# US 11,079,319 B2 · Porous mirror for optical detection of an analyte in a fluid

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- Number: US 11,079,319 B2
- Document ID: US11079319B2
- Status: Granted
- Kind: B2
- Application number: 16/854,136
- Filed: 2020-04-21
- Published: 2020-08-06
- Granted: 2021-08-03
- Earliest claimed: 2015-11-18
- Assignees: Radiometer Medical ApS
- Applicants: Radiometer Medical Aps
- Inventors: Thomas Kjaer
- Web page: https://patentgrep.com/patent/US11079319B2

## CPC

- G01N 21/31: Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry {(G01N21/72 takes precedence)}
- B01L 3/502715: {characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces}
- G01N 33/49: Blood {(chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80)}
- G01N 33/491: {by separating the blood components (G01N15/05 takes precedence)}
- G01N 33/721: {Haemoglobin}
- G01N 33/728: {Bilirubin; including biliverdin}
- A61B 5/0075: {by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy (A61B5/0071 takes precedence)}
- A61B 5/15: Devices for taking samples of blood
- B01L 3/502753: {characterised by bulk separation arrangements on lab-on-a-chip devices, e.g. for filtration or centrifugation}
- G01N 15/01: specially adapted for biological cells, e.g. blood cells (investigating sedimentation of particle suspensions in blood G01N15/05)
- G01N 2021/0357: {Sets of cuvettes}
- G01N 2201/061: Sources
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A porous mirror (1) for detection of an analyte (96) in a fluid (99) by optical probing, comprising a translucent slab (2) with a front side (3), and a backside (4) facing away from the front side (3), wherein the front side (3) is adapted for being contacted with a fluid (99), and a reflective layer (5) at the front side (3) of the translucent slab (2), the reflective layer (5) being adapted to reflect light reaching the reflective layer from the backside (4) of the translucent slab (2), wherein the translucent slab (2) comprises pores (6), wherein the pores (6) are dead end pores (6) extending from respective openings (7) at the front side (3) into the translucent slab (2), through the reflective layer (5), wherein a cross-sectional dimension of the openings (7) of the pores (6) is dimensioned so as to prevent larger particles or debris, if any included the fluid, from entering the pores (6), while allowing the analyte (96) in the fluid (99) to enter the pores (6) via diffusion.

## Claims

### Claim 1

A device for detecting an analyte in a fluid comprising a porous mirror comprising:
a translucent article comprising (a) at least one membrane comprising pores and (b) a transparent element with a front side, and a backside facing away from the front side, wherein the front side is in contact with a fluid chamber;
a reflective layer at the front side of the translucent article, which reflects light reaching the reflective layer from the backside of the translucent article;
wherein the pores are dead end pores extending from respective openings at the front side into the at least one membrane, through the reflective layer;
wherein the pores are only in fluid communication with the fluid at the front side of the at least one membrane;
a light source, to illuminate at least the pores in the translucent article; and
a light detector, wherein the detector is arranged to receive light emerging from the pores in response to an illumination by the light source, and wherein the detector generates a signal representative of the detected light.

### Claim 2 (depends on 1)

The device of claim 1, wherein the fluid chamber comprises an inlet and outlet port for feeding and discharging the fluid.

### Claim 3 (depends on 1)

The device of claim 1, further comprising one or more further detectors.

### Claim 4 (depends on 1)

The device of claim 1, wherein a cross-sectional dimension of the openings of the pores is about 1 μm or less and/or wherein a length of the pores in an axial direction along the pores is less than 100 μm.

### Claim 5 (depends on 1)

The device of claim 1, wherein a porosity of a given volume of the translucent article is between 50% and 5% by volume.

### Claim 6 (depends on 1)

The device of claim 1, wherein an equivalent pore volume depth (DELTA) is less than 20 μm, wherein the equivalent pore volume depth (DELTA) is defined as the total volume of the pores (V) divided by the front side area (A) over which the openings of the pores are distributed.

### Claim 7 (depends on 1)

The device of claim 1, wherein an inner wall surface of the pores is coated with a hydrophilic coating.

### Claim 8 (depends on 1)

The device of claim 1, wherein the translucent article is provided with further reflective elements arranged inside the pores, in a mouth portion thereof, adjacent to the opening at the front side of the translucent article.

### Claim 9 (depends on 8)

The device of claim 8, wherein the further reflective elements are provided as a reflective coating covering only a fraction of the circumference of the mouth portion of the pores in the vicinity of the opening, wherein the fraction is about 70% or less.

### Claim 10 (depends on 1)

The device of claim 1, wherein a transparent backing side of the translucent article is provided with a 60° angled surface to minimize the effect of the shift in refractive index between outside air and the transparent backing slide.

### Claim 11 (depends on 1)

The device of claim 1, wherein the pores are track-etched in the translucent article and reflective layer.

### Claim 12 (depends on 1)

The device of claim 1, wherein the pores are rinsed by diffusion.

### Claim 13 (depends on 1)

The device of claim 1, wherein at least one of the at least one membranes comprising pores is made of a transparent polymer.

### Claim 14 (depends on 1)

The device of claim 1, wherein a cross-sectional dimension of the openings of the pores is about 500 nm or less and/or wherein a length of the pores in an axial direction along the pores is less than 50 μm.

### Claim 15 (depends on 1)

The device of claim 1, wherein a porosity of a given volume of the translucent article is between 30% and 10% by volume.

### Claim 16 (depends on 1)

The device of claim 1, wherein an equivalent pore volume depth (DELTA) is less than 10 μm, wherein the equivalent pore volume depth (DELTA) is defined as the total volume of the pores (V) divided by the front side area (A) over which the openings of the pores are distributed.

### Claim 17 (depends on 8)

The device of claim 8, wherein the further reflective elements are provided as a reflective coating covering only a fraction of the circumference of the mouth portion of the pores in the vicinity of the opening, wherein the fraction is about 50% or less.

### Claim 18 (depends on 1)

The device of claim 1, wherein the pores are track-etched pores.

### Claim 19 (depends on 18)

The device of claim 18, wherein at least one of the at least one membranes comprising pores translucent slab is made of a transparent polymer.

### Claim 20 (depends on 1)

The device of claim 1, wherein the fluid is a whole blood sample, the plasma fraction of whole blood, spinal cord fluid, urine, pleura, ascites, wastewater, a pre-prepared fluid for any kind of injection, a fluid with a constituent detectable by spectroscopy, or a gas.

### Claim 21 (depends on 1)

The device of claim 1, wherein the reflective layer is made of metal.

### Claim 22 (depends on 1)

A method for optically detecting an analyte in a fluid comprising
providing the device according to claim 1,
contacting the porous mirror with a reference liquid so as to fill the pores with the reference liquid,
contacting the front side of the porous mirror with the fluid,
waiting for a diffusion time to allow for diffusion of the analyte in the fluid into the pores to stabilize,
optically probing the fluid inside the pores from the side of the reflective layer, and
based on the result of the optical probing, establishing an analyte level of the fluid.

### Claim 23 (depends on 22)

The method according to claim 22, wherein the analyte is bilirubin, carbon dioxide, Patent Blue V, or methylene blue and the fluid is whole blood.

### Claim 24 (depends on 22)

The method according to claim 22, wherein the fluid is a whole blood sample, the plasma fraction of whole blood, spinal cord fluid, urine, pleura, ascites, wastewater, a pre-prepared fluid for any kind of injection, a fluid with a constituent detectable by spectroscopy, or a gas.