Acoustophoretic separation of lipid particles from red blood cells

Patent metadata

Field	Value
Publication number	US-10201652-B2
Application number	US-201313866584-A
Country	US
Kind code	B2
Filing date	Apr 19, 2013
Priority date	Apr 20, 2012
Publication date	Feb 12, 2019
Grant date	Feb 12, 2019

Abstract

A system for removing lipids from blood during cardiopulmonary bypass surgery is disclosed. The system uses an acoustophoretic separator having improved trapping force. The transducer of the acoustophoretic seperator includes a ceramic crystal. Blood flows through the separator, and lipids are trapped and removed.

First claim

The invention claimed is:

1. A method of separating lipids from blood, the method comprising:
flowing the blood through a flow chamber, wherein the flow chamber has a source of acoustic energy with an initial shape and, on an opposing side of the flow chamber, a reflector of acoustic energy, and wherein the blood contains lipids;
driving the source of acoustic energy at a frequency that generates a higher order mode shape than the initial shape to create a plurality of three-dimensional standing waves in the blood; and
removing lipids trapped in the three-dimensional standing waves from the blood;
wherein each three-dimensional standing wave results in an acoustic radiation force with an axial force component and a lateral force component that are of the same order of magnitude.

2. The method of claim 1 , wherein the blood is continuously flowed through the flow chamber.

3. The method of claim 1 , wherein the standing waves create nodal lines and the lateral forces trap the lipids in the nodal lines.

4. The method of claim 3 , wherein the lipids trapped in the nodal lines coalesce or agglomerate such that the lipids are separated through enhanced buoyancy.

5. The method of claim 1 , wherein the lipids are collected in a collection pocket at the top of the flow chamber.

6. The method of claim 1 , wherein the blood is mediastinal blood collected via a suction.

7. The method of claim 1 , wherein the source of acoustic energy is an ultrasonic transducer comprising:
a housing with a top end, a bottom end, and an interior volume; and
a crystal at the bottom end of the housing with an exposed exterior surface and an interior surface, the crystal being able to vibrate when driven by a voltage signal; and
an air gap between the crystal and the top end of the housing.

8. A method of separating lipids from blood, the method comprising:
flowing the blood through a flow chamber, wherein the flow chamber has a source of acoustic energy with an initial shape and, on an opposing side of the flow chamber, a reflector of acoustic energy, and wherein the blood contains lipids;
driving the source of acoustic energy at a frequency that generates a higher order mode shape than the initial shape to create a plurality of three-dimensional standing waves in the blood; and
removing lipids trapped in the three-dimensional standing waves from the blood;
wherein each three-dimensional standing wave results in an acoustic radiation force with an axial force component and a lateral force component that are of the same order of magnitude; and
wherein the source of acoustic energy is an ultrasonic transducer comprising:
a housing with a top end, a bottom end, and an interior volume; and
a crystal at the bottom end of the housing with an exposed exterior surface and an interior surface, the crystal being able to vibrate when driven by a voltage signal, wherein a backing layer contacts the interior surface of the crystal, the backing layer being made of a substantially acoustically transparent material.

9. The method of claim 8 , wherein the substantially acoustically transparent material is balsa wood, cork, or foam.

10. The method of claim 8 , wherein the substantially acoustically transparent material has a thickness of up to 1 inch.

11. The method of claim 8 , wherein the substantially acoustically transparent material is in the form of a lattice.

12. The method of claim 7 , wherein an exterior surface of the crystal is covered by a wear surface material with a thickness of a half wavelength or less, the wear surface material being a urethane, epoxy, or silicone coating.

13. The method of claim 7 , wherein the crystal has no backing layer or wear layer.

14. The method of claim 7 , further comprising driving the crystal in a non-uniform displacement mode.

15. The method of claim 14 , further comprising driving the crystal in a higher order mode shape to produce more than one nodal trapping line.

Assignees

• Flodesign Sonics Inc

Inventors

• Dutra Brian
• Lipkens Bart
• Kennedy Daniel
• Rust Michael J

Classifications

• A61M1/3678 Primary

  Separation of cells using wave pressure; Manipulation of individual corpuscles · CPC title

• A61M1/363 Primary

  Degassing by using vibrations · CPC title

• A61M2202/08

  Lipoids · CPC title

• A61M1/3681 Primary

  by irradiation · CPC title

• B01D21/283

  Settling tanks provided with vibrators · CPC title