  Despite the ubiquitous use over the past 150 years, the functions of the
current medical needle are facilitated only by mechanical shear and cutting by
the needle tip,i.e.the lancet. In this study, we demonstrate how nonlinear
ultrasonics (NLU) extends the functionality of the medical needle far beyond
its present capability. The NLU actions were found to be localized to the
proximity of the needle tip, the SonoLancet, but the effects extend several
millimeters from the physical needle boundary. The observed nonlinear
phenomena, transient cavitation, fluid streams, translation of micro- and
nanoparticles and atomization, were quantitatively characterized. In the
fine-needle biopsy application, the SonoLancet contributed to obtaining tissue
cores with increase in tissue yield by 3-6x in different tissue types compared
to conventional needle biopsy technique using the same 21G needle. In
conclusion, the SonoLancet could be of interest to several other medical
applications, including drug or gene delivery, cell modulation, and minimally
invasive surgical procedures.
