Fingerprint Technology May Have Medical Uses

Dennis Faas's picture

CSI cast members take note, a new technology called DESI (desorption electrospray ionisation) can tell much more from fingerprints than someone's identity.

The system, pioneered by chemists at Purdue University in Indiana, "involves spraying a tiny (0.15x0.15mm) area of a fingerprint with an electrically charged mixture of methanol and water. When these charged droplets come into contact with the surface of the print they collect any substances deposited on it, creating a thin liquid film. As more drops are sprayed on the same spot, some of this film is scattered and sucked into a mass spectrometer, which can identify the molecules collected. All this takes only a few tenths of a second. Then the spray is moved along to the next patch on the fingerprint and the process is repeated. It will work on any surface on which there are fingerprints." (Source:

The mass spectrometer then provides a reading of what chemicals are represented in the sample, as well as providing an image of the print detailed enough to be used by recognition software. And all this without any brushes or black powder.

DESI is unique in its ability to not only detect what substances were on the print, but can provide clues about the health of the print's owner. By identifying substances that could have come from inside the body and left as part of the print, DESI offers police one more tool for weeding out potential suspects.

Another possible use for the technology, says DESI chemist Graham Cooks, could be in diagnosing diseases whose symptoms may not be discernible through other medical methods, such as urine or blood samples. He cautions, however, that this type of technology needs to be used with absolute discretion, since "the implications for privacy are written all over this." (Source:

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