Acetylated cashew-gum-based silver nanoparticles for the development of latent fingerprints on porous surfaces

Fingerprints have been used in forensic investigations as a powerful tool for human identification. However, it is desirable to find new sustainable sources and synthesis for fingerprint developers, in order to reduce the production costs, to improve the sensitivity and to reduce environment impact after the disposal. This report describes a study involving the production of acetylated cashew-gum-based silver nanoparticles (ACG-AgNPs), using three concentrations of ACG (0.5, 1.0 and 5.0 mg/mL). The nanoparticles were characterized by UV-VIS spectroscopy, AFM (atomic force microscopy) and TEM (transmission electron microscopy). In addition, computer simulations and evaluation of their effect as a potential fingerprint developer on paper were studied, using ninhydrin as a positive control. The results showed that samples were able to reveal the lines contained in the fingerprint residues on paper. Positive results were obtained for all the samples in tests performed 1, 6 and 24 h after application. Howeverthe best performance was observed with the sample containing ACG 0.5 mg/mL. ACG-AgNPs have potential for practical and rapid latent fingerprint development on porous surfaces, which allows the development of a product to be used even at the crime scene. Another advantage was the synthesis process: simple, fast, low-cost and using a biocompatible and biodegradable material as stabilizer, providing a non-toxic material. In addition, this material, is likely to cause less environmental damage than the reagents used by conventional techniques.