The penetration of a soft solid by a liquid jet, with application to the administration of a needle-free injection

J Biomech. 2006;39(14):2593-602. doi: 10.1016/j.jbiomech.2005.08.028. Epub 2005 Nov 8.


Liquid jet injections have been performed on human skin in vivo and silicone rubber using Intraject needle-free injectors. The discharge characteristics of the liquid jet were measured using a custom-built test instrument. The experiments reveal that a high-speed liquid jet penetrates a soft solid by the formation and opening of a planar crack. The fluid stagnation pressure required for skin penetration decreases with increasing diameter of the liquid jet. These findings are consistent with the slow-speed penetration of a soft solid by a sharp-tipped punch. It is demonstrated that the Shergold-Fleck sharp-tipped punch penetration model [Shergold, O.A., Fleck, N.A., 2004. Mechanisms of deep penetration of soft solids. Proc. Roy. Soc. Lond. A 460, 3037-3058.] gives adequate predictions for the pressure required to penetrate a soft solid by a high-speed liquid jet.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomechanical Phenomena
  • Drug Delivery Systems / instrumentation
  • Drug Delivery Systems / methods*
  • Humans
  • Injections, Jet / instrumentation
  • Injections, Jet / methods
  • Models, Theoretical
  • Pressure
  • Punctures
  • Shear Strength
  • Silicone Elastomers / chemistry
  • Skin / physiopathology*
  • Wounds, Penetrating / physiopathology*


  • Silicone Elastomers