Shock wave driven liquid microjets for drug delivery

A nonintrusive, minimally invasive, needle-less technique to deliver liquids into soft targets is presented. The technique uses a laser-induced shock wave to drive a liquid microjet at a very high speed such that the jet has sufficient momentum to penetrate soft targets. The method can be used to deliver liquid drugs into soft tissues in the human body. The liquid to be delivered is sandwiched between 200 mu m thick aluminum foil and a base plate with a perforation of 100 mu m diameter. The aluminum foil is ablated using an Nd:YAG laser beam in order to launch a shock wave through it. The shock wave from the foil is transmitted to the sandwiched liquid, which becomes pressurized by the shock propagation and emanates as a microjet through the perforation in the base plate. The microjet thus generated has a steady, average speed of over 200 m/s. The technique has been tested on gelatin models (5% gelatin), in which the jet penetrated to a depth of more than a millimeter. (C) 2009 [doi:10.1063/1.3245320]