So what is new in fingerprinting? Hazarika and Russel bring you up to speed in a Angewandte mini review (DOI). We have already seen in a previous episode of this blog how fingerprints can reveal the owners smoking or chewing gum habits with the use of coated gold nanoparticles.
In a similar vein magnetic particles coated with the right antibodies not only reveal the fingerprint pattern but by a specific colouration (amplified by fluorescence) also cannabis, cocaine or heroin use. Quantum dots QD's apparently have superior luminescence making them popular in fingerprint visualization. CeTe QD's have been shown to uncover a print left from a bloody finger.
With its ever increasing detection capabilities, liquid chromatography-mass spectrometry (LC-MS) is also making modest contributions to the field. The detection of methadone and lorazepam has been demonstrated in a laboratory setting.
And why stop there, if you have the funds you can equip your forensics lab with a SALDI/MS or desorption electrospray ionization/MS unit. On the other hand all these techniques basically destroy the evidence so moving on to non-invasive methods ATR infrared spectroscopy is also capable of images fingerprints. In one demonstration it was possible to detect particles of explosive residue in between the ridges.
But why all this focus on drugs and explosives? In many advanced societies (one this blog pretends to live in) there are bigger worries than drug abuse or terrorism, like say theft, robbery and random violence. You may want to focus instead on the detection of pharmaceuticals in general or legal vices such as the nicotine already mentioned or alcohol. That would be more helpful in preselecting the suspects.