title: More Than Bubbles: Creating Phase-Shift Droplets from Commercially Available Ultrasound Contrast Agents.
abstract: Phase-shift perfluorocarbon droplets have been investigated for over 20 years as pre-clinical ultrasound contrast agents with distinctive advantages in imaging and therapy. A number of formulation strategies exist, each with inherent advantages and limitations. In this note, we demonstrate a unique opportunity: that phase-shift droplets can be generated directly from commercially available microbubbles. This may facilitate pre-clinical and translational development by reducing the in-house synthesis expertise and resources required to generate high concentration droplet emulsions. Proof-of-principle in vitro and in vivo is given using droplets created from Definity and MicroMarker. The results demonstrate the role of perfluorocarbon choice in the trade-off between thermal stability and vaporization threshold, and suggest that commercial microbubbles with decafluorobutane cores may be ideal for this approach.
authors.affiliation: Physical Sciences Department, Sunnybrook Research Institute, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Canada. Electronic address: pssheeran@gmail.com.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Sheeran
authors.affiliation: Physical Sciences Department, Sunnybrook Research Institute, Toronto, ON, Canada.
authors.forename: Kimoon
authors.initials: K
authors.lastname: Yoo
authors.affiliation: Physical Sciences Department, Sunnybrook Research Institute, Toronto, ON, Canada.
authors.forename: Ross
authors.initials: R
authors.lastname: Williams
authors.affiliation: Physical Sciences Department, Sunnybrook Research Institute, Toronto, ON, Canada.
authors.forename: Melissa
authors.initials: M
authors.lastname: Yin
authors.affiliation: Physical Sciences Department, Sunnybrook Research Institute, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Canada.
authors.forename: F Stuart
authors.initials: FS
authors.lastname: Foster
authors.affiliation: Physical Sciences Department, Sunnybrook Research Institute, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Canada.
authors.forename: Peter N
authors.initials: PN
authors.lastname: Burns
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry*; D007089:Image Enhancement / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging; D051379:Mice; D008809:Mice, Inbred C3H; D045423:Microbubbles; D023421:Models, Animal; D019047:Phantoms, Imaging; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media; D005466:Fluorocarbons; C108042:perfluorobutane; C042852:perflutren
keywords: Acoustic droplet vaporization; Definity; MicroMarker; Perfluorocarbon; Phase-shift droplets; Ultrasound contrast agents