Recent progress on fingerprint visualization and analysis by imaging ridge residue components.

Fingerprints have long been and are still considered to be the gold standard for personal identification in forensic investigations. Developing or enhancing the visualization of invisible fingerprints, so-called latent fingerprints (LFPs), remains to be the core subject in forensic science. Moreover, the past few years have witnessed a renewal of research interest in the possibility that a fingerprint can provide additional information than just identification of individuals, such as personal traits, the presence of human metabolites with diagnostic values, and the evidence of contact with explosives or illicit drugs. Fingerprint analysis has manifested itself as a research area far beyond the scope of forensics, to which not only conventional fingerprint examiners but also researchers from chemistry, biochemistry, medical science, material science, and nanotechnology fields have made significant contributions in recent years. Beginning with a brief overview of the components present in LFP residue that essentially determines which method or reagent will give the best visualization result, this paper reviews the progress since 2007 on new reagents and methods developed for LFP visualization and simultaneous detection of specific chemicals present in the LFP residue, with an emphasis on the utilization of mass spectrometry, infrared spectroscopy, nanoparticles, and immunogenic and nucleic acid reagents.