Stable Encapsulated Air Nanobubbles in Water

Abstract

The dispersion into water of nanocapsules bearing a highly hydrophobic fluorinated internal lining yielded encapsulated air nanobubbles. These bubbles, like their micrometer-sized counterparts (microbubbles), effectively reflected ultrasound. More importantly, the nanobubbles survived under ultrasonication 100-times longer than a commercial microbubble sample that is currently in clinical use. We justify this unprecedented stability theoretically. These nanobubbles, owing to their small size and potential ability to permeate the capillary networks of tissues, may expand the applications of microbubbles in diagnostic ultrasonography and find new applications in ultrasound-regulated drug delivery.

Semi‐Fluorinated Methacrylates: A Class of Versatile Monomers for Polymerization‐Induced Self‐Assembly

“…Besides, their corresponding polymers have tunable lipophobicity depending on the side‐chain length of the monomers. As a result, they have significant applications in self‐assembly, 19 F NMR imaging, coating, etc . More importantly, they are soluble in the common organic solvents, such as alcohols, toluene, and dioxane, while the corresponding polymers are not, which meets the criterion of the monomers for PISA.…”

“…As a result, they have significant applications in self-assembly, [51,52] 19 F NMR imaging, [53] coating, [54] etc. [55,56] More importantly, they are soluble in the common organic solvents, such as alcohols, toluene, and dioxane, while the corresponding polymers are not, which meets the criterion of the monomers for PISA. In fact, Armes and co-workers realized the PISA of 2,2,2-trifluoroethyl methacrylate (TFEMA), [57] which enlightens us that semi-fluorinated methacrylates may largely enrich the monomer/solvent toolkit of PISA.…”

Nucleation, mapping and control of cavitation for drug delivery

“…Finally, gaseous 'nanobubbles' with diameter < 1μm have also been studied. These offer the advantages of droplets in terms of circulatory stability and extravasation [G] potential, but respond at much lower ultrasound pressures than droplets do 93 . However, there is some controversy about the mechanism of cavitation enhancement 94 .…”

Breaking free from vascular confinement: status and prospects for submicron ultrasound contrast agents

“…However, many reports of nanobubbles have now been made for intravascular and extravascular imaging applications, demonstrating both stability and signal from size isolated subpopulations or interesting alternative shell components, such as the copolymer Pluronic proposed by Krupka et al, which controlled bubble size, enhanced stability and echogenicity, and acted as a chemo‐ and thermal‐sensitizer by altering target cell membrane fluidity. Generally, there are two explanations for the seemingly anomalous observations of nanobubbles: First, the thick polymer or thin surfactant‐based encapsulating layer introduced in the second generation of bubbles can facilitate the generation of nonlinear signals above a pressure threshold .…”