Method and apparatus for generating bubbles

Patent metadata

Field	Value
Publication number	US-11007495-B2
Application number	US-201716071699-A
Country	US
Kind code	B2
Filing date	Jan 20, 2017
Priority date	Jan 20, 2016
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

A method of generating bubbles of a first fluid in a second fluid, the method comprising: flowing a stream of the second fluid through a microfluidic channel; injecting a stream of the first fluid into the microfluidic channel through an aperture such that bubbles of the first fluid form in the second fluid; and sonicating the microfluidic channel with ultrasound so as to cause the bubbles formed at the aperture to divide.

First claim

The invention claimed is:

1. The method of generating bubbles of a first fluid in a second fluid, the method comprising:
flowing a stream of the second fluid through a microfluidic channel;
injecting a stream of the first fluid into the microfluidic channel through an aperture such that bubbles of the first fluid form in the second fluid; and
sonicating the microfluidic channel with ultrasound using an ultrasound source so as to cause the bubbles formed at the aperture to divide;
wherein the ultrasound has a frequency corresponding to a resonance of the microfluidic channel.

2. A method according to claim 1 , wherein the sonication is applied to the microfluidic channel at a location adjacent to the aperture.

3. A method according to claim 1 , wherein the sonication is applied to a length of the microfluidic channel of at least 10 mm and/or to a length of the microfluidic channel of at most 100 mm.

4. A method according to claim 1 , wherein the ultrasound has a frequency of at least 20 kHz.

5. A method according to claim 1 , further comprising:
measuring the impedance and/or phase angle of the ultrasound source sonicating the microfluidic channel;
wherein the frequency corresponding to a resonance of the microfluidic channel is determined based on measuring impedance and/or phase angle.

6. A method according to claim 1 , wherein the microfluidic channel has a hydraulic diameter of 1 mm or less.

7. A method according to claim 1 , wherein the undivided bubbles formed at the aperture have an average diameter of at least 100 μm.

8. A method according to claim 1 , wherein the divided bubbles after sonication have an average diameter of at most 10 μm and/or the diameters of the divided bubbles after sonication have a coefficient of variation of less than 60%.

9. A method according to claim 1 , wherein the second fluid is a liquid.

10. A method according to claim 9 , wherein the second fluid is an aqueous solution.

11. A method according to claim 1 , wherein the first fluid is a gas or a liquid.

12. A method according to claim 1 , wherein the step of injecting the first fluid into the microfluidic channel is performed in the presence of a surfactant such that the bubbles formed at the aperture comprise the surfactant at an interface with the second fluid.

13. A method according to claim 12 , wherein the stream of the second fluid further comprises the surfactant.

14. A method according to claim 12 , wherein the surfactant comprises a phospholipid, a protein or a polymer.

15. A method according to claim 12 , wherein the surfactant and/or the first fluid comprises a pharmaceutical product.

Assignees

• Univ Oxford Innovation Ltd

Inventors

• Stride Eleanor
• Carugo Dario
• Browning Richard

Classifications

• A61K49/223 Primary

  Microbubbles, hollow microspheres, free gas bubbles, gas microspheres · CPC title

• B01F23/413

  Homogenising a raw emulsion or making monodisperse or fine emulsions · CPC title

• B01F33/30

  Micromixers · CPC title

• B01F23/4111

  using vibrations · CPC title

• B01F23/238 Primary

  using vibrations, electrical or magnetic energy, radiations · CPC title