New laser injection more painless and accurate than needle injection

New research from Seoul National University in South Korea is exploring the possibility of injecting flu shots through painless microjet injections instead of through hypodermic needles.

The Er:YAG laser microjet transdermal device uses an erbium-doped yttrium aluminum garnet laser to drive a tiny, precise stream of the liquid drug with just the right amount of force. It delivers a higher dose than a previous version, the Nd:YAG system, through the use of multiple pulses of laser beam at lower energy, according to senior author Jack Yoh, a professor of mechanical and aerospace engineering, Medical News Today reports.

They hypodermic needle is still the instrument of choice for injections, though researchers have tried to develop microjet systems, most of which have proven to be ineffective or inaccurate.

The new system, though, can precisely control the dose and the depth of drug penetration underneath the skin, acting as a major advancement over other devices, according to Yoh, Medical News Today reports.

The laser used in the device is often used by dermatologists in facial cosmetic treatments.

The instrument uses a miniature jet nozzle that has a small chamber behind it containing a liquid form of the drug to be injected. Behind that is a "driving fluid," in this case water. A flexible membrane keeps the liquids separate.

Short laser pulses lasting no more than 250 millionths of a second generate a vapor bubble in the driving fluid that puts pressure on the membrane, forcing the drug to be injected through a tiny nozzle that forms a narrow jet thinner than 150 micrometers, or slightly thicker than a human hair.

Yoh said that the pressure of the jet is higher than the tensile strength of skin, so it penetrates smoothly with no splashback, according to Medical News Today.

The speed and narrowness of the jet should make the procedure painless because it aims for the epidermal layer under the surface of the skin where there are no nerve-endings.

The device has gone through many different stages before being perfected in this latest version, which uses a laser wavelength of 2,940 nanometers.

"This is ideal for creating the jet and significantly improves skin penetration," Yoh said, Medical News Today reports.

More work, though, will be needed before the device can be used in settings like mass vaccination of children.