title: Delivery of colloidal particles and red blood cells to tissue through microvessel ruptures created by targeted microbubble destruction with ultrasound.
abstract: BACKGROUND
  We have previously shown that the application of ultrasound to thin-shelled microbubbles flowing through small microvessels (<7 microm in diameter) produces vessel wall ruptures in vivo. Because many intravascular drug- and gene-delivery vehicles are limited by the endothelial barrier, we hypothesized that this phenomenon could be used to deliver drug-bearing vehicles to tissue.
  
  
  RESULTS
  An exteriorized rat spinotrapezius muscle preparation was used. Intravascular fluorescent red blood cells and polymer microspheres (PM) (205 and 503 nm in diameter) were delivered to the interstitium of rat skeletal muscle through microvessel ruptures created by insonifying microbubbles in vivo. On intravital microscopy, mean dispersion areas per rupture for red blood cells, 503-nm PM, and 205-nm PM were 14.5x10(3) microm2, 24. 2x10(3) microm2, and 27.2x10(3) microm2, respectively. PM dispersion areas were significantly larger than the mean dispersion area for red blood cells (P<0.05).
  
  
  CONCLUSIONS
  Microvessel ruptures caused by insonification of microbubbles in vivo may provide a minimally invasive means for delivering colloidal particles and engineered red blood cells across the endothelial lining of a targeted tissue region.
authors.affiliation: Department of Biomedical Engineering and the Cardiovascular Division, University of Virginia, Charlottesville, VA, USA. rprice@virginia.edu
authors.forename: R J
authors.initials: RJ
authors.lastname: Price
authors.forename: D M
authors.initials: DM
authors.lastname: Skyba
authors.forename: S
authors.initials: S
authors.lastname: Kaul
authors.forename: T C
authors.initials: TC
authors.lastname: Skalak
mesh_terms: D000818:Animals; D003102:Colloids; D016503:Drug Delivery Systems; D004730:Endothelium, Vascular / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D008863:Microspheres; D051381:Rats; D017207:Rats, Sprague-Dawley; D014465:Ultrasonics
chemical_list: D003102:Colloids