A rapid and dual-mode visualization of latent and bloody fingermarks using Cr- and Sb-codoped titanium dioxide nanoparticles

Abstract

In forensic science, the demand for the discovery and extraction of latent fingermarks at crime scenes in a fast and convenient way is still urgent. Herein, a rutile Cr- and Sb-codoped TiO2 nanoparticle was synthesized via homogeneous precipitation and was characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, and X-ray fluorescence. Subsequently, the as-prepared nanoparticle was used to visualize latent fingermarks using a powder dusting method and to enhance the visualization of bloody fingermarks using a small particle reagent method on porous, semiporous, and nonporous substrates. Notably, the anti-ultraviolet property of this yellow nanoparticle was investigated. This intriguing property contributed to the detection of latent fingermarks on strong-fluorescence or multicolored surfaces in a negative-image manner. Moreover, two potential interaction mechanisms were proposed between hemoglobin and surfactants in bloody fingermark enhancement. This work showed that this rutile TiO2 nanoparticle doped with Cr and Sb is a versatile eikonogen for the rapid visualization of latent and bloody fingermarks and has high sensitivity, selectivity, contrast as well as wide applicability compared with traditional developing methods.