Visualizing latent fingerprints by electrodeposition of metal nanoparticles

A novel and simple strategy for visualizing both sebaceous and eccrine latent fingerprints on conductive surfaces (indium/tin oxide-coated glass, gold, platinum and stainless steel coin) has been developed by the use of spatially selective electrodeposition of gold or silver nanoparticles (NPs). In this technique, the fingerprint residue acted as an insulator to the electrodeposition process, so that the metal NPs could only be generated on the areas without residue, which resulted in a negative image of the fingerprint with high contrast. In addition, latent fingerprints could be effectively visualized on various conductive surfaces no matter they were smooth or rough, clean or dirty. The surface morphology of AuNPs was characterized by the field emission scanning electron microscopy (FE-SEM).

► A novel and facile strategy was proposed for visualization of latent fingerprints.
► NPs were selectively electrodeposited only on the valleys of latent fingerprints and the free conductive surfaces.
► Latent fingerprints could be effectively visualized on both smooth and rough conductive surfaces.
► The approach of electrodeposition is simple, rapid, high resolution and eco-friendly.