While it's very important to know if a "date rape" drug has been sneaked into your drink, whipping out a full test kit in a bar may be awkward and time-consuming. That's why scientists have developed a temporary tattoo that can detect such drugs in just one second.
Due to some of their most prominent effects – such as sedation, lowered inhibition, and amnesia – drugs like GHB (gamma hydroxybutyrate), ketamine and Rohypnol are sometimes surreptitiously added to people's drinks in order to facilitate the sexual assault of those individuals.
Unfortunately, because the drugs are odorless, tasteless and colorless, they have long been difficult to detect outside of a lab. And while there are now cards, test strips and other devices that can be used to indicate the presence of such drugs on-location, those gadgets may take several rather awkward minutes to deliver results. This means that some people might not bother using them.
Seeking a quicker and simpler alternative, scientists from Korea's Sungkyunkwan University developed an inexpensive temporary tattoo.
OK, it's really just a skin sticker. Whatever the case, it can be applied to the forearm or some other easy-to-reach part of the body before heading out for the evening.
Using the device is as simple as subtly dipping a finger into your drink, using that finger to transfer a drop of the liquid over to the tattoo, then wetting the surface of the tattoo with that drop. In the current version of the technology, if even trace amounts of GHB are present in the liquid, graphics on the tattoo will change color from yellow to red in just one second.
As an added bonus, the tattoo will retain the red coloration for up to 30 days after being peeled off the skin, for possible use in criminal proceedings.
The base material of the sticker is an adhesive-backed thin film of a flexible, stretchable polymer known as polydimethylsiloxane (PDMS). The graphics, which are applied to select areas of the film, are composed of a gel containing a chemical called 2-(3-bromo-4-hydroxystyryl)-3-ethylbenzothiazol-3-ium iodide (BHEI).
It is the BHEI that changes color when exposed to GHB. Future versions of the tattoo could contain additional chemicals aimed at the detection of other drugs.
In lab tests, the current prototype stood up well to twisting, stretching, water exposure, and abrasion. Even after such abuse, it was still able to detect GHB in concentrations as low as 0.01 micrograms per 1 millilter of beverages such as whiskey, vodka, beer, and coffee.
"Our GHB detection tattoo sticker can be used as a crucial tool in preventing DFSAs [drug-facilitated sexual assaults] by offering a proactive solution for GHB detection and empowering potential victims to safeguard themselves," the scientists say in a paper on their research, which was recently published in the journal ACS Sensors.
Source: American Chemical Society