Nanoparticles for Chemical Imaging of Latent Fingerprint

As submitted by the proposer: For over one hundred years, fingerprinting has been a major tool for identification in the criminal justice system.

Currently, latent fingerprint identification is limited to visualizing the print and then comparing the ridge patterns against those in the FBI database. Unfortunately, prints are often smudged, distorted, or overlapped with another print.

There may be multiple hits from the database if only a partial print is recovered, or no match at all if the subject's prints are not on file. To overcome these limitations, additional revolutionary steps are necessary beyond the mere visualization of fingerprints.

Chemical fingerprinting is a new method to uncover the hidden chemical nature of latent fingerprints. This chemical signature includes external compounds such as drugs or explosives with which the suspect has come into contact, as well as inherent compounds in fingerprints such as lipids or amino acids that might be specific to the suspect's gender, ethnicity, or medical conditions.

A plethora of information can be derived from chemical fingerprinting, providing a new avenue in individual identification in addition to the fingerprint database search. Mass spectrometry imaging (MSI) is the most promising method for chemical fingerprinting due to its extremely high sensitivity, label-free detection, and unbiased molecular characterization.

In spite of the promise, MSI based chemical fingerprinting is still far from practical use because of a few major bottlenecks: 1) low sensitivity for small molecules, 2) ambiguity of chemical identifications, and 3) lack of robust protocols.

The proposed research is designed to overcome such limitations and advance MSI as a practical tool for routine criminal investigations. Innovative new approaches are proposed that are specifically designed to be compatible with the current forensic practice as well as to dramatically improve the sensitivity of low mass compounds of forensic interest. The most innovative aspect of the proposed research is the adoption of nanoparticles for forensic use.

Various nanoparticles will be screened as a mediator to absorb laser energy and assist in the desorption of fingerprint chemicals. Nanoparticles have no background in the low mass region and provide efficient ionization of many small molecule compounds. Additionally, nanoparticles will be used to visualize latent fingerprints as forensic fingerprint powders in a crime scene. Advanced MSI technology will be developed and applied for chemical fingerprinting, including high-spatial resolution imaging to visualize level 3 finger pore images and multiplex MSI for confident analyte identifications.

This project contains a research and/or development component, as defined in the applicable law, and complies with Part 200 Uniform Requirements – 2 CFR 200.210(a) (14). nca/ncf

A latent finger print recovered from a crime scene can only be used to identify an unknown perpetrator if there is a matching print on file against which it can be compared. However, there may be additional information associated with latent prints that could be used to identify the perpetrator or better inform a criminal investigation. Latent fingerprints are made when the sweat and oil on the skin are transferred to a surface by touch. Those fluids may contain useful amounts of DNA to help identify the perpetrator as well as information regarding their ethnicity and gender. Other residue from material that the perpetrator touched such explosives and drugs may also be transferred. The applicant proposes research to extract such additional information from finger prints using nanomaterials. "Note: This project contains a research and/or development component, as defined in applicable law," and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14). NCA/NCF