Fingermark detection using upconverting nanoparticles and comparison with cyanoacrylate fuming

Area of Science:

• Materials Science
• Nanotechnology
• Forensic Science

Background:

• Upconverting nanoparticles (UCNPs) offer unique optical properties for various applications.
• Developing novel methods for latent fingermark detection is crucial for forensic investigations.
• Current fingermark detection techniques have limitations, especially on complex surfaces.

Purpose of the Study:

• To synthesize and characterize tailor-made upconverting nanoparticles (UCNPs) for fingermark detection.
• To evaluate the effectiveness of a nanoparticle-based fingermark detection technique.
• To systematically compare UCNP performance against a benchmark method (cyanoacrylate fuming) for forensic applications.

Main Methods:

• Synthesis of silica-shelled sodium yttrium tetrafluoride (NaYF4:Yb,Er) upconverting nanoparticles capped with phenyl groups.
• Application of water-based UCNP solutions to latent fingermarks on diverse substrates (aluminium foil, polyethylene, polypropylene, glass).
• Comparative analysis of UCNP detection against cyanoacrylate fuming (CAF) followed by luminescent dye staining, using 300 fingermark specimens.

Main Results:

• Upconverting nanoparticles (UCNPs) were successfully synthesized with desired properties.
• Cyanoacrylate fuming (CAF) demonstrated superior average performance across tested substrates compared to UCNPs.
• UCNPs exhibited advantages for detecting fingermarks on multicoloured, patterned, or luminescent surfaces due to their unique optical properties.

Conclusions:

• While CAF is currently more effective on average, UCNPs present a valuable alternative for specific challenging forensic scenarios.
• Further research is needed to address synthesis and application shortfalls before UCNPs can be implemented in routine law enforcement practice.
• The unique optical properties of UCNPs warrant continued investigation for advanced fingermark detection methods.