Sensor apparatus and method of making same

Patent metadata

Field	Value
Publication number	US-2022323005-A1
Application number	US-202016910740-A
Country	US
Kind code	A1
Filing date	Jun 24, 2020
Priority date	Oct 13, 2017
Publication date	Oct 13, 2022
Grant date	—

Abstract

A sensor apparatus includes at least one substrate layer of an elastically deformable material, the substrate layer extending longitudinally between spaced apart ends thereof. A conductive layer is attached to and extends longitudinally between the spaced apart ends of the at least one substrate layer. The conductive layer includes an electrically conductive material adapted to form a strain gauge having an electrical resistance that varies based on deformation of the conductive layer in at least one direction.

First claim

What is claimed is:

1 . A sensor apparatus comprising:
at least one substrate layer of an elastically deformable material, the substrate layer extending longitudinally between spaced apart ends thereof; and a conductive layer attached to and extending longitudinally between the spaced apart ends of the at least one substrate layer, the conductive layer including an electrically conductive material adapted to form a strain gauge having an electrical resistance that varies based on deformation of the conductive layer in at least one direction.

2 . The sensor apparatus of claim 1 , wherein the at least one substrate layer further comprises a plurality of substrate layers of the elastically deformable material, the conductive layer being sandwiched between at least two substrate layers.

3 . The sensor apparatus of claim 2 , wherein the elastically deformable material comprises polydimethylsiloxane (PDMS), and the electrically conductive material comprises electrically conductive particles integrated with PDMS.

4 . The sensor apparatus of claim 2 , wherein the plurality of substrate layers and the conductive layer are configured to exhibit anisotropic compliance a given direction and direction transverse to the given direction.

5 . The sensor apparatus of claim 4 , wherein each of the substrate layers and the conductive layer includes a plurality of substantially parallel strands of its material arranged in a direction that is parallel or transverse to the given direction, the direction of the strands and spacing between strands in each respective layer defining the anisotropic compliance of the apparatus along respective strand directions.

6 . The sensor apparatus of claim 4 , wherein the given direction is longitudinal or radial.

7 . The sensor apparatus of claim 1 , wherein the conductive layer further comprises:
at least one conductive strip extending along a path between the apart ends of the conductive layer; and electrical contacts at ends of the conductive strip.

8 . The sensor apparatus of claim 7 , further comprising a measurement system coupled to the electrical contacts and adapted to provide a measure of the electrical resistance between the electrical contacts.

9 . The sensor apparatus of claim 8 , further comprising a wireless transmitter to communicate sensor data based on the measure of the electrical resistance between the electrical contacts.

10 . The sensor apparatus of claim 7 , wherein the path of the conductive strip comprises a zig-zag pattern extending between the spaced apart ends of the conductive layer.

11 . The sensor apparatus of claim 1 , wherein the layers circumscribe a central axis to form a cylindrical sensor body such that the deformation of the conductive layer corresponds to radial expansion or contraction of the cylindrical sensor body.

12 . A graft comprising the sensor apparatus of claim 11 , the graft including an annular sidewall, the sensor apparatus attached to and extending circumferentially along the annular sidewall of the graft.

13 . The sensor apparatus of claim 1 , wherein the at least one substrate layer includes a contact surface adapted to attach to a three-dimensional surface and deform commensurately with deformation of the three-dimensional surface.

14 . The sensor apparatus of claim 1 , wherein the at least one substrate layer is a graft and the conductive layer disposed on a surface of the graft.

15 . A method of sensing a biological function, the method comprising mounting the sensor apparatus of claim 1 to circumscribe a tubular structure such that the deformation of the conductive layer corresponds to radial expansion or contraction of the tubular structure responsive to a biological function, wherein the tubular structure is a graft or biological tissue.

16 . A method of making a sensor device, comprising:
providing a substrate layer of an elastically deformable material, the substrate layer extending longitudinally between spaced apart ends thereof; and forming a conductive layer onto a surface of the substrate layer, the conductive layer extending longitudinally between the spaced apart ends of the substrate layer, the conductive layer including an electrically conductive material adapted to form a strain gauge having an electrical resistance that varies based on deformation of the conductive layer in at least one direction.

17 . The method of claim 16 , further comprising forming at least one other substrate layer over the conductive layer such that the conductive layer is sandwiched between at least two substrate layers, wherein the substrate layers and the conductive layer are configured to exhibit anisotropic compliance a given direction and direction transverse to the given direction.

18 . The method of claim 17 , wherein each of the substrate layers and the conductive layer is formed by extruding a plurality of substantially parallel strands of its material arranged in a direction that is parallel or transverse to the given direction, wherein a direction and spacing between strands in each respective layer determines the anisotropic compliance of the apparatus along respective strand directions.

19 . The method of claim 16 , wherein the elastically deformable material comprises polydimethylsiloxane (PDMS), and
wherein the electrically conductive material comprises electrically conductive particles integrated within PDMS.

20 . The method of claim 16 , further comprising mounting the sensor apparatus to an outer surface of biological tissue.

21 . The method of claim 16 , further comprising mounting the sensor device around a cylindrical sidewall of an annular graft.

22 . The method of claim 16 , wherein the substrate layer is a graft, the method including disposing the conductive layer directly on a surface of the graft.

Assignees

• Univ Case Western Reserve

Inventors

• Majerus Steve Ja
• Dunning Jeremy
• Bogie Katherine M
• Potkay Joseph A

Classifications

• A61B5/02141

  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 title

• A61B5/6876

  Blood vessel · CPC title

• A61B5/026

  Measuring blood flow {(A61B3/1233, A61B3/1241 take precedence)} · CPC title

• A61B2562/12

  Manufacturing methods specially adapted for producing sensors for in-vivo measurements · CPC title

• A61B5/683 Primary

  Means for maintaining contact with the body (A61B5/6802 takes precedence) · CPC title