Laser-induced liquid micro-jets for needle-free injection into biological tissue (Conference Presentation)

Abstract

Fast liquid jets (<150 m/s) are used as a needle-free fluid injection into elastomeric tissue such as skin. Because the fluid droplets are smaller than a typical needle diameter, there is less collateral damage caused by the jets in the intervened body. In this study, we aim to investigate the potential of the method to deliver liquids into biological tissues with higher stiffness than skin. To address this challenge we have implemented an optofluidic jetting system capable of generating supersonic liquid microjets driven by laser cavitation. Considering microfluidic properties of the system, we have exceeded a method to produce jets in a repetitive regime with rates of up to 6 Hz, diameters of 10, 15 and 30 µm and velocities exceeding 550 m/s. We have characterized the injection depth with respect to jet speed, jet diameter and elastic modulus of the sample material. Experiments were performed on hydrogels with Young’s modulus from 8 kPa to 1 MPa, which covers the wide spectrum of biological elastomers like inner body organ tissues, blood vessels, skin or cartilage.