Related Experiment Video
Updated: Jul 8, 2026
08:20
Capillary-based Centrifugal Microfluidic Device for Size-controllable Formation of Monodisperse Microdroplets
Published on: February 22, 2016
Maintaining monodispersity in a microbubble population formed by flow-focusing
Esra Talu1, Kanaka Hettiarachchi, Robert L Powell
1Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, California 95616, USA.
Langmuir : the ACS Journal of Surfaces and Colloids
|January 22, 2008
Summary
Stable, monodisperse lipid-encapsulated microbubbles were achieved by controlling gas conditions during flow-focusing. This method avoids Ostwald ripening, yielding microbubbles suitable for ultrasound contrast agents and other applications.
Area of Science:
- Materials Science
- Fluid Dynamics
- Biotechnology
Background:
- Microbubble size distribution is critical for applications like ultrasound imaging.
- Flow-focusing is a common method for microbubble generation.
- Ostwald ripening can lead to instability and loss of desired microbubble characteristics.
Purpose of the Study:
- To investigate dynamic processes affecting lipid-encapsulated microbubble size distribution.
- To identify conditions that promote stable, monodisperse microbubbles.
- To explore potential applications for long-lived microbubbles.
Main Methods:
- Video optical microscopy was used to observe microbubble formation and evolution.
- Flow-focusing technique was employed for microbubble generation.
- Parameters varied included filling gas, surrounding solution saturation, and initial microbubble size.
Main Results:
- Typically, microbubbles exhibited dissolution/growth followed by Ostwald ripening.
- Small nitrogen-filled microbubbles in air-saturated solution avoided Ostwald ripening for at least 9 hours.
- A stable, monodisperse final size distribution of 1.5 ± 0.1 micrometers was achieved under specific conditions.
Conclusions:
- Allowing microbubbles to reach a terminal size before aggregation is crucial.
- Conditions preventing Ostwald ripening yield long-lived, monodisperse microbubbles.
- These stable microbubbles have potential in ultrasound contrast agents, microfabrication, food science, and research.