Multi-use acoustic levitation trap

Abstract

Disclosed is a device, suitable for use as an acoustic resonator, including a base adapted to be coupled to at least one acoustic wave generator, a spacer including an aperture and a reflector, wherein the base includes a protruding part having a thickness t; the aperture of the spacer is complementary to the protruding part of the base; the device further includes a housing having an aperture complementary to the protruding part of the base and wherein the inner edge of the aperture has the same thickness t than the protruding part; and the housing is positioned between the spacer and the reflector, such that the thickness of the inner edge of the spacer defined the thickness of a cavity between the protruding part and the reflector. Also disclosed is a method of trapping particles in a fluid.

Claims

1. A device (1), suitable for use as an acoustic resonator, comprising a base (2) adapted to be coupled to at least one acoustic wave generator, a spacer (3) comprising an aperture (31) and a reflector, wherein: the base (2) comprises a protruding part (21) having a thickness t; the aperture of the spacer (31) is complementary to the protruding part of the base (21); the device (1) further comprises a housing (4) having an aperture (41) complementary to the protruding part of the base (21) and wherein the inner edge of the aperture (41) has the same thickness t as the protruding part (21); and the housing (4) is positioned between the spacer (3) and the reflector (5), such that the thickness of the inner edge of the spacer (3) defines the thickness of a cavity between the protruding part (21) and the reflector (5).

2. The device according to claim 1, wherein the protruding part (21) is axisymmetric.

3. The device of claim 2, wherein the protruding part (21) is cylindrical, rhombohedral, parallelepiped or ribbon-shaped.

4. The device of claim 2, wherein the protruding part (21) is cylindrical or rhombohedral.

5. The device of claim 2, wherein the protruding part (21) is parallelepiped or ribbon-shaped.

6. The device according to claim 1, further comprising a supporting base (6) and a top part (7), wherein the base (2), the spacer (3), the housing (4) and the reflector (5) are held in position between the supporting base (6) and the top part (7).

7. The device according to claim 1, comprising a supporting base (6) and a top part (7), wherein the base (2), the spacer (3), the housing (4) and the reflector (5) are held in position between the supporting base (6) and the top part (7), wherein the supporting base (6) extends outwardly from the base (2); the top part (7) encompasses the base (2), the spacer (3), the housing (4) and the reflector (5); and the supporting base (6) and the top plate (7) are secured together.

8. The device according to claim 1, comprising a supporting base (6) and a top part (7), wherein the base (2), the spacer (3), the housing (4) and the reflector (5) are held in position between the supporting base (6) and the top part (7) and further comprising a gasket (8) ensuring tightness between the supporting base (6) and the top part (7).

9. The device according to claim 1, wherein the protruding part (21) comprises at least one inlet (22) and at least one outlet (23).

10. The device according to claim 1, wherein the base (2), the protruding part (21) or the housing (4) comprises a material selected from metal or plastic.

11. The device according to claim 1, wherein the reflector (5) comprises an optically transparent material selected from glass, quartz or plastic.

12. The device according to claim 1, wherein the protruding part (21) comprises an optically transparent material selected from glass, quartz or plastic.

13. The device according to claim 1, wherein the top part (7) comprises at the top an optically transparent window.

14. The device according to claim 1, wherein the spacer (3) comprises a material selected from polyimide or a polyethylene terephthalate.

15. An acoustic resonator (8) comprising the device according The device according to claim 1, and at least one acoustic wave generator (9) coupled to the base.

16. The acoustic resonator according to claim 15, wherein the at least one acoustic wave generator (9) is located below the protruding part of the base (21).

17. The acoustic resonator according to claim 15, wherein the at least one acoustic wave generator (9) is an ultrasonic wave generator.

18. The acoustic resonator according to claim 15, wherein the at least one acoustic wave generator (9) is a piezo transducer.

19. The acoustic resonator according to claim 15, wherein the at least one acoustic wave generator (9) is ring-shaped.

20. A method of trapping particles in a fluid comprising the steps of: i. providing an acoustic resonator (11) comprising; at least on acoustic wave generator (9) for generating a sound wave of frequency f; a base (2) adapted to be coupled to the at least one acoustic wave generator (9); a spacer (3) comprising an aperture (31); an housing (4) comprising an aperture (41); and a reflector (5); wherein the base (2) comprises a protruding part (21) having a thickness t; the aperture of the spacer (31) is complementary to the protruding part of the base (21); the aperture of the housing (41) is complementary to the protruding part of the base (21); the inner edge of the aperture of the housing (41) has the same thickness t as the protruding part (21); and the housing (4) is positioned between the spacer (3) and the reflector (5), such that the thickness of the spacer (3) defines the thickness of a cavity between the protruding part (21) and the reflector (5); ii. introducing a fluid comprising particles into the cavity; iii. selecting the frequency f such that the path length of the standing wave in the cavity is a multiple of of the wavelength of the sound wave therein; and iv. trapping the particles.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an exploded view of the device according to one embodiment of the present invention.

(2) FIG. 2 is an exploded view of the device according to another embodiment of the present invention.

(3) FIG. 3 is an exploded view of an acoustic resonator comprising a plurality of acoustic wave generators according to one embodiment of the present invention.

(4) FIG. 4 is an exploded view of the device according to another embodiment of the present invention.

(5) FIG. 5 illustrates the density profile of two species of particles during the separation of said particles by means of the acoustic resonator of the invention.

REFERENCES

(6) 1Device suitable for use as an acoustic resonator;

(7) 11Acoustic resonator;

(8) 2Base;

(9) 21Protruding part;

(10) 211Groove;

(11) 212Bottom plate;

(12) 22Inlet;

(13) 23Outlet;

(14) 24Separator;

(15) 3Spacer;

(16) 31Aperture of the spacer;

(17) 4Housing;

(18) 41Aperture of the housing;

(19) 42Peripheral wall;

(20) 5Reflector;

(21) 6Supporting base;

(22) 61Protruding part;

(23) 7Top part

(24) 8Gasket;

(25) 9Acoustic wave generator.

EXAMPLES

(26) The present invention is further illustrated by the following examples.

Example 1

Bacteria Manipulation

(27) Bacteria suspension is injected within the cavity of the acoustic resonator of the present invention. The concentration of bacteria may vary from high concentration to very diluted samples.

(28) An acoustic force field is implemented within the cavity by means of the acoustic wave generator and several thousands or millions of bacteria are trapped under the acoustic force field, thereby inducing a stable aggregate in levitation.

(29) A stable colony of bacteria can therefore be studied by observing its time evolution in function of the suspending medium. The entire colony can be trapped and the medium modified in order to establish new equilibriums. It is also possible within the present acoustic resonator to eliminate specific bacteria by modifying the medium.

(30) Once the sample has been manipulated, the cavity may be demounted and the sample may be collected after the assay in order to be submitted to other studies with any technique known to one skilled in the art.

Example 2

Separation of Particulate Species

(31) A suspension comprising different species or different concentrations of species is injected within the cavity of the acoustic resonator of the present invention. Species could differ on size or even on acoustic properties such as acoustic impedance. Within the present example, a suspension of two species of polystyrene particles of 7 m diameter (A) and of 2 m diameter (B) are injected within the cavity.

(32) By selecting a suitable frequency, the different species are trapped and positioned at different distances from the walls of the cavity. Once different equilibrium positions have been reached, a flow is established in such a way that only one kind species remains trapped while the other(s) are eluted, and the sample collected is filtered of the trapped species.

(33) As acoustic force depends on particles size, acoustic force is much stronger for bigger species, at least 40 times stronger for species of 7 m diameter relative to species of 2 m diameter. Therefore, two effects are used: a) the time required for species to reach the equilibrium position is much smaller for bigger species; and b) the force to keep trapped bigger species is much stronger.

(34) Consequently, when a flow is established; the average position of different species is different generating a differential transport along the cavity.

(35) Within the present example, the smallest species can be eluted while the 7 m particles remain trapped. FIG. 5 illustrate the density profile with peaks corresponding to the two species. Especially, FIGS. 5A, 5B, 5C, 5D and 5E show successively the different positions of both species, after respectively 0, 2, 3.4 and 5 seconds.