Laser induced jets in needle free drug delivery

Various actuation mechanisms have been used in the past for needle-free injection systems, predominantly springs and compressed gas. However, recent innovation has seen use of pulsed and continuous wave lasers for precise injection of ultra-low doses. Here, we have investigated the feasibility of laser-induced micro-jets as a needle-free injection technique. Effect of various parameters such as capillary diameter, laser pulse energy and distance of the laser focal point on jet dynamics were studied in the past, however, we also varied the fluid viscosity and orifice stand-off relative to the target. To quantify the penetration dynamics and dispersion of the liquid delivered, both gelatin gel (in-vitro) and porcine tissue (ex-vivo) were used as skin models. Lastly, we also discuss the possibility of using a spark-cavitation system to generate high-speed micro-jets instead of pulsed lasers.