Development research of latent fingermarks based on aggregation-induced emission technique

Area of Science:

• Forensic Science
• Chemistry
• Materials Science

Background:

• Latent fingermarks (LFMs) are crucial for individual identification in criminal investigations.
• Developing sensitive, efficient, and convenient visualization methods for LFMs remains a priority.
• Existing techniques may face limitations with diverse or challenging surfaces.

Purpose of the Study:

• To introduce and evaluate an aggregation-induced emission atomization technique (AIE-AT) for high-quality latent fingermark visualization.
• To assess the effectiveness, applicability, and selectivity of the AIE molecule C27H19N3SO for fingermark development.
• To determine the stability of the AIE molecule for potential long-term preservation.

Main Methods:

• Developed an aggregation-induced emission atomization technique (AIE-AT) using the molecule C27H19N3SO.
• Collected over 1566 fingermark samples from six volunteers on 17 different object types.
• Evaluated fingermark quality using grayscale analysis, ridge fluency, and level 2/3 feature clarity, alongside qualitative assessments.

Main Results:

• AIE-AT produced high-quality fingermark images with a grayscale ratio of at least 2 and high brightness contrast.
• The technique demonstrated effectiveness on nonporous, porous, and semiporous objects, including challenging surfaces.
• The AIE molecule exhibited high stability, suitable for long-term preservation, and showed low selectivity, aiding in situ DNA extraction.

Conclusions:

• AIE-AT is a highly effective method for visualizing latent fingermarks on a wide range of common and challenging objects.
• The technique provides clear visualization of intricate fingermark features, facilitating individual identification.
• AIE-AT supports the localization of LFMs for subsequent in situ extraction of touch DNA, advancing forensic capabilities.