INTEGRATED SENSOR ASSEMBLY UNIT

Abstract

Sensor assembly comprising a first substrate, a second substrate and a sensor. The first substrate comprises at least one plurality of capillary bores defining a fluid path. The fluid path is extending through said first substrate from a top side to a fluid channel on a bottom side of said first substrate. The second substrate is arranged in connection with the first substrate and the fluid channel of the first substrate is in fluid communication with a first metallised via and a second metallised via formed in the second substrate. Thereby extending the fluid path through the first metallised via and the second metallised via. The sensor comprise a first electrode and a second electrode. The first electrode and the second electrode are arranged on the second substrate in fluid communication with the fluid channel of the first substrate. The first electrode is in electric contact with the first metallised via and the second electrode is in electric contact with the second metallised via.

Claims

1. A sensor assembly, comprising: a first substrate comprising at least one capillary bore defining a fluid path extending through said first substrate from a top side to a fluid channel on a bottom side of said first substrate; a second substrate arranged in connection with the first substrate, the fluid channel of the first substrate is in fluid communication with a first metallized via and a second metallized via formed in the second substrate, thereby extending the fluid path through the first metallized via and the second metallized via; a sensor comprising a first electrode and a second electrode arranged on the second substrate in fluid communication with the fluid channel of the first substrate; wherein the first electrode is in electric contact with the first metallized via and wherein the second electrode is in electric contact with the second metallized via.

2. A sensor assembly according to claim 1, wherein the first substrate comprise a plurality of bores.

3. A sensor assembly according to claim 1, further comprising: means for applying sub-pressure to the fluid path to draw fluid from the capillary bores towards the second substrate.

4. A sensor assembly according to claim 1, further comprising: a plurality of microneedles integrally formed on the first substrate, wherein each microneedle comprising: an elongated body extending from a distal end thereof with a bevel to a proximal end thereof on the first substrate along a longitudinal axis; wherein the capillary bores extend through the elongated body in a longitudinal direction thereof and further defining the fluid path; wherein the proximal end is integrally formed with the first substrate and the fluid path is in fluid communication with the fluid channel of the first substrate.

5. A sensor assembly according to claim 4, wherein the second substrate is arranged in connection with the first substrate on a side opposite the plurality of microneedles.

6. A sensor assembly according to claim 1, wherein the first electrode is shaped as a spiral and the second electrode is shaped as a spiral, and wherein the spiral shapes of the first and second electrodes are nested.

7. A sensor assembly according to claim 1, wherein the sensor is located on a side of the second substrate directed towards the first substrate.

8. A sensor assembly according to claim 1, wherein the sensor is at least partly located on the side of the second substrate that is directed towards the first substrate.

9. A sensor assembly according to claim 1, wherein the sensor is at least partly located in the first and second vias.

10. A sensor assembly according to claim 1, wherein the via further comprise a signal path extending through the second substrate and the sensor is arranged in electrical connection with the signal path.

11. A sensor assembly according to claim 1, wherein the via is hollow, thereby providing fluid communication between two opposite sides of the second substrate.

12. A sensor assembly according to claim 1, wherein the sensor is an electro-chemical sensor.

13. A sensor assembly according to claim 1, wherein the wall surface of the vias are hydrophilic.

14. A measurement device comprising a sensor assembly according to claim 1, further comprising a sub-pressurization device arranged in connection with the sensor assembly on a side opposite the at least one microneedle and in fluid communication with the via of the second substrate, thereby providing sub-pressure through the via and the fluid channel of the chip.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] A more thorough understanding of the abovementioned and other features and advantages of the present invention will be evident from the following detailed description of embodiments with reference to the enclosed drawings, on which:

[0052] FIG. 1 is a schematic cross section view of a sensor assembly.

[0053] FIG. 2a is a schematic perspective view of a sensor assembly shown from above with a plurality of microneedles.

[0054] FIG. 2b is a schematic perspective view of a sensor assembly shown from below.

[0055] FIG. 3 is a schematic perspective view of a cross section of a sensor assembly with a plurality of microneedles.

[0056] FIG. 4 is a cross-sectional view of a sensor assembly with a microneedle.

[0057] FIG. 5a is a cross-sectional view along the longitudinal axis of a microneedle according to an embodiment.

[0058] FIG. 5b is a cross-sectional view along the longitudinal axis of a microneedle according to an embodiment.

[0059] FIG. 5c is a cross-sectional view along the longitudinal axis of a microneedle according to an embodiment.

[0060] FIG. 6 is a bottom view of a chip.

[0061] FIG. 7 is a perspective top view of the second substrate with vias and a sensor.

[0062] FIG. 8 is a schematic cross section view of a sensor assembly having multiple bores and a plurality of microneedles.

DETAILED DESCRIPTION

[0063] The present invention is based on the insights disclosed. When examined carefully it's clear that the sensor assemblies in the prior art for sampling of bodily fluids either can't apply under-pressure or be provided in an integrated unit. Solution that are able to apply under-pressure rely on transfer of the sample to the sensing device. Similarly, solutions that are able to provide integrated units are not able to provide under-pressure. Under-pressure which improves or even is demanded for some samplings.

[0064] In order to combine the improved extraction of fluids such as ISF by use of an applied under-pressure with the improve usage that an integrated unit provides, an improved sensor assembly is described.

[0065] For increased understanding, some figures illustrates the substrates of the sensor assembly as separated, it is understood that substrates illustrated as separated typically is joint. For an example, the substrates may be joint by means of anodic/direct bonding, which provides a strong and fluid tight seal without the risk of clogging the fluid channels with adhesive. Other means of joining the substrates may be envisioned, such as clamping or by an adhesive.

[0066] FIG. 1 is a schematic cross section view of a sensor assembly 100 according to an embodiment of the present invention having a first substrate 110, a second substrate 120 and a sensor 130.

[0067] The first substrate 110 has a capillary bore 111 defining a fluid path 112 extending through said first substrate 110 from a top side 113 to a fluid channel 114 on a bottom side 115 of said first substrate 110.

[0068] The second substrate 120 is arranged in connection with the first substrate 110, the fluid channel 114 of the first substrate is in fluid communication with a first metallised via 121 and a second metallised via 122 formed in the second substrate 120, thereby extending the fluid path 112 through the first metallised via 121 and the second metallised via 122.

[0069] The sensor 130 comprising a first electrode and a second electrode is arranged on the second substrate 120 in fluid communication with the fluid channel 114 of the first substrate 110. The first electrode is in electric contact with the first metallised via 121 and the second electrode is in electric contact with the second metallised via 122.

[0070] The first metallised via 121 and the second metallised via 122 may be hollow, thereby providing fluid communication between two opposing sides of the second substrate 120.

[0071] The sides of the vias may further comprise a substance with a specified surface energy. By this, the flow behaviour of the fluid may be controlled by its interaction with the specified surface energy. For an example, the sides of the via may comprise a hydrophobic substance or a hydrophilic substance.

[0072] The interior dimensions and geometry of the bore may also be designed to allow capillary forces to act on liquid in part or all the way through the fluid channel of the sensor assembly 100. These capillary forces may be used together with an applied under-pressure.

[0073] In addition, the sensor assembly may further comprise means for applying under-pressure to the fluid path to draw fluid from the capillary bores towards the second substrate. An under-pressure may for example be created with a syringe connected to the fluid channel.

[0074] FIG. 2a is a schematic perspective view of a sensor assembly 200 shown from above. The sensor assembly 200 is having a first substrate 210, a second substrate 220 and a sensor 230. The first substrate 210 has a capillary bore 211, here shown on a microneedle, defining a fluid path extending through said first substrate 210 from a top side 213 to a fluid channel 214 on a bottom side of said first substrate 210. The first substrate is here shown with a plurality of microneedles. In other embodiments, the first substrate 210 may be without microneedles, the capillary bore 211 may then be located on the top side 213.

[0075] The second substrate 220 is illustrated at a distance from the first substrate 210, the fluid channel of the first substrate is in fluid communication with a first metallised via 221 and a second metallised via 222 formed in the second substrate 220, thereby extending the fluid path through the first metallised via 221 and the second metallised via 222.

[0076] The sensor 230 comprising a first electrode 231 and a second electrode 232 is arranged on the second substrate 220 in fluid communication with the fluid channel of the first substrate 210. The first electrode 231 is in electric contact with the first metallised via 221 and the second electrode 232 is in electric contact with the second metallised via 222.

[0077] The sensor assembly 200 may have one or a plurality of microneedles. The microneedles may be integrally formed on the first substrate 210. Each microneedle may comprise an elongated body extending from a distal end thereof to a proximal end thereof on the top side 213 of the first substrate 210 along a longitudinal axis. Each microneedle may further have a bevel at the distal end. The capillary bores may extend through the elongated body in a longitudinal direction thereof and further define the fluid path. The proximal end may be integrally formed with the first substrate 210 and the fluid path may be in fluid communication with the fluid channel 214 of the first substrate 210.

[0078] The sensor 230 is here illustrated on a side of the second substrate 220 that is directed towards the first substrate 210. In other examples, the sensor may comprise an elongated portion extending in the vias in the second substrate 220. For example, the sensor may be a electro chemical sensor.

[0079] The vias may each further comprise a signal path that may be extending through the second substrate 220. The sensor 230 may be arranged in electrical connection with the signal paths.

[0080] The first electrode 231 may be shaped as a spiral and the second electrode 232 may be shaped as a spiral, and wherein the spiral shapes of the first and second electrodes may be nested.

[0081] FIG. 2b is a schematic perspective view of a sensor assembly 200 shown from below. The sensor assembly 200 is having a first substrate 210, a second substrate 220 and a sensor.

[0082] The first substrate 210 has a capillary bore defining a fluid path extending through said first substrate 210 from a top side to a fluid channel 214, here shown as extending over a surface, on a bottom side 215 of said first substrate 210.

[0083] The second substrate 220 is illustrated at a distance from the first substrate 210, the fluid channel 214 of the first substrate is in fluid communication with a first metallised via 221 and a second metallised via 222 formed in the second substrate 220, thereby extending the fluid path through the first metallised via 221 and the second metallised via 222.

[0084] The sensor comprising a first electrode and a second electrode is arranged on the second substrate 220 in fluid communication with the fluid channel 214 of the first substrate 210. The first electrode is in electric contact with the first metallised via 221 and the second electrode is in electric contact with the second metallised via 222.

[0085] The fluid channel 214 on the backside of the first substrate 210 is shown in the figure. At least one fluid channel port on the backside of the first substrate 210 is connected between the fluid path through the first substrate to at least one fluid channel 214, thereby fluidly connecting the at least one capillary bores with the fluid channel 214. The at least one fluid channel 214 may for example be a network of interconnected channels. The fluid channel 214 may have a width that is larger than the depth of the fluid channel 214.

[0086] FIG. 3 is a schematic perspective view of a cross section of a sensor assembly 300 with a plurality of microneedles showing the fluid path of the sensor assembly. The sensor assembly 300 is having a first substrate 310, a second substrate 320 and a sensor.

[0087] The first substrate 310 has a plurality of capillary bores 311, here shown through a plurality of microneedles, defining a fluid path extending through said first substrate 310 from a top side 313 to a fluid channel 314 on a bottom side of said first substrate 310. In the present figure, the cross section of the fluid channel 314 can be seen.

[0088] The second substrate 320 and the sensor is arranged according to the previously presented figures.

[0089] The sensor assembly may also have a frame structure dimensioned to support the tip of a finger constructed as structure protruding along the longitudinal direction of the microneedles, and preferably having a diameter of less than 15 mm.

[0090] The sensor assembly may in some examples be at least partly surrounded by a frame structure dimensioned to support the tip of a finger. Thereby the skin of the tip of the finger may be supported and tensioned to facilitate penetration of the at least one microneedle into the skin.

[0091] The sensor assembly may also be protected by a surrounding structure protruding to at least the same plane as the tip of the needles enabling for instance handling of wafers in the case of MEMS manufacturing of the herein described chipset.

[0092] The sensor assembly may also have a surrounding structure that stretches the skin prior to penetration by the above mentioned plurality of needles.

[0093] An example of a surrounding frame structure 340 on the top side of the first substrate 310 is also illustrated in FIG. 3.

[0094] FIG. 4 is a cross-sectional view of a schematic sensor assembly 400 with a microneedle 416. The sensor assembly 400 is having a first substrate 410, a second substrate 420 and a sensor 430.

[0095] The first substrate 410 has a capillary bore 411 defining a fluid path 412 extending through said first substrate 410 from the microneedle 416 on the top side 413 to a fluid channel 414 on a bottom side 415 of said first substrate 410.

[0096] The second substrate 420 and the sensor 430 are arranged according to the previously presented figures. At least by this, the fluid path 412 extends through the microneedle 416, the fluid channel 414 and the metallised vias 421, 422. Thereby a fluid in the fluid path 412 may pass the sensor 430 while passing the first substrate 410 and the second substrate 420.

[0097] The microneedle 416 may have a sharp tip defined by crystallographic planes. For example, the microneedle may have a bevel slope that for each needle or needles is defined by the 111 planes.

[0098] Each microneedle 416 may comprise a capillary bore 411, e.g. a single capillary bore. Thereby bodily fluid may be extracted by means of capillary suction through the microneedle 416.

[0099] The microneedle 416 may be provided with a cap at a distal end for shielding the capillary bore from clogging, whereby at least one opening to the capillary bore is provided in a lateral direction of the microneedle, perpendicular to the axial or longitudinal extension of the microneedle.

[0100] The capillary bore of each microneedle may be provided with a hydrophilic surface. Thereby capillary flow of bodily fluid may be assisted.

[0101] The microneedle may comprise a plurality of cutting elements extending along a longitudinal direction of the microneedle. Thereby the skin may be cut and opened to facilitate extraction of bodily fluid.

[0102] The perimeter of the bore hole in each microneedle as projected on the bevel of the needle may be located at a distance from the tip in a way where the tip is outside the perimeter.

[0103] The microneedle 416 may have a length of 200-1000 μm, preferably 400-900 μm, more preferably 300-600 μm, and an outer circumference of 400-800 μm. By this, the microneedle 416 has dimensions suitable for penetration of the skin and extraction of bodily fluid.

[0104] A portion of the bore hole as projected on the side that contains the capillary system may be outside the connecting capillary generating a maximized wall surface that minimizes surface tension.

[0105] The connection between the bore hole and the capillary may for example be designed with a minimized contact angle, thereby enabling a tension driven flow.

[0106] The shaft of each needle may be provided both with or without a hilt.

[0107] The vertical bore holes may be filled with material that is selective and specific to certain molecules and thereby creating an integrated extraction and sensing chipset. The filler material could for instance be glucose oxidase and carbon powder and thereby creating a glucose specific extraction and sensing chipset.

[0108] A plurality of openings may be provided in a lateral direction, around a circumference of the microneedle 416. The at least one opening may be provided about midways along a longitudinal extension of the microneedle 416. Thereby the extraction of bodily fluid is facilitated and the risk for clogging is further reduced.

[0109] The bores may with their hollow structure constitute inlets for sampling of bodily fluid. Thereby bodily fluid, such as interstitial fluid (ISF) may be extracted and introduced into the sensor 430 with minimal discomfort for the patient.

[0110] The sensor 430 may have a collecting network of capillaries in different patterns and as an advantage is collection of liquid and storage made without evaporation problems. Hence, the chip can sample and the analysis can also be made ex situ.

[0111] The sensor 430 may have an interface between the vertical bore holes and the collecting capillary laterally misaligned to allow liquid to wet the walls and hence by capillary action fill the collecting channels on the backside.

[0112] The microneedle 416 may have the bevel oriented in the crystallographic directions or preferred in the same direction.

[0113] FIG. 5a is a cross-sectional view along the longitudinal axis of a microneedle 516 according to an embodiment. In this figure a circular cross-section of the capillary bore 511 is shown.

[0114] FIG. 5b is a cross-sectional view along the longitudinal axis of a microneedle 516 according to an embodiment. In this figure an uneven cross-section of the capillary bore 511 is shown. The microneedle 516 shown has two rounded corners. Other designs are also possible, such as one or three rounded corners. The corners may have the same or different radiuses of curvature. In addition, the corners may be cut in such a way that the triangle may be described as having six corners, with three sides that are considerably larger than the other three sides.

[0115] FIG. 5c is a cross-sectional view along the longitudinal axis of a microneedle 516 according to an embodiment. In this figure a triangular cross-section of the capillary bore 511 is shown.

[0116] In this application a triangular cross-section of should encompass a shape with three edges connected with corresponding corners. The edges may be straight, curved, convex or concave. The corners may be sharp, blunt or rounded with different or the same radius. Thus, within this application a cross-section with the shape of an egg or a heart is considered to be triangular. This reasoning applies both to the shape of the bore as to the shape of the microneedle.

[0117] For example a triangular shape of the capillary bore 511 may be substantially triangular with a convex base connected to straight sections via a curved corner. This shape of the capillary bore has been demonstrated to be very efficient for extracting interstitial fluid from a finger of a human test subject.

[0118] For example, the cross-sectional area of the capillary bore in the distal end may be larger than the cross-sectional area of the capillary bore in the proximal end. In addition, the fluid channel may further comprise a decreasing cross-sectional area in order to further enhance a fluid flow in the fluid channel. The cross sectional area of the capillary bore of the microneedles may for example gradually decrease from the distal end towards the proximal end along the longitudinal direction.

[0119] FIG. 6 is a schematic bottom view of a chip having a sensor assembly according to an embodiment of the present invention. Shown is a first substrate 610 and a second substrate 620. The second substrate 620 has a first metallised via 621 and a second metallised via 621. The metalized vias may be used to communicate readings from a sensor on the opposing side of the second substrate 620 and is in electric contact with extended pads. The extended pads may be used to further simplify reading from the sensor.

[0120] FIG. 7 is a top view of the second substrate 720 with vias and a sensor. The view is in perspective, hence there may be some distortion present in the figure.

[0121] On the second substrate 720 a first metallised via 721 and a second metallised via 722 is formed. The second substrate further comprise a sensor having a first electrode 731 and a second electrode 732, both can be seen in the figure as spirals. The first electrode 731 is in electric contact with the first metallised via 721 and the second electrode 732 is in electric contact with the second metallised via 722. By this, readings from the electrodes may be communicated through the second substrate 720 by the first metallised via 721 and the second metallised via 722.

[0122] The sensor assembly may also be provided with a plurality of needles organized in an array or matrix at a minimum distance from each other of 100 micrometres but not greater than 1 mm apart, has a sharp tip in the same plane or slightly below a surrounding structure and where the tip may have a 54.7 degree bevel and the needle a hollow bore with a capillary dimension that allows extraction without clogging and a shaft, longer than 200 micrometres.

[0123] FIG. 8 is a schematic cross section view of a schematic sensor assembly having multiple bores 812 from a plurality of microneedles 816. The sensor assembly 800 is having a first substrate 810, a second substrate 820.

[0124] The first substrate 810 has multiple capillary bores defining a fluid path 812 extending through the first substrate 810 from the plurality of microneedles 816 on the top side 813 to a fluid channel 814 on a bottom side 815 of said first substrate 810. The figure is illustrated with capillary bores in two of the plurality of microneedles 816, it is however understood that there may be capillary bores in several of the plurality of microneedles 816 and that each of the capillary bores may be connected with the fluid channel 814.

[0125] Each capillary bore may extend from top side 813 of the first substrate 810 to a fluid channel port on the bottom side 815 of the first substrate 810. Should the sensor assembly be provided with microneedles, the capillary bore may extend from the tip of the microneedles to a fluid channel port on the bottom side 815 of the first substrate 810.

[0126] The second substrate 820 comprise a sensor 830 that is arranged according to the previously presented figures. At least by this, the fluid path 812 extends through the plurality of microneedles 816, the fluid channel 814 and the metallised vias 821, 822. Thereby a fluid in the fluid path 812 may pass the sensor 830 while passing the first substrate 810 and the second substrate 820.

[0127] The microneedles 816 may for example be located at minimum distance from each other of 200 microns in order to avoid the effect of bed of nails.

[0128] The microneedles 816 may be oriented in a way that enables connection between at least a subset of microneedles using integrated, for instance etched, capillaries.

[0129] The microneedles 816 may all be combined with a capillary system enabling a capillary flow to a fluid exit port.

[0130] The second substrate may be wafer bonded or attached to the first substrate by other means, but may also be connected through capillary tubing or an equivalent flow system.

[0131] The sensor may also be configured for detecting a level of glucose in bodily fluid, i.e. a glucose sensor. Thereby a sensor for rapid and accurate detection of the level of glucose in bodily fluid may be provided.

[0132] The sensor may be configured for detecting a concentration or presence of lactate, carbon dioxide, or other molecules in bodily fluid. Thereby a sensor for rapid and accurate detection of the level of above mentioned molecule or other molecules, ions or biomarkers in bodily fluid may be provided.

[0133] While specific embodiments have been described, the skilled person will understand that various modifications and alterations are conceivable within the scope as defined in the appended claims. All prior art documents cited herein are expressly incorporated by reference in their entirety in the present disclosure.