David A. Russell and his coworkers from the University of East Anglia which is in Norwich, UK, find out a different way to differentiate between smokers and nonsmokers, without using blood tests.
This study used fingerprints to distinguish between smokers and nonsmokers. Usually a fingerprint leaves tiny traces of perspiration, because the skin need to expel some substances, so they used this perspiration to determinate the existences or not of cotinine, which is a metabolite formed by the body when the person consumes nicotine.
In order to do it, they wet participants' fingerprints with a solution which had cotinine antibodies ( not nicotine antibodies to avoid results' misinterpretations, because anyone can touch nicotine), and after cotinine antibody is bound to cotinine, the antibody was tagged with a fluorescent dye so they could see cotinine , if they saw fluorescence the person was a smoker, and if they didn't the person wasn't. As you can see this technique allows lots of possibilities, thought they haven't been tested yet. But in a future it will make possible to obtain more information of a fingerprint for forensic investigators, like the suspect's habits and diseases or drugs and medications consumed by the suspect.
If you want to know more about this you can look for it in the magazine Angewandte Chemie International Edition, year 2007, No. 22, pages 4100-4103 by the name of "Intelligent" Fingerprinting: Simultaneous Identification of Drug Metabolites and Individuals with Antibody-Functionalized Nanoparticles" or you can read it at this website: http://www.medicalnewstoday.com/medicalnews.php?newsid=71233
