Non-linear response and viscoelastic properties of lipid-coated microbubbles: DSPC versus DPPC.
For successful in vivo contrast-enhanced ultrasound imaging (CEUS) and ultrasound molecular imaging, detailed knowledge of stability and acoustical properties of the microbubbles is essential. Here, we compare these aspects of lipid-coated microbubbles that have either 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) or 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) as their main lipid; the other components were identical. The microbubbles were investigated in vitro over the frequency range 1-4 MHz at pressures between 10 and 100 kPa, and their response to the applied ultrasound was recorded using ultrahigh-speed imaging (15 Mfps). Relative to DPPC-coated microbubbles, DSPC-coated microbubbles had (i) higher acoustical stability; (ii) higher shell elasticity as derived using the Marmottant model (DSPC: 0.26 ± 0.13 N/m, DPPC: 0.06 ± 0.06 N/m); (iii) pressure amplitudes twice as high at the second harmonic frequency; and (iv) a smaller amount of microbubbles that responded at the subharmonic frequency. Because of their higher acoustical stability and higher non-linear response, DSPC-coated microbubbles may be more suitable for contrast-enhanced ultrasound.
Department of Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands. Electronic address: t.vanrooij@erasmusmc.nl.
Tom
T
van Rooij
Department of Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands.
Ying
Y
Luan
Department of Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands; Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 7371, INSERM UMR S 1146, Laboratoire d'Imagerie Biomédicale, Paris, France.
Guillaume
G
Renaud
Department of Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands; Laboratory of Acoustical Wavefield Imaging, Faculty of Applied Sciences, Technical University Delft, Delft, The Netherlands.
Antonius F W
AF
van der Steen
Physics of Fluids Group, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands.
Michel
M
Versluis
Department of Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands; Laboratory of Acoustical Wavefield Imaging, Faculty of Applied Sciences, Technical University Delft, Delft, The Netherlands; Interuniversity Cardiology Institute of the Netherlands, Utrecht, The Netherlands.
Nico
N
de Jong
Department of Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands.
Klazina
K
Kooiman
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry* / Q000528:radiation effects; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000528:radiation effects; D003198:Computer Simulation; D003287:Contrast Media / Q000737:chemistry* / Q000528:radiation effects; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry* / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D055119:Elastic Modulus / Q000528:radiation effects; D008422:Materials Testing; D045423:Microbubbles; D008956:Models, Chemical; D017711:Nonlinear Dynamics; D011829:Radiation Dosage; D013314:Stress, Mechanical; D000069453:Ultrasonic Waves; D014783:Viscosity / Q000528:radiation effects
D020099:Coated Materials, Biocompatible; D003287:Contrast Media; D015060:1,2-Dipalmitoylphosphatidylcholine; D004134:Dimyristoylphosphatidylcholine
Elasticity; High-speed optical imaging; Lipid-coated microbubbles; Non-linear; Second harmonic; Stability; Subharmonic; Ultrasound contrast agent; Viscosity