Ultrasonically actuated needle pump system

• US 20040204680A1
• Filed: 04/29/2004
• Published: 10/14/2004
• Est. Priority Date: 07/17/2000
• Status: Active Grant

• Current Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Original Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Inventors: Lal, Amit, Lee, Chung-Hoon
• Granted Patent: US 6,869,420 B2
• Time in Patent Office: Days
• US Class Current: 604/151
• CPC Class Codes: A61B 2010/008 Interstitial fluid
• CPC Class Codes: A61B 2017/00765 Decreasing the barrier function of skin tissue by radiated energy, e.g. using ultrasound, using laser for skin perforation
• CPC Class Codes: A61B 5/14514 using means for aiding extraction of interstitial fluid, e.g. microneedles or suction
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150083 by vibration, e.g. ultrasound
• CPC Class Codes: A61B 5/150297 for piercing devices, i.e. devices ready to be used for lancing or piercing for piercing elements A61B5/150282, for driving devices A61B5/15029
• CPC Class Codes: A61B 5/150389 Hollow piercing elements, e.g. canulas, needles, for piercing the skin
• CPC Class Codes: A61B 5/150503 Single-ended needles hollow piercing element tip design A61B5/150396, needle sets for catheters A61M25/06, needles for bringing media into the body A61M5/32
• CPC Class Codes: A61B 5/150946 Means for varying, regulating, indicating or limiting the speed or time of blood collection
• CPC Class Codes: A61B 5/150977 Arrays of piercing elements for simultaneous piercing
• CPC Class Codes: A61B 5/15142 Devices intended for single use, i.e. disposable
• CPC Class Codes: A61M 37/0092 using ultrasonic, sonic or infrasonic vibrations, e.g. phonophoresis

Abstract

An ultrasonically driven pump, which may be used for sampling body fluids or atomizing liquids, has a stationary outer needle and an inner needle mounted within the bore of the outer needle. The distal end of the inner needle is positioned adjacent to the distal end of the outer needle. The inner needle is ultrasonically vibrated by an ultrasonic actuator without vibrating the outer needle, with resulting draw of liquid through the distal end of the outer needle into the bore of the inner needle for discharge through the proximal end of the inner needle. The outer needle can be formed to have a penetrating tip suited for penetrating the skin of a subject to allow sampling of body fluids including interstitial fluids. The pump can also be used for atomizing liquid, by drawing liquid from a supply that is pumped from the distal end to an open proximal end of the inner needle where the liquid is discharged by atomization into the atmosphere.

Claims

1. An ultrasonically actuated pump comprising:

(a) an outer needle having a distal end and a hollow bore;

(b) an inner needle having a hollow bore mounted within the bore of the outer needle and having a distal end positioned adjacent to the distal end of the outer needle and a proximal end; and

(c) an ultrasonic actuator, coupled to the inner needle to selectively apply ultrasonic vibrations thereto without vibrating the outer needle.

2. The ultrasonically actuated pump of claim 1 wherein the distal end of the outer needle is cut at a bias to form a skin penetrating tip.

3. The ultrasonically actuated pump of claim 1 further including a base to which the outer needle is fixed, and supports coupling the inner needle to the base without transmission of vibrations from the inner needle through the base to the outer needle.

4. The ultrasonically actuated pump of claim 1 wherein the ultrasonic actuator comprises a piezoelectric transducer.

5. The ultrasonically actuated pump of claim 4 wherein the piezoelectric transducer comprises a PZT ceramic plate.

6. The ultrasonically actuated pump of claim 1 wherein the outer needle is a tube of a material selected from the group consisting of a metal, glass, and silicon, and the inner needle is a capillary tube of a material selected from the group consisting of glass, metal, and silicon.

7. The ultrasonically actuated pump of claim 1 including a silicon base to which the outer needle is fixed, and a silicon horn formed to concentrate ultrasonic energy at a tip of the horn, wherein the inner needle is bonded to the silicon horn to vibrate therewith, and wherein the ultrasonic actuator is bonded to the silicon horn, such that actuation of the ultrasonic actuator drives vibrations in the silicon horn which are transmitted to the inner needle bonded thereto.

8. The ultrasonically actuated pump of claim 7 wherein the silicon base and the silicon horn are formed from a unitary piece of crystalline silicon and are joined together by connectors extending between the base and the silicon horn at a node of vibration in the silicon horn so that vibrations of the horn are not substantially transmitted to the base.

9. The ultrasonically actuated pump of claim 1 wherein the proximal end of the inner needle is open to the atmosphere so that liquid pumped from the distal end of the inner needle to its proximal end is atomized into the atmosphere at the proximal end.

10. The ultrasonically actuated pump of claim 1 wherein the outside diameter of the outer needle is less than or equal to about 600 micrometers.

11. The ultrasonically actuated pump of claim 1 wherein the ultrasonic actuator is a piezoelectric transducer, and further including an electrical power driver connected to supply oscillating electrical power to the piezoelectric transducer.

12. An ultrasonically actuated pump comprising:

(a) a plurality of parallel outer needles mounted together to a mounting plate, each outer needle having a hollow bore and a distal end at a position spaced away from the mounting plate;

(b) a plurality of inner needles, each inner needle mounted within the bore of an outer needle and free to vibrate with respect to the outer needle, each inner needle having a hollow bore, a proximal end, and a distal end positioned adjacent to the distal end of the outer needle in which it is mounted;

(c) an ultrasonic actuator coupled to the inner needles to selectively vibrate the inner needles at ultrasonic frequencies without vibrating the outer needles.

13. The ultrasonically actuated pump of claim 12 wherein each of the inner needles are secured to a vibration transmitting plate, and wherein the ultrasonic actuator is at least one piezoelectric transducer bonded to the vibration transmitting plate to transmit vibrations therethrough to the inner needles.

14. The ultrasonically actuated pump of claim 13 further including spacers between the mounting plate for the outer needles and the vibration transmitting plate for the inner needles to secure the two plates together without substantially transmitting vibrations from the vibration transmitting plate to the mounting plate.

15. The ultrasonically actuated pump of claim 12 wherein the distal end of each outer needle is cut at a bias to form a skin penetrating tip.

16. The ultrasonically actuated pump of claim 12 wherein the ultrasonic actuator comprises a piezoelectric transducer.

17. The ultrasonically actuated pump of claim 16 wherein the piezoelectric transducer comprises a PZT ceramic plate.

18. The ultrasonically actuated pump of claim 12 wherein each outer needle is formed of a metal tube and each inner needle is formed of a glass capillary tube.

19. The ultrasonically actuated pump of claim 12 wherein the proximal end of each inner needle is open to the atmosphere so that liquid pumped from the distal end of each inner needle to its proximal end is atomized into the atmosphere at the proximal end.

20. The ultrasonically actuated pump of claim 12 wherein the ultrasonic actuator is a piezoelectric transducer, and further including an electrical power driver connected to supply oscillating electrical power to the piezoelectric transducer.

21. A method of drawing a sample of body fluid comprising:

(a) puncturing the skin of a subject with a penetrating tip located at a distal end of an outer needle having a hollow bore;

(b) ultrasonically vibrating an inner needle within the bore of the outer needle without substantially vibrating the outer needle, the inner needle having a hollow bore and a distal end and a proximal end, the distal end positioned adjacent to the penetrating tip of the outer tubular needle, so as to draw fluid into the inner needle from its distal end to its proximal end by the ultrasonic vibration of the inner needle.

22. A method of atomizing a liquid comprising:

(a) inserting the distal end of an outer needle with a hollow bore into a supply of liquid to be atomized;

(b) ultrasonically vibrating an inner needle mounted within the bore of the outer needle, the inner needle having a hollow bore and a distal end and a proximal end, the distal end of the inner needle located adjacent to the distal end of the outer needle, to draw liquid by the vibration of the inner needle from the distal end of the inner needle to the proximal end of the inner needle where it is discharged by atomization into the atmosphere.