Improved volatile organic compound sensor

Abstract

The present invention relates to a sensor for determining a volatile organic compound (volatile compound sensor) configured for determining at least one volatile organic compound in a gaseous sample of a subject, wherein the volatile compound sensor comprises at least one substrate membrane and a plurality of receptors configured to interact with one or more volatile organic compounds, wherein the plurality of receptors are immobilized on various sites of a surface of the substrate membrane, and wherein the surface of the substrate membrane has an arithmetic mean height of at least 0.04 µm, and to systems, methods, and uses related thereto.

Description

[0001] P39297 29. August 2025

[0002] - 1 -

[0003] Improved volatile organic compound sensor

[0004] Technical Field

[0005] The present invention relates to a sensor for determining a volatile organic compound (volatile compound sensor) configured for determining at least one volatile organic compound in a gaseous sample of a subject, wherein the volatile compound sensor comprises at least one substrate membrane and a plurality of receptors configured to interact with one or more volatile organic compounds, wherein the plurality of receptors are immobilized on various sites of the substrate membrane, and wherein the substrate membrane has an arithmetic mean height of the surface of at least 0.04 pm, and to systems, methods, and uses related thereto.

[0006] Background art

[0007] The human body is a major source of volatile organic compounds (VOCs) that originate from various parts and processes within the body. Endogenous VOCs originate from metabolic processes within the body. An important organ involved in generating and transforming such endogenous VOCs is the liver. VOCs originating from the environment are called exogenous VOCs, e.g. entering the body via respiratory air, food intake or diffusion through skin or originating from the microbiome, e.g. of the digestive tract. VOCs generated or absorbed in various parts of the body enter the bloodstream and pass into the exhaled breath by gas exchange in the lungs. VOCs from skin originate from secretion by eccrine, sebaceous or apocrine glands. Sensors for measuring VOCs are known in the art, e.g. from WO 2021 / 053284 Al, WO 2022 / 258559 Al, and WO 2022 / 189292 Al. P39297 29. August 2025

[0008] - 2 -

[0009] CA 2805676 A discloses means for extracting and capturing volatile compounds from exhaled air of a patient to analyze the captured volatile compounds by chromatography, mass spectrometry, infrared or ultra-violet spectrophotometry, gas sensors, or electronic noses. The capturing means may comprise a means of diffusing the exhaled air made of a porous material, e.g. a membrane. The small holes of the porous material guarantee the formation of sufficiently small air bubbles, and the smaller the air bubbles the greater is the contact surface between the air, i.e. the volatile compounds in the air bubble, and the liquid element which is a substance having a high chemical affinity to acetone and therewith forms a means for extracting and capturing the volatile compound.

[0010] WO 2022 / 192599 Al discloses a device for collecting and transferring volatile organic compounds comprising an absorbent material capable of adsorbing volatile organic compounds, e.g. a membrane folded or crumpled to increase a surface to volume ratio.

[0011] WO 2022 / 258559 Al discloses a system for multiplexed detection of VOCs in a gaseous sample that comprises a matrix of Mach-Zehnder interferometers, each interferometer having measurement and reference arms made of e.g. N4Si3 / SiO2, wherein the measurement arm is provided with a plurality of receptors (peptides) that are immobilized on the sensor surface as an array by means of a layer of organosilane.

[0012] SOPHIE BRENET ET AL: "Highly-Selective Optoelectronic Nose Based on Surface Plasmon Resonance Imaging for Sensing Volatile Organic Compounds", ANALYTICAL CHEMISTRY, vol. 90, no. 16, 19 July 2018 (2018-07-19), pages 9879-9887, XP055630144, discloses a system for multiplexed detection of VOCs in a gaseous sample based on surface plasmon resonance imaging (SPRi). The key element of this system is an optical prism coated with a gold layer that is functionalized with an array of bioreceptors (peptides) immobilized on gold by self-assembly driven by Au-thiol adsorption interactions.

[0013] TERRIER C ET AL: "Imaging a smell: from plasmonic-based device to an array of Mach- Zehnder interferometers", PROCEEDINGS OF THE SPE, SPE, US, vol. 12145, 1 June 2022 (2022-06-01), pages 1214503-1214503, XP060159943, ISSN: 0277-786X, aims to compare electronic noses based on different technologies. P39297 29. August 2025

[0014] - 3 -

[0015] GAGGIOTTI SARA ET AL: "Development of an optoelectronic nose based on surface plasmon resonance imaging with peptide and hairpin DNA for sensing volatile organic compounds", SENSORS AND ACTUATORS B: CHEMICAL, ELSEVIER BV, NL, vol. 303, 9 October 2019 (2019-10-09), XP085898712, discloses a SPRi system using peptides and hairpin DNA as recognition molecules. The receptors are immobilized as an array on the gold surface by self-assembly using Au-thiol interactions. Hairpin DNA receptors are provided with a thiolated spacer to that purpose (see supplemental information).

[0016] KAZZY MARIELLE EL ET AL: "Odorant binding protein-based optoelectronic nose: Hydration and protein activity", 2022 IEEE INTERNATIONAL SYMPOSIUM ON OLFACTION AND ELECTRONIC NOSE (ISOEN), IEEE, 29 May 2022 (2022-05-29), pages 1-3, XP034133349, discloses a similar SPRi system using odorant binding proteins as receptor. The proteins are immobilized as an array on the gold surface by adsorption of cysteine groups on the gold surface.

[0017] GAO ANRAN ET AL: "Highly sensitive and selective detection of human-derived volatile organic compounds based on odorant binding proteins functionalized silicon nanowire array", SENSORS AND ACTUATORS B: CHEMICAL, ELSEVIER BV, NL, vol. 309, 22 January 2020 (2020-01-22), XP086049098, discloses another type pf sensor for multiplexed detection of VOCs in a human-derived gaseous sample which comprises an array of silicon nanowires functionalized with odorant binding proteins. The proteins are immobilized on the silicon substrate via an intermediate linking layer that is formed by covalent attachment of an aminosilane and glutardialdehyde.

[0018] LIEDBERG BO ET AL: "Surface plasmon resonance for gas detection and biosensing", SENSORS AND ACTUATORS, vol. 4, 1 January 1983 (1983-01-01), pages 299-304, XP093260218, discloses a SPR gas sensor in which the gold sensing layer is coated with a layer of silicon-gylcol copolymer.

[0019] HUA YONGBIAO ET AL: "Molecularly imprinted polymers for sensing gaseous volatile organic compounds: opportunities and challenges", ENVIRONMENTAL POLLUTION, P39297 29. August 2025

[0020] - 4 - vol. 311, 1 October 2022 (2022-10-01), page 119931, XP093261444, is a review paper focusing on the use of molecularly imprinted polymers as recognition element in VOC sensors.

[0021] Problem to be solved

[0022] Despite the above, depending on the specific application envisaged, VOC sensors still are limited in sensitivity and / or specificity. In particular, in order to use VOC sensing for non- invasive blood glucose monitoring, improved sensors are needed.

[0023] This problem is addressed by the means, methods, and uses described herein, with the features of the independent claims. Advantageous embodiments which might be realized in an isolated fashion or in any arbitrary combinations are listed in the dependent claims as well as throughout the specification.

[0024] Summary

[0025] The present invention relates to a sensor for determining a volatile organic compound (volatile compound sensor) configured for determining at least one volatile organic compound in a gaseous sample of a subject, wherein the volatile compound sensor comprises at least one substrate membrane and a plurality of receptors configured to interact with one or more volatile organic compounds, wherein the plurality of receptors are immobilized on various sites of a surface of the substrate membrane, and wherein the surface of the substrate membrane has an arithmetic mean height of at least 0.04 pm.

[0026] The present invention also relates to a sensor for determining a volatile organic compound (volatile compound sensor) configured for detecting at least one volatile organic compound in a sample of a subject, wherein the volatile compound sensor comprises at least one substrate membrane and a plurality of receptors configured to interact with one or more volatile organic markers, wherein the plurality of receptors are immobilized on various sites of the substrate membrane, and wherein the substrate membrane comprises, in an embodiment consists of, a silane modified polyether polymer. P39297 29. August 2025

[0027] - 5 -

[0028] Further, the present invention relates to a non-invasive glucose monitoring system comprising at least one volatile compound sensor described herein, wherein the volatile compound sensor is configured for determining at least one change in concentration of at least one volatile organic compound indicative for glucose.

[0029] The present invention moreover relates to a method for determining at least one volatile organic compound in a gaseous sample of a subject, wherein the method comprises passing said gaseous sample over a volatile compound sensor described herein.

[0030] Also, the present invention relates to a use of a volatile compound sensor described herein for detecting at least one volatile organic marker.

[0031] In general, terms used herein are to be given their ordinary and customary meaning to a person of ordinary skill in the art and, unless indicated otherwise, are not to be limited to a special or customized meaning. As used in the following, the terms “have”, “comprise” or “include” or any arbitrary grammatical variations thereof are used in a non-exclusive way. Thus, these terms may both refer to a situation in which, besides the feature introduced by these terms, no further features are present in the entity described in this context and to a situation in which one or more further features are present. As an example, the expressions “A has B”, “A comprises B” and “A includes B” may both refer to a situation in which, besides B, no other element is present in A (i.e. a situation in which A solely and exclusively consists of B) and to a situation in which, besides B, one or more further elements are present in entity A, such as element C, elements C and D or even further elements. Also, as is understood by the skilled person, the expressions "comprising a" and "comprising an" in an embodiment refer to "comprising one or more", i.e. are equivalent to "comprising at least one". In accordance, expressions relating to one item of a plurality, unless otherwise indicated, in an embodiment relate to at least one such item, in a further embodiment a plurality thereof; thus, e.g. identifying "a cell" relates to identifying at least one cell, in an embodiment to identifying a multitude of cells. P39297 29. August 2025

[0032] - 6 -

[0033] Further, as used in the following, the terms "preferably", "more preferably", "most preferably", "particularly", "more particularly", "specifically", "more specifically" or similar terms are used in conjunction with optional features, without restricting further possibilities. Thus, features introduced by these terms are optional features and are not intended to restrict the scope of the claims in any way. The invention may, as the skilled person will recognize, be performed by using alternative features. Similarly, features introduced by "in an embodiment" or similar expressions are intended to be optional features, without any restriction regarding further embodiments of the invention, without any restrictions regarding the scope of the invention and without any restriction regarding the possibility of combining the features introduced in such way with other optional or non-optional features of the invention.

[0034] The methods specified herein below, in an embodiment, are in vitro methods. The method steps may, in principle, be performed in any arbitrary sequence deemed suitable by the skilled person, but in an embodiment are performed in the indicated sequence; also, one or more, in an embodiment all, of said steps may be assisted or performed by automated equipment. Moreover, the methods may comprise steps in addition to those explicitly mentioned above.

[0035] As used herein, if not otherwise indicated, the term "about" relates to the indicated value with the commonly accepted technical precision in the relevant field, in an embodiment relates to the indicated value ± 20%, in a further embodiment ± 10%, in a further embodiment ± 5%. Further, the term "essentially" indicates that deviations having influence on the indicated result or use are absent, i.e. potential deviations do not cause the indicated result to deviate by more than ± 20%, in a further embodiment ± 10%, in a further embodiment ± 5%. Thus, “consisting essentially of’ means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to provide the components, and components added for a purpose other than achieving the technical effect of the invention. For example, a composition defined using the phrase “consisting essentially of’ encompasses any known acceptable additive, excipient, diluent, carrier, and the like. In an embodiment, a composition consisting essentially of a set of components will comprise less than 5% by weight, in a P39297 29. August 2025

[0036] - 7 - further embodiment less than 3% by weight, in a further embodiment less than 1% by weight, in a further embodiment less than 0.1% by weight of non-specified component(s).

[0037] The term “determining” as used herein refers to a qualitative, semiquantitative, or quantitative determination of a volatile organic compound referred to herein. Determining the amount of a volatile organic compound may be carried out by any technique using a sensor as specified herein which allows for establishing a measure of the presence, in an embodiment the quantity, of a volatile organic compound. Suitable techniques depend on the molecular nature and the properties of the volatile organic compound and are discussed elsewhere herein in more detail. Typically, the amount of a volatile organic compound can be determined by determining a complex of the analyte with a receptor, in particular an antibody or fragment thereof. Typical techniques particularly envisaged for determining the volatile organic markers referred to herein are described herein below.

[0038] In an embodiment, determining a VOC, a volatile organic marker, and / or an analyte is establishing whether said compound is present or absent in the gaseous ample at a concentration above the detection limit of the method, i.e., in an embodiment, the determining is qualitative. Methods of determining a detection limit are known to the skilled person. In a further embodiment, determining is determining semi -quantitatively or quantitatively the amount or concentration of a VOC, volatile organic marker, and / or an analyte in a gaseous sample. For semi -quantitative determining, the amount may be assigned e.g. to two or more pre-defined categories, e.g. above or not above a reference value, or low, medium, or high. For quantitative determination, either the absolute or precise amount of the a VOC, volatile organic marker, and / or an analyte will be determined or the relative amount of the analyte will be determined. The relative amount may be determined in a case were the precise amount of a compound can or shall not be determined. In said case, it can be determined whether the amount in which a VOC, volatile organic marker, and / or an analyte is present is increased or diminished with respect to a reference sample comprising said a VOC, volatile organic marker, and / or an analyte in a pre-determined amount. For quantitative determination, any parameter (a "quantitative parameter") correlating with the amount or concentration of the VOC, volatile organic marker, and / or analyte in the gaseous sample or any value derived therefrom by standard mathematical and / or evaluation P39297 29. August 2025

[0039] - 8 - operations, including in particular multiplication, division, reciprocal formation, scaling, normalization, standardization, error correction, background correction, or mean or median calculation, may be determined and / or output.

[0040] The term “analyte”, as used herein, refers to a molecule which may or may not be present in a subject and the presence of which and / or the amount of which shall be detected. Thus, the analyte typically is a compound of interest. Typically, the analyte is a small molecule compound, such as a substrate for an enzyme of a metabolic pathway, an intermediate of such a pathway, or a product produced by a metabolic pathway. Thus, more typically, the analyte in accordance with the present invention may be a metabolite. Metabolic pathways are well known in the art and may vary between species. Preferably, said pathways include at least citric acid cycle, respiratory chain, glycolysis, gluconeogenesis, hexose monophosphate pathway, pentose phosphate pathway, production and P-oxidation of fatty acids, urea cycle, amino acid biosynthesis pathways, protein degradation pathways such as proteasomal degradation, amino acid degrading pathways, biosynthesis or degradation of: lipids, polyketides (including e.g. flavonoids and isoflavonoids), isoprenoids (including, e.g., steroids), carbohydrates, hormones, vitamins, cofactors such as prosthetic groups or electron carriers, purines, pyrimidines, nucleosides, nucleotides and related molecules such as tRNAs, microRNAs (miRNA) or mRNAs. Accordingly, small molecule analytes are usually composed of the following classes of compounds: alcohols, alkanes, alkenes, alkines, aromatic compounds, ketones, aldehydes, carboxylic acids, esters, amines, imines, amides, cyanides, amino acids, peptides, thiols, thioesters, phosphate esters, sulfate esters, thioethers, sulfoxides, ethers, or combinations or derivatives of the aforementioned compounds. The small molecules among the metabolites may be primary metabolites which are required for normal cellular function, organ function or animal growth, development or health. Moreover, small molecule metabolites further comprise secondary metabolites having essential ecological function, e.g. metabolites which allow an organism to adapt to its environment. Furthermore, metabolites are not limited to said primary and secondary metabolites and further encompass artificial small molecule compounds. Said artificial small molecule compounds are derived from exogenously provided small molecules which are administered or taken up by an organism but are not primary or secondary metabolites as defined above. For instance, artificial small molecule compounds may be metabolic products obtained from P39297 29. August 2025

[0041] - 9 - drugs by metabolic pathways of the animal. In an embodiment, the analyte, i.e. the compound of interest, is glucose; in a further embodiment, according to the description herein, a blood glucose concentration shall be determined.

[0042] The term "volatile organic compound", abbreviated as "VOC", relates to each and every organic chemical compound, i.e. a compound comprising at least one carbon atom, that is detectable in the breath of a mammal, in an embodiment a human. Thus, as referred to herein, in an embodiment, the term VOC includes each and every organic compound measurable in a gaseous phase. Thus, as referred to herein, a volatile organic compound may also be referred to as "breath-detectable compound". In accordance, the VOC may have a high vapor pressure, such as at least 2.3 kPa at 20°C and / or a low boiling point, in an embodiment at most 37°C. Thus, the VOC may in particular be volatile at rather low temperatures such as room temperature.

[0043] In an embodiment, the VOC is an endogenous VOC of a mammalian body, in a further embodiment of a human body, in particular is an endogenous analyte or a derivative thereof, i.e. an analyte generated by an endogenous metabolic process. Thus, the analyte may be a VOC. The VOC may, however, also be a compound generated by a body as a consequence of the presence or absence of an analyte, in which case the VOC may also be referred to as "volatile organic marker". I.e., the VOC does not necessarily have to be the analyte or a derivative thereof, but may also be a compound produced by a subject in response to a physiological state, e.g. a disease state, which correlates with the physiological state and / or the analyte. Thus, the volatile organic marker in an embodiment is a surrogate marker of a physiological state of a subject, e.g. a disease state. Thus, the volatile organic marker in an embodiment is a volatile organic marker of a physiological state of a subject. The aforesaid physiological state may in particular be hyperglycemia, e.g. in a subject suffering from diabetes.

[0044] In view of the description herein, the volatile organic marker in an embodiment is a VOC correlating with at least one physiological state of a subject, and in an embodiment specifically correlates with a physiological state of interest; i.e. the volatile organic marker in an embodiment is directly and unambiguously indicative of said physiological state. In a P39297 29. August 2025

[0045] - 10 - further embodiment, a multitude of volatile organic markers is determined; in such case, a single volatile organic marker of the volatile organic markers determined does not necessarily have to be a specific marker of said physiological state, provided that the combination of volatile organic markers is. Thus, it may e.g. be envisaged to determine two volatile organic markers, of which one may be indicative of two physiological states, wherein the second volatile organic marker allows differentiation between said two physiological states. Volatile organic markers indicative of blood glucose levels are known and include in particular indole, formaldehyde, methanol, acetone, and the like, as described e.g. in EP 4085832 Bl. Thus, the volatile organic marker may in particular be indole (114- indole, CAS NO. 120-72-9), formaldehyde (CAS No. 50-00-0), methanol (CAS No. 67-56- 1), acetone (propan-2-one, CAS No. 67-64-1), acrolein (prop-2-enal, CAS No. 107-02-8, acetic acid (CAS No. 64-19-7), butanone (butan-2-one, CAS No. 78-93-3), propionic acid (propanoic acid, CAS No. 79-09-4), phenol (CAS No. 108-95-2), propionamide (propanamide, CAS NO. 79-05-0) and / or butyric acid (butanoic acid, CAS No. 107-92-6). In an embodiment, the volatile organic marker is indole, formaldehyde, and / or methanol. In view of the above, the volatile organic marker may also be a derivative of indole, such as e.g. an aliphatic C8-amine like cyclohexyl-ethylamine (2-cyclohexylethanamine, CAS N. 4442-85-7) or octylamine (octan-1 -amine, CAS No. 111-86-4).

[0046] The term "gaseous sample" is understood by the skilled person. In an embodiment, the term includes each and every sample being a gas or comprising a gas as the dispersion medium. Thus, the gaseous sample may be a gas, a gas mixture, in particular air, a liquid aerosol, and / or a solid aerosol. In an embodiment, the gaseous sample is known or suspected to comprise at least one volatile organic compound as specified herein above. Also in an embodiment, the gaseous sample is known or suspected to comprise a volatile organic compound produced by a body of a subject. Thus, the gaseous sample may in particular be a breath sample, i.e. a sample of air exhaled by a subject, or a sample of a gaseous emanation from the skin of a subject, in particular from a skin area, of the subject’s body. Exemplarily, the skin, specifically the skin area, may be selected from the group consisting of: head, chest, back, armpit, waist, arm or genital area. However, also other skin areas may be possible. The breath sample in an embodiment is a sample of exhaled breath, in a further embodiment exhaled breath originating from the subject’s nostrils and / or from the subject’s mouth. It is, P39297 29. August 2025

[0047] - 11 - however, also envisaged that the sample is taken from within a body cavity of the subject, in particular from at least one of the respiratory cavities, in particular the mouth, nose, pharynx, hypopharynx, trachea, and / or the lung of a subject. As is known to the skilled person, a breath sample in an embodiment may be a gas mixture comprising considerable amounts of moisture, e.g. as gaseous water and / or as water droplets. A sample of exhaled breath may be captured using a mouthpiece, a nasal cannula, a handheld breath analyzer or any other device suitable to capture at least a fraction of the exhaled breath.

[0048] The term “subject”, as used herein, refers to a vertebrate animal, in an embodiment a mammal and, in a further embodiment, to a human. In an embodiment, the subject is known or suspected to produce at least one volatile organic compound as specified herein. Also in an embodiment, the subject is known or suspected to suffer from diabetes, in an embodiment diabetes type II or type I and / or shows signs and / or symptoms of diabetes, hyperglycemia, and / or hypoglycemia, which are known from medical textbooks. Suspicion to suffer from diabetes may in particular stem from preceding diagnostic measures, such as anamnesis, physical examination, clinical chemistry diagnostics, in particular blood glucose measurement, and the like.

[0049] As referred to herein, the term "membrane" includes each and every composition of matter having a small extension in one dimension compared to its other two dimensions. Thus, in an embodiment, the membrane has a breadth and length in the mm range, in an embodiment at least 1 mm, in a further embodiment at least 5 mm, while the height is in the pm or nm rage, in an embodiment at most 100 pm, in a further embodiment at most 10 pm, in a further embodiment at most 1 pm, in a further embodiment at most 0.1 pm. In an embodiment, the membrane is flexible. Also in an embodiment, the membrane is transparent to the eye and / or to a detection device as specified herein below.

[0050] The term "substrate membrane" is used herein to relate to a membrane to which the receptors as specified herein are immobilized. Thus, the substrate membrane in an embodiment is adapted to immobilize the receptors as specified herein elsewhere and to maintain the receptors in a configuration allowing binding of the volatile organic compound(s) to the receptors. As the skilled person is aware of, depending on the method used for P39297 29. August 2025

[0051] - 12 - immobilization of the receptors, it may be that not each and every receptor molecule will be in a configuration allowing binding of the volatile organic compound(s); in an embodiment, however, at least 10%, in a further embodiment at least 25%, at least 50%, receptor molecules will be in a configuration allowing binding of the volatile organic compound(s) after immobilization to said substrate membrane.

[0052] The material of the substrate membrane in an embodiment comprises or is a polymer, in an embodiment a polyether polymer, the term "polyether polymer" including each and every polymer comprising repeating groups connected via ether linkage, and / or comprises or is an aromatic, optionally halogenated, polymer such as a parylene, e.g. poly-p-xylylene (Parylene N). The polymer molecules of the substrate membrane in an embodiment are silane modified; in an embodiment, the end groups of the polymer molecules are silane modified. Thus, the substrate membrane in an embodiment comprises or consists of a polyether polymer in which the polymer molecules are silane modified; in an embodiment, the end groups of the polyether polymer molecules are silane modified.

[0053] The substrate membrane may comprise or consist of the polymer specified herein above. Thus, the substrate membrane may be a mixture of polymers comprising the polymer as specified. The substrate membrane may, however also comprise a multitude, i.e. at least two, layers, of which one comprises, in an embodiment consists of the specified polymer. In an embodiment, in case the substrate membrane comprises more than one layer, the layer exposed to the gaseous sample consists of the polymer as specified. In a further embodiment, the substrate membrane consists of one layer consisting of the polymer as specified. In a further embodiment, the substrate membrane consists of an organofunctional silane, e.g. a silane modified polymer such as the polymer known under the tradename Geniosil®, in an embodiment Geniosil® WP.

[0054] The substrate membrane in an embodiment has a thickness as indicated herein above. In a further embodiment, the thickness of the substrate membrane is of from 2 nm to 50 pm, in a further embodiment of from 3 nm to 25 pm, in a further embodiment of from 5 nm to 10 pm, in a further embodiment of from 20 nm to 2pm, in a further embodiment of from 50 nm to 1 pm, in a further embodiment of abour 80 nm. Methods for producing substrate P39297 29. August 2025

[0055] - 13 - membranes having the aforesaid thicknesses are known in the art and include in particular spin coating and vacuum deposition.

[0056] The substrate membrane in an embodiment has a roughness, measured as an arithmetic mean height of the surface (Sa), of at least 0.04 pm. The term "arithmetic mean height of the surface" is used herein in its common general meaning known to the skilled person. Methods for determining an arithmetic mean height of the surface are known in the art; in an embodiment the arithmetic mean height of the surface is determined by an optical measurement, for example laser scanning microscopy with a magnification of 200x. In an embodiment, arithmetic mean height of the surface is determined according to ISO 25178, section 606 or 607, in particular section 607. In an embodiment, the arithmetic mean height of the surface is at least 1.5fold, in a further embodiment at least 2fold, in a further embodiment at least 3fold, compared to an Ra of 0.02 pm. The arithmetic mean height of the surface is at least 0.04 pm, in an embodiment at least 0.05 pm, in a further embodiment at least 0.06 pm. In a further embodiment, the arithmetic mean height of the surface is of from 0.04 pm to 0.25 pm, in a further embodiment of from 0.05 pm to 0.2 pm, in a further embodiment of from 0.06 pm to 0.15 pm. . As the skilled person understands, in case the sensor further comprises a cover membrane, the roughness of the substrate membrane is determined before application of the cover membrane.

[0057] A membrane having the aforesaid arithmetic mean height of the surface (Sa) (roughness) can be produced by applying the membrane by spin coating or vacuum deposition to a substrate. The roughness of the surface of the substrate membrane in an embodiment is the result of the aforesaid application. The roughness of the substrate membrane may, however, also be an intrinsic property of the material the substrate membrane is comprised of. In a further embodiment, the desired roughness of the substrate membrane is produced by applying the substrate membrane onto a substrate having an arithmetic mean height of the surface of at least 0.04 pm; in such case, the substrate membrane in an embodiment is applied by a method preserving the roughness of the underlying substrate. Also, application of a thin substrate membrane may be envisaged in such case, e.g. with a thickness of less than 1 pm, in an embodiment less than 100 nm, in a further embodiment less than 25 nm. Thus, in case the roughness of the substrate membrane is essentially defined by the roughness of the P39297 29. August 2025

[0058] - 14 - underlying substrate, application of the substrate membrane by vacuum deposition may be particularly envisaged.

[0059] The substrate membrane optionally is comprised on a substrate. The term "substrate" relates to any substrate that the person skilled in the art would consider suitable for use in the context of the present invention. The substrate is one of the form building parts of the sensor, so if not specified differently the specifications for sensor shape and dimensions also apply for the substrate. The substrate and in an embodiment also the sensor can have a shape at least in two dimensions, selected from the group consisting of round, oval, angular or a mixture of at least two thereof. The substrate and / or the sensor can furthermore have a shape selected from the group consisting of a plate, a strip, a tape, a cube, a cuboid, a cone, a ball, a pyramid, a disc, a needle or a mixture of at least two thereof. The substrate may be of any material deemed appropriate by the skilled person, e.g. plastic, glass, fused silica, and / or quartz. The sensor may be fabricated as a single assembly. For example, it may be fabricated monolithically using semiconductor technology and / or micro-electromechanical systems (MEMS) technology. In this case, the a sensor may have a substrate which may have a uniform or varying thickness.

[0060] The term "receptor" is used herein in a broad sense to relate to any molecule or composition of matter capable of binding at least one volatile organic compound, in an embodiment specifically binding at least one volatile organic compound. Said binding typically is of sufficient stability to allow detection of complexes comprising the receptor and the volatile organic compound; nonetheless, the binding of the volatile organic compound to the receptor in an embodiment is reversible, i.e. the volatile organic compound may diffuse off the receptor after measurement, allowing another measurement cycle to start. Thus, in an embodiment, the dissociation constant (Ka) of the volatile organic compound / receptor complex is at most 10’4mol / 1, in a further embodiment at most 10'5mol / 1, in a further embodiment at most 10'6mol / 1, in a further embodiment at most 10'7mol / 1, in a further embodiment at most 10'8mol / 1, in a further embodiment at most 10'9mol / 1.

[0061] As the skilled person will appreciate, the term "specific binding" and grammatical variations thereof are used herein to indicate that other compounds, typically biomolecules, present in P39297 29. August 2025

[0062] - 15 - a gaseous sample do not bind to a receptor to an extent causing a significant deviation of a measured value from the correct value. Thus, in an embodiment, in a specific binding, other compounds comprised in a gaseous sample which are not a volatile organic compound of interest essentially do not bind to a receptor. In an embodiment, the dissociation constant of the cognate volatile organic compound / receptor complex is at least a factor of 5, in an embodiment at least a factor of ten, in a further embodiment at least a factor of 100, lower than the dissociation constant of a non-cognate complex between any other volatile organic compound in the sample and the receptor.

[0063] As specified herein below, the receptor may be any molecule or composition of matter capable of binding at least one volatile organic compound, in an embodiment specifically binding at least one volatile organic compound. Appropriate molecules or compositions of matter are selected by the skilled person depending on the specific volatile organic compound of interest. In an embodiment, the receptor is an organic macromolecule, in a further embodiment a protein, polypeptide, or peptide. In a further embodiment, the receptor is an antibody, an aptamer, a ligand protein, or an enzyme. Also in an embodiment, the receptor is a peptide as specified herein below having affinity for at least one volatile organic compound, in an embodiment with the aforesaid dissociation constant for the VOC / receptor pair. Corresponding peptide receptors are known in the art.

[0064] The term "protein" is understood by the skilled person; preferably, the protein comprises at least one amino acid chain, i.e. a polypeptide as specified herein below, more preferably comprises a multitude of polypeptides. Thus, the protein may be a multimer, e.g. a dimer, a trimer, or the like, wherein the polypeptides in the multimer may be connected covalently, e.g. by a disulfide bridge, or non-covalently, e.g. by ionic interactions, hydrophobic interactions, and / or van der Waals interactions. The protein may consist of identical polypeptides, e.g. may be a homodimer, or may comprise at least two non-identical polypeptides, e.g. may be a heterodimer. More preferably, the protein as specified comprises all structural components as indicated comprised in one continuous covalent polypeptide chain, thus, the protein preferably is or is comprised in a fusion polypeptide. The term “polypeptide”, as used herein, refers to a molecule consisting of a multitude of amino acids that are covalently linked to each other by peptide bonds. Preferably, the polypeptide P39297 29. August 2025

[0065] - 16 - comprises of from 5 to 1000, more preferably of from 5 to 500 amino acids. The polypeptide may also be comprised in a fusion polypeptide, i.e. may comprise amino acid sequences in addition to those specifically indicated. Also, the polypeptide may comprise additional, non- peptidic structures, such as at least one glycosylation, lipid conjugation, and the like. As referred to herein, polypeptides comprised of 15 amino acids or less, in particular of from 5 to 15 amino acids, in an embodiment of from 10 to 15 amino acids, may also be referred to as "peptides".

[0066] In an embodiment, the receptor is an antibody, the term "antibody", as used herein, including monoclonal antibodies, multispecific antibodies (e.g. bispecific antibodies) formed from at least two intact antibodies, and antibody fragments so long as they exhibit the desired binding activity as specified elsewhere herein. In an embodiment, the antibody is a monoclonal antibody. In an embodiment, the antibody is a full-length antibody or an antibody fragment. The terms “full-length antibody,” “intact antibody,” and “whole antibody” are used herein interchangeably to refer to an antibody in its substantially intact form, not antibody fragments as defined below. The terms particularly refer to an antibody with heavy chains that contain an Fc region. “Antibody fragments” comprise a portion of an intact antibody, in an embodiment, comprising the antigen-binding region thereof. Examples of antibody fragments include Fab, Fab', F(ab')2, and Fvfragments; diabodies; linear antibodies; single-chain antibody molecules, nanobodies, and multispecific antibodies formed from antibody fragments, all of which are in principle known in the art.

[0067] The term "aptamer", as referred to herein, encompasses nucleic acid and peptide aptamers. In addition to their ability to base pair, nucleic acids may also be used as aptamers to detect analytes due to their capability of forming three dimensional structures which specifically bind to target molecules, in particular as small molecules such as volatile organic compounds. Nucleic acid aptamers can be engineered through repeated rounds of in vitro selection or through the systematic evolution of ligands by exponential enrichment (SELEX) technology to bind to various molecular targets. Peptide aptamers are artificial peptides selected or engineered to bind specific target molecules. These peptides consist usually of one or more peptide loops of variable sequence displayed by a protein scaffold. They are P39297 29. August 2025

[0068] - 17 - typically isolated from combinatorial libraries and usually subsequently improved by directed mutation or rounds of variable region mutagenesis and selection.

[0069] As referred to herein, the term "ligand protein" refers to a protein which is capable of specifically recognizing at least one volatile organic marker. Typically, ligand proteins are capable of specifically interacting with volatile organic compound. Therefore, ligand proteins may be used as detection agents for such volatile organic markers which interact therewith. It will be understood that a ligand protein may also encompass parts of entire biologically active receptors or ligands and, typically, parts encompassing the binding domains thereof. Ligand proteins may be naturally occurring receptors or artificially generated ones. Typical artificial ligand proteins as detection agents also include cyclic peptides.

[0070] Also typically suitable as receptors are enzymes. Enzymes are proteins which specifically bind to molecules (substrates) and which are capable of enzymatically converting said molecules into others compounds (products). Accordingly, an enzyme is, typically, capable of specifically binding to a substrate and, thus, can be used for detecting such a substrate, e.g. a volatile organic compound, as an analyte being present in a gaseous sample. Suitable enzymes and their substrates are, in principle, well known in the art. As the skilled person understands in view of the description herein, the enzyme used as a receptor does not necessarily have to be enzymatically active, provided that affinity to a substrate being a volatile organic compound is retained. Thus, an enzyme may also be an enzymatically inactive protein, e.g. an enzymatically inactive variant of an enzymatically active enzyme.

[0071] The term "immobilized" is understood by the skilled person. In an embodiment, the term relates to a receptor being fixed to a substrate membrane such as to prevent the receptor from dissociating from the substrate membrane or significantly reducing the degree of such dissociation. As the skilled person understand in view of the description herein, immobilization may in particular be caused by an interaction between the receptor and the substrate membrane. In cases where the receptor further comprises a cover membrane, said cover membrane may contribute to immobilization of the receptor as well. In an embodiment, the receptors are immobilized on the surface of the substrate membrane. P39297 29. August 2025

[0072] - 18 -

[0073] Methods for immobilizing receptors on the substrate membrane are selected by the skilled person without further ado taking into account the material the substrate membrane consists of and the chemical nature of the receptor(s). As the skilled person understands, since the sample applied to the sensor is a gaseous sample, the risk of receptors being washed off the substrate membrane is low, so relatively weak interactions between the receptors and the substrate membrane may be sufficient. Thus, the receptors may be bound to the substrate membrane in particular via covalent bonds, via ionic interaction, via hydrophobic interaction, and / or via van der Waals interaction. Alternatively or in addition, receptors may be immobilized by covering with a cover membrane, wherein said cover membrane in an embodiment has pores too small for the receptor to diffuse through, but allowing diffusion of at least one volatile organic compound.

[0074] The receptors are immobilized on various sites of the substrate membrane. As used herein, the location of the "various sites" may be selected as deemed appropriate by the skilled person. Thus, the receptors may be immobilized in one area of the substrate membrane, or may be immobilized in a multitude of areas of the substrate membrane. In case more than one type of receptor is immobilized, a mixture of receptors may be immobilized; in an embodiment, however, non-identical receptors are immobilized on different areas of the substrate membrane, e.g. to form a pattern, allowing allocation of a receptor type to one or more locations within the substrate membrane. Thus, non-identical receptors may in particular be immobilized in a patterned manner. An area of the substrate membrane comprising a predetermined type of receptor may also be referred to as a "reactive site" of a sensor.

[0075] The term "sensor" is, in principle known to the skilled person. The term, in an embodiment, includes any and all sensing devices deemed appropriate by the skilled person and having the features as described herein. Thus, in an embodiment, the sensor comprises at least one substrate membrane and a plurality of receptors, both as specified herein above. As referred to herein, a sensor does not necessarily have to comprise all elements required to determine at least one volatile organic compound; as referred to herein, it is sufficient that the sensor provides a detectable signal which can be used for determining a volatile organic compound. P39297 29. August 2025

[0076] - 19 -

[0077] Also, the sensor may be a use-once sensor, or may be a sensor usable in a multitude of measurement cycles, e.g. as in continuous or periodic (including pseudo-continuous) measurement. The sensor may be used to occasionally measure VOCs in exhaled breath, in an embodiment in a ” spot-monitoring” approach, i.e. from time to time during the day, in an embodiment similar to the use of glucose test strips in glucose monitoring. In a further embodiment, the sensor may be used in a continuous manner, e.g. by obtaining a signal with each exhalation, or in a pseudo-continuous manner, e.g. by obtaining a signal at a predetermined frequency, e.g. every 10s or every Is. Obtaining a signal in an embodiment is coordinated with breathing activity of the subject, in order ensure that the sample is taken from an exhaled breath sample. Thus, the sensor may in particular be a senor element of a sensor system comprising a sensor device and said sensor element, or may be self-contained sensor device comprising all units required for determining a volatile organic compound.

[0078] Sensor elements, in principle, comprise at least one substrate membrane with immobilized receptors as specified herein above. Binding of volatile organic compound to a receptor causes a change in at least one detectable property of the senor element, more particularly a physically and / or chemically detectable property. In an embodiment, this property change occurs specifically only in the presence of the volatile organic compound to be detected, but not in the presence of other VOCs. The at least one property change in an embodiment is a change in a property detectable by one of the measurement principles specified herein below, i.e. by optical methods and / or mechanical methods. The further elements comprised by a sensor element are selected by the skilled person depending on the selected detection method without further ado; e.g. in case of optical determination, no further elements may be required within the sensor element, while a corresponding sensor device may comprise the further elements required. As the skilled person understands in view of the description herein, in case the sensor element is a use-once sensor element, the number of additional components may be kept as low as possible to simplify production and to reduce cost. On the other hand, in case the sensor element is a multi-use sensor element, addition of further elements may be acceptable more easily. Thus, a test element may e.g. be a test strip for single use in combination with a test device, similar to corresponding sensor systems in blood glucose determination. The sensor element may, however, also be a multi-use sensor element, such as a sensor cartridge, for use in or in combination with a test device; in such P39297 29. August 2025

[0079] - 20 - case, the multi-use sensor element in an embodiment is configured to be exchageable in the device. Thus, the sensor may be embodied essentially similar to continuous blood glucose sensors known in the art, except that the sensor is configured to use a gaseous sample as specified herein above instead of blood or interstitial fluid, and detects at least one volatile organic marker instead of glucose. It is, in principle, also envisaged that the sensor is a single device comprising all components to provide measurement results of at least one volatile organic compound and, in an embodiment, of the analyte. Thus, in an embodiment, the sensor may be embodied essentially similar to alcometer devices known in the art.

[0080] The sensor referred to herein is a sensor for determining a volatile organic compound; thus, the sensor is configured for detecting at least one volatile organic compound in a gaseous sample of a subject. Appropriate configurations and embodiments have been described herein above. In an embodiment, the volatile compound sensor comprises at least one substrate membrane and a plurality of receptors configured to interact with one or more volatile organic compounds, wherein the plurality of receptors are immobilized on various sites of the substrate membrane, and wherein the substrate membrane comprises, in an embodiment consists of, a silane modified polyether polymer. In a further embodiment, the volatile compound sensor is a multivariate volatile organic sensor comprising a plurality of reactive sites, each configured for interacting with one or more volatile organic markers, wherein the reactive sites comprise non-identical receptors having specific reactive binding properties with volatile organic compounds.

[0081] Optionally, the sensor comprises at least one cover membrane configured for covering at least partially the substrate membrane with the immobilized receptors. As used herein, the term "cover membrane" relates to a membrane as specified herein above which is gas permeable and, in an embodiment, water-impermeable and / or water-repellent. Thus, the cover membrane in an embodiment is configured to protect the receptors and / or the substrate membrane from humidity, in particular from moisture and water droplets possibly comprised in the gaseous sample. Thus, a cover membrane is in particular envisaged in case the gaseous sample is a high-humidity sample, such as a breath sample as specified herein above. Suitable materials for a cover membrane are in principle known in the art and include in particular polydimethylsiloxane (PDMS, CAS No. 63148-62-9) and aromatic, optionally P39297 29. August 2025

[0082] - 21 - halogenated, polymers such as a parylene, e.g. poly-p-xylylene (Parylene N). The cover membrane covers the substrate membrane at least partially, in an embodiment at least in a measurement area, i.e. an area in which determination of the at least one VOC is performed. The cover membrane may also cover the substrate membrane in a multitude of areas, or may cover the substrate membrane completely. In case receptors are not immobilized over the whole area of the substrate membrane, the cover membrane in an embodiment at least covers the area(s) of the substrate membrane on which receptors are immobilized. Cover membranes and methods for producing them are, in principle, known in the art, e.g. from Yang et al. (2022), Microsystems & Nanoengineering 8:78.

[0083] Also optionally, the sensor further comprises at least one detection device configured for determining at least one detectable property of the substrate membrane changing in the presence of the at least one volatile organic compound, wherein the detection device is selected from the group consisting of: at least one Mach-Zehnder interferometer; at least one surface plasmonic resonance imaging device; at least one Capacitive Micromachines Ultrasonic Transducer (CMUT). Appropriate detection devices are known in the art. In an embodiment, the detection device may be an arbitrary component which is designed to actuate a sensor, to record signals from the sensor, to derive at least one item of information on a VOC from the signals, to evaluate these signals in whole or part, and / or to transmit said signals to an evaluation device. Thus, the evaluation device may specifically be or may comprise an electronic component. The electronic component may be configured for performing a measurement with a sensor.

[0084] In an embodiment, the sensor and / or the detection device is arranged on one of a wristband, a patch placeable on a subject’s skin such as via an adhesive, a pair of glasses, a nose-clip, a nose-ring, a nose-piercing, a headband, a headset, a chest strap, a piece of clothing, a pillow, or a device on a bedside table. The sensor and / or detection device may be configured for establishing a skin contact with a subject’s skin, in an embodiment continuously and / or permanently, or may be configured for being arranged below a subj ect’ s nostril and / or below a subject’s mouth, either continuously and / or permanently and / or discontinuously. P39297 29. August 2025

[0085] - 22 -

[0086] Also optionally, the sensor comprises at least one gas distribution member configured for bringing a gaseous sample in contact with a detection device. Thus, the device may in particular be a handheld device with a mouthpiece into which the breath sample is exhaled by the subject, and from which the sample or an aliquot thereof is distributed to the substrate membrane.

[0087] Also optionally, the sensor comprises at least one evaluation device configured for determining a presence of the at least one volatile organic compound by evaluating the change determined by the detection device. As used herein, the term "evaluation device" relates to a device applying at least one calculation to a change determined by the detection device as specified herein above to determine a qualitative, in an embodiment quantitative, measure of at least one VOC, in an embodiment an volatile organic marker. Thus, in an embodiment, the evaluation device is adapted to determine a quantification parameter for at least one VOC. In a further embodiment, the evaluation device further is configured to determine a quantitative parameter for an analyte based on the quantitative parameter of a volatile organic marker. In an embodiment, the evaluation device is adapted to perform all calculations and evaluations required to print out a value of a quantitative parameter of at least one VOC or volatile organic marker and / or of an analyte; and / or to print out a result of a comparison of said value of a quantitative parameter to a threshold value. In an embodiment, the evaluation device comprises a data processing device, in an embodiment a microprocessor. In a further embodiment, the evaluation device comprises a database and / or an algorithm configured for determining a quantitative parameter of an analyte based on a quantitative parameter of a volatile organic marker. The evaluation device specifically may comprise a signal receiver, a signal transmitter, an analog-digital converter, an electronic filter, an energy storage device, a data storage device, such as a memory, and / or a data processing device, such as a microprocessor.

[0088] Advantageously, it was found that the inventive increase of the roughness of a surface of a substrate membrane, i.e. the membrane carrying the receptors, significantly enhances the sensitivity of a sensor, such as Aryballe’s NeOse sensor, to an extent which makes e.g. detection of glucose markers in breath samples possible. Without wishing to be bound by P39297 29. August 2025

[0089] - 23 - theory, it is assumed that the increased roughness increases the sensor surface and thus allows immobilization of more receptor molecules, thus increasing sensor sensitivity.

[0090] The definitions made above apply mutatis mutandis to the following. Additional definitions and explanations made further below also apply for all embodiments described in this specification mutatis mutandis.

[0091] In a further aspect, the present invention relates to a non-invasive glucose monitoring system comprising at least one volatile compound sensor as specified herein above, wherein the volatile compound sensor is configured for determining at least one change in concentration of at least one volatile organic compound indicative for glucose.

[0092] The term "non-invasive" is understood by the skilled person and in an embodiment relates to a proceeding not breaking a physical barrier of a body. Thus, a non-invasive method in particular does not require piercing of a skin or mucosa and, in an embodiment, does not require penetration into a body cavity or tissue.

[0093] The term “system”, as used herein, relates to a group of at least two elements or components, in an embodiment devices, which are configured to interact in order to perform at least one determination as specified herein elsewhere, in a further embodiment to determine a quantitative parameter of at least one VOC, volatile organic marker, and / or analyte, or to contribute to such determination. The system may comprise an assembly of two or more components capable of interacting with each other, such as in order to perform one or more diagnostic purposes, such as in order to perform a medical analysis. The system generally may also be referred to as an assembly or as a kit. The system, in an embodiment, comprises a sensor as specified herein above; a detection device as specified herein above; and an evaluation device as specified herein above. The system may further comprise a gas distribution member as specified herein above.

[0094] The components of the system, in particular the sensor, the detection device, and / or the evaluation device, may be connected or connectable to each other, specifically via wireless communication, in an embodiment via wireless far-field communication, in a further P39297 29. August 2025

[0095] - 24 - embodiment via radio frequency transmission. As used herein, the term "wireless far-field communication" generally refers to a wireless communication adapted to transmit data over long distances, such as distances of more than 10 cm. As an example, the wireless far-field communication may be an arbitrary long-range communication using electromagnetic waves in the radio frequency range, i.e. may be a radio communication. Thus, as an example, a wireless far-field communication may comprise at least one radio module, having at least one radio antenna, for transmitting data via radio transmission to another device. Specifically, a detection device may be configured for transferring data to at least one external device, e.g. an evaluation device, which may e.g. be a smartphone or a smartwatch, or any other device having the required features.

[0096] Optionally, the system is configured for permanent and / or discontinuous or continuous monitoring, in particular for permanent and pseudo-continuous or continuous monitoring, in particular of blood glucose, wherein the term "pseudo-continuous" relates to measurement at discrete time points but at a frequency to provide for an information density equaling continuous measurement. In the case of blood glucose measurement, said frequency may be e.g. every 5 min, in an embodiment every 10 min, in a further embodiment every 15 min, in a further embodiment every 30 min, in a further embodiment every 60 min.

[0097] In a further aspect, the present invention relates to a method for determining at least one volatile organic marker in a gaseous sample of a subject, wherein the method comprises passing said gaseous sample over a volatile compound sensor as described herein above. The method may in particular comprise the following steps:

[0098] (i) receiving a breath sample of the subject by the volatile compound sensor;

[0099] (ii) determining a physical change of the substrate membrane by using at least one detection device;

[0100] (iii) determining a presence of the volatile organic compound by evaluating the determined physical change.

[0101] As indicated herein above, the method in an embodiment is an in vitro method, i.e. uses a gaseous sample isolated from a subject. As the case may be, the method may also be performed in vivo, i.e. on the body of a subject. P39297 29. August 2025

[0102] - 25 -

[0103] The term “passing over”, as used in the context of the methods of the present invention, is understood by the skilled person. In an embodiment, the term relates to bringing a gaseous sample in physical contact with a sensor as specified herein elsewhere and thereby allowing compounds comprised in the gaseous sample and the receptors on the substrate membrane of the sensor to interact.

[0104] The term "physical change of the substrate membrane" is used herein in a broad sense to relate to each and every physical change related to and / or measureable on the substrate membrane. Thus the physical change may be a physical change of one of the components of the membrane, in an embodiment of the receptors comprised by the substrate membranes. As the skilled person understands, such change may be detected by measuring directly the component which changes, in an embodiment the receptors, or may be measured as a property of the substrate membrane.

[0105] In a further aspect, the present invention also relates to a method for assessing a blood glucose value in a subject, comprising the steps of the method for determining at least one volatile organic marker of the preceding claim and the further step of correlating the volatile organic marker to said blood glucose value.

[0106] The term "blood glucose value" is understand by the skilled person to relate to a value correlating to the blood glucose concentration in the blood of a subject. As the skilled person understands as well, an increased blood glucose value is a symptom which a such is not directly, but which may be, indicative of a disease, in particular diabetes.

[0107] In view of the above, the term “assessing”, as used herein, refers to establishing information and / or data about the status of the indicated condition. Said assessing, in an embodiment, is a measure of a physiological state of a subject, which as such is not diagnostic of a disease. The assessing may, however, be an aid in diagnosing the indicated disease; as the skilled person will understand, establishing a diagnosis may be based on the aforesaid assessment in combination with further diagnostic information, such as anamnesis data, general physical, mental examination findings, and / or additional metabolic data. Accordingly, P39297 29. August 2025

[0108] - 26 - assessing as used herein includes information useful for diagnosing diabetes, predicting the risk for developing diabetes, and / or predicting any deterioration of diabetes of the subject, in particular, with respect to signs and symptoms accompanying diabetes. Assessment referred to herein may also be the assessment of a risk of developing diabetes.

[0109] In a further aspect, the present invention relates to a use of a volatile compound sensor as described herein for determining at least one volatile organic compound.

[0110] Further disclosed and proposed herein is a computer program including computer-executable instructions for performing the method according to the present invention in one or more of the embodiments enclosed herein when the instructions are executed on a computer or computer network. Specifically, the computer program may be stored on a computer- readable data carrier and / or on a computer-readable storage medium.

[0111] As used herein, the terms “computer-readable data carrier” and “computer-readable storage medium” specifically may refer to non-transitory data storage means, such as a hardware storage medium having stored thereon computer-executable instructions. The computer- readable data carrier or storage medium specifically may be or may comprise a storage medium such as a random-access memory (RAM) and / or a read-only memory (ROM).

[0112] Thus, specifically, one, more than one or even all of method steps a) to d) as indicated above may be performed by using a computer or a computer network, preferably by using a computer program.

[0113] Further disclosed and proposed herein is a computer program product having program code means, in order to perform the method according to the present invention in one or more of the embodiments enclosed herein when the program is executed on a computer or computer network. Specifically, the program code means may be stored on a computer-readable data carrier and / or on a computer-readable storage medium.

[0114] Further disclosed and proposed herein is a data carrier having a data structure stored thereon, which, after loading into a computer or computer network, such as into a working memory P39297 29. August 2025

[0115] - 27 - or main memory of the computer or computer network, may execute the method according to one or more of the embodiments disclosed herein.

[0116] Further disclosed and proposed herein is a non-transient computer-readable medium including instructions that, when executed by one or more processors, cause the one or more processors to perform . . .

[0117] Further disclosed and proposed herein is a computer program product with program code means stored on a machine-readable carrier, in order to perform the method according to one or more of the embodiments disclosed herein, when the program is executed on a computer or computer network. As used herein, a computer program product refers to the program as a tradable product. The product may generally exist in an arbitrary format, such as in a paper format, or on a computer-readable data carrier and / or on a computer-readable storage medium. Specifically, the computer program product may be distributed over a data network.

[0118] Finally, disclosed and proposed herein is a modulated data signal which contains instructions readable by a computer system or computer network, for performing the method according to one or more of the embodiments disclosed herein.

[0119] Referring to the computer-implemented aspects of the invention, one or more of the method steps or even all of the method steps of the method according to one or more of the embodiments disclosed herein may be performed by using a computer or computer network. Thus, generally, any of the method steps including provision and / or manipulation of data may be performed by using a computer or computer network. Generally, these method steps may include any of the method steps, typically except for method steps requiring manual work, such as providing the samples and / or certain aspects of performing the actual measurements.

[0120] Specifically, further disclosed herein are:

[0121] - a computer or computer network comprising at least one processor, wherein the processor is adapted to perform the method according to one of the embodiments described in this description, P39297 29. August 2025

[0122] - 28 -

[0123] - a computer loadable data structure that is adapted to perform the method according to one of the embodiments described in this description while the data structure is being executed on a computer,

[0124] - a computer program, wherein the computer program is adapted to perform the method according to one of the embodiments described in this description while the program is being executed on a computer,

[0125] - a computer program comprising program means for performing the method according to one of the embodiments described in this description while the computer program is being executed on a computer or on a computer network,

[0126] - a computer program comprising program means according to the preceding embodiment, wherein the program means are stored on a storage medium readable to a computer,

[0127] - a storage medium, wherein a data structure is stored on the storage medium and wherein the data structure is adapted to perform the method according to one of the embodiments described in this description after having been loaded into a main and / or working storage of a computer or of a computer network, and

[0128] - a computer program product having program code means, wherein the program code means can be stored or are stored on a storage medium, for performing the method according to one of the embodiments described in this description, if the program code means are executed on a computer or on a computer network.

[0129] Summarizing and without excluding further possible embodiments, the following embodiments may be envisaged:

[0130] Embodiment 1 : A sensor for determining a volatile organic compound (volatile compound sensor) configured for determining at least one volatile organic compound in a gaseous sample of a subject, wherein the volatile compound sensor comprises at least one substrate membrane and a plurality of receptors configured to interact with one or more volatile organic compounds, wherein the plurality of receptors are immobilized on various sites of the substrate membrane, and wherein the substrate membrane has an arithmetic mean height of the surface of at least 0.04 pm. P39297 29. August 2025

[0131] - 29 -

[0132] Embodiment 2: The volatile compound sensor according to the preceding embodiment, wherein said substrate membrane comprises, in an embodiment consists of, a polyether polymer or an aromatic polymer.

[0133] Embodiment 3 : The volatile compound sensor according to any of the preceding embodiments, wherein said arithmetic mean height of the surface (Sa) is determined according to ISO 25178.

[0134] Embodiment 4: A sensor for determining a volatile organic compound (volatile compound sensor) configured for determining at least one volatile organic compound in a sample of a subject, wherein the volatile compound sensor comprises at least one substrate membrane and a plurality of receptors configured to interact with one or more volatile organic compounds, wherein the plurality of receptors are immobilized on various sites of the substrate membrane, and wherein the substrate membrane comprises, in an embodiment consists of, a silane modified polyether polymer.

[0135] Embodiment s: The volatile compound sensor according to any of the preceding embodiments, wherein said substrate membrane comprises, in an embodiment consists of, a silane modified polyether polymer or an halogenated aromatic polymer.

[0136] Embodiment 6: The volatile compound sensor according to any one of the preceding embodiments, wherein the volatile compound sensor further comprises at least one cover membrane configured for covering at least partially the substrate membrane with the immobilized receptors.

[0137] Embodiment 7: The volatile compound sensor according to the preceding embodiment, wherein the cover membrane is water resistant and gas permeable.

[0138] Embodiment 8: The volatile compound sensor according to any one of the two preceding embodiments, wherein the cover membrane comprises, in an embodiment consists of polydimethylsiloxane (PDMS).

[0139] Embodiment 9: The volatile compound sensor according to any one of the preceding embodiments, wherein the receptors are proteins.

[0140] Embodiment 10: The volatile compound sensor according to any one of the preceding embodiments, wherein the volatile compound sensor is a multivariate volatile organic sensor comprising a plurality of reactive sites configured for interacting with one or more volatile organic compounds, wherein the reactive sites comprise non-identical receptors having specific reactive binding properties with volatile organic compounds. P39297 29. August 2025

[0141] - 30 -

[0142] Embodiment 11 : The volatile compound sensor according to any one of the preceding embodiments, wherein the volatile compound sensor comprises at least one detection device configured for determining at least one detectable property of the substrate membrane changing in the presence of the at least one volatile organic compound, wherein the detection device is selected from the group consisting of: at least one Mach-Zehnder interferometer; at least one surface plasmonic resonance imaging device; at least one Capacitive Micromachines Ultrasonic Transducer (CMUT).

[0143] Embodiment 12: The volatile compound sensor according to the preceding embodiment, wherein the volatile compound sensor comprises at least one evaluation device configured for determining a presence of the at least one volatile organic compound by evaluating the determined physical change.

[0144] Embodiment 13: The volatile compound sensor according to any one of the preceding embodiments, wherein said gaseous sample is a breath sample or a skin emanation sample. Embodiment 14: The volatile compound sensor according to any one of the preceding embodiments, wherein said gaseous sample is a breath sample.

[0145] Embodiment 15: A non-invasive glucose monitoring system comprising at least one volatile compound sensor according to any one of the preceding embodiments, wherein the volatile compound sensor is configured for determining at least one change in concentration of at least one volatile substance compound indicative for glucose.

[0146] Embodiment 16: The non-invasive glucose monitoring system according to the preceding embodiment, wherein the non-invasive glucose monitoring system is configured for continuous monitoring.

[0147] Embodiment 17: A method for determining at least one volatile organic compound in a gaseous sample of a subject, wherein the method comprises passing said gaseous sample over a volatile compound sensor according to any one of the preceding embodiments referring to a volatile compound sensor.

[0148] Embodiment 18 : The method according to the preceding embodiment, wherein the method comprises the following steps:

[0149] (i) receiving a breath sample of the subject by the volatile compound sensor;

[0150] (ii) determining a physical change of the substrate membrane by using at least one detection device; P39297 29. August 2025

[0151] - 31 -

[0152] (iii) determining a presence of the volatile organic compound by evaluating the determined physical change.

[0153] Embodiment 19: The method according to any of the preceding embodiments relating to a method, wherein said volatile organic compound is a volatile organic marker.

[0154] Embodiment 20: A method for assessing a blood glucose value in a subject, comprising the steps of the method for determining at least one volatile organic marker of the preceding embodiment and the further step of correlating the volatile organic marker to said blood glucose value.

[0155] Embodiment 21 : Use of a volatile compound sensor according to any one of the preceding embodiments referring to a volatile compound sensor for determining at least one volatile organic compound.

[0156] Embodiment 22: The subject matter of any of the preceding embodiments, wherein said subject is suffering from diabetes or is suspected to suffer from diabetes.

[0157] Embodiment 23 : The subject matter of any of the preceding embodiments, wherein said at least one volatile organic compound is indole, formaldehyde, propionic acid, phenol and / or methanol.

[0158] Embodiment 24: The subject matter of the preceding embodiment, wherein said volatile organic compound is a volatile organic marker.

[0159] Short description of the Figures

[0160] Further optional features and embodiments will be disclosed in more detail in the subsequent description of embodiments, preferably in conjunction with the dependent claims. Therein, the respective optional features may be realized in an isolated fashion as well as in any arbitrary feasible combination, as the skilled person will realize. The scope of the invention is not restricted by the preferred embodiments. The embodiments are schematically depicted in the Figures. Therein, identical reference numbers in these Figures refer to identical or functionally comparable elements.

[0161] In the Figures: P39297 29. August 2025

[0162] - 32 -

[0163] Figure 1 shows schematically a non-invasive glucose monitoring system 100 (Fig. 1 A) and a measurement method 1000 (Fig. IB) as described herein. The system shown in Fig. 1A comprises a gas sampler 110, a VOC sensor 120, an evaluation device 130, and an output device 140. The method 1000 shown in Fig. IB comprises acquisition of a gaseous sample 1010, sample application to the VOC sensor 1020, registration of sensor signal(s) 1030, feature extraction 1040, and determination of VOC magnitude and / or VOC signature 1050.

[0164] Figure 2 shows two exemplary measurement principles suitable for the VOC sensor of the present invention, i.e. surface plasmon resonance measurement (Fig. 2 A) and interferometry (Fig. 2B). For details, cf. the description in Example 3.

[0165] Figure 3 shows schematically cross-sections of VOC sensors known in the art (Fig. 3 A) or according to the invention (Fig. 3B, C). In all embodiments, a substrate membrane 150 is applied to a substrate 170. While the substrate membrane of the prior art has a low roughness, and thus a low surface area per support area (Fig. 3A), the sensors according to the invention have a high roughness of the substrate membrane and therefore a high support membrane area per support area (Fig. 3B, C)

[0166] Detailed description of the embodiments

[0167] Example 1 : Non-invasive glucose monitoring system

[0168] In an exemplary embodiment shown schematically in Fig. 1A, the non-invasive glucose monitoring system 100 comprises an optional gas sampler 110, e.g. a mouthpiece, connected via a gas distribution member to the VOC sensor 120. Signals from the sensor 120 are transferred to an evaluation device 130, and output generated by the evaluation device 130 may be output, e.g. presented to a user, via an optional output device 140, e.g. a display or a communication unit allowing e.g. wireless communication.

[0169] Example 2: Measurement using the VOC sensor P39297 29. August 2025

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[0171] In an exemplary embodiment, the method 1000 of measurement of VOC with the VOC sensor comprises the steps shown schematically in Fig. IB: initially, a gas sample, e.g. a breath sample is obtained 1010, e.g. by causing a subject to exhale into a gas sampler 110 as shown in Fig. 1 A. The gas sample or an aliquot thereof may be distributed to the VOC sensor 1020 and a time series of the VOC signal after contacting with the sample may be registered 1030. The data from the time series obtained in step 1030 may be applied to a feature extraction algorithm 1040, whereafter a VOC magnitude and / or a VOC signature may be determined based on said data.

[0172] Example 3: VOC sensor measurement principles

[0173] VOC binding to the receptors of the VOC sensor may, on an exemplary basis, be detected by means in principle known in the art and schematically shown in Fig. 2. Shown in Fig. 2A is a VOC sensor using surface plasmon resonance as the measurement principle. The principal setup of a corresponding sensor is known to the skilled person and comprises providing a sensor 120 comprising a support 170, e.g. a thin gold film, onto which a substrate membrane 150 comprising receptors 160 is applied. A corresponding measurement device provides incident light 180, e.g. from a light source, and comprises a detection unit measuring light reflected from the support 170, wherein the angle of light reflection is a measure of adsorption of VOCs to the receptors 160.

[0174] Shown in Fig. 2B is a VOC sensor using a change of optical density of sensor surface as the measurement principle; corresponding sensors are known in principle in the art as well. A coherent light beam from a light source 200 such as a laser is split into a sensing arm 210 and a reference arm 220. The sensing arm 210 passes through a measurement field 230 comprising the substrate membrane and the receptors 160. Depending on the amount of VOCs bound by the receptors 160, the light passing through the sensing arm 210 and the measurement field 230 is retarded compared to the light passing through the reference arm 220, which can be measured by an optical detection unit 240, e.g. a Machs-Zehnder interferometer.

[0175] Example 4: Substrate membrane roughness P39297 29. August 2025

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[0177] In VOC sensors 120 known in the art, shown schematically in Fig. 3 A, the support membrane 150, if present at all, has a low roughness, and, thus, a small surface, such that only a small number of receptors can be applied. As schematically shown in Fig. 3B and C, the support membrane 150 of the invention has a high roughness and, thereby, an increased surface, allowing a higher number of receptors to be applied per area. The higher roughness may be provided by applying the support membrane 160 such that it has a high roughness (Fig. 3B), or by using a support 170 having a high roughness and applying a support membrane 150 in a contour-preserving manner (Fig. 3C). The increased support membrane surface allows application of a higher number of receptors per pre-determined support area, and thus an increased sensitivity of the sensor.

[0178] Example 5

[0179] A sensor substrate from Aryballe Technologies is coated by an optimized CVD-process with a polymeric membrane having a surface roughness of > 0.04 pm. Onto the substrate membrane thus produced, receptors are applied. Optionally, the substrate membrane is covered with a PDMS cover membrane with a layer thickness in the range < 10 pm. In measurements of VOCs indicative of blood glucose using appropriate receptors, the sensitivity of the sensor modified by the substrate membrane with higher surface roughness is at least approx. 2fold higher compared to a standard sensor. Also, the impact of humidity from the sample on the sensor signal is reduced by the PDMS cover membrane.

[0180] Literature

[0181] CA 2805676 A

[0182] EP 4085832 Bl

[0183] WO 2021 / 053284 Al

[0184] WO 2022 / 189292 Al

[0185] WO 2022 / 192599 Al P39297 29. August 2025

[0186] - 35 -

[0187] WO 2022 / 258559 Al

[0188] Yang et al. (2022), Microsystems & Nanoengineering 8:7

[0189] P39297 29. August 2025

[0190] - 36 -

[0191] List of reference numbers

[0192] 100 non-invasive glucose monitoring system

[0193] 110 gas sampler

[0194] 120 VOC sensor

[0195] 130 evaluation device

[0196] 140 output device

[0197] 150 support membrane

[0198] 160 receptors

[0199] 170 support

[0200] 180 incident light

[0201] 190 reflected light

[0202] 200 light source

[0203] 210 sensing arm

[0204] 220 reference arm

[0205] 230 measurement field

[0206] 240 detection unit

[0207] 1000 measurement method

[0208] 1010 sample acquisition step

[0209] 1020 sample application to VOC sensor

[0210] 1030 registration of sensor signal

[0211] 1040 feature extraction

[0212] 1050 determination of VOC magnitude and / or VOC signature

Claims

P39297 29. August 2025- 37 -Claims1. A sensor for determining a volatile organic compound (volatile compound sensor) configured for determining at least one volatile organic compound in a gaseous sample of a subject, wherein the volatile compound sensor comprises at least one substrate membrane and a plurality of receptors configured to interact with one or more volatile organic compounds, wherein the plurality of receptors are immobilized on various sites of a surface of the substrate membrane, and wherein the surface of the substrate membrane has an arithmetic mean height of at least 0.04 pm.

2. The volatile compound sensor according to the preceding claim, wherein said substrate membrane comprises, in an embodiment consists of a silane modified polyether polymer and / or an aromatic, optionally halogenated, polymer.

3. The volatile compound sensor according to any of the preceding claims, wherein said arithmetic mean height of the surface (Sa) is determined according to ISO 25178.

4. The volatile compound sensor according to any one of the preceding claims, wherein the volatile compound sensor further comprises at least one cover membrane configured for covering at least partially the substrate membrane with the immobilized receptors.

5. The volatile compound sensor according to the preceding claim, wherein the cover membrane is water resistant and gas permeable.

6. The volatile compound sensor according to any one of the two preceding claims, wherein the cover membrane comprises at least one material selected from the group consisting of: polydimethylsiloxane (PDMS).

7. The volatile compound sensor according to any one of the preceding claims, wherein the receptors are peptides, polypeptides, or proteins.P39297 29. August 2025- 38 -8. The volatile compound sensor according to any one of the preceding claims, wherein the volatile compound sensor comprises at least one detection device configured for determining at least one detectable property of the substrate membrane changing in the presence of the at least one volatile organic compound, wherein the detection device is selected from the group consisting of: at least one Mach-Zehnder interferometer; at least one surface plasmonic resonance imaging device; at least one Capacitive Micromachines Ultrasonic Transducer (CMUT).

9. The volatile compound sensor according to the preceding claim, wherein the volatile compound sensor comprises at least one evaluation device configured for determining a presence of the at least one volatile organic compound by evaluating the determined physical change.

10. The volatile compound sensor according to any one of the preceding claims, wherein said gaseous sample is a breath sample or a skin emanation sample.

11. A non-invasive glucose monitoring system comprising at least one volatile compound sensor according to any one of the preceding claims, wherein the volatile compound sensor is configured for determining at least one change in concentration of at least one volatile organic compound indicative for glucose.

12. A method for determining at least one volatile organic compound in a gaseous sample of a subject, wherein the method comprises passing said gaseous sample over a volatile compound sensor according to any one of the preceding claims referring to a volatile compound sensor.

13. The method according to the preceding claim, wherein the method comprises the following steps:(i) receiving a breath sample of the subject by the volatile compound sensor;(ii) determining a physical change of the substrate membrane by using at least one detection device;(iii) determining a presence of the volatile organic compound by evaluating the determined physical change.P39297 29. August 2025- 39 -14. Use of a volatile compound sensor according to any one of the preceding claims referring to a volatile compound sensor for determining at least one volatile organic compound.

15. The subject matter of any of the preceding claims, wherein said at least one volatile organic compound is indole, formaldehyde, phenol, propionic acid and / or methanol.

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