Method and apparatus for generating bubbles

Patent metadata

Field	Value
Publication number	US-2019282973-A1
Application number	US-201716071699-A
Country	US
Kind code	A1
Filing date	Jan 20, 2017
Priority date	Jan 20, 2016
Publication date	Sep 19, 2019
Grant date	—

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

1 . 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.

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 2 , wherein a length of the microchannel between the aperture and the location at which the sonication is applied is no more than 10 mm.

4 . A method according to any preceding claim, wherein the sonication is applied to a length of the microfluidic channel of at least 10 mm.

5 . A method according to any preceding claim, wherein the sonication is applied to a length of the microfluidic channel of at most 100 mm.

6 . A method according to any preceding claim, wherein the ultrasound has a frequency of at least 20 kHz.

7 . A method according to any preceding claim, wherein the ultrasound has a frequency corresponding to a resonance of the microfluidic channel.

8 . A method according to claim 7 , further comprising:
measuring the impedance and/or phase angle of an ultrasound source sonicating the microfluidic channel; wherein the frequency corresponding to a resonance of the microfluidic channel is determined based on the measured impedance and/or phase angle.

9 . A method according to any preceding claim, wherein the ultrasound has a frequency of in a range from 70 kHz to 75 kHz.

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

11 . A method according to any preceding claim, wherein the microfluidic channel has a hydraulic diameter of in a range from 100 μm to 500 μm.

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

13 . A method according to any preceding claim, wherein the divided bubbles after sonication have an average diameter of at most 10 μm.

14 . A method according to any preceding claim, wherein the diameters of the divided bubbles after sonication have a coefficient of variation of less than 60%.

15 . A method according to any preceding claim, wherein the ratio of the hydraulic diameter of the microfluidic channel and the average diameter of the divided bubbles after sonication is in a range from 10 to 500.

16 . A method according to any preceding claim, wherein the first fluid is immiscible with the second fluid.

17 . A method according to any preceding claim, wherein the second fluid is a liquid.

18 . A method according to claim 16 or 17 , wherein the second fluid is an aqueous solution.

19 . A method according to any preceding claim, wherein the first fluid is a gas or a liquid.

20 . A method according to any preceding claim, 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.

21 . A method according to claim 20 , wherein the stream of the second fluid further comprises the surfactant.

22 . A method according to claim 20 or 21 , wherein the surfactant comprises a phospholipid, a protein or a polymer.

23 . A method according to claim 20 , 21 or 22 , wherein the surfactant and/or the first fluid comprises a pharmaceutical product.

24 . A method according to any preceding claim, wherein the first fluid comprises a contrast agent for ultrasound imaging.

25 . An apparatus for generating bubbles of a first fluid dispersed in a second fluid, the apparatus comprising:
a microfluidic channel configured to provide a flow path for the second fluid; an aperture in the microfluidic channel configured to allow injection of a stream of the first fluid into the microfluidic channel such that bubbles of the first fluid form in the second fluid; and an ultrasound source configured to sonicate the microfluidic channel with ultrasound so as to cause the bubbles to divide.

26 . An apparatus according to claim 25 , wherein the ultrasound source is configured to sonicate the microfluidic channel at a location adjacent to the aperture.

27 . An apparatus according to claim 25 or 26 , wherein a length of the microchannel between the aperture and the location at which the sonication is applied is no more than 10 mm.

28 . An apparatus according to any one of claims 25 to 27 , wherein ultrasound source is configured to sonicate a length of the microfluidic channel of at least 10 mm.

29 . An apparatus according to any one of claims 25 to 27 , wherein ultrasound source is configured to sonicate a length of the microfluidic channel of at most 100 mm.

30 . An apparatus according to any one of claims 25 to 29 , wherein the ultrasound has a frequency of at least 20 kHz.

31 . An apparatus according to any one of claims 25 to 30 , wherein the ultrasound has a frequency corresponding to a resonance of the microfluidic channel.

32 . An apparatus according to any one of claims 25 to 31 , wherein the ultrasound has a frequency in a range of from 70 kHz to 75 kHz.

33 . An apparatus according to any one of claims 25 to 32 , wherein the microfluidic channel has a hydraulic diameter of at most 1 mm.

34 . An apparatus according to any one of claims 25 to 34 , wherein the microfluidic channel has a hydraulic diameter in a range of from 100 μm to 500 μm.

Assignees

• Univ Oxford Innovation Ltd

Inventors

• Stride Eleanor
• Carugo Dario
• Browning Richard

Classifications

• B01F2215/0454

  Numerical frequency values · CPC title

• B01F2215/0431

  Numerical size values, e.g. diameter of a hole or conduit, area, volume, length, width, or ratios thereof · CPC title

• A61K49/226

  Solutes, emulsions, suspensions, dispersions, semi-solid forms, e.g. hydrogels · CPC title

• B01F2215/0032

  Operations & Transport · mapped topic

• B01F3/0819

  Operations & Transport · mapped topic