Could laser-focused microjets mean pain-free injections?
Researchers at Seoul University, South Korea, looked at an erbium-doped yttrium aluminium garnet laser – known as Er:YAG – to launch a jet of drug-loaded liquid onto the skin.
The team found the laser, commonly used by dermatologists for anti-aging treatments, was powerful enough to deliver the drugload underneath the skin with little or no pain.
Lead researcher Jack Yoh, professor of mechanical and aerospace engineering at Seoul University, said the Er:YAG beam is the reason the system succeeds where other jet-based systems fail because it absorbs the liquid therefore avoiding splash-back or evaporation of the active.
“The new injection scheme uses the beam wavelength best absorbable by water at a longer pulse mode for elongated microjet penetration into a skin target,” he said.
However, though tests on guinea pig skin have so far showed delivery of the drug below the skin surface with no tissue damage – otherwise known as intravenous delivery – the study has thus far focused largely on topical applications.
“The immediate delivery would enable minimised prescription of topical drugs intended to work on the outer layers of the skin, avoiding any skin irritation or allergic reaction and preventing uncontrolled evaporation of active ingredient and unpleasant odor associated with non-invasive procedures,” the team wrote.
Speaking to R&D Magazine, Yoh said they are now working with an un-named company over tech for clinical use.
“In the immediate future, this technology could be most easily adopted to situations where small doses of drugs are injected at multiple sites,” he said. “Further work would be necessary to adopt it for scenarios like mass vaccine injections for children.”
How it works
Like the hypodermic needle, the Er:YAG used in the study – published in Optical Letters Journal – is attached to a vial containing liquid drug.
The drug chamber is also loaded with a “driving fluid” which is separated from the therapy by a membrane.
Pulses created by the laser then create gas bubbles inside the driving fluid, which causes a pressure release of the drug.
“The present scheme of injection via Er:YAG laser beam at 250 μs pulse duration generates pressure by the displacement of liquid via laser-induced vapor bubbles and the elastic pumping of the drug through a nozzle by a membrane separating the driving liquid from the drug,” Yoh explained.