Scientists have in recent years developed "microneedle patches" that are less painful and safer than hypodermic needles. And by replicating the structure of a viper's fangs, new attempts at the technique could make them work even better. Most existing patches contain rows of thin needles on their underside, made of biocompatible, water-soluble polymers that contain a given type of drug. When the patch is pressed against the skin, the needles penetrate its outer layer. They then dissolve, releasing the drug into the bloodstream.
Not only is the process painless, but it also carries less risk of infection than hypodermic injections and doesn't produce dangerous "sharp" debris. In addition, because medications are usually freeze-dried or non-liquid, the patches remain effective even after relatively long periods of storage at room temperature. That said, freeze-drying medications can be a time-consuming and complicated process, and many medications are also more effective in liquid form. In light of this fact, scientists from several research institutions in South Korea, as well as the University of Connecticut, have studied the venom delivery system used by the Post-Venomous Tooth Snake. In contrast to the hollow fangs of the venomous fanged snake, these reptiles have an open groove along their outer fangs through which venom flows rapidly by capillary action.
Scientists have replicated this structure in a new patch that combines fang-inspired microneedles with microchannels filled with liquid medicine. Each needle has up to six grooves along its surface that naturally draw the drug out of the channel when slight thumb pressure is applied to the back of the patch. In tests on mice and guinea pigs, the patches were successfully used to deliver lidocaine or inactivated influenza virus through the skin - they did so in less than 15 seconds. This produced an immune response, which protected the animals from a lethal dose of the flu virus. Scientists say that before clinical trials can begin, they must be tested on larger animals, including humans.