Nanotechnology has been the cause of many great advances in science since it allows the manipulation of molecules to obtain products on a microscale, known as nanoparticles. In the forensic science field there are different techniques for lifting fingerprints. Among the traditional methods we have: fluorescent, magnetic, carbon and aluminum powders. These methods are important tools for the identification of fingerprints at a crime scene. Currently researchers are investigating the potential for the use of nanotechnology for the improvement of fingerprint development to overcome the disadvantages of traditional methods. Previous work carried out in our laboratory, demonstrated that Silica (SiO₂) and Zinc Oxide (ZnO) nano powders showed higher definition in latent fingerprints development on nonporous surfaces. In this project, we worked with SiO₂, ZnO nano powders, silver (AgNO₃) and gold (HAuCl₄.2H₂O) nanoparticles salt precursors for the preparation of metallic nanoparticles. For the analysis of ridge characteristics metallic salts and nanoparticles were applied to the latent fingerprints. We modified the nanoparticles, salt concentrations and varied kinetic parameters to obtain a better definition of the ridge characteristics. The characterization of the nanoparticles was performed by Dynamic Light Scattering (DLS) and Zeta Potential Measurements in solid films and FTIR studies. For our study, different surfaces such as paper, glass, and aluminum foil were evaluated and different time ranges were also performed. Our findings demonstrate that, compared to the traditional methods, the nanomaterials presented better-quality details for the development of the fingerprints. The bimetallic Silver@gold nanoparticles show the better definition of the ridges characteristics on paper. Future projects in our laboratory will study the effectiveness of these exact methods applied to the development of lip prints.

Joanelis Pagan Soto

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