|This time-lapse image shows a microjet fired from the injection system--Credit: Optic Letters|
Shots hurt. Period. But laser-powered "needles" that blast jets of drug into the skin could take the ouch out of the process. The technique, developed at Seoul National University in South Korea, uses the same laser as is used for the treatment of skin conditions, and the research is published in Optics Letters.
The system uses extremely short pulses of laser energy to heat tiny balloons of water next to reservoirs of drug. This creates steam, which stretches the balloon and pushes the drug from its reservoirs at a very high speed through a nozzle a little larger than the width of a human hair.
Bench tests on guinea pig skin show that the pressure of the jet is strong enough to push the drug in a stream through the skin, and the dose and depth of drug penetration can be controlled very precisely, potentially making this method more accurate than piston-type injectors that are currently in use.
Researcher Jack Yoh of Seoul National University predicts that the speed and size of the jet means that the method should cause little or no pain, potentially being as painless as "a puff of air." However, as the focus of the research is on getting drugs through the top layer of the skin, and this region of the skin has no nerve endings, Yoh says that the method "will be completely pain-free."
Yoh is working with a company to produce a low-cost version for clinical use, and suggests that with further work it could be adapted for mass vaccination programs, particularly for use with children.