scholarly journals The Impact of Lipid Handling and Phase Distribution on the Acoustic Behavior of Microbubbles

Pharmaceutics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 119
Author(s):  
Simone A.G. Langeveld ◽  
Inés Beekers ◽  
Gonzalo Collado-Lara ◽  
Antonius F. W. van der Steen ◽  
Nico de Jong ◽  
...  

Phospholipid-coated microbubbles are ultrasound contrast agents that can be employed for ultrasound molecular imaging and drug delivery. For safe and effective implementation, microbubbles must respond uniformly and predictably to ultrasound. Therefore, we investigated how lipid handling and phase distribution affected the variability in the acoustic behavior of microbubbles. Cholesterol was used to modify the lateral molecular packing of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)-based microbubbles. To assess the effect of lipid handling, microbubbles were produced by a direct method, i.e., lipids directly dispersed in an aqueous medium or indirect method, i.e., lipids first dissolved in an organic solvent. The lipid phase and ligand distribution in the microbubble coating were investigated using confocal microscopy, and the acoustic response was recorded with the Brandaris 128 ultra-high-speed camera. In microbubbles with 12 mol% cholesterol, the lipids were miscible and all in the same phase, which resulted in more buckle formation, lower shell elasticity and higher shell viscosity. Indirect DSPC microbubbles had a more uniform response to ultrasound than direct DSPC and indirect DSPC-cholesterol microbubbles. The difference in lipid handling between direct and indirect DSPC microbubbles significantly affected the acoustic behavior. Indirect DSPC microbubbles are the most promising candidate for ultrasound molecular imaging and drug delivery applications.

2009 ◽  
Vol 42 (7) ◽  
pp. 881-892 ◽  
Author(s):  
Katherine W. Ferrara ◽  
Mark A. Borden ◽  
Hua Zhang

2015 ◽  
Vol 31 (2) ◽  
pp. 90-106 ◽  
Author(s):  
Tom van Rooij ◽  
Verya Daeichin ◽  
Ilya Skachkov ◽  
Nico de Jong ◽  
Klazina Kooiman

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
ZhongQian Hu ◽  
Bin Yang ◽  
Tiankuan Li ◽  
Jia Li

Background. Contrast-enhanced ultrasound imaging has been widely used in the ultrasound diagnosis of a variety of tumours with high diagnostic accuracy, especially in patients with hepatic carcinoma, while its application is rarely reported in thyroid cancer. The currently used ultrasound contrast agents, microbubbles, cannot be targeted to molecular markers expressed in tumour cells due to their big size, leading to a big challenge for ultrasound molecular imaging. Phase-changeable perfluorocarbon nanoparticles may resolve the penetrability limitation of microbubbles and serve as a promising probe for ultrasound molecular imaging. Methods. 65 thyroid tumour samples and 40 normal samples adjacent to thyroid cancers were determined for SHP2 expression by IHC. SHP2-targeted PLGA nanoparticles (NPs-SHP2) encapsulating perfluoropentane (PFP) were prepared with PLGA-PEG as a shell material, and their specific target-binding ability was assessed in vitro and in vivo, and the effect on the enhancement of ultrasonic imaging induced by LIFU was studied in vivo. Results. In the present study, we verified that tumour overexpression of SHP2 and other protein tyrosine phosphatases regulated several cellular processes and contributed to tumorigenesis, which could be introduced to ultrasound molecular imaging for differentiating normal from malignant thyroid diagnostic nodes. The IHC test showed remarkably high expression of SHP2 in human thyroid carcinoma specimens. In thyroid tumour xenografts in mice, the imaging signal was significantly enhanced by SHP2-targeted nanoparticles after LIFU induction. Conclusion. This study provides a basis for preclinical exploration of ultrasound molecular imaging with NPs-SHP2 for clinical thyroid nodule detection to enhance diagnostic accuracy.


Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Shivani Bowry ◽  
Jianjun Wang ◽  
Sue Ottoboni ◽  
Tom Ottoboni ◽  
William R Wagner ◽  
...  

Background: Targeted microsphere (μSPH) adhesion to endothelial epitopes forms the basis for ultrasound molecular imaging. The fate of targeted μSPH, once bound to the endothelial target, is unknown. This has limited the optimization of ultrasound imaging strategies; for example, the appropriate time to commence imaging after μSPH injection is uncertain, and in part depends on the time course and duration of μSPH binding. We therefore sought to characterize the behavior of adhered μSPH as a function of time using serial observations of rat cremaster microcirculation after μSPH injection. Methods: Fluorescent nitrogen-encapsulated polymer μSPH (diameter 3.0 ± 1.4 μm) bearing control non-specific IgG (μSPH CTL ) or monoclonal antibody against VCAM (μSPH VCAM ) or ICAM (μSPH ICAM ) were prepared. Inflamed cremaster muscle of 21 anesthetized Wistar rats was exteriorized for intravital microscopy 4 hours after intrascrotal injection of TNF-α (5μg). Each rat received 1 venous injection of a single μSPH species (n=7 rats/μSPH; 10 8 μSPH/injection). An index venule was identified for serial microscopic observation every 5 min starting 10 min after μSPH injection. Results: The cumulative sum of adhered μSPH during 1 hr observation was higher for μSPH ICAM (24±11) and μSPH VCAM (18±1) than μSPH CTL (3±2, p=0.005). The number of μSPH ICAM adherent to the index venule was stable over time (10 min: 2 ± 3; 30 min: 3±2; 80 min: 3 ± 5, ANOVA p=0.9). The number of adhered μSPH VCAM trended downwards (10 min: 5±4; 30 min: 2±2; 80 min: 1±2; ANOVA p=0.08). By 1 hr, adhered μSPH appeared altered in shape; no μSPH transmigration was seen. Conclusions: Nitrogen-filled polymer μSPH targeted to leukocyte adhesion molecules adhere to inflamed endothelium. The extent of μSPH adhesion remains relatively constant over a time period relevant for imaging applications, although beyond 1hr, the μSPH appear morphologically altered and could have different acoustic properties. These data provide a useful and broad time window for effective ultrasound imaging of molecular targets. The time course of μSPH attachment to endothelium is an important consideration when devising strategies for ultrasound molecular imaging and should be characterized in a μSPH- and target- specific manner.


2014 ◽  
Vol 52 (11) ◽  
pp. 1268-1276 ◽  
Author(s):  
F. Tranquart ◽  
M. Arditi ◽  
T. Bettinger ◽  
P. Frinking ◽  
J. Hyvelin ◽  
...  

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