Methods and apparatus for generating droplets

Patent metadata

Field	Value
Publication number	US-10252271-B2
Application number	US-201515306996-A
Country	US
Kind code	B2
Filing date	Apr 30, 2015
Priority date	Apr 30, 2014
Publication date	Apr 9, 2019
Grant date	Apr 9, 2019

Abstract

Methods and apparatus for generating droplets are disclosed. In one arrangement a peristaltic screw pump is configured to drive pulsatile flows of fluids in different conduits which are phased relative to each other such that a sequence of droplets are formed at a junction downstream from the pump.

First claim

The invention claimed is:

1. A method of generating droplets, comprising:
using a pumping mechanism to transport a first fluid in a first conduit; and
using a pumping mechanism to transport a second fluid in a second conduit;
wherein the pumping mechanism comprises a first rotatable member having one or more radially peripheral portions that rotate in unison with each other on rotation of the first rotatable member and engage against the first and second conduits to apply a dynamic deformation to the first and second conduits on rotation of the first rotatable member, the dynamic deformation being such as to drive a pulsatile motion of the first and second fluids in the first and second conduits,
the pulsatile motions of the first and second fluids are phase shifted relative to each other at a first junction between the first and second conduits downstream of the pumping mechanism resulting in the formation of droplets of the second fluid in the first fluid at the first junction;
the first fluid comprises a carrier fluid and the second fluid comprises a sample fluid, the sample fluid being immiscible with the carrier fluid, and either:
the one or more radially peripheral portions comprises a thread winding around the axis of the first rotatable member and the phase shifting of the pulsatile motions of the first and second fluids at the first junction is provided by positioning the first and second conduits at different angular positions around the circumference of the first rotatable member; or
a longitudinal axis of each of the first and second conduits is non-parallel to the axis of rotation of the first rotatable member in a region where the one or more radially peripheral portions engage against the first or second conduit, a set of radially peripheral portions that engage against the first conduit is different from a set of radially peripheral portions that engage against the second conduit, and the phase shifting of the pulsatile motions of the first and second fluids is provided by an angular offset between the set of radially peripheral portions that engage against the first conduit and the set of radially peripheral portions that engage against the second conduit.

2. The method according to claim 1 , wherein, in the case where the one or more radially peripheral portions comprises the thread, longitudinal axes of the first and second conduits are parallel to the axis of rotation of the first rotatable member in a region where the one or more radially peripheral portions engage against the first and second conduits.

3. The method according to claim 1 , wherein:
the set of radially peripheral portions that engage against the first conduit engage against the first conduit exclusively within a first range of positions along an axis of rotation of the first rotatable member;
the set of radially peripheral portions that engage against the second conduit engage against the second conduit exclusively within a second range of positions along the axis of rotation of the first rotatable member; and
the first range of positions is different to the second range of positions.

4. The method according to claim 1 , wherein the pumping mechanism is further used to pump fluid along one or more further conduits, each configured such that the one or more radially peripheral portions engage against each of the one or more further conduits and apply a dynamic deformation to each of the one or more further conduits, on rotation of the first rotatable member, thereby driving a corresponding pulsatile motion of fluid in each of the one or more further conduits.

5. The method according to claim 4 , wherein the one or more further conduits are configured such that fluid in these conduits can be driven into the first fluid at the first junction between the first and second conduits in order to form droplets in the first fluid that comprise a mixture of the second fluid and fluid from the one or more further conduits.

6. The method according to claim 4 , wherein each of the first, second and one or more further conduits are positioned at different angular positions around the circumference of the first rotatable member.

7. The method according to claim 4 , wherein at least one of the one or more further conduits is configured such that fluid in the conduit can be driven into the first fluid at a second junction with the first conduit, the second junction being at a different location to the first junction, thereby allowing droplets of different compositions to be formed in parallel at the first and second junctions.

8. The method according to claim 1 , wherein the pumping mechanism comprises one or more further rotatable members configured to be rotated in unison with the first rotatable member.

9. The method according to claim 8 , wherein each of the one or more further rotatable members comprises one or more radially peripheral portions that engage against one or more of the following:
a further instance of the first conduit,
a further instance of the second conduit, and
where not previously provided, one or more further conduits, or
where previously provided, a further instance of the one or more further conduits, wherein
the one or more radially peripheral portions apply a dynamic deformation to the conduit or conduits with which they engage, on rotation of the rotatable member, thereby driving a corresponding pulsatile motion of fluid in the conduit or conduits with which they engage.

10. The method according to claim 9 , wherein at least one of the one or more further rotatable members and corresponding conduits are configured such that a dynamic deformation is applied to at least one of the conduits that has a different form than the dynamic deformation applied by the first rotatable member to the corresponding conduit for the same speed of rotation.

11. The method according to claim 10 , wherein the dynamic deformation having a different form results in a pulsatile motion having a different wavelength than the pulsatile motion driven by the first rotatable member for the same speed of rotation.

12. The method according to claim 1 , wherein one or more of the radially peripheral portions are configured to engage with at least one of the conduits in such a way that for all angles of rotation of the first rotatable member the at least one conduit is substantially sealed longitudinally by a portion of the one or more radially peripheral portions to prevent backflow in the at least one conduit.

13. The method according to claim 1 , wherein one or more of the conduits are detachably connected to the pumping mechanism to allow reuse of the pumping mechanism with different sets of conduits.

14. The method according to claim 1 , wherein the pumping mechanism is configured to operate as a peristaltic pump.

15. The method according to claim 1 , wherein an output conduit configured to transport the droplets downstream from the first junction, and/or where provided the second junction, is routed such that over a range of positions downstream from the first junction, and/or where provided the second junction, the one or more radially peripheral portions engage against the output conduit and apply a dynamic deformation to the output conduit, on rotation of the first rotatable member, thereby further driving a corresponding pulsatile motion of fluid in the output conduit.

16. The method according to claim 1 , wherein a conduit support structure is provided that comprises a lumen defining the first conduit and a lumen defining the second conduit.

17. The method according to claim 16 , wherein the condu

Assignees

• Univ Southampton

Inventors

• Niu Xize

Classifications

• F04B43/043

  Micropumps · CPC title

• G01N30/32

  of pressure or speed (G01N30/36 takes precedence) · CPC title

• B01L2400/0481

  squeezing of channels or chambers · CPC title

• F04B43/1269

  the rotary axes of the rollers lying in a plane perpendicular to the rotary axis of the driving motor · CPC title

• B01L9/527

  for microfluidic devices, e.g. used for lab-on-a-chip · CPC title