Design of Novel Polymer Shelled Ultrasound Contrast Agents: Towards an Ultrasound Triggered Drug Delivery

  • Mariarosaria Tortora
  • Letizia Oddo
  • Silvia Margheritelli
  • Gaio Paradossi


Ultrasound contrast agents (UCA) have been used for years in the clinical field, for applications such as blood pool enhancement, characterization of liver lesions or perfusion imaging [12, 13, 14, 15, 20]. The contrast agents are generally in the form of spherical voids or cavities filled by a gas, called microbubbles (MB). MBs are stabilized by a coating material such as phospholipids, surfactants, denatured human serum albumin or synthetic polymers. As gas is less dense than liquids or solids, sound travels more slowly in gas than it does in liquid. The difference in the sound speed in the microbubbles creates an acoustic mismatch between tissue and blood surrounding a microbubble, making it an efficient reflector of ultrasound energy. The ability to produce strong signals from microbubbles depends on the stability of the gas particle. Stability has been enhanced by varying the gas composition (air, nitrogen, sulphur hexafluoride, perfluorocarbons) and/or by chemical modification of the microbubble shell [20]. As microbubbles stay in the vascular space and have a behavior similar to red blood cells in the microcirculation, they can be used as intravascular tracers. The possibility to introduce a targeting ligand for a specific interaction with its receptor onto the microbubble shell can be a way to selectively accumulate the contrast agent in the deseased region. Moreover, targeted MBs can be used to carry different drugs to the desired sites and release them after their destruction/cavitation with ultrasound radiation or by chemical/enzymatic cleavage.


Electron Paramagnetic Resonance Shell Thickness Reductive Amination Ultrasound Contrast Agent Sodium Metaperiodate 
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Copyright information

© Springer-Verlag Italia 2010

Authors and Affiliations

  • Mariarosaria Tortora
    • 1
  • Letizia Oddo
    • 1
  • Silvia Margheritelli
    • 1
  • Gaio Paradossi
    • 1
  1. 1.Dipartimento di Scienze e Tecnologie ChimicheUniversità di Roma Tor VergataRomaItaly

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