Photoacoustic and Colorimetric Visualization of Latent Fingerprints

Area of Science:

• Forensic Science
• Nanotechnology
• Analytical Chemistry

Background:

• Latent fingerprint (LFP) detection requires simple, rapid, accurate, user-friendly, cost-effective, and nondestructive universal methods.
• Existing methods often lack universality, require multiple steps, or involve signal amplification like silver staining.

Purpose of the Study:

• To develop a general, single-step, and high-resolution imaging strategy for latent fingerprint visualization.
• To integrate colorimetric and photoacoustic imaging for enhanced LFP detection.
• To utilize poly(styrene-alt-maleic anhydride)-b-polystyrene (PSMA-b-PS) functionalized gold nanoparticles (GNPs) for LFP detection.

Main Methods:

• Functionalized gold nanoparticles (PSMA-b-PS-GNPs) were synthesized for latent fingerprint detection.
• A dual-modality imaging approach combining colorimetric and photoacoustic imaging was employed.
• The method was tested for its ability to visualize LFPs on various substrates without silver enhancement.

Main Results:

• The PSMA-b-PS-GNPs demonstrated good stability, tunable color, and high affinity for fingerprint residues.
• The dual-modality imaging strategy provided high-resolution visualization of LFPs.
• Photoacoustic imaging allowed for the observation of level 3 hyperfine features, including pores and ridge contours.

Conclusions:

• This single-step, dual-modality imaging technique offers a universal, rapid, and accurate method for LFP detection.
• The approach's flexibility and high resolution present significant potential for forensic investigations and medical diagnostics.
• The technique may also enable chemical identification within LFP residues.