Ionic liquid-solvated near infrared dyes for detection of trace blood spatter in textiles under ambient lighting conditions

In forensic serology, the analysis of any bodily fluids deposited at the scene of a violent crime can provide investigators with valuable information. Blood and Semen are the most encountered, and serology labs utilize a variety of methods to detect the presence of each. Focusing on blood, luminol has long been the predominantly used presumptive test. Luminol, like all currently developed presumptive tests, works by undergoing chemiluminescence in the presence of hemoglobin. Despite its widespread use, the luminol test faces a number of challenges: 1) The length of time for viewing the chemiluminescence is <1 minute; 2) The emitted light can best be seen in darker conditions; 3) It is mostly a technique suitable for only surface detection; 4) Many chemical agents used to clean up violent crimes can trigger the luminol reaction, making it prone to false positive and false negative results. To combat these challenges, we are proposing the design of near-infrared (NIR) dye-ionic liquid (IL) systems for presumptive blood testing. The NIR dyes designed work by fluorescing upon interaction with serum albumin. This fluorescence can easily be detected by NIR cameras, and lasts for days and even weeks. Prior research has shown that ILs can promote the stabilization of compounds present in blood. Our preliminary data evidences record-breaking emission upon contact with human blood, biocompatibility, stability, low cost, and compatibility with RSID confirmatory tests for blood. We propose to develop more dye-IL systems that are capable of having a longer emission lifetime, are more nondestructive to the biological samples, and are better suited for detecting stains. We partner with the Mississippi Forensics Lab to ensure maximum applicability of our technology. The long-term impacts of this research include: 1) Developing a sensitive, selective, low cost, biocompatible detection method that is not limited to surface analysis, 2) Providing investigators with information that aids in crime scene recreation; 3) Allowing investigators to identify and sample additional sources of DNA. CA/NCF