title: Ultrasound internal tattooing.
abstract: OBJECTIVE
  The ability of remotely tagging tissues in a controlled and three-dimensional manner during preoperative imaging could greatly help surgeons to identify targets for resection. The authors' objective is to selectively and noninvasively deposit markers under image guidance for such internal tattooing.
  
  
  METHODS
  This study describes the production of new ultrasound-inducible droplets carrying large payloads of fluorescent markers and the in vivo proof of concept of their remote and controlled deposition via focused ultrasound. The droplets are monodispersed multiple emulsions produced in a microfluidic system, consisting of aqueous fluorescein in perfluorocarbon in water. Their conversion (either by vaporization or cavitation) is performed remotely using a clinical ultrasonic imaging probe.
  
  
  RESULTS
  When submitted to 5 MHz imaging pulses, the droplets vaporize in vitro at 1.4 MPa peak-negative pressure and eject their content. After several seconds, a brightly fluorescent spot (0.5 mm diameter) is observed at the focus of the transducer. Experiments in the chorioallantoique membrane of chicken eggs and chicken embryo demonstrate that the spot is stable and is easily seen by naked eye.
  
  
  CONCLUSIONS
  These ultrasound-inducible multiple emulsions could be used to deliver large amounts of contrast agents, chemotherapy, and genetic materials in vivo using a conventional ultrasound scanner.
authors: ESPCI, Paris 75005, France. olivier.couture@espci.fr
authors: Olivier
authors: O
authors: Couture
authors: Magalie
authors: M
authors: Faivre
authors: Nicolas
authors: N
authors: Pannacci
authors: Avin
authors: A
authors: Babataheri
authors: Vincent
authors: V
authors: Servois
authors: Patrick
authors: P
authors: Tabeling
authors: Mickael
authors: M
authors: Tanter
mesh_terms: D000818:Animals; D002642:Chick Embryo; D005456:Fluorescent Dyes / Q000378:metabolism*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014465:Ultrasonics
chemical_list: D005456:Fluorescent Dyes