SENSING AND ACTUATION OF BIOLOGICAL FUNCTION USING ADDRESSABLE TRANSMITTERS OPERATED AS MAGNETIC SPINS

• US 20150153319A1
• Filed: 12/04/2014
• Published: 06/04/2015
• Est. Priority Date: 12/04/2013
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: SHAPIRO, Mikhail, EMAMI, Azita, MONGE OSORIO, Manuel Alejandro
• Granted Patent: US 9,915,641 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0522 Magnetic induction tomography
• CPC Class Codes: A61B 5/073 Intestinal transmitters
• CPC Class Codes: G01N 33/483 Physical analysis of biological material
• CPC Class Codes: G01R 33/066 field-effect magnetic sensors, e.g. magnetic transistor
• CPC Class Codes: G01R 33/077 Vertical Hall-effect devices
• CPC Class Codes: G01R 33/1269 of molecules labeled with magnetic beads magnetic particles for bio assay G01N33/54326
• CPC Class Codes: G01R 33/1284 Spin resolved measurements; Influencing spins during measurements, e.g. in spintronics devices G01R33/093 takes precedence; semiconductor devices using spin polarized carriers H01L29/66984
• CPC Class Codes: H04B 1/40 Circuits

Abstract

Methods and apparatuses for sensing biological functions are disclosed. Sensors can be implanted in an organ, such as the brain, and a magnetic field gradient applied to the biological tissue. The field causes the sensors to have different resonant frequencies allowing their spatial localization. The sensors can harvest power from the external coils to be able to retransmit data.

Claims

1. A device comprising:

a substrate;

an antenna attached to a surface of the substrate, the antenna being substantially planar;

an oscillator circuit on the surface of the substrate;

a transmitter and receiver circuit on the surface of the substrate;

a control logic circuit on the surface of the substrate; and

at least one sensor on the surface of the substrate, the at least one sensor comprising at least one magnetic sensor,

wherein

the antenna is configured to transmit and receive electromagnetic waves at a first frequency and a first phase between the device and a communication device,

the transmitter and receiver circuit is configured to operate the antenna,

the at least one sensor is configured to sense an applied magnetic field, and to shift a transmitting or receiving frequency from the first frequency to a second frequency, or a transmitting or receiving phase from the first phase to a second phase, said shift being based on the applied magnetic field;

the dimensions of the antenna and the oscillator circuit are configured to allow spatial localization of the device when the device is within a magnetic field gradient.

2. The device of claim 1, further comprising a power harvesting configured to harvest power from said received electromagnetic waves.

3. The device of claim 1, wherein the oscillator circuit comprises a resistance, a capacitor, an inductor and at least one transistor.

4. The device of claim 1, wherein said shift of the transmitting or receiving frequency or said shift of the transmitting or receiving phase is monotonic with respect to the applied magnetic field.

5. The device of claim 1, wherein said shift of the transmitting or receiving frequency or said shift of the transmitting or receiving phase is linear with respect to the applied magnetic field.

6. The device of claim 1, wherein said shift of the transmitting or receiving frequency amounts to at least 1 ppm per Gauss and has a peak width of less than 160 ppm, thereby allowing a spatial resolution of 1 mm within a field gradient of 4000 Gauss per meter.

7. The device of claim 1, wherein said shift of the transmitting or receiving phase amounts to at least 0.2 rad, thereby allowing a spatial resolution of 1 mm within a field gradient of 4000 Gauss per meter.

8. The device of claim 2, wherein the power harvesting circuit is further configured to harvest power at the first frequency.

9. The device of claim 1, wherein the device is programmed to perform a desired action upon receiving a particular sequence of pulses at a resonant frequency.

10. The device of claim 1, wherein said electromagnetic waves have a frequency between 100 and 2000 MHz.

11. The device of claim 1, wherein the at least one magnetic sensor comprises a magnetic field effect transistor.

12. The device of claim 1, wherein the at least one magnetic sensor comprises horizontal and vertical Hall-plates.

13. The device of claim 1, wherein the at least one magnetic sensor comprises paramagnetic nanoparticles.

14. The device of claim 1, wherein the at least one magnetic sensor comprises a paramagnetic thin film.

15. The device of claim 1, wherein the device is further configured to lock to a transmitted base frequency and to maintain a resonance frequency at the transmitted base frequency during subsequent reception and transmission of said electromagnetic waves.

16. The device of claim 1, wherein the at least one magnetic sensor comprises a plurality of magnetic sensors.

17. The device of claim 1, wherein the at least one magnetic sensor is configured to calculate its orientation by independently sensing magnetic fields in two or three mutually perpendicular directions.

18. The device of claim 17, wherein the at least one magnetic sensor is further configured to calculate its orientation by sensing a temporal direction.

19. The device of claim 1, wherein the at least one sensor comprises a plurality of magnetic sensors in different locations of the surface of the substrate, and the device is configured to calculate its orientation by sensing the magnetic field gradient and readings from the plurality of magnetic sensors in the different locations.

20. The device of claim 1, wherein said shift of the transmitting or receiving frequency is based on a magnetic field in a first direction and said shift in the transmitting or receiving phase is based on a magnetic field in a second direction.

21. The device of claim 1, further comprising a phase locked loop configured to keep its oscillation frequency for 4 ms after a reference signal is removed.

22. The device of claim 1, wherein the antenna is a metallic strip formed in a substantially square shape with a gap in one edge of the square shape.

23. The device of claim 1, wherein the device is encapsulated in a biological-compatible material.

24. The device of claim 1, wherein the oscillator circuit is configured to change its resonance frequency upon application of a magnetic field.

25. The device of claim 23, wherein the device is located within a biological tissue and the communication device is located externally to the biological tissue.

26. The device of claim 23, wherein the at least one sensor comprises at least one non-magnetic sensor, the at least one non-magnetic sensor being configured to sense a biological function.

27. The device of claim 1, wherein the at least one sensor comprises at least one sensor configured to sense a non-biological function.

28. The device of claim 1, wherein the electromagnetic waves transmitted to the communication device are modulated so as to contain information about the sensed biological function.

29. The device of claim 25, wherein the device is further configured to be swallowed or injected.

30. The device of claim 1, wherein the oscillator circuit comprises a resistance, a capacitor and at least one transistor.

31. A system comprising the device of claim 1 and the communication device of claim 1, wherein the communication device comprises:

at least one magnetic field generator, configured to generate a linear or non linear magnetic field gradient; and

at least one radio frequency coil for transmitting and receiving electromagnetic waves.

32. The system of claim 31, wherein the at least one radio frequency coil comprises a coil for each desired direction of transmission and reception.

33. The system of claim 31, wherein the communication device further comprises a locating device for relating said shifts in the transmitting or receiving frequency or said shifts in the transmitting or receiving phase to a location in space for the device.

35. The method of claim 34, wherein the device comprises the device of claim 1.

38. The method of claim 37, wherein the plurality of devices comprises the device of claim 1.

34. A method to sense a biological function, the method comprising:

providing a device comprising

a sensor to sense the biological function,

an oscillator circuit configured to change its resonance frequency upon application of a magnetic field, and

a communication device external to the biological tissue and configured to communicate through electromagnetic waves with the device implanted in the biological tissue;

inserting the device in the biological tissue;

applying a magnetic field gradient to the device; and

spatially locating the device by its resonance frequency.

36. The method of claim 34, wherein the inserting the device in the biological tissue is carried out by implanting, swallowing or injecting.

37. A method to sense a biological function, the method comprising:

providing a system, the system comprising

a plurality of devices, each device comprising

a sensor configured to sense a biological function, and

an oscillator circuit configured to change a resonance frequency upon application of a magnetic field, and

a communication device external to a biological tissue and configured to communicate through electromagnetic waves with the plurality of devices implanted in the biological tissue;

inserting the plurality of devices in the biological tissue;

applying a magnetic field gradient to the plurality of devices; and

spatially locating each device of the plurality of devices by its resonance frequency.

39. The method of claim 37, wherein the inserting the plurality of devices in the biological tissue is carried out by implanting, swallowing or injecting.

40. A communication device, comprising:

an antenna;

an oscillator circuit;

a transmitter and receiver circuit configured to operate the antenna to transmit and receive electromagnetic waves at a first frequency and a first phase;

a control logic circuit; and

at least one sensor including at least one magnetic sensor configured to sense an applied magnetic field, the sensor being configured to shift a transmitting or receiving frequency from the first frequency to a second frequency or to shift a transmitting or receiving phase from the first phase to a second phase.