Generic integrated implantable potentiostat telemetry unit for electrochemical sensors

• US 6,366,794 B1
• Filed: 11/19/1999
• Issued: 04/02/2002
• Est. Priority Date: 11/20/1998
• Status: Expired due to Fees

• Current Assignee: Precision Control Design Incorporated, University of Connecticut (State of Connecticut)
• Original Assignee: University of Connecticut (State of Connecticut)
• Inventors: Moussy, Francis, Conlan, Robert W., Beach, Richard D., Godwin, Markham C.
• Primary Examiner(s): Nasser, Robert S.
• Application Number:
  US09/443,764
• Time in Patent Office: 865 Days
• Field of Search: 600/345-350, 600/365
• US Class Current: 600/345
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61L 2300/00 Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/14 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence
• CPC Class Codes: C08L 27/12 containing fluorine atoms
• CPC Class Codes: C08L 33/14 of esters containing halogen, nitrogen, sulfur, or oxygen atoms in addition to the carboxy oxygen
• CPC Class Codes: C08L 39/06 Homopolymers or copolymers of N-vinyl-pyrrolidones
• CPC Class Codes: C08L 89/00 Compositions of proteins; Compositions of derivatives thereof foodstuff preparations A23J3/00

Abstract

A generic implantable puck that can be used with a number of biosensor configurations. This generic implantable potentiostat telemetry unit (the puck) can also be part of a system to detect glucose concentrations. An electrochemical system partially implantable into a body for detecting glucose concentrations therein is presented. The system comprises an electrochemical sensor, a transmitting puck including an electric circuit connected to the electrochemical sensor for transmitting a signal indicative of the glucose concentrations in the body. There is at least one receiver for receiving the signal from the transmitting puck and a computer system coupled tlo the at least one receiver for processing the signal for patient diagnosis and treatment.

Claims

1. An electrochemical system for detecting glucose concentrations in a body, the system comprising:

an electrochemical sensor for implantation into the body including at least one electrode;

a telemetry unit for implantation into the body including an electric circuit having a first operational amplifier having a first output terminal connected to a first electrode of the at least one electrode, means for switching the electric circuit between a potentiostat circuit and a galvanostat circuit providing thereby an excitation voltage to a first electrode of the at least one electrode of the electrochemical sensor and generating thereby a first signal indicative of glucose concentrations;

wherein the first operational amplifier includes first and second input terminals connected to means for switching the electric circuit between a potentiostat circuit and a galvanostat circuit and a first feedback circuit having at least one electric device therein connected to a second electrode of the at least one electrode, the second input terminal and means for switching means the electric circuit between a potentiostat circuit and a galvanostat circuit;

at least one signal converter connected to means for switching the electric circuit between a potentiostat circuit and a galvanostat circuit;

a microprocessor connected to means for switching the electric circuit between a potentiostat circuit and a galvanostat circuit and to the at least one signal converter for controlling switching the electric circuit between a potentiostat circuit and a galvanostat circuit;

at least one receiver for receiving the signal from the telemetry unit; and

a power supply for energizing the electric circuit.

2. The electrochemical system as set forth in claim 1 further comprising:

a second operational amplifier having

a third input terminal connected to a third electrode of the at least one electrode,

a fourth input terminal connected to the at least one signal converter, a second output terminal; and

a second feedback circuit having at least one electric device therein connected to the second output terminal, the third input terminal and the microprocessor.

3. The electrochemical system as set forth in claim 2 wherein the first feedback circuit is a negative feedback circuit including a direct connection from the first output terminal to the second input terminal.

4. The electrochemical system as set forth in claim 2 wherein the first feedback circuit is a negative feedback circuit including a first resistor connected to the second input terminal and the second switch.

5. The electrochemical system as set forth in claim 2 wherein the second feedback circuit is a negative feedback circuit including a second resistor connected to the second output terminal and the third input terminal.

6. The electrochemical system as set forth in claim 5 wherein the second resistor is controlled by the microprocessor.

7. The electrochemical system as set forth in claim 2 wherein the second electrode of the at least one electrode is an auxiliary electrode.

8. The electrochemical system as set forth in claim 2 wherein the second electrode of the at least one electrode is a reference electrode.

9. The electrochemical system as set forth in claim 2 wherein the second electrode of the at least one electrode is a working electrode and the third input terminal is disconnected from the third electrode.

10. The electrochemical system as set forth in claim 1 wherein the electric circuit further comprises a filter circuit connected to the potentiostat circuit and the at least one signal converter.

11. The electrochemical system as set forth in claim 10 wherein the filter circuit is a low pass filter circuit.

12. The electrochemical system as set forth in claim 11 wherein the filter circuit comprises:

a first operational amplifier having

a first output terminal connected to the at least one signal converter;

a first input terminal;

a second input terminal

a first feedback circuit having at least one electrical device therein connected to the first output terminal and the first input terminal;

a second feedback circuit having at least one electrical device therein connected to the first output terminal and the second input terminal.

13. The electrochemical system as set forth in claim 12 wherein the first feedback circuit is a negative feedback circuit.

14. The electrochemical system as set forth in claim 12 wherein the first feedback circuit comprises a direct connection.

15. The electrochemical system as set forth in claim 12 wherein the second feedback circuit is a positive feedback circuit.

16. The electrochemical system as set forth in claim 12 wherein the second feedback circuit comprises:

a first capacitor connected to the second input terminal and a first reference voltage;

a first resistor connected to the second input terminal,

a second capacitor connected to the first output terminal and the first resistor; and

a second resistor connected to the first resistor and the second capacitor.

17. The electrochemical system as set forth in claim 1 wherein the electric circuit further comprises a transmitter connected to the microprocessor for transmitting a signal indicative of glucose concentrations.

18. The electrochemical system as set forth in claim 17 further comprising a computer system coupled to the at least one receiver for processing the signal indicative of glucose concentrations.

19. The electrochemical system as set forth in claim 18 wherein the at least one receiver comprises a radio frequency receiver for receiving a serial data signal.

20. The electrochemical system as set forth in claim 18 wherein the computer system comprises a computer network for processing the serial data signal.

21. The electrochemical system as set forth in claim 17 wherein the transmitter comprises a radio frequency transmitter for transmitting a serial data signal.

22. The electrochemical system as set forth in claim 1 wherein the potentiostat circuit comprises:

a first operational amplifier connected to the power supply and the electrochemical sensor for maintaining the first electrode of the electrochemical sensor at a substantially constant excitation voltage;

a second operational amplifier connected to the power supply and the electrochemical sensor for converting the sensor current into an output voltage;

an optocoupler connected to the second operational amplifier for converting the output voltage into a changing resistance value; and

a transmitter for transmitting the resistance value to the receiver.

23. The electrochemical system as set forth in claim 22 wherein the power supply comprises:

a first switch having an open and closed position;

a battery connected to the first switch and a first reference voltage; and

a voltage converter connected to a second and third reference voltage.

24. The electrochemical system as set forth in claim 23 wherein the first feedback circuit comprises a direct connection.

25. The electrochemical system as set forth in claim 23 wherein the second operational amplifier comprises:

a third input lead;

a fourth input lead connected to a fourth reference voltage;

a second output lead;

a second switch connected to the third input lead and a second electrode of the electrochemical sensor;

the second switch having an open and closed position;

a third switch connected to the second output lead and the optocoupler;

the third switch having an open and closed position;

a second feedback circuit connected to the second output lead and the third input lead; and

an offset voltage compensation circuit connected to the third input lead and a fifth reference voltage.

26. The electrochemical system as set forth in claim 25 wherein the second feedback circuit comprises a first electrical device in parallel with a second electrical device.

27. The electrochemical system as set forth in claim 26 wherein the first electrical device is a capacitor.

28. The electrochemical system as set forth in claim 26 wherein the second electrical device is a resistor.

29. The electrochemical system as set forth in claim 25 wherein the offset voltage compensation circuit comprises:

a fourth switch connected to the third input lead; and

a variable resistor connected to the fourth switch and the fifth reference voltage.

30. The electrochemical system as set forth in claim 25 wherein the third input lead is an inverting input lead and the fourth input lead is a noninverting input lead.

31. The electrochemical system as set forth in claim 30 wherein the fourth input terminal is at electrical ground.

32. The electrochemical system as set forth in claim 31 wherein the fifth reference voltage is approximately 1.2 volts.

33. The electrochemical system as set forth in claim 22 wherein the first operational amplifier comprises:

a first input lead;

a second input lead;

a first output lead connected to a first electrode of the electrochemical sensor;

a first feedback circuit connected to the first input lead and the first output lead; and

a first potentiometer connected to a first reference voltage, the second input lead and a second reference voltage.

34. The electrochemical system as set forth in claim 33 wherein the first potentiometer comprises a voltage divider connected to a reference voltage, the second input lead and the second reference voltage.

35. The electrochemical system as set forth in claim 33 wherein the first reference voltage is approximately 1.2 volts and the second reference voltage is electrical ground.

36. The electrochemical system as set forth in claim 33 wherein the first input lead is an inverting input lead and the second input lead is a noninverting lead.

37. The electrochemical system as set forth in claim 22 wherein the optocoupler comprises:

a first optical device for generating an optical signal;

a second optical device responsive to the optical signal connected to the transmitter.

38. The electrochemical system as set forth in claim 1 wherein the at least one electrode of the electrochemical sensor comprises a platinum electrode.

39. The electrochemical system as set forth in claim 1 wherein the at least one electrode of the electrochemical sensor is a silver/silver chloride electrode.

40. A telemetry unit for implantation into a body connected to an electrochemical system having at least one electrode therein for detecting analyte concentrations, the telemetry unit comprising:

an electric circuit convertible between a potentiostat circuit and a galvanostat circuit connected to the electrochemical sensor for providing an excitation voltage to a first electrode of the at least one electrode of the electrochemical sensor and generating thereby a first signal indicative of analyte concentrations;

at least one signal converter connected to the convertible electric circuit;

a microprocessor connected to the convertible electric circuit and the at least one signal converter; and

a power supply for energizing the electric circuit.

41. The telemetry unit as set forth in claim 40 wherein the electric circuit comprises:

a first operational amplifier having

a first output terminal connected to a first electrode of the at least one electrode,

a first switch having at least one position connected to the at least one signal converter,

a second switch having at least one position connected to the at least one signal converter,

a first input terminal connected to the first switch, a second input terminal,

a first feedback circuit having at least one electric device therein connected to a second electrode of the at least one electrode, the second input terminal and the second switch; and

a second operational amplifier having

a third input terminal connected to a third electrode of the at least one electrode,

a fourth input terminal connected to the at least one signal converter,

a second output terminal and

a second feedback circuit having at least one electric device therein connected to the second output terminal, the third input terminal and the microprocessor.

42. The telemetry unit as set forth in claim 41 wherein the first feedback circuit is a negative feedback circuit including a direct connection from the first output terminal to the second input terminal.

43. The telemetry unit as set forth in claim 41 wherein the first feedback circuit is a negative feedback circuit including a first resistor connected to the second input terminal and the second switch.

44. The telemetry unit as set forth in claim 41 wherein the second feedback circuit is a negative feedback circuit including a second resistor connected to the second output terminal and the third input terminal.

45. The telemetry unit as set forth in claim 44 wherein the second resistor is controlled by the microprocessor.

46. The telemetry unit as set forth in claim 41 wherein the second electrode of the at least one electrode is an auxiliary electrode.

47. The telemetry unit as set forth in claim 41 wherein the second electrode of the at least one electrode is a reference electrode.

48. The telemetry unit as set forth in claim 41 wherein the second electrode of the at least one electrode is a working electrode and the third input terminal is disconnected from the third electrode.

49. The telemetry unit as set forth in claim 40 wherein the electric circuit further comprises a filter circuit connected to the potentiostat circuit and the at least one signal converter.

50. The telemetry unit as set forth in claim 40 wherein the electric circuit further comprises a transmitter connected to the microprocessor for transmitting a signal indicative of analyte concentrations.

51. A telemetry unit for implantation into a body connected to an electrochemical system having at least one electrode therein for detecting glucose concentrations, the telemetry unit comprising:

an electric circuit convertible between a potentiostat circuit and a galvanostat circuit connected to the electrochemical sensor for providing an excitation voltage to a first electrode of the at least one electrode of the electrochemical sensor and generating thereby a first signal indicative of analyte concentrations;

at least one signal converter connected to the convertible electric circuit;

a microprocessor connected to the convertible electric circuit and the at least one signal converter; and

a power supply for energizing the electric circuit.

52. An electrochemical system for detecting analyte concentrations in a body, the system comprising:

an electrochemical sensor for implantation into the body including at least one electrode;

a telemetry unit for implantation into the body including an electric circuit having a first operational amplifier having a first output terminal connected to a first electrode of the at least one electrode, means for switching the electric circuit between a potentiostat circuit and a galvanostat circuit providing thereby an excitation voltage to a first electrode of the at least one electrode of the electrochemical sensor and generating thereby a first signal indicative of glucose concentrations;

wherein the first operational amplifier includes first and second input terminals connected to means for switching the electric circuit between a potentiostat circuit and a galvanostat circuit and a first feedback circuit having at least one electric device therein connected to a second electrode of the at least one electrode, the second input terminal and means for switching means the electric circuit between a potentiostat circuit and a galvanostat circuit;

at least one signal converter connected to means for switching the electric circuit between a potentiostat circuit and a galvanostat circuit;

a microprocessor connected to means for switching the electric circuit between a potentiostat circuit and a galvanostat circuit and to the at least one signal converter for controlling switching the electric circuit between a potentiostat circuit and a galvanostat circuit;

at least one receiver for receiving the signal from the telemetry unit; and

a power supply for energizing the electric circuit.