New Polymer-Based Technology for Visualizing Latent Blood Fingerprints

Latent blood fingerprints (LBFPs) are a vital form of forensic evidenceEvidence is any form of proof, such as objects, materials, or scientific findings, presented to establish or disprove a fact in a legal proceeding. It is used to reconstruct events and link or exclude individuals Read Full Definition at crime scenes, especially in violent incidents. These fingerprintsFingerprint, impression made by the papillary ridges on the ends of the fingers and thumbs. Fingerprints afford an infallible means of personal identification, because the ridge arrangement on every finger of every human being is Read Full Definition can provide critical clues about suspects, timelines, and actions, but their effective visualization remains a significant challenge. Existing methods for revealing LBFPs often suffer from low sensitivityIn the context of laboratory equipment or analytical techniques, the term "sensitive" describes the capability of a machine or method to detect even very small amounts or concentrations of a substance. Sensitivity is a quantitative Read Full Definition or complex procedures, limiting their usability in real-world forensic applications.

Introducing a Novel Visualization Strategy for LBFPs

Researchers have developed an innovative and effective strategy for the visualization of LBFPs using a new amphiphilic fluorescent amino-functionalized conjugated polymer. This method combines simplicity with high sensitivity and can be applied using a cotton-pad soaked in polymer solution to develop LBFPs on various substrates, even difficult surfaces like painted wood or multicolored cans.

This technique not only displays clear fingerprint patterns and ridge details but also successfully visualizes sweat pores. It is a highly stable method capable of visualizing fingerprints that are contaminated or over 600 days old. Moreover, the developed fingerprints show superior stability against solvent washing and can be stored for long periods without degradation. This allows forensic scientists to capture evidence effectively and preserves the option for DNA profiling DNA profiling, also known as DNA fingerprinting, is a significant technique in forensic science that identifies individual's unique DNA patterns for various purposes such as establishing familial relationships or tracing genealogical roots. The technique, which Read Full Definition.

Mechanism Behind the Polymer’s Effectiveness

The key to the polymer’s effectiveness lies in the covalent bonding between the fluorescent conjugated polymer and proteins in the blood. This bond is what grants the developed fingerprints their stability. Additionally, the synergy between the polymer’s affinity to both the blood and the substrate ensures the formation of clear images.

Advantages of the New LBFP Visualization Technique

1. Highly Sensitive: The method provides clear and detailed fingerprint patterns, even on challenging surfaces and with older fingerprints.
2. Nondestructive: Unlike many chemical methods that can degrade or destroy DNADNA, or Deoxyribonucleic Acid, is the genetic material found in cells, composed of a double helix structure. It serves as the genetic blueprint for all living organisms. Read Full Definition in blood samples, this polymer-based method preserves the integrity of DNA, allowing for further analysis, such as DNA profiling.
3. Simple and Quick: The cotton-pad technique is easy to apply and takes less than 10 seconds to develop the fingerprint image.
4. Stable Over Time: Fingerprints developed using this method are stable against various environmental factors and remain intact during long storage periods.
5. Versatile: The polymer solution works effectively on a wide range of substrates, including aluminum foil, glass, painted wood, dark plastic, and even multicolored cans.

Potential Applications in Forensic Investigations

The potential applications of this polymer-based technology extend across various forensic contexts:

• Violent Crime Investigations: LBFPs are crucial in violent crimes like homicide or assault, where blood is often present at the scene.
• Cold Cases: With its ability to develop aged fingerprints, this technique can reinvestigate cold cases. It reveals fingerprints that were previously invisible.
• Non-Invasive Crime Scene Analysis: Since the method is nondestructive, it preserves all potential forensic evidence, ensuring that investigations can proceed without compromising critical information like DNA.

Conclusion: A New Horizon in Forensic ScienceDiscover the fascinating field of Forensic Science, the application of scientific principles to legal matters. This post delves into its many disciplines, from DNA analysis to crime scene investigation, its importance in the justice system, Read Full Definition

The development of this fluorescent conjugated polymer technique represents a significant breakthrough in forensic science. By addressing the limitations of previous methods, it offers a simple, effective, and nondestructive approach to LBFP visualization. Its ability to work on challenging surfaces and preserve DNA integrity ensures that forensic investigators have a powerful new tool at their disposal.

As forensic technology continues to evolve, methods like this will play an increasingly important role. These methods are crucial in solving crimes and delivering justice.

This article is based on findings from a study authored by Zhinan Fan, Chi Zhang, Jiajun Chen, Rongliang Ma, Yaoqi Lu, Jia-Wei Wu, and Li-Juan Fan.

Zhinan Fan, Chi Zhang, Jiajun Chen, Rongliang Ma, Yaoqi Lu, Jia-Wei Wu, Li-Juan Fan. Highly Stable, Nondestructive, and Simple Visualization of Latent Blood Fingerprints Based on Covalent Bonding Between the Fluorescent Conjugated Polymer and Proteins in Blood. ACS Applied Materials & Interfaces, 2021; 13 (13): 15621 DOI: 10.1021/acsami.1c00710