Needle-Free Drug Injection Using a Shock Wave Focusing System with the Function of Real-Time Microbubble-Based Distance Sensing

In this paper, we proposed a novel needle-free injection method using electrically induced microbubbles. This microbubble needle-free injector is developed to achieve the depth-controlled drug injection. A focusing device was developed to enhance the pressure of microbubble-induced shock wave and improve the perforation ability of injector. Due to the injection depth being related to the distance between injector tip and target, we propose to control the injection depth by sensing and adjusting the distance. We developed the distance measurement by microbubble injector itself. In this work, the microbubble injector was both the actuator and sensor. This needle-free microbubble is a promising tool to achieve the injection depth-controlled in the future.