Single Bubble Acoustic Characterization and Stability Measurement of Adherent Microbubbles

Casey, Jonathan; Sennoga, Charles A.; Mulvana, Helen; Hajnal, Joseph V.; Tang, Meng‐Xing; Eckersley, Robert J.

doi:10.1016/j.ultrasmedbio.2012.12.007

Cited by 11 publications

(12 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, the above-mentioned studies show an opposite effect on the resonance frequency upon binding of the MBs. For streptavidin-functionalised MBs in an OptiCell insonified at pressures between 2 and 4 MHz, the resonance frequency decreased [82], while for biotinylated MBs in a streptavidin-coated capillary insonified at 2 and 3.5 MHz the resonance frequency increased [87]. At higher frequencies streptavidin-coated bubbles at 11 MHz showed an increase in resonance frequency, while they showed a decrease at 25 MHz [88].…”

Section: Discriminating Free From Adhered Mbsmentioning

confidence: 94%

“…Prior to the acoustical measurements, the biotinylated bubbles were sized by optical microscopy and subsequently injected in a capillary with or without streptavidin-coating [87]. Scattering of nonbiotinylated bubbles and biotinylated bubbles at the fundamental frequency (2 MHz) was similar, whether or not the capillary was coated.…”

Section: Discriminating Free From Adhered Mbsmentioning

confidence: 99%

See 1 more Smart Citation

Targeted ultrasound contrast agents for ultrasound molecular imaging and therapy

Rooij

Daeichin

Skachkov

et al. 2015

International Journal of Hyperthermia

View full text Add to dashboard Cite

Ultrasound contrast agents (UCAs) are used routinely in the clinic to enhance contrast in ultrasonography. More recently, UCAs have been functionalised by conjugating ligands to their surface to target specific biomarkers of a disease or a disease process. These targeted UCAs (tUCAs) are used for a wide range of pre-clinical applications including diagnosis, monitoring of drug treatment, and therapy. In this review, recent achievements with tUCAs in the field of molecular imaging, evaluation of therapy, drug delivery, and therapeutic applications are discussed. We present the different coating materials and aspects that have to be considered when manufacturing tUCAs. Next to tUCA design and the choice of ligands for specific biomarkers, additional techniques are discussed that are applied to improve binding of the tUCAs to their target and to quantify the strength of this bond. As imaging techniques rely on the specific behaviour of tUCAs in an ultrasound field, it is crucial to understand the characteristics of both free and adhered tUCAs. To image and quantify the adhered tUCAs, the state-of-the-art techniques used for ultrasound molecular imaging and quantification are presented. This review concludes with the potential of tUCAs for drug delivery and therapeutic applications.

show abstract

Section: Discriminating Free From Adhered Mbsmentioning

confidence: 94%

Section: Discriminating Free From Adhered Mbsmentioning

confidence: 99%

Targeted ultrasound contrast agents for ultrasound molecular imaging and therapy

Rooij

Daeichin

Skachkov

et al. 2015

International Journal of Hyperthermia

View full text Add to dashboard Cite

show abstract

“…In addition, researchers have presented several methods for acoustic detection of bubble fragmentation relying on different physical phenomena including rebound signals arising from shell rupture and reformation (Ammi et al 2006), post-excitation signals (King et al 2010), or narrowband or broadband harmonics of uncertain origin (Madanshetty et al 1991; Everbach et al 1997; Tung et al 2010; Vignon et al 2013). The proximity of a microbubble to a vessel wall has been shown to influence the number of pulses required for fragmentation of a population of microbubbles, with bubbles at or near a wall requiring fewer pulses for fragmentation and exhibiting a reduced resonance frequency (Caskey et al 2007; Couture et al 2009; Casey et al 2013). Interactions between bubbles have resulted in an increase in bubble fragmentation threshold as concentration increases (Chang et al 2001; Yasui et al 2009).…”

Section: Introductionmentioning

confidence: 99%

“…In previous studies characterizing the various mechanisms of ultrasound-induced cavitation phenomena in lipid-shelled microbubbles, observed phenomena have been described as fragmentation, dissolution without visible fragmentation, or shrinkage to a stable diameter (Chomas et al 2001a; Chomas et al 2001b; Chen et al 2002; Borden et al 2005; Bouakaz et al 2005; Cox and Thomas 2010; Guidi et al 2010; Kwan and Borden 2010; Casey et al 2013). Physical mechanisms of core gas loss have been classified as rapid fragmentation, active diffusion, and passive diffusion (Chomas et al 2001a).…”

Section: Introductionmentioning

confidence: 99%

On the Relationship Between Microbubble Fragmentation, Deflation and Broadband Superharmonic Signal Production

Lindsey¹,

Rojas²,

Dayton³

2015

Ultrasound in Medicine & Biology

View full text Add to dashboard Cite

Acoustic angiography imaging of microbubble contrast agents utilizes the superharmonic energy produced from excited microbubbles, and enables high-contrast, high-resolution imaging. However, the exact mechanism by which broadband harmonic energy is produced is not fully understood. In order to elucidate the role of microbubble shell fragmentation in superharmonic signal production, simultaneous optical and acoustic measurements were performed on individual microbubbles at transmit frequencies from 1.75 to 3.75 MHz and pressures near the shell fragmentation threshold for microbubbles of varying diameter. High-amplitude, broadband superharmonic signals were produced with shell fragmentation, while weaker signals (approximately 25% of peak amplitude) were observed in the presence of shrinking bubbles. Furthermore, when imaging populations of stationary microbubbles with a dual-frequency ultrasound imaging system, a sharper decline in image intensity with respect to frame number was observed for 1 μm bubbles than for 4 μm bubbles. Finally, in a study of two rodents, increasing frame rate from 4 to 7 Hz resulted in a decrease in mean steady-state image intensity of 27% at 1000 kPa and 29% at 1300 kPa. While the existence of superharmonic signals when bubbles shrink has the potential to prolong the imaging efficacy of microbubbles, parameters such as frame rate and peak pressure must be balanced with expected re-perfusion rate in order to maintain adequate contrast during in vivo imaging.

show abstract

“…As for the 254 properties of the bubbles themselves, κ s was 5x10 -9 N and χ, 0.1Nm -1 . These values were obtained by 255 matching the simulated results to experimental measurements of attached targeted microbubbles obtained 256 through single bubble acoustic experiments under the same conditions (Casey et al, 2012). 257…”

mentioning

confidence: 99%

Effect of ultrasound on adherent microbubble contrast agents

et al. 2012

Self Cite

View full text Add to dashboard Cite

An investigation into the effect of clinical ultrasound exposure on adherent microbubbles is described. A flow phantom was constructed in which targeted microbubbles were attached using biotin-streptavidin linkages. Microbubbles were insonated by broadband imaging pulses (centred at 2.25 MHz) over a range of pressures (peak negative pressure (PNP) = 60-375 kPa). Individual adherent bubbles were observed optically and classified as either being isolated or with a single neighbouring bubble. It is found that bubble detachment and deflation are two significant effects, even during low amplitude ultrasound exposure. Specifically, while at very low acoustic pressure (PNP < 75 kPa) 95% of the bubbles were not affected, at medium pressure (151 kPa < P < 225 kPa) 53% of the bubbles detached and at higher pressures (301 kPa < P < 375 kPa) 96% of the bubbles detached. In addition, more than 50% of the bubbles underwent deflation at pressures between 301 and 375 kPa. At pressures between 226 and 300 kPa, more adherent bubbles detached when there was a neighbouring bubble, suggesting the role of multiple scattering and secondary Bjerknes force on bubble detachment. The flow shear, primary and secondary Bjerknes forces exerted on each bubble were calculated and compared to the estimated forces acting on the bubble due to oscillations. The oscillation force is shown to be much higher than other forces. The mechanisms of bubble detachment are discussed.

show abstract

Single Bubble Acoustic Characterization and Stability Measurement of Adherent Microbubbles

Cited by 11 publications

References 45 publications

Targeted ultrasound contrast agents for ultrasound molecular imaging and therapy

Targeted ultrasound contrast agents for ultrasound molecular imaging and therapy

On the Relationship Between Microbubble Fragmentation, Deflation and Broadband Superharmonic Signal Production

Effect of ultrasound on adherent microbubble contrast agents

Contact Info

Product

Resources

About