BIOMEMS SENSOR AND APPARATUSES AND METHODS THEREFOR

• US 20110152725A1
• Filed: 02/25/2011
• Published: 06/23/2011
• Est. Priority Date: 09/02/2008
• Status: Active Grant

• Current Assignee: Innovative In Vivo Sensing, LLC
• Original Assignee: Christian M. Puttlitz Consulting, LLC
• Inventors: PUTTLITZ, Christian Matthew, MELIK, Rohat, DEMIR, Hilmi Volkan
• Granted Patent: US 9,326,728 B2
• Time in Patent Office: Days
• US Class Current: 600/587
• CPC Class Codes: A61B 2562/02 Details of sensors specially adapted for in-vivo measurements
• CPC Class Codes: A61B 2562/0261 Strain gauges
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/103 Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes A61B5/08 takes precedence; measuring aids for tailors A41H1/00; measuring instruments specially adapted for dentistry A61C19/04
• CPC Class Codes: A61B 5/4504 Bones A61B5/4547 takes precedence
• CPC Class Codes: A61B 5/6846 specially adapted to be brought in contact with an internal body part, i.e. invasive
• CPC Class Codes: G01L 1/144 with associated circuitry G01L1/146 and G01L1/148 take precedence
• CPC Class Codes: H01F 2017/006 flexible printed inductors
• CPC Class Codes: H01F 41/042 by thin film techniques
• CPC Class Codes: Y10T 29/49103 Strain gauge making

Abstract

Electronic devices, apparatus, systems, and methods of operating and constructing the devices, apparatus, and/or systems include a wireless sensor configured to measure strain of hardware implanted in a subject. In various embodiments, temporal measurement of the hardware strain includes monitoring changes of the resonant frequency of the sensor. The sensor can be realized as an inductively powered device that operates as an all-on-chip resonator, where the components of the sensor are biocompatible. Additional apparatus, systems, and methods are disclosed.

Claims

1. A method of monitoring changes in a hardware device using a sensor device mounted to the hardware device, which is implantable in a subject, the method comprising the steps of:

receiving signals from the sensor device, the sensor device having a sensing element that undergoes strain as the hardware device undergoes strain;

determining a shift in a resonant frequency of the sensing element of the sensor device based on the received signals over a period; and

determining a temporal change in strain of the hardware device based on the determined shift in the resonant frequency of the sensing element of the sensor device over the period.

2. The method of claim 1, further including the step of subjecting the sensor device to an alternating magnetic or electromagnetic field to generate the signals from the sensor device.

3. The method of claim 1, further including the step of determining a change in the subject based on the temporal change in strain of the hardware device.

4. The method of claim 1, further including the steps of:

inductively powering the sensor device with an alternating magnetic or electromagnetic field;

wirelessly sending the signals from the sensor device; and

determining the shift in the resonant frequency of the sensing element of the sensor device over the period based on the wirelessly received signals from the sensor device, wherein the hardware device is implanted in a biological subject.

5. The method of claim 4, wherein:

the resonant frequency of the sensing element of the sensor device is determined by inputting the received signals to a spectrum analyzer,

wherein the sensing element of the sensor device is configured to have a resonant frequency ranging from 50 MHz to 7 GHz at no load.

6. The method of claim 4, further including the step of determining a change in the biological subject based on the temporal change in strain of the hardware device.

7. The method of claim 4, wherein the temporal change in strain of the hardware device is determined using a strain-frequency calibration of the hardware device.

8. The method of claim 4, further including the step of monitoring surface bending strains of the hardware device.

9. The method of claim 4, wherein the hardware device includes a fracture fixation plate and the sensor is attached to a surface of the fracture fixation plate.

10. A sensor device comprising:

a substrate;

a dielectric material disposed over the substrate as a capacitor dielectric, the dielectric material being a solid material that undergoes strain as a structure on which it is mounted undergoes strain; and

at least one conductive coil disposed on the dielectric material,

wherein the dielectric material and the conductive coil are configured as a resonator and a strain gauge,

wherein the substrate, the dielectric material, and the conductive coil are configured as a biocompatible sensor device for implantation in a biological subject, and

wherein the sensor device is capable of being inductively powered without a power supply directly connected in the sensor device.

11. The sensor device of claim 10, wherein the substrate is configured as a flexible tape.

12. The sensor device of claim 10, wherein the sensor device includes a conductive layer between the substrate and the dielectric material and in contact with the substrate and the dielectric material.

13. The sensor device of claim 10, wherein the dielectric material is composed of silicon nitride and the conductive coil is composed of gold.

14. The sensor device of claim 10, wherein the resonator is composed of a metamaterial.

15. The sensor device of claim 10, wherein the conductive coil has one of a spiral, split-ring, or nested split-ring configuration.

16. The sensor device of claim 15, wherein the spiral configuration has a continuous length of conductive material with at least two spiral turns.

17. The sensor device of claim 15, wherein the nested split-ring configuration includes an inner square and an outer square, the outer square including a first break and the inner square including a second break, the first break being along a length of the outer square that is opposite a length of the inner square having the second break.

18. The sensor device of claim 17, wherein the sensor device includes an array of nested split-ring configuration.

19. The sensor device of claim 15, wherein the spiral coil configuration has at least two spiral turns.

20. The sensor device of claim 15, wherein the nested split-ring configuration has a plurality of rectangles with a common base side but having different heights, and each having a gap opposite the base side.

21. The sensor device of claim 10, wherein the sensor device includes an array of conductive coils.

22. The sensor device of claim 21, wherein the array of conductive coils includes at least two different coil configurations.

23. The sensor device of claim 10, wherein the resonator has a suspended resonator structure.

24. The sensor device of claim 10, wherein the conductive coil includes a triplet configuration.

25. The sensor device of claim 24, wherein each resonator of the triplet configuration is one of a rectangular spiral coil resonator, a circular spiral coil resonator, a suspended resonator, or a split-ring-resonator.

26. The sensor device of claim 10, wherein the sensor device is configured to have a resonant frequency ranging from 50 MHz to 7 GHz at no load.

27. An apparatus implantable in a biological subject, the apparatus comprising:

a hardware device; and

a sensor device attachable to or integral with the hardware device, the sensor device including;

a substrate; and

a dielectric material disposed over the substrate; and

at least one conductive coil disposed on the dielectric material,

wherein the dielectric material and the conductive coil are configured as a resonator,

wherein the substrate, the dielectric material, and the conductive coil are configured as a biocompatible sensor device for implantation in a biological subject, and

wherein the sensor device is inductively powered.

28. The apparatus of claim 27, wherein the substrate is attachable to the hardware device by an epoxy.

29. The apparatus of claim 27, wherein the hardware device includes a fracture fixation plate.

30. The apparatus of claim 27, wherein the substrate is configured as a flexible tape.

31. The apparatus of claim 27, wherein the dielectric material is composed of silicon nitride and the conductive coil is composed of gold.

32. The apparatus of claim 27, wherein the resonator is composed of a metamaterial.

33. The apparatus of claim 27, wherein the conductive coil has one of a spiral, split-ring, or nested split-ring configuration.

34. The apparatus of claim 27, wherein the sensor device is configured to have a resonant frequency ranging from 50 MHz to 7 GHz at no load.

35. A monitoring system comprising:

an apparatus implantable in a biological subject, the apparatus including a hardware device and a sensor device mounted to or integral with the hardware device;

an electromagnetic field generator configured to generate an electromagnetic field to power the sensor device;

a receiver for receiving signals from the sensor device generated in response to the sensor device being excited by electromagnetic fields;

a device for determining resonant frequency of the sensor from the received signals; and

an analyzer for determining a temporal change in strain of the hardware device based on a shift in resonant frequency of the sensor device over a period.

36. The monitoring system of claim 35, wherein the analyzer determines a change in the biological subject based on a temporal change in strain of the hardware device.

37. The monitoring system of claim 35, further including a machine-readable storage medium that stores instructions executable by a processor of the monitoring system, for carrying out the instructions to:

determine a resonant frequency of the sensor device;

determine the shift in the resonant frequency of the sensor device based on wireless signals from the sensor device, the wireless signals being generated from the sensor device in response to electromagnetic probe signals applied; and

determine a temporal change in strain of the hardware device based on the shift in resonant frequency of the sensor device over the period.

38. The monitoring system of claim 37, wherein machine-readable medium includes instructions to store data of a strain-frequency calibration of the hardware device.

39. The monitoring system of claim 37, wherein machine-readable medium includes instructions to generate data representing fracture healing of the biological subject, the data based on the temporal changes in strain of the hardware implanted in the biological subject relative to the fracture.

40. The monitoring system of claim 35, wherein the analyzer includes memory to store data of a strain-frequency calibration of the hardware device.

41. The monitoring system of claim 35, further including a memory device that stores data representing fracture healing of the biological subject, the data being based on the temporal changes in strain of the hardware device implanted in the biological subject relative to the fracture.

42. A method of manufacturing a hardware device implantable in a subject, the method comprising the steps of:

fabricating a biocompatible sensor for measuring a change in strain the hardware device; and

disposing the biocompatible sensor on the hardware device.

43. The method of claim 42, wherein the biocompatible sensor is an inductively powered device.

44. The method of claim 42, wherein the sensor is configured to have a resonant frequency ranging from 50 MHz to 7 GHz at no load.

45. The method of claim 42, wherein the fabricating step comprises the steps of:

disposing a dielectric material on a substrate;

forming a conductive coil on the dielectric material,

wherein the dielectric material and the conductive coil are configured as a resonator that outputs signals when excited with a magnetic or electromagnetic field.

46. A sensor device comprising:

a substrate;

a dielectric material disposed over the substrate; and

at least one conductive coil disposed on the dielectric material,

wherein the dielectric material and the conductive coil are configured as a resonator,

wherein the sensor is inductively powered,

wherein the sensor device wirelessly outputs signals corresponding to a resonant frequency of the sensor device, and

wherein the resonant frequency shifts in correspondence with strain applied to the resonator.

47. The sensor device of claim 46, wherein the sensor device is configured to have a resonant frequency ranging from 50 MHz to 7 GHz at no load.

48. A monitoring system comprising:

a sensor device mountable to a structural member;

an electromagnetic field generator configured to generate an electromagnetic field to power the sensor device;

a receiver for receiving signals from the sensor device generated in response to the sensor device being excited by electromagnetic fields;

a device for determining resonant frequency of the sensor from the received signals; and

an analyzer for determining strain applied to sensor device based on the resonant frequency of the sensor device.

49. The monitoring system of claim 48, wherein the sensor device is configured to have a resonant frequency ranging from 50 MHz to 7 GHz at no load.