Microfluidic Generation of Monodisperse Nanobubbles by Selective Gas Dissolution

Area of Science:

• Nanotechnology
• Microfluidics
• Biomedical Imaging

Background:

• Uniform nanoparticles and nano-emulsions are producible, but not uniform gaseous nanobubbles (NBs).
• Existing methods lack precise control over nanobubble size and uniformity.

Purpose of the Study:

• To report the first microfluidic method for directly producing monodisperse gaseous nanobubbles (NBs).
• To demonstrate the utility of these monodisperse NBs in ultrasound imaging applications.

Main Methods:

• Utilized a microfluidic bubble generator with a two-component gas mixture (nitrogen and octafluoropropane).
• Generated monodisperse microbubbles (MBs) and controlled their shrinkage to nanobubble size via gas dissolution.
• Tuned the ratio of soluble to insoluble gas components to precisely control final NB size.

Main Results:

• Achieved monodisperse nanobubbles (NBs) with controllable sizes around 100 nm.
• Demonstrated superior homogeneity of monodisperse NBs compared to polydisperse NBs in vitro.
• Successfully performed proof-of-concept in vivo kidney imaging in mice, showing enhanced contrast.

Conclusions:

• Microfluidics enables the direct, controlled production of monodisperse gaseous nanobubbles.
• Monodisperse NBs offer improved homogeneity and enhanced contrast in ultrasound imaging.
• Microfluidically generated NBs show promise as ultrasound contrast agents and for molecular imaging.