POLYMER-BASED CARDIOVASCULAR BIOSENSORS, MANUFACTURE, AND USES THEREOF

• US 20080302675A1
• Filed: 06/06/2008
• Published: 12/11/2008
• Est. Priority Date: 06/06/2007
• Status: Abandoned Application

• Current Assignee: University of Southern California
• Original Assignee: University of Southern California
• Inventors: Kim, Eun Sok, Hsiai, Tzung K., Yu, Hongyu, Ai, Lisong
• Application Number:
  US12/134,938
• Publication Number:
  US 20080302675A1
• Time in Patent Office: Days
• US Class Current: 205/777.5
• CPC Class Codes: A61B 2562/0261 Strain gauges
• CPC Class Codes: A61B 2562/0271 Thermal or temperature sensors
• CPC Class Codes: A61B 2562/12 Manufacturing methods specially adapted for producing sensors for in-vivo measurements
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61B 2562/222 Electrical cables or leads therefor, e.g. coaxial cables or ribbon cables
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/02141 Details of apparatus construction, e.g. pump units or housings therefor, cuff pressurising systems, arrangements of fluid conduits or circuits A61B5/02233, A61B5/0235 take precedence
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/02156 Calibration means
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/027 using catheters
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: A61M 2025/0002 with a pressure sensor at the distal end
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: B05D 7/50 Multilayers
• CPC Class Codes: G01K 13/20 Clinical contact thermometers for use with humans or animals

Abstract

A flexible, polymer-based biosensor deployable into the arterial system which can assess shear stress in the arterial geometry in the presence of time-varying component of blood flow. Also, a method of fabricating a biosensor which may be used for in vivo procedures, involving the sequential depositing onto a substrate of a silicon dioxide layer, a metal heating element on the silicon dioxide layer, and a biocompatible polymer on the heating element, followed by etching the polymer layer to provide holes to allow for electrode contact with the heating element. A second metal layer is then deposited to form electrodes, followed by a second biocompatible polymer layer to form the device structure and removing the fabricated biosensor from the substrate by etching the substrate. In addition, a method of determining intravascular shear stress by measuring the temperature, flow rate and pressure of a bodily fluid with a biocompatible biosensor is disclosed.

Claims

1. A biosensor comprising:

a sensing element;

a first and a second metal electrode both of which are in contact with the sensing element; and

a biocompatible polymer layer encompassing the first and second electrodes.

2. The biosensor of claim 1, wherein the sensing element further comprises a heating element.

3. The biosensor of claim 1, wherein the biocompatible plastic resin layer is comprised of at least one from the group of poly p-chloroxylylene, polyamide, polyimide, polyurethane, and epoxide resin.

4. The biosensor of claim 1, wherein the biocompatible plastic resin layer is comprised of poly-p-chloroxylylene.

5. The biosensor of claim 1, further comprising:

a center signal wire in contact with the first electrode;

an insulating layer encompassing the periphery of the center signal wire;

a metal ground in contact with the second electrode and encompassing the periphery of the insulating layer; and

a biocompatible polymer layer encompassing the periphery of the metal ground.

6. The biosensor of claim 5, wherein the sensing element is attached to the center signal wire with a conductive biocompatible polymer.

7. The biosensor of claim 6, wherein the sensing element is further attached to the metal ground with conductive biocompatible polymer.

8. The biosensor of claim 6, wherein the conductive biocompatible polymer is comprised of conductive epoxy resin.

9. The biosensor of claim 7, wherein the conductive biocompatible polymer is comprised of conductive epoxy resin.

10. A method of manufacturing a biosensor comprising the steps of:

a) depositing a silicon oxide layer on a substrate;

b) depositing and patterning a first metal sensor on the silicon oxide layer;

c) depositing a first plastic resin layer on the metal sensor;

d) etching at least two through holes in the first plastic resin layer;

e) depositing a second metal layer on the plastic resin layer such that a portion of the second metal layer contacts the first metal layer and a portion of the second metal layer contacts the plastic resin layer; and

f) depositing a second plastic resin layer over the second metal layer.

11. The method of manufacturing a biosensor in accordance with claim 10, further comprising the step of:

g) separating the substrate from the silicon oxide layer.

12. The method of manufacturing a biosensor according to claim 10, wherein the substrate is comprised of silicon or silicon and an insulating material.

13. The method of manufacturing a biosensor according to claim 10, wherein the first metal layer is comprised of Pt and Ti.

14. The method of manufacturing a biosensor according to claim 10, wherein the second metal layer is comprised of Au and Cr.

15. The method of manufacturing a biosensor according to claim 10, wherein the metal sensor further comprises a heating element.

16. The method of manufacturing a biosensor according to claim 14, wherein the second metal layer is in direct contact with the first metal layer.

17. A method of measuring the temperature of bodily fluid comprising the steps of:

a) equipping the inner portion of a catheter with a biosensor capable of measuring electrical resistance in a living organism;

b) inserting the catheter into a living organism;

c) cannulating the biosensor attached to a terminal end of a coaxial wire through the catheter into direct contact with the bodily fluid;

d) determining the temperature of the bodily fluid by converting the electrical resistance measured into temperature based on a coefficient of resistance of the biosensor.

18. The method of measuring the temperature of bodily fluid according to claim 17, wherein in step a) the biosensor is attached to the terminal end of a coaxial wire with a biocompatible polymer insulating layer.

19. The method of measuring the temperature of bodily fluid according to claim 17, further comprising a step e) of determining the flow rate of the bodily fluid by calibrating the resistance measurement with flow rate.

20. The method of measuring the temperature of bodily fluid according to claim 17, further comprising a step f) of determining the pressure of the bodily fluid by calibrating the resistance measurement with pressure.