Wireless microactuators and control methods

Patent metadata

Field	Value
Publication number	US-9370628-B2
Application number	US-201113324587-A
Country	US
Kind code	B2
Filing date	Dec 13, 2011
Priority date	Jun 5, 2011
Publication date	Jun 21, 2016
Grant date	Jun 21, 2016

Abstract

Embodiments of the present technology include a micromachined implantable drug delivery devices, grippers, and syringes that are wirelessly powered and controlled by frequency tuning of external radiofrequency (RF) magnetic fields. An illustrative device can be designed and constructed with passive circuitry and microvalves that operate without batteries, e.g., through thermal actuation of hydrogel microvalves and/or shape-memory alloy members. The frequency selectivity in the device control provides not only a path to achieving reliable and safe operation of drug delivery but also potential applications for selective delivery of multiple drugs.

First claim

What is claimed is:

1. A microfluidic device comprising:
a reservoir to hold a substance, wherein the reservoir includes a release hole to dispense the substance;
a hydrogel microvalve disposed within the release hole, wherein the hydrogel microvalve comprises a photosensitive hydrogel that is cured via ultraviolet radiation; and
a resonant heater in thermal communication with the hydrogel microvalve to actuate the hydrogel microvalve, wherein the resonant heater is configured to absorb alternating current electromagnetic energy at only a predefined resonance, wherein the predefined resonance has a center frequency between of 10 MHz and 1 GHz, to power the resonant heater.

2. The microfluidic device of claim 1 , wherein the substance is a fluid.

3. The microfluidic device of claim 1 , wherein the substance is a powder.

4. The microfluidic device of claim 1 , wherein the substance is a drug.

5. The microfluidic device of claim 1 , wherein the hydrogel microvalve is self-aligned to the release hole.

6. The microfluidic device of claim 1 , wherein the hydrogel microvalve comprises at least one of poly(N-isopropylacrylamide), poly(N,N-dimethylacrylamide-co-N-phenylacrylamide), and poly(glycidyl methacrylate-co-N-isopropylacrylamide).

7. The microfluidic device of claim 1 , wherein the resonant heater is a planar resonant heater.

8. The microfluidic device of claim 1 , wherein the predefined resonance has an active width between 1 kHz and 10 MHz.

9. The microfluidic device of claim 1 , wherein the release hole is a first release hole, the hydrogel microvalve is a first hydrogel microvalve, the resonant heater is a first resonant heater configured to absorb electromagnetic energy at a first resonant frequency so as to actuate the first hydrogel microvalve, and further comprising:
a second release hole formed in the reservoir;
a second hydrogel microvalve disposed with the second release hole to prevent the substance from transiting the second release hole; and
a second resonant heater configured to absorb electromagnetic energy at a second resonance frequency so as to actuate the second hydrogel microvalve.

10. A method of fabricating a hydrogel microvalve, the method comprising:
filling a reservoir having first and second release holes with a photosensitive hydrogel;
exposing the first release hole to ultraviolet radiation to cure photosensitive hydrogel disposed within the first release hole; and
withdrawing uncured photosensitive hydrogel from the reservoir via the second release hole to form the cured photosensitive hydrogel in the first release hole into a hydrogel microvalve.

11. The method of claim 10 , wherein the photosensitive hydrogel comprises at least one of poly(N-isopropylacrylamide), poly(N,N-dimethylacrylamide-co-N-phenylacrylamide), and poly(glycidyl methacrylate-co-N-isopropylacrylamide).

12. The method of claim 10 , wherein exposing the first release hole to ultraviolet radiation includes adjusting at least one of an exposure time and an exposure intensity to control dimensions of the hydrogel microvalve.

13. The method of claim 10 , wherein an interior surface of the reservoir is formed or coated with polyimide, and further comprising:
treating the interior surface with an oxygen plasma before filling the reservoir with the photosensitive hydrogel to prevent adhesion of the photosensitive hydrogel to the interior surface.

14. The method of claim 10 , further comprising:
placing a resonant heater in thermal communication with the hydrogel microvalve.

15. The method of claim 14 , further comprising absorbing, by the resonant heater, alternating current electromagnetic energy only at a predefined resonance.

Assignees

• Takahata Kenichi
• Ali Mohamed Sultan Mohamed
• Rahimi Somayyeh
• Univ British Columbia

Inventors

• Takahata Kenichi
• Ali Mohamed Sultan Mohamed
• Rahimi Somayyeh

Classifications

• Y10T156/10

  Methods of surface bonding and/or assembly therefor · CPC title

• B29C2035/0827

  using UV radiation · CPC title

• B29C2035/0811

  using induction · CPC title

• A61M5/44 Primary

  having means for cooling or heating the devices or media · CPC title