IMPLANTABLE BIOSENSOR WITH AUTOMATIC CALIBRATION

• US 20100228110A1
• Filed: 03/09/2010
• Published: 09/09/2010
• Est. Priority Date: 03/09/2009
• Status: Active Grant

• Current Assignee: Achilleas Tsoukalis
• Original Assignee: Achilleas Tsoukalis
• Inventors: TSOUKALIS, ACHILLEAS
• Granted Patent: US 8,548,552 B2
• Time in Patent Office: Days
• US Class Current: 600/347
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2562/028 Microscale sensors, e.g. electromechanical sensors [MEMS]
• CPC Class Codes: A61B 5/14528 invasively
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/685 Microneedles
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence

Abstract

Implantable self-calibrating biosensor Subcutaneously or intracorporeally implantable biosensor, characterized by a closed microfluidic circuit with calibrating fluids, which communicates by a backward micro-dialysis logic with the exterior of said circuit, an open and in contact with the tissues and the interstitial fluid working electrode, for its self-calibration. One or more working electrodes may be positioned inside openable boxes from EAP, and be opened for the duration of the measurement and closed immediately after, succeeding one another in the measurement, as their sensitivity is diminished.

Claims

1. Self-calibrating disposable biosensor comprising an electronic part and an electrochemical part, wherein the electrochemical part comprises

a microfluidic circuit (8, 9) for the circulation of at least one calibration fluid, and

two or three electrodes (1,2,3) arranged on the exterior of the microfluidic circuit (8, 9), one of the electrodes being a working electrode (1) comprising porous bio-chemical sensing materials (30-32), in contact with living tissues after the implantation, characterized by means for diffusion communication (4) of the internal microfluidic circuit (8,9) with the exterior.

2. Biosensor as in claim 1, wherein in the disposable nonimplantable extracorporeal part (40) comprises bags (5,6) with or without a protective metal cover, the bags containing calibration and draining fluids, a drain vessel (7) and pumps and flow control valves and contacts with the permanent electronic part both for the measurement and for the control of the calibration microflow, or alternatively the whole circuit of bag pumping and measuring electronics consists of an electromechanical MEMS circuit and/or of an electromechanical autonomous circuit.

3. Biosensor as in claim 1 for measuring glucose, wherein the working electrode (1) comprises a conductive base made preferably of carbon or ferrocyanide/carbon or platinum or gold (29), nanofibers (30) with embedded immobilized glucose oxidase (31) and a coating of biomimetically synthesized silicon dioxide matrix (32).

4. Biosensor as in claim 1, wherein in the interior microfluidic circuit (8, 9) intermittently one or more glucose solutions and fluids without glucose can be circulated for the self-calibration with a curve of two or more points of the sensor.

5. Biosensor as in claim 1, wherein the pumping of the microflow and the selection of the circulating fluid is effected through pumping fingers and valves (10-14) of electroactive polymers.

6. Biosensor as in claim 1, wherein the electronic part comprises a processing section comprising neural networks capable of processing the glucose measurement in the subcutaneous tissue taking into account the insulin injection and of putting out a prediction of venal blood glucose concentration, current and 30 minutes, for triggering alerts.

7. Biosensor as in claim 6, wherein the processing section comprises means for current glucose prediction, those means allowing for algebraic addition of the concentration prediction by means of the kinetics of meal digestion and of the prediction of the consumption kinetics during and after exercise, to obtain a global blood glucose concentration prediction for triggering alarms and calculating the closed-loop injection.

8. Biosensor as in claim 7, wherein the processing section comprises means for feeding differences between the predicted blood glucose value and the desired glucose value preferably to a PID (proportional/Integral/Differential) algorithm to obtain the corresponding insulin injection correction and the robotic (closed loop) insulin injection correction.

9. Biosensor as in claim 1 further comprising a mechanical introducer for the implantation.

10. Implantable device comprising a plurality of biosensors comprising at least one biosensor according to claim 1, wherein each sensor comprises a lid, preferably of electroactive polymers, the lids being capable of exposing only the currently active sensor for a short interval, necessary for a measurement or a calibration and remaining closed for most of the day, while the others remaining hermetically closed till replacing the active one and wherein said lids can have a protective filter to avoid the introduction of larger than desired particles or molecules.

11. Implantable artificial pancreas comprising

a sensor according to claim 1,

means for closed-loop injection algorithms,

vessels for insulin, aqueous buffer, calibration and corrective injection glucose solution, those vessels being arranged at different heights, the vessels being elastic or collapsible bags, and

insulin-injection dual pumps effecting the transport of insulin injection and calibration fluids and the drainage of calibration wastes.

12. Implantable artificial pancreas according to claim 11, comprising a filling pumping system comprising a multilumen catheter which has at its end a needle with position sensors for assessing the correct position of the needle, the multilumen having holes at various heights provided with valves allowing for communication with the vessels of the artificial pancreas and interruption of the fluid transport from and toward the artificial pancreas in the event of the identification of an error by said sensors.