A novel needle‐free microjet drug injector using Er:YAG LASER: A completely new concept of transdermal drug delivery system

Abstract

The skin barrier effectively inhibits the penetration of substances; therefore, drug delivery, especially the delivery of drugs that are hydrophilic, through the skin, is challenging. Objectives: Physicians in the esthetic field now use the transdermal drug delivery system to attempt to deliver esthetic materials, such as hyaluronic acid and poly‐DL‐lactic acid into the skin. Conventionally, esthetic physicians manually injected these materials using needle syringes into the dermis layer. However, the injection is often irregular, imprecise, slow, and painful. Injector devices have been developed to overcome these limitations. A total of five Korean cadavers (that of three men and two women with a mean age of 69.2 years; range, 60–73 years) underwent laser injection. We used a device called Er:YAG LASER to create the pressure needed for microjet delivery to the skin of the cadaver. Discussion: In this study, the first LASER pressure‐based, needle‐free microjet injector was used to deliver drugs effectively into the dermis of a cadaver. This study showed that a novel needle‐free microjet injector using Er:YAG LASER can introduce beneficial, liquid, esthetic drugs into the papillary dermal layer (depth of 300um) with minimal epidermal damage.

Needleless laser injector versus needle injection for skin enhancement and rejuvenation effect of dermal filler

“…This was also shown in a previous study using cadavers, where the punctures from the laser injections were not visible on the surface of the skin. 4 Furthermore, although the texture-and wrinkle-related parameters were improved in the laser-induced microjet injection group, the changes were not statistically significant. This may be because treatment was performed only once in the current study.…”

“…2,3 It is the simplest and most economical method, but it has drawbacks such as pain during procedures, needle fear/phobia, possibility of irregular and inaccurate injections, and long treatment time. 4 To overcome these disadvantages, mesogun multineedle injectors or needleless jet injectors that use compressed springs or gas (pneumatic pressure) as an energy source have been used. 1 Although these methods allow for more stable and accurate injections than manual injection techniques, there are still limitations owing to the restricted adjustability of the amount of input energy during the injection of the target material.…”

“…8,9 Mirajet (JSK Biomed) was the first laser-induced microjet injector to acquire Conformité Européenne certification for medical devices in the European Union, and this device uses an Er:YAG laser that generates vapor bubbles to generate pressure energy. 4 It is composed of two chambers: an upper chamber filled with water and a lower chamber filled with injection material. When the laser is focused and blasted in the upper chamber, the pressure generated by the explosion pushes the membrane downward, thus leading to the microjet injection of the drug (Figure 1).…”

“…5,10 One study used Mirajet to inject polylactic acid (PLA)/hyaluronic acid (HA) composite filler into five Korean cadavers and observed that PLA/HA filler substances were localized precisely and uniformly at the same level of the papillary dermis. 4 However, no clinical study has been conducted on living humans for the evaluation of the skin rejuvenating effect after PLA/HA injection by using this laser-induced microjet injector. In the current study, we conducted a single-center, randomized, double-blind, split-face clinical study to compare the laser-induced microjet injection versus needle injection of PLA/HA filler to achieve skin enhancement and rejuvenating effects.…”

Design and Analysis: Servo-Tube-Powered Liquid Jet Injector for Drug Delivery Applications

“…In order to overcome the aforementioned limitations and improve the controllability of liquid jet injection, it is necessary to precisely control the pressure profile exhibited by the liquid jet. Among more recently proposed concepts to drive needle-free liquid injectors, such as: the use of a single piezoelectric crystal [29] or a piezoelectric crystal stack [30] to actuate a piston, expansion of vapor bubbles using laser radiation [31][32][33][34][35][36][37], electrical current discharge [38], and pyrotechnics [39], it seems that electronic linear actuators provide one of the most practical and efficient methods for complete closed-loop control of liquid jet production. They offer real-time control and do not require high voltages or subject the fluid to electric charges or laser radiation as in other experimental techniques.…”