Maintaining monodispersity in a microbubble population formed by flow-focusing.
The dynamic processes impacting the size distributions of lipid-encapsulated microbubbles formed by flow-focusing were observed by video optical microscopy. Parameters studied included the filling gas, gas saturating the surrounding solution, and microbubble size (initial size 2-12 microm) to simulate typical laboratory conditions. Typically, dissolution or growth, followed by Ostwald ripening at a collection cover glass, were observed and quantified. However, in the case of small nitrogen-filled microbubbles surrounded by an air-saturated solution, Ostwald ripening was avoided for at least 9 h. These bubbles had a final size distribution of 1.5 +/- 0.1 microm. This work suggests that lipid-encapsulated microbubbles formed by flow-focusing should be given sufficient time to reach a terminal size before coming into contact with each other. These long-lived mondisperse microbubbles should be of interest in ultrasound contrast agents, microfabrication, food, and research applications.
Talu
Esra
E
Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, California 95616, USA.
Hettiarachchi
Kanaka
K
Powell
Robert L
RL
Lee
Abraham P
AP
Dayton
Paul A
PA
Longo
Marjorie L
ML
D000388:Air; D045423:Microbubbles; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods; D009584:Nitrogen / Q000737:chemistry*; D010316:Particle Size; D014783:Viscosity
D009584:Nitrogen