Latent fingerprint development by using silver nanoparticles and silver nitrate-A comparative study.

The beginning of latent fingerprint development on porous surface was first achieved by silver nitrate (AgNO3 ) method. But the significantly increasing cost has caused forensic experts to look for an alternative means. Silver nitrate (AgNO3 ) is the main component in the synthesis of metal nanoparticles, namely silver nanoparticles (AgNPs). Owing to its unique property to adhere with fingerprint residue, AgNPs have attracted a great attention in the domain of nano-forensic fingerprinting. This study mainly focuses on the use of lower concentration of silver nitrate through new AgNP development method. The AgNPs were synthesized by wet chemical method with different molar concentrations (0.1, 0.01, and 0.001 M) of silver nitrate, characterized by ultraviolet visible spectrophotometer and high-resolution transmission electron microscope (HR-TEM). The average diameter of AgNPs calculated by HR-TEM was 10.66 ± 1.22 nm at 0.1 M, 12.50 ± 2.64 nm at 0.01 M, and 14.44 ± 2.68 nm at 0.001 M, respectively. A comparative analysis was also carried out to see the quality and stability of fingerprints produced on paper or porous substrate by using AgNO3 and AgNPs, respectively. During the study, AgNPs were able to develop distinct ridge details and were found to be stable for more than a month. Comparatively, when AgNO3 was used as the developing agent for the latent fingerprints, only faint ridge patterns were observed which further showed degradation of fingerprint stability within about 20 days. Overall, the current AgNP method showed good visibility and stability by using lower concentration of silver nitrate which can be used in place of conventional AgNO3 method.

Role of Nanomaterials for Forensic Investigation and Latent Fingerprinting-A Review.

The imminent nanotechnology and progressive instrumentations together have vast applications in the field of forensic science. Few prominent examples are gold nanoparticles for improvising the efficiency of polymerase chain reaction and atomic force microscopy for examining ink and bloodstains. Characteristics like distinct ridge details of fingerprints could be obtained by applying different nanoparticles such as silver, zinc oxide, silicon dioxide, aluminum oxide, gold (with silver physical developer), europium, fluorescent carbon, and amphiphilic silica on a range of object surfaces, and among all, gold is most commonly used. Fingerprint is considered noteworthy evidence in any crime scene, and nano-based techniques hold immense future potential in fingerprint investigations. Therefore, this paper focuses on the applications of nanoparticles in developing and detecting the latent fingerprints.