfaces for a long time.
To overcome the drawbacks of traditional fingerprint-detecting methods, scientists from the National Institute of Technology in Durgapur, the Indian Institute of Science in Bangalore and the Indian Institute of Technology in Gujarat prepared the nanoparticles by doping zinc sulphide nanoparticles with copper and manganese ions.
The researchers, led by Pathik Kumbhakar, then used the nanoparticles to image latent fingerprints of an adult individual on a transparent adhesive tape, smooth paper, an optical mouse and polymer film surfaces, in the presence of ultraviolet light.
The fingerprint images, captured using a smartphone, displayed all the minute patterns such as the ridge patterns of the fingers. The nanoparticles even detected two-month-old fingerprints more efficiently than a specific dye.
The adhesion of the nanoparticles to the skin-secreted components present in the fingerprint increased the visibility of the images. A coat of the nanoparticles on the surface of a near-ultraviolet light-emitting diode chip converted it into a white-light-emitting diode. This property could be exploited to make white-light-emitting diodes that can be used in mobile screens and flashlights of digital cameras.
1. Kumbhakar, P. et al. Tailoring of structural and photoluminescence emissions by Mn and Cu co-doping in 2D nanostructures of ZnS for visualization of latent fingerprints and generation of white light. Nanoscale. (2018) doi:10.1039/C8NR09074B