Condensation phase diagrams for lipid-coated perfluorobutane microbubbles
| Autor: | Paul A. Mountford, Shashank R. Sirsi, Mark A. Borden |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Surface Properties
Contrast Media Polyethylene Glycols chemistry.chemical_compound Drug Delivery Systems Metastability Electrochemistry Pressure Nanotechnology General Materials Science Dissolution Spectroscopy Phase diagram Supersaturation Fluorocarbons Aqueous solution Chromatography Microbubbles Perfluorobutane Condensation Temperature Surfaces and Interfaces Equipment Design Condensed Matter Physics Lipids Chemical engineering chemistry Phosphatidylcholines lipids (amino acids peptides and proteins) Gases |
| Zdroj: | LANGMUIR Artículos CONICYT CONICYT Chile instacron:CONICYT |
| Popis: | The goal of this study was to explore the thermodynamic conditions necessary to condense aqueous suspensions of lipid-coated gas-filled microbubbles into metastable liquid-filled nanodrops as well as the physicochemical mechanisms involved with this process. Individual perfluorobutane microbubbles and their lipid shells were observed as they were pressurized at 34.5 kPa s(-1) in a microscopic viewing chamber maintained at temperatures ranging from 5 to 75 °C. The microbubbles contracted under pressure, ultimately leading to either full dissolution or microbubble-to-nanodrop condensation. Temperature-pressure phase diagrams conveying condensation and stability transitions were constructed for microbubbles coated with saturated diacylphosphatidylcholine lipids of varying acyl chain length (C16 to C24). The onset of full dissolution was shifted to higher temperatures with the use of longer acyl chain lipids or supersaturated media. Longer chain lipid shells resisted both dissolution of the gas core and mechanical compression through a pronounced wrinkle-to-fold collapse transition. Interestingly, the lipid shell also provided a mechanical resistance to condensation, shifting the vapor-to-liquid transition to higher pressures than for bulk perfluorobutane. This result indicated that the lipid shell can provide a negative apparent surface tension under compression. Overall, the results of this study will aid in the design and formulation of vaporizable fluorocarbon nanodrops for various applications, such as diagnostic ultrasound imaging, targeted drug delivery, and thermal ablation. |
| Databáze: | OpenAIRE |
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