Delivering medications has always been a complicated undertaking. Imagine how tough it is to give injections to a herd of sheep–a problem the commercial livestock industry endures. In such an environment, using a needle is not feasible or sanitary due to issues such as needle breakage and transmittance of diseases.
To overcome this problem, a speedy and reliable multi-dose device was essential. To meet this demand, the Cobra Needle-Free Injector was developed at MIT’s BioInstrumentation Laboratory. Moving at a high velocity, drug injection is achieved by penetrating the skin with a micro-stream of liquid drug. Other systems use gas or springs to propel the liquid, however, the Cobra uses Shape Memory alloy to thrust the liquid drug through the nozzle at 300 m/s. The Shape Memory alloy generates a large force and contracts quicker than conventional actuators. A patent application has been filed for this technique.
Here is the full thesis Needle-less injection thesis