One-Step Synthesis of Polyethylenimine-Coated Fe3O4 Superparamagnetic Nanoparticles for Latent Fingermark Enhancement

摘要

We report a one-step synthesis procedure for obtaining polyethyleneimine-coated Fe3O4 superparamagnetic nanoparticles (PEI-Fe3O4 NPs) for latent fingermark enhancement. The as-prepared nanoparticles were then characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), zeta potential analyzer (ZetaPALS), vibrating sample magnetometer (VSM) and thermal gravimetric analyzer (TGA). The experiment displayed the PEI-Fe3O4 NPs with high magnetization and well-defined structure were successfully synthesized and the cladding rate of PEI was 33.3%. The PEI-Fe3O4 NPs were later applied to develop latent fingermarks on various surfaces, including porous and nonporous, which showed clear ridges and good contrast, even for the minutiae and pores. To compare with Fe3O4 NPs, the PEI-Fe3O4 NPs were used to detect aged fingermarks, and it achieved great advantages especially for porous surfaces. Above all, the PEI-Fe3O4 NPs can efficiently enhance latent fingermarks, and thus have great potential in forensic investigations.