title: Optimal design and experimental investigation of surfactant encapsulated microbubbles.
abstract: The diagnostic capabilities of ultrasound imaging can be improved with contrast-specific nonlinear imaging modalities such as harmonic and subharmonic imaging. The nonlinear response of an encapsulated microbubble in an acoustic field is strongly influenced by the shell viscoelastic properties that are determined by the shell composition and thickness. In this paper, the subharmonic performance of a surfactant encapsulated microbubble was optimized by choosing the appropriate composition of shell material with the aid of theoretical model. To study the effects of viscoelastic properties of microbubble shell materials on the nonlinear scattered response of microbubbles, a theoretical model-modified Herring equation for the oscillation of encapsulated microbubbles in the ultrasound field was employed. Based on this model, a computer aided design system was developed to optimize and analyze the acoustic properties, particularly subharmonic responses, of microbubbles under different shell parameters. Furthermore, surfactant encapsulated microbubbles with different viscoelastic properties were prepared by changing the shell composition. Their shell viscoelastic behavior was measured indirectly as dilational modulus of monolayer film formed with surfactant molecular. Moreover, in vitro quantitative acoustic properties measurements of these microbubbles were carried out to evaluate their subharmonic performance. Both of the theoretical simulation and acoustic measurement showed that the surfactant encapsulated microbubbles with good subharmonic properties could be designed and prepared by adjusting the shell material composition with the guide of the computer aided design system.
authors.affiliation: The Key Laboratory of Biomedical Information Engineering of Ministry of Education, and Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, PR China.
authors.forename: Yujin
authors.initials: Y
authors.lastname: Zong
authors.forename: Mingxi
authors.initials: M
authors.lastname: Wan
authors.forename: Supin
authors.initials: S
authors.lastname: Wang
authors.forename: Guolu
authors.initials: G
authors.lastname: Zhang
mesh_terms: D002214:Capsules / Q000737:chemistry* / Q000528:radiation effects*; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000528:radiation effects; D003198:Computer Simulation; D017076:Computer-Aided Design; D015195:Drug Design; D004548:Elasticity; D045423:Microbubbles; D008956:Models, Chemical; D014677:Pharmaceutical Vehicles / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D014463:Ultrasonography / Q000379:methods*; D014783:Viscosity
chemical_list: D002214:Capsules; D020099:Coated Materials, Biocompatible; D014677:Pharmaceutical Vehicles; D013501:Surface-Active Agents