In situ growth of gold nanoparticles on latent fingerprints-from forensic applications to inkjet printed nanoparticle patterns.

Latent fingerprints are made visible in a single step by in situ growth of gold nanoparticles on ridge patterns. The chemicals, among the essential components of human sweat, found responsible for the formation and assembly of gold nanoparticles are screened and used as ink to write invisible patterns, using common ball pen and inkjet printer, which are then developed by selectively growing gold nanoparticles by soaking them in gold salt solution.