An aggregation-induced emission luminogen combined with a cyanoacrylate fuming method for latent fingerprint analysis

Fingerprint remains topologically unchanged in one’s whole life, and therefore, has been used as a means to biometrically identify individuals in forensic investigations, law enforcement and access control. Appropriate methods are essential to obtain high-quality fingerprint images. In this contribution, an aggregation-induced emission luminogen tetraphenylethene-based dye FLA-2, was synthesized and characterized for the visualization of the latent fingerprints (LFPs). LFPs can be directly visualized by incubating with the dye FLA-2 solution. And, after a cyanoacrylate fuming method pre-treatment stage, fine fingerprint structures can be obtained from level-1 to level-3 details. Two methods were compared by resolution, fluorescent intensity, and scanning electron microscopy imaging to investigate the influence of the cyanoacrylate fuming method pre-treatment stage. Furthermore, the visualization of old LFPs (7 d, 16 d and 30 d) on glass slides, aluminum foil and coin substrates also became effective after the pre-treatment step. The fluorescent LFP images above were all validated by the Automated Fingerprint Identification System obtaining positive matches. These results demonstrate the potential of this method to be applied into visualizing LFPs in the field of public security.