Sensor device for biomarker measurement through animal skin

Abstract

A sensor device for biomarker measurement through animal skin, the device comprising a microneedle pad (10), an electronic unit that has a printed circuit board (11) and an evaluation unit (12) and is connected to the microneedle pad (10), and a communication module (13) that is connected to the electronic unit and is configured to transfer measurement data. The microneedle pad (10) comprises - an arrangement consisting of microneedles, the arrangement comprising at least one reference electrode microneedle (20), at least one counter electrode microneedle (21), and at least as many working electrode microneedles (22) as the number of the biomarkers to be tested, wherein an electrochemical sensor specific to the given biomarker to be tested is disposed on a surface of each working electrode microneedle (22); and - an anchoring adapted to mechanically anchor the device to the animal skin.

Description

[0001] SENSOR DEVICE FOR BIOMARKER MEASUREMENT THROUGH ANIMAL SKIN

[0002] TECHNICAL FIELD

[0003] The invention relates to a sensor device for biomarker measurement through animal skin. The invention is preferably a microneedle solution for monitoring veterinary status, and a device that facilitates making big-data based diagnoses obtained from biomarkers and preparing treatment and therapy plans.

[0004] BACKGROUND ART

[0005] Animal health is a serious global issue that requires appropriate scientific techniques. To that end, innovative approaches such as the application of biosensors in veterinary care may become more and more widespread. In human healthcare, these sensors are at various stages of commercialisation, but they are also being gradually introduced in practical veterinary / animal health applications. Certain techniques can be used for diagnosing an exact health state and a particular disease only in the case of animals. By way of modifications and testing for livestock farming, these innovative technologies can be applicable also in the field of livestock farming.

[0006] WO 2015 / 145422 A1 discloses a headlock system having a plurality of headlock cells, each of the cells being adapted to enclose at least one animal. The system is able to locate the position of at least one animal, and comprises the following: at least one identification means adapted to transmit at least one identification signal associated with said at least one animal; at least one locating means adapted to generate at least one location signal associated with said at least one animal; and, a data processing system in communication with said at least one identification means and said at least one locating means, adapted to analyse said signals, said analysed signals comprising the position within a predetermined region in said headlock system of each of said at least one animals as a function of time.

[0007] In WO 2005 / 104930 A1 a remote animal health and location monitoring system is disclosed that comprises an implantable / wearable monitoring device. The monitoring device includes a housing. The housing comprises a monitoring device controller in communication with the sensors for receiving signals indicative of the conditions. A monitoring device transmitter is in communication with the sensors for receiving signals indicative of the conditions. A monitoring device transmitter is in communication with the monitoring device controller and is configured for transmitting or broadcasting signals as sensed by the sensors.

[0008] The device according to FR 2842692 A1 comprises miniature sensors for acquiring the biometric data of an individual, a unit for collecting and processing information from the sensors, and a transmitter unit integrated into a portable single body support in communication with a fixed control or monitoring unit at a remote location.

[0009] In US 2017 / 0000372 A1 an invention called a “Health-monitor patch” is described, wherein at least one physiological sensor and digital processor is configured to be adhered to the skin of a subject. The health-monitor patch may further include an accelerometer and may detect cardiac waveforms, activity performed by the subject, and a body orientation of the subject. In some embodiments, the health-monitor patch may be disposable, and used for outpatient monitoring.

[0010] US 2008 / 0030348 A1 discloses a method and system for agricultural data collection and management, such as for tracking a product in a supply chain. In this approach, a data collection interface is applied between a first supply management device and a transaction database, the data collection interface providing the transaction database with access to identification data and event data.

[0011] The application of biosensors and wearable technologies is gaining importance in animal health management. These devices, when built accurately and used properly, may diagnose diseases in animals in time, which in turn may reduce economic losses and promote ethical livestock farming. Such devices are especially useful for dairy cattle breeders and farmers.

[0012] Approaches related to a microneedle dermal patch and to biosensing are disclosed in EP 2,750,754 B1 and WO 2022 / 221403 A1. The prior art contains such devices in the field of human health, but the known approaches include hollow microneedles, wherein the electrodes are located at the inside of the cavities, i.e. , the liquids to be tested must be introduced into the interior of the needles. Another drawback is that in the case of livestock farming, animals tend to rub off the patches, and adhesion may also deteriorate due to hair growing under the patch.

[0013] A widely applied prior art technology is microfluidics, which allows for the quick detection of analytes. In animal farms, such as in dairy farms, detecting animal analytes is of primary importance, and in this regard this technology has proven to be advantageous. With microfluidics technology it is possible to utilise small-scale samples that can be detected quickly and thus to reduce reagent waste. This conventional technique requires permanently installed equipment, which involves significant costs.

[0014] Fluorescence resonance energy transfer (FRET)

[0015] The integration of microfluidics and fluorescent devices not only ensures compliance with the requirement of minimal sample volume but also increases sensitivity while successfully reducing background noise. Microfluidic technology also helps reducing noise and maximising signal-to-noise ratio, however, it is necessary to install a Raman spectrometer that is adapted for detecting biomarkers or analytes by measuring Raman scattering and Rayleigh-scattered light signals. The material of the chip applied for the microfluidic technique must be suitable for microscopy and must have certain characteristics such as the non-adsorption of molecules. FRET technology is an approach that also involves significant costs and expenditures. Quantum dots

[0016] Certain features of microfluidics such as enabling spatial and temporal resolution and the easy discrimination between hybridization and non-hybridization DNA oligomers have made it more advantageous compared with previously applied technologies. However, as FRET-based techniques have issues related to pH-sensitivity and photobleaching, in order to ensure stability quantum dots (QD) are often applied. QD-s have an extended emission wavelength that can be modified by adding other nanomaterials for changing QD dimensions and composition. This solution is also very capital- and technology-sensitive.

[0017] At present, several non-invasive techniques are known in the technical field of the present invention.

[0018] Sweat analyser devices

[0019] Sweat analysis may provide useful information on the health state of certain animals. Wearable sweat analyser devices have not yet been made commercially available, primarily due to the size constraints of the device. However, cheap and robust implementations have already been developed in labs. Non-invasive sweat analysis methods include using electric current for introducing a chemical stimulant into the skin (iontophoresis), but this method still requires means for gathering, analysing, and monitoring sweat during the day (or as needed).

[0020] Agricultural (farm) monitoring

[0021] Conventional farm monitoring, i.e. , using written records or simple devices without data sharing capability is inaccurate and is prone to errors. Although there were earlier suggestions to apply global positioning systems, using GPS required detailed field maps, and was costly due to the need for satellite data transmission. Systems with audio-based input also have their own known disadvantages.

[0022] RFID tagging

[0023] RFID tagging, used in various diagnostic devices, for example implants and collars, has recently stirred attention in the international livestock market. However, the manufacturing and sale of these advanced products has caused legal issues because certain dog training collars were used to administer electric shocks to dogs.

[0024] Milk fat analysis

[0025] Sensor / detection systems for measuring the fat and protein content of milk are frequently used nowadays in livestock farms. The applied sensor systems are different for each livestock farm corresponding to the applied milking systems. These sensors are adapted to provide the health and fertility data of the animals. According to reports, the sensor / detection systems are able to detect 80-85% of cows in heat. It is not fully known whether the application of sensor systems also has beneficial effects on cow health and productivity. It has been proven in earlier studies that improved detection of in-heat cows results in shorter calving periods, which consequently leads to increased dairy production. Higher somatic cell counts have been associated with reduced dairy production. The application of automatic milking systems has been shown to improve dairy production.

[0026] Detection of bacteria with SERS

[0027] SERS (surface-enhanced Raman scattering) is an unlabelled biosensor method for detecting bacteria. It provides information on the chemical makeup of the analytes that is very robust but only allows the testing of animals one-by-one. SERS uses the inherent vibration fingerprint of the analytes for detecting molecules, but only in vitro. Furthermore, the performance of Raman spectroscopy is not affected by surrounding water, allowing for the easy detection of bacteria. Raman spectroscopy has found its applications in the analysis of chemical and biological components even in unlabelled modes.

[0028] PCR analysis

[0029] Enzymes applied for PCR analysis include polymerases, reverse transcriptases, nucleases, etc. Using thermostable polymerases enables amplification through thermostatic cycling. The PCR products can be visualised by agarose gel electrophoresis using fluorescent dyes. Electrophoresis enables amplicon length estimation and maintains specificity. However, the application of gel-based PCR may sometimes be tiring and does not allow for the quantification of the initial virus amount. The lack of specificity causes issues like false positive results. This problem has been solved by real-time PCR, which allows assays using sealed tubes with minimal cross-contamination risks. In these assays, the product is being monitored during the reaction by DNA-bonding particles that bond to the amplified DNA and emit fluorescence without necessitating a gel forming step.

[0030] GPS systems

[0031] GPS systems facilitate the detection of predators by recording movement history.

[0032] Camera sensors

[0033] In pig farms, camera sensors may easily detect relationships between dust concentration and pig behaviour. Various image processing systems can be applied for classifying / assessing the thermal comfort state of pigs and for analysing pig behaviour. The circadian rhythms of pig farms operating under windowless, round-the-clock-illumination conditions can also be studied. These video-stream analysis systems are also able to analyse weaning behaviour and the behaviour of individual piglets.

[0034] Stress detection

[0035] Stress negatively affects livestock productivity, so a quick and accurate stress measurement technology would be advantageous. Audio analysis is a reliable method for detecting cow stress. A cheap automatic prototype has recently been developed that sends stress level notifications to the farmer based on audio data. The prototype consists of three binary classifier support vector machines. First, the sounds emitted by the cows are detected, and then the classification module identifies and classifies the stress indicated by the sounds. This is followed by preparing an experimental evaluation using real-time audio data from an audio monitoring system.

[0036] Metabolism analysis

[0037] Metabolic disorders in cows can be detected through the elevated concentration of non-esterified fatty acids in biological fluids (which function as significant biomarkers). Cost-efficient and environmentally friendly sensor elements can be applied that are based on graphene oxide nanofibers modified with a ruthenium bipyridine complex and can be used for early diagnosis of metabolic diseases in cows.

[0038] Temperature measurement

[0039] The body temperature of animals is an important indicator of their physiological wellbeing. Thermistors, thermocouples, and infrared radiation detectors can be utilised for this purpose. By coupling these technologies with user-friendly interfaces new portable devices can be developed for farmers. Data gathered through the monitoring of thermal regulation processes in animals with regulated body temperature, such as pregnancy, giving birth, and lactation, can be utilised for determining the baseline condition of the animals. Core body temperature and rectal basal temperature can be used for analysing body temperature fluctuations and can be associated with various disorders. Core body temperature indicates the temperature of the major organs of the body, such as the heart, the viscera, and the brain. This temperature can be measured by rectal, vaginal, vascular, and gastric sensors. Central peripheral temperature, however, is the temperature of the body parts between the body core and the surface. It thus can be evaluated by means of intramuscular chips. Peripheral temperature is measured through the outside surface of the body of animals; to measure this temperature, microchips are embedded in the skin at a depth of a few centimetres. Likewise, infrared cameras may function as infrared radiation thermometers that measure the body temperature at several points / locations, thereby generating a two-dimensional image called a “thermogram.” This software-intensive technology allows for the monitoring of the body temperature of animals in various environments.

[0040] Saliva analysers

[0041] Biological fluids of animals, such as tear, sweat, and saliva, can be used for monitoring health state and for detecting disease conditions. Likewise, breath and the interstitial fluids of the body can also be used for this purpose. Non-invasive monitoring of uric acid in the saliva can be performed applying a mouth guard provided with a built-in screen-printed electrode system. Tracing lactate variants in saliva is another practical method for monitoring the health state of animals. Materials like carbon nanotubes and graphene may be used for producing and popularising such healthcare-related technologies.

[0042] Metabolite monitoring

[0043] It is important to monitor the metabolic activity of animals. The integration of bio-nanosensors for the detecting such metabolites as lactate, glucose and ATP are evaluated using animal models. These sensors comprise electrochemical components that are combined with a radio-frequency communications system provided with an antenna.

[0044] Breath analysers

[0045] The composition of volatile organic compounds in breath may provide deep insights into blood sugar levels. To this end, volatile organic compounds (VOC) are isolated and determined quantitatively. The glucose level of the blood is usually related to such volatile organic compounds as ketone bodies, ethanol, methanol, and exogenous compounds. In addition to that, the volatile composition of exhaled air can be utilised for the analysis of breathing - a non-invasive approach for providing an urgent diagnosis. These diseases include several cardiovascular (CVD) and chronic respiratory diseases. The volatile composition of breath reflects the composition of the bloodstream and the airways, which gives an overview of the metabolism of the organism. Methods like solid-phase and needle-trap microextraction may be combined with modern analytical techniques such as mass spectrometry, allowing for the analysis of exhaled air.

[0046] A disadvantage of wearable technologies currently applied in animal farming is that they apply non-invasive sensors that only provide basic data, and even when aggregated, these data are not sufficient for providing useful and actually usable information to livestock farmers.

[0047] Known sensors mountable on animals and wearable technologies are not suited for detecting the components of animal sweat, for measuring body temperature, for monitoring behaviour and movements, for stress detection, for analysing the animals’ sounds, for determining pH values, for preventing diseases, and for detecting the presence of viruses and pathogens on skin surface. However, even an aggregate of these data has not proven to provide sufficient information that could be effectively applied in disease prevention and therapy.

[0048] Wearable sensors could help farmers in the early detection of diseases and thus help them prevent livestock deaths. Thanks to the predictions, farmers would be able to kill sick animals in time to prevent the disease from spreading in livestock, such as in cattle herds. However, known approaches have not proven sufficient for providing adequate data in a sufficient amount for performing database and big data analyses aided by artificial intelligence.

[0049] Several systems have been developed for mobile phones and handheld devices to reduce the efforts related to manual data recording in livestock farming. However, these systems do not provide information suitable for prediction and planning.

[0050] Another issue is that with the unrestricted and frequent use of antibiotics in animal farming, antibiotics resistance poses a serious threat to farmers. In concentrated animal farming operations, ecological instability results from the uncontrolled application of subtherapeutic antibiotics, which in turn causes antibiotic resistance in the animals. A device that effectively implements biomarker measurement through the skin would also be desirable for this field of application.

[0051] DISCLOSURE OF THE INVENTION

[0052] The objective of the invention is to provide a sensor device for biomarker measurement through animal skin that eliminates the drawbacks of prior art approaches to the greatest possible extent and fulfils the objective cost-effectively, reliably, and humanely.

[0053] The objective of the invention has been accomplished by providing the device according to claim 1. Preferred embodiments of the invention are defined in the dependent claims. In addition to gathering useful data related to the health state of animals, farm monitoring in general can also be made simpler and more reliable applying the device according to the invention, which for example allows the use of biosensors integrated with mobile phones and other handheld devices. This can for example eliminate taking notes by hand and can replace keeping a log-book of the farming operations or using simple devices without data-sharing functions.

[0054] The sensor device according to the invention provides reliable data on the physiological state of the animals by means of measuring biomarkers and communicating them by a microneedle unit inserted into the skin. The invention thus implements a precision animal farming technology that, also in contrast to many sensor types applied in human healthcare, goes much further than technologies hitherto applied in animal farming.

[0055] With the solution according to the invention, i.e. , by integrating through-skin sensors and providing an effective online monitoring system, it becomes possible to monitor animal health in real time, without delay.

[0056] The real-time dissemination of data gathered from farms with the help of the invasive biosensors also has value outside the farms; i.e., it makes it possible for food industry stakeholders to access information that may prove crucially important for the agricultural industry in terms of issues requiring social approval, and are of key importance for our sustained global competitiveness.

[0057] The early detection of diseases with the help of biosensors allows for shifting the epidemic curve to the left because it allows quick reaction, slowing the spread of the disease and damping the related manufacturing, societal and economic consequences. Shortening the time required for diagnosing the biomarkers of infectious diseases in farms in real time provides an early warning system for intelligent animal health management.

[0058] The measurement of biomarkers, such as the quick and reliable detection of the presence, absence, or the quantity of particular chemical compounds in farm animals can be a matter of life and death. Keeping track of glucose or proteins or enzymes in the bloodstream, detecting harmful chemicals, for example metals or antibiotic residues in animals, and providing early warning for certain biological and chemical agents requires sensitive and reliable detection means in the livestock farming and veterinary fields. There is therefore a more and more urgent need for the real-time detection of diseases utilising sensors and other devices.

[0059] The device according to the invention can be applied for the prolonged and simultaneous monitoring of multiple biomarkers in the animal interstitial fluid with the help of a custom-designed microneedle “patch” (Veterinary Monitoring Patch, VMP) that has integrated sensors, the system adapted to penetrate animal skin is at the same time also capable of transferring information utilising the printed circuit board located in the device, and with the help of a communications and evaluation unit connected to it.

[0060] In particularly preferred embodiments of the invention, measurements are preformed on the surface of the microneedles. On the one hand, this provides a simpler configuration, and on the other, the concentration changes of the analyte in the fluid to be tested appear much more quickly than in the case of hollow needles, where the concentration change must also appear inside the needle cavity.

[0061] It is particularly preferable if the microneedles are long enough to penetrate the skin and reach the interstitial fluid in the dermis layer of the animal but are not long enough to reach the nerves and blood vessels. This results in a safe and humanely applicable sensor device that can be worn for prolonged periods.

[0062] BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Preferred embodiments of the invention will be explained referring to the accompanying drawings, where

[0064] Fig. 1 is a schematic structural drawing of the sensor device according to the invention,

[0065] Fig. 2 is a schematic spatial drawing of the microneedle pad of the sensor device according to Fig. 1 , Fig. 3 is a schematic side view of the microneedle pad according to Fig. 2, Fig. 4 is a schematic front view of the microneedle pad of Fig. 2,

[0066] Fig. 5 is a schematic underside view of the microneedle pad of Fig. 2,

[0067] Fig. 6 is a schematic underside view of another preferred microneedle pad, Fig. 7 is a schematic underside view of a microneedle pad provided with a diaphragm for inducing a flow of interstitial fluid,

[0068] Fig. 8 is a schematic underside view of a microneedle pad adapted to induce a flow of interstitial fluid based on the electrophoretic principle,

[0069] Fig. 9 is a schematic view of an electric sensor disposed on the outer surface of a working electrode microneedle,

[0070] Fig. 10 is a schematic view of an electric sensor disposed in a longitudinal recess formed in the outer surface of a working electrode microneedle,

[0071] Fig. 11 is a schematic view of an electric sensor disposed at the tip a working electrode microneedle, and

[0072] Fig. 12 is a schematic view of an embodiment applying a ribbon cable.

[0073] MODES FOR CARRYING OUT THE INVENTION

[0074] In the following, the embodiments of a wearable microneedle monitoring device will be described; the device is preferably suited for the simultaneous and continuous invasive monitoring of a plurality of biomarkers in the interstitial fluid present in the dermis layer of animal skin.

[0075] In some embodiments, for example, the wearable microneedle device comprises a sensor device having rows of microneedles, an electric circuit connected to the needles, electric sensors, and a casing structure with a connected unit adapted to assist evaluation. The microneedle sensor unit includes one or more rows of microneedles that are each configured to enter into an interaction with a given biomarker. The electric sensors issue the initial electric signal associated with the electrochemical reaction concerning the given biomarker; the acquired signal is transmitted up to the evaluation unit. The electric sensor is in connection with a power supply, with the data processing unit, and a wireless transmitter that is capable of Long Range communication. The casing structure is configured to encompass the electric unit but leave the row of microneedles exposed. The device can be configured as a skin-wearable unit wearable by the animal to be tested.

[0076] The invention is therefore a sensor device for biomarker measurement through animal skin that, as shown in Fig. 1, comprises a microneedle pad 10, an electronic unit that has a printed circuit board 11 and an evaluation unit 12 and is connected to the microneedle pad, and a communication module 13 that is connected to the electronic unit and is configured for transferring measurement data. The microneedle pad 10 according to the invention comprises

[0077] - an arrangement consisting of microneedles, the arrangement comprising at least one reference electrode microneedle 20, at least one counter electrode microneedle 21 , and at least as many working electrode microneedles 22 as the number of the biomarkers to be tested, wherein an electrochemical sensor specific to the given biomarker to be tested is disposed on the surface of each working electrode microneedle 22; and

[0078] - an anchoring adapted for mechanically anchoring the device to the animal skin.

[0079] To ensure a quick sensing of the biomarkers without the biomarkers entering the needle cavities, the electrochemical sensors are disposed on the outer surface of the needles of the microneedle pad 10 of the veterinary sensor device developed for a preferably continuous and simultaneous monitoring of animal biomarker levels via invasive testing through animal skin.

[0080] The microneedle pad 10 can preferably have any such configuration that provides long-term wearability on animal skin. The skin-facing surface of the microneedle pad 10 is preferably soft or cushioned, but variants having hard surfaces may also be applicable.

[0081] The microneedles 20, 21 , 22 are preferably configured to have a height that reaches the interstitial fluid present in the dermis layer of the given animal but does not reach nerves and blood vessels, i.e., preferably a height between 750 pm and 1450 pm. Thereby, sampling can be carried out in a pain-free manner, without causing any bleeding.

[0082] The reference electrode microneedle 20 preferably has Ag / AgCI coating, or is made of or has a coating made of a precious metal, for example platinum, gold, or an alloy thereof.

[0083] It is preferable if the microneedles 20, 21, 22 are configured to have lance-point shaped tips adapted to non-destructively separate the columnar epithelial cells of animal skin.

[0084] As it can be seen in Fig. 1, and also in Figs. 2-4 showing the microneedle pad 10 of Fig. 1 in a spatial view, in a side view and a front view, the microneedles 20, 21 , 22 are arranged in groups of three in the microneedle pad 10, wherein each group is configured for sensing a given biomarker, and each group comprises a reference electrode microneedle 20, a counter electrode microneedle 21 and a working electrode microneedle 22.

[0085] Such an embodiment is also conceivable in which the device comprises a single common reference electrode microneedle 20 and a single common counter electrode microneedle 21 for all the working electrode microneedles 22.

[0086] In the device according to the invention the anchoring preferably comprises anchor needles 23 without a sensing functionality; the needles being arranged at four comers of the rectangular microneedle pad 10 as shown in Figs. 1-4. Although the anchor needles 23 are longer than the sensing microneedles, preferably even they are not long enough to reach nerves and blood vessels; preferably, they have a “barbed” tip configuration to prevent them from slipping out. The anchor needles 23 without a sensing functionality are adapted for providing long-term, displacement-free mechanical anchoring to the skin of an animal. Optionally, the anchoring may also be implemented in other ways, for example as an ear-tag like anchoring, and it is also possible to combine these anchoring options. In Fig. 1 it is also schematically illustrated that the electronic unit is connected to the microneedle pad 10 with a releasable mechanical and electrical connector. The electrical connection is preferably brought about by means of hemispherical-tip contacts made of gold or other materials that are located opposite each other at the bottom side of the printed circuit board 11 and at the upper side of the microneedle pad 10, in which case the contacts located on the upper side opposite from the hemisphericals have flat ends. The exact number and arrangement of the protrusions are determined by the number and arrangement of the sensor microneedles. The releasable mechanical connection can, for example, be a flexibly clamped buckle design. Thanks to the releasable connection, used microneedle pads 10 can be discarded; also, separately provided microneedle pads 10 are easier to push into the skin using an applicator compared with pads integrated with the other functional units.

[0087] The printed circuit board 11 and the evaluation unit 12 are preferably interconnected in a non-releasable way; the printed circuit board 11 and the evaluation unit 12 together constitute a reusable electronic unit. The communication module 13 is, in turn, connected to the electronic unit preferably via a releasable mechanical and electric connection. The communication module 13 can be replaced according to the given communication protocol and task. However, in the case of a system prepared and used for a given task the above-described components constitute a single functional unit in normal operation, i.e. , they are not to be pulled apart. The communication module 13 is preferably disposed above the electronic unit in order to improve the signal-to-noise ratio and antenna efficiency. The communication module 13 preferably operates applying a long-range, low energy consumption protocol, i.e., LoRa or Sigfox, NB-loT, LTE-M, LTE, 4G, 5G, Zigbee, or even LoRaWAN, enabling reliable data transmission within large livestock farms.

[0088] The distances within livestock farms are typically large, and thus BLE and WIFI are not necessarily the best communications solutions. The invention can also be applied with such gates in which cattle are made to stop for a brief time while the system reads the data from the sensor by means of RFID while also charging the battery. Fig. 5 shows a schematic underside view of the microneedle pad according to Fig.

[0089] 2, depicting the bases of the microneedles (which preferably have a pyramidal shape) and showing that the microneedles are arranged in groups of three and in rows. Fig. 6 is a schematic underside view of another preferred microneedle pad wherein the groups of three are configured as islands. The variant having four groups of electrodes shown in Figs. 5 and 6 is a potential example; based on the same principle fewer or more groups of electrodes can also be included.

[0090] Therefore, the microneedles are preferably arranged on the tab in functional groups, where each group is configured for detecting a particular biomarker, thereby implementing the simultaneous monitoring of multiple biomarkers. However, by applying multiplexed measurements it is possible to monitor multiple biomarkers even utilising a single reference needle and a single counter electrode needle by a temporally staggered switching of the measurement circuit between the microneedles adapted for detecting the different biomarkers, thereby reducing the number of required electrodes and microneedles, and the number of electric wires (channels) included between the electric unit and the tab.

[0091] Fig. 7 is a schematic underside view of a microneedle pad provided with a diaphragm for inducing a flow of interstitial fluid. In this embodiment, a diaphragm 30 adapted to be vibrated electrically and, by way of the vibration, to induce a flow of interstitial fluid of the animal skin in the vicinity of the working electrode microneedles 22, is disposed on the skin-facing side of the microneedle pad 10. The diaphragm 30 operates as a microfluidic diaphragm pump driven by the electronic unit. The diaphragm 30 is controlled such that it directs the flow of interstitial fluid to the electrochemical sensors (located on the surface of the microneedles) in a targeted manner for sampling.

[0092] Fig. 8 is a schematic underside view of a microneedle pad adapted to induce a flow of interstitial fluid based on the electrophoretic principle. This preferred embodiment comprises electrophoretic means adapted to induce a flow of interstitial fluid in the vicinity of the working electrode microneedles 22 utilising the electrophoretic principle, the electrophoretic means comprising an electric field generation unit 40 adapted to generate an electric field between microneedles other than the working electrode microneedles 22.

[0093] The electric field generation unit 40 preferably comprises a digital to analogue converter or a pulse-width modulated signal generator adapted to generate a voltage profile consisting of voltage pulses and gaps, and to periodically switch the roles of anode and cathode.

[0094] The electric field generation unit 40 is expediently connected to microneedles 24 of the microneedle pad 10 that are dedicated for this purpose and do not perform any other function, to the anchor needles 23, and / or to the counter electrode microneedles 21.

[0095] The electric field generation unit 40 preferably also comprises a multiplexer circuit adapted to select, of the connected microneedles, those microneedles that are currently taking part in the electrophoretic induction of flow.

[0096] Thus, on the underside of the microneedle pad adapted for inducing a flow on the electrophoretic principle, the anchor needles 23 and sensing needles are also present, but it is also possible to apply designated needles or needle groups as an anode or cathode for electrophoretic liquid movement (EPhN or electrophoretic needles). The EPhN needles may be driven applying the unidirectional square-wave signal depicted as an example in the figure, but other control voltage profiles, such as bidirectional square-wave, triangle-wave, and sinusoidal-wave signals are also possible.

[0097] The preferred embodiment described above is therefore characterised in that the interstitial fluid is sampled, in the vicinity of the microneedles, based on the electrophoretic principle, with the help of the generated electric field. Active sampling is based on the phenomenon of reverse iontophoresis, more precisely on electroosmosis. Instead of passive diffusion, this method implements an active, directed movement of liquids to improve the efficacy of the sensor. The operating principle is based on the phenomenon that the tissues of the skin and the dermis have a net negative charge in a physiological medium due to the presence of proteins. When a low-voltage electric field is generated between the microneedles, the positive ions - mainly sodium ions - present in the interstitial fluid are attracted to the negatively charged tissue matrix. This mass of mobile positive charges starts to move towards the microneedle functioning as a cathode (i.e. a negative pole), carrying with it the water molecules in its hydration shell (and also the charge-neutral biomarkers, such as glucose, dissolved therein). This dominant electroosmotic flow generates a type of micro-level controlled “pumping” which transports the “fresh” interstitial fluid to the measuring electrodes. This is complemented by the secondary electrophoretic effect, which moves the charged biomarkers towards the needle with the appropriate polarity.

[0098] Precise control of the electrophoretic process is performed by the device applying, i.e., by means of, the printed circuit board 11. The exact voltage profile is generated by a microcontroller with the help of the digital-to-analogue converted (DAC) or the pulse width modulated (PWM) signal generator. It is important that the electric field is not generated by the sensitive working electrode 22 microneedles applied for performing the measurements but by needles dedicated for the purpose, or by the anchor needles and the counter electrode microneedles. A multiplexer circuit may be responsible for dynamically selecting which needles should perform the function of anode and cathode, and the measuring electrodes should expediently be disposed in the immediate vicinity of the needles functioning as anode.

[0099] Sampling is preferably not performed continuously but in a pulse-like manner. The control device feeds a short voltage pulse to the needles, which starts the flow of the liquid. This is followed by a relatively longer pause such that the tissue may regenerate, and the ion concentrations may return to their equilibrium state. For long-term stability, the system periodically switches the roles of anode and cathode, preventing electrode polarization and the “unidirectional” accumulation of ions. To ensure biocompatibility and safety, the operating parameters are subject to strict regulations. The applied voltage is preferably kept in the range between 0.5 V and 0.8 V by the electronics, which is safely under the potential of ~1 ,23 V required for water decomposition, so gas formation and the modification of the pH of the tissue can be prevented. The current in the circuit is restricted by the control device to an extremely low maximum current value between 10 and 100 microamperes, which prevents the tissue from heating up, and also prevents the stimulation of nerve receptors, so the process remains completely unnoticed by the animal. Over a preferred sampling cycle, a “fresh” sample is made to flow to the electrochemical sensor by a voltage pulse with a duration between 200 milliseconds and 1 second, followed by a pause of 2 to 10 minutes.

[0100] As it is schematically depicted in Figs. 9-11, the electrochemical sensor can be preferably disposed

[0101] - on the outer surface of the working electrode microneedle 22 (Fig. 9), - in a recess formed longitudinally in the outer surface of the working electrode microneedle 22 (Fig. 10), or

[0102] - at the tip of the working electrode microneedle 22 (Fig. 11 ).

[0103] The electrochemical sensor disposed on the surface of the working electrode microneedle 22 expediently comprises a charge-transfer base layer 50 that is for example made from graphene paste, an enzyme or aptamer active layer 51 arranged on the base layer 50, and a protective layer 52 or protective mesh arranged on the active layer 51.

[0104] The working electrode microneedle 22 is preferably configured as a solid body, with a conductive layer made of precious metal being disposed on its external coating. The electrochemical sensors disposed in the recess and at the needle tip are preferably sunk into the surface.

[0105] The electrochemical sensors preferably form part of a three-electrode electrochemical cell consisting of a reference electrode, a counter electrode, and a working electrode having a specific layer sequence, the electrodes being constituted, respectively, by the microneedles 20, 21, and 22. According to a preferred implementation of the invention, the base layer 50 of the layer sequence is constituted by a graphene paste layer modified by an ionic liquid (IL) and a phenanthroline dione (PD) redox modifier; this simultaneously provides secure anchoring of the biological molecules and a disturbance-free detection of NADH at a low potential. The active layer 51 performing biological detection, i.e. , a layer crosslinked applying glutaraldehyde (GA) and comprising NAD+co-factor, is built upon this layer. The system is protected from biofouling and electroactive disturbing substances by an internal semi-permeable chitosan diaphragm, and an external poly(vinyl chloride) (PVC) protective layer 52 with added Triton X-100 surfactant.

[0106] Another conceivable configuration makes use of precious-metal based electrodes, for example, gold, on the surface of which a mediator layer made of Prussian Blue facilitates electron transfer. In this case, instead of cross-linking, the enzyme is immobilised by means of covalent bonds via self-arranging monolayers (SAM), while external protection is provided by a biocompatible anti-fouling poly(ethylene glycol) (PEG) hydrogel coating.

[0107] Alternatively, the layer sequence can be based on intrinsically conductive polymers, such as PEDOTPSS. In this solution, anchoring of the enzyme is performed directly during the electrochemical separation of the polymer, i.e., the enzyme molecules are embedded in the growing polymer film. To improve biocompatibility and protection against disturbing ions, the surface can be coated with a Nation ion exchange polymer, or a cell-membrane-mimetic, extremely biocompatible phosphoryl choline (MPC)-based polymer.

[0108] Another possible approach applies high-surface area carbon nanostructures, for example carbon nanotubes (CNT), with a ferrocene derivative mediator being applied to their surface. Here, the enzyme is anchored by adsorption that is followed by embedding in a poly(vinil alcohol) (PVA) hydrogel. The function of the outer protective layer 52 can also be performed by a cross-linked bovine serum albumin (BSA) layer which is able to effectively prevent the adhesion of larger proteins. Another feasible alternative is to integrate the entire layer sequence in a robust, porous silica-based sol-gel matrix. In this technology, the enzyme, the cofactor, and the mediator are also enclosed in the generated glass-like but still porous structure during the polymerization of the silicate precursors. To improve the blood compatibility of the system, the outside surface can be coated with a heparin-conjugated polymer that is known for its anticoagulation and antifouling properties.

[0109] In another preferred implementation, instead of an enzyme the middle layer of the working electrode comprises an adsorption location that is able to selectively bond a target molecule, for example a bonding location for a complex, a crown ether derivative, or a custom-designed aptamer. In this case the measurement is based on that the potential of the system changes when the target molecule is bonded, and this potential differential can be measured. Technically, here the measurement is voltage measurement instead of current measurement.

[0110] In a similar, preferred alternative configuration the layer in contact with the surface of the needle does not comprise an ionic liquid and a redox mediator, i.e. , it only comprises a graphene paste.

[0111] Other implementation options are provided by any of the above-described preferred embodiments modified in that the layer in contact with the surface of the microneedle 22 comprises other types of nanostructured carbon instead of graphene paste, for example graphite and / or single-walled carbon nanotubes and / or multi-walled carbon nanotubes.

[0112] The microneedles 20, 21, 22 are preferably pyramid-shaped; the base of the pyramid preferably has a surface area of 250 microns x 250 microns that gradually diminishes to zero with height. The height of the microneedles 20, 21, 22 is preferably approximately 800 microns, the width of the trough formed in the outside surface is preferably between 5-10 microns, and its depth is preferably between 3 and 5 microns. Therefore, the microneedles of the device according to the invention can be implemented applying two different geometrical configurations. The electrochemical sensors may be disposed on the outer surface of solid needles (i.e. needles without an internal cavity), or on the protected inner surfaces of needles provided with a longitudinal trough or recess machined into the microneedle’s outer surface. It is important to note that this recess is not a penetrable channel extending along the microneedle but an “incision” (a slot) that has the primary function of protecting the functional layers and stabilising the measurement environment. Compared with solid needles, disposing the active sensor layers (e.g. enzyme, mediator, polymer matrix layers) in a recess machined into the side of the needle provides two technical advantages of key importance. Puncturing the skin places significant mechanical stress on the microneedles. The shearing and rubbing forces occurring during penetration are concentrated on the external surface of the needle. In case the sensitive biochemical layers are disposed in this protected trough, the outer edges of the recess function as a shield, absorbing the overwhelming majority of mechanical loads. This prevents the active layers from being rubbed off or delaminated, and thus significantly prolongs the operational life and improves the reliability of the sensor. The sensor retains its calibrated sensitivity even after repeated use or after long-duration implantation, because the biologically active components remain undamaged. In addition to providing mechanical protection, the recess also functions as some kind of a reaction chamber. The flow of the interstitial fluid around the needles subsides in this confined space, resulting in a diffusionlimited, more stable microenvironment directly at the sensor surface. This controlled environment reduces measurement noise and improves signal-to-noise ratio, because the biochemical reaction (e.g. enzymatic transformation) and the subsequent electrochemical detection may take place in a “calmer,” less variable environment. This results in more accurate, more reproducible measurements that are less sensitive to transient effects caused by movement or the variations of local circulation.

[0113] Fig. 12 shows a possible alternative implementation of the basic modular structure. Here, a thin, low-mass plate connector 15 is connected to the microneedle pad 10 with releasable electronic and mechanical connections. The plate connector 15 is interconnected by a multiwire cable 14 with an electronic unit secured to the animal elsewhere, i.e., farther from the measurement location.

[0114] The invention preferably further comprises a casing structure for enshrouding the reusable electric unit; the casing leaves the connector of the replaceable microneedle pad exposed. It preferably further comprises a circuit adapted for wireless charging and for short-distance transmission of RFID signals that can be applied for charging the electric unit and for reading out the measured data with devices built into special gates or resting boxes for cattle.

[0115] In our invention the microneedle device performs dual functions: it detects / measures the biomarkers, and it is also able to transmit the data over a communications channel for remote evaluation. The data received by the processing centre may even be evaluated applying artificial intelligence in order to help prepare the therapy.

[0116] The invention primarily concerns non-degradable microneedles without cavities, using poly(vinyl alcohol) (PVA)-based hydrogels or various methacrylates, mono-and copolymers and other cross-linked structures. A preferred variant of the invention is characterised by a needle point arrangement configured applying a novel lance point configuration, which, by entering the upper dermis layer takes a sufficient amount of sample material for evaluation, as due to the aggregation of the several small-sized needles a sufficiently large hole is punched in the skin.

[0117] The lancet-forming technology of the invention has been custom-developed by analysing cattle and pig skin to establish needle dimensions that “open up” the columnar epithelial cells of the dermis in a sheet-like fashion, the “sheets” closing together upon one another after removing the needle. In such a way, columnar epithelial cells are not damaged, and wound healing is also much faster after removing the needle due to the columnar epithelial cell surfaces closing together in a sheet-like fashion. The biosensor technology according to the invention provides a promising possibility for improving livestock production, and for improving costs and productivity in the treatment of livestock diseases. The development and introduction of reliable and quick tests and Al-based prediction and analytics allow for earlier and more specific treatment of diseases, which may potentially result in the reduced use of antimicrobial agents and may improve animal welfare. Besides that, the technology according to the invention may alert livestock farmers to diseases even before the appearance of the disease and may constitute a component of controlling models of integrated livestock farms. The application of this technology opens up new possibilities for reducing risks associated with diseases and factors affecting dairy production, and thus for improving livestock care and biological safety.

[0118] Based on the biomarker data acquired by the sensor device, a predictive analysis can be performed for the early detection of diseases at the asymptomatic stage, and for supporting the preparation of treatment plans.

[0119] The integration of the inventive diagnostic and disease detection system with mobile devices with the help of the biosensors is able to keep livestock farming and agriculture one step before invisible diseases. Intelligent, precision livestock farming and veterinary management will have increasing importance for satisfying the growing demand for food and for the creation of a sustainable agriculture.

[0120] In the following, the advantages and application possibilities of the invention will be described briefly in relation to preferred embodiments and preferred biomarkers. The solutions may also be applicable for example for detecting antibiotics.

[0121] The sensor device according to the invention may be freely combined for example with the non-invasive techniques mentioned in the introduction, or even with other sensing and monitoring techniques. For example, one of the microneedles may comprise an integrated thermometer. Furthermore, the invention may support digital animal health applications, as described below, by integrating further techniques. Monitoring and Al data management

[0122] The wearable microneedle sensor devices according to the invention can provide optimal performance due to the quality of the signal detectable by the microneedle sensor device and to the practical applicability of the device, enabling farmers to use the microneedle sensor device effectively for the preplanned time period and at the optimal location. The proposed microneedle sensor device has robust interfaces between the microneedle electrodes and the electronics, the interfaces being adapted for transferring the low-intensity electric signals corresponding to the electrochemically detectable biomarkers. The present invention discloses a robust, single-use microneedle sensor device that is only minimally invasive due to the applied special lancets, the device comprising a multi-sensor microneedle-electrode unit that is connected to a fully integrated electronic unit for the continuous monitoring of multiplex biomarkers. The animal interstitial fluid (ISF) can still be accessed by applying the specially shaped microneedles that have significantly lower height than conventional needle-based sensors. In some embodiments, the height of the microneedles of the sensor device is 750-1450 pm.

[0123] The invention is suited for the simultaneous, continuous monitoring of several biomarkers. In contrast to other commercially available wearable sensor devices, the solution according to the invention is capable of the multiplexed sensing / detection of the biomarkers of multiple animal injuries (for example, biomarkers released simultaneously due to a brain injury and bleeding, or biomarkers related to other injuries, including glucose, insulin, lactates, antibiotic analytes, electrolytes, and biomarkers of other injuries).

[0124] The electronics of the exemplary sensor device having rows of microneedles is preferably configured such that it can measure the low-intensity signals coming from the microneedle-based sensors. In addition to that, the connections between the microneedle sensor contingent and the electronics are preferably configured such that they allow for the production tolerances of both the microneedles and the electronics, while at the same time allowing the reuse of the electronics applying disposable microneedle pads 10 and ensuring communication with the printed circuit board 11. More particularly, the connection between the microneedles and the electronics is preferably configured such that the end user may simply and reliably secure the disposable microneedle array to the reusable electronics.

[0125] The microneedle-based microsensors, including the exemplary variant having rows of microneedles, are designed to penetrate the animal epidermis in a pain-free manner and access the ISF present in the dermis. For making the bases of the microneedles and microposts, biocompatible polyether ether ketone (PEEK) materials can be used. The sensor device can be made pain-free and reliable and can be left on / is able to stay on a shaved portion of the animal’s body for as long as seven days. For example, the secondary electric component of the sensor spot having serially arranged microneedles is reusable and is able to measure the biomarkers continuously for as long as seven days without recharging. The invention is preferably remotely switchable between an active and an inactive state, so it allows for savings concerning the electric power supply.

[0126] In contrast to prior art systems, the sensor system having a microneedle array described herein can also be applied for the multiplexed sensing / detection of multiple biomarkers related to an injury, or to several interrelated (or noninterrelated) injuries. The wearable electronic system is reconfigurable, which facilitates measuring multiple biomarkers and supports various sensor configurations. The quick-connect interface has been designed such that it can be quickly replaced after the rated lifetime of the microneedle sensor array has run out. The wearable sensor system can be configured such that remote activation prolongs its battery life. A preferred feature of the electronics included in the exemplary wearable sensor system is that multiple biomarkers can be measured by sequencing different combinations of the electrodes in the microneedle arrangement. The system is capable of analysing local data and of streaming the data real-time to the accompanying mobile app. The mobile app allows the wireless reconfiguration of the system such that it can adapt to changing conditions or to the new microneedle arrays.

[0127] In some embodiments the sensor device consists of the sensor elements comprising microneedles that are configured such that they penetrate the skin safely and in a pain-free manner to access the ISF, while at the same time supporting quick wound healing after removing the needles. The microsensor component is electrically connected to a printed circuit board via a quick connect interface. The microcontroller located on the printed circuit board allows the detected data to be sent to an external unit running an application software.

[0128] The device according to the invention preferably further comprises a software application and an artificial intelligence algorithm that - based on an analysis of the continuously gathered biomarker data - performs predictions in relation to the foreseeable health state of the animal being tested. The algorithm implements a predictive analytic system aimed at the early detection of disease conditions. The system processes the biomarker (e.g. glucose, lactate) time series data being continuously gathered by the sensor, the recorded master data of the animal (e.g. age, species), and optionally other environmental and behavioural data (e.g. activity). It removes noise from the received raw data, followed by generating relevant characteristic features such as the trends and rates of change of the biomarker levels, correlations between biomarkers, and deviations from biological data patterns. The central component is a neural network (typically with LSTM or GRU architecture) that is adapted for analysing time series data and is trained on health-related data validated by veterinarians. The outputs of the predictive model are: risk score - it assigns probability values to concrete diseases (e.g. ketosis, mastitis); anomaly detection - it recognises atypical patterns that deviate from healthy ones; automatic alerts - it sends an alert when a critical risk level is reached.

[0129] The remote software application

[0130] In the case of some embodiments the electronics included in some embodiments of the microneedle device comprises an electric sensor running on an embedded microcontroller that can be applied for controlling the measurements, while it also manages the device, performs data analysis and transmission and controls system performance. In such exemplary embodiments, the microcontroller may comprise an embedded Long Range communication module for data transmission between the sensor device and a mobile software application running on a connected device. The mobile software application preferably provides a flexible measurement control interface and real-time data visualisation, data analysis, and data export functionalities.

[0131] Microneedle electrodes / interface

[0132] The integrated system described herein also includes an efficient interface, with connectors, for the microneedle sensor platform for the electronic interface and the microneedle sensor array. The connector must also enable the end user to easily and reliably adjust the position of the microneedle pad 10 and connect it to the electronic connection points. In the exemplary embodiment a dual-layer printed circuit board (PCB) is applied for the integration of the electronic components. The microneedle pad 10 can be connected to the underside of this printed circuit board with electrical contact arrangements providing mutual contact.

[0133] The devices according to the invention may also be used for preparing wearable sensing and therapeutic applications. The interface allows setting up the single-use microelectric platforms reliably and enables them to be reliably connected to the reusable electronics. The electronics is suited for multichannel operation and for testing interconnections between components in addition to its primary function of monitoring the concentration of various biomarkers relevant for veterinary and biological aspects. The interface described herein has small size and comprises a repeatable connection mechanism and waterproof connectors.

[0134] The exemplary micro-interface provides a platform for wearable applications that require skin penetration of the microelectrodes to access the subepidermal fluids, such as the interstitial fluid (ISF) and blood. These fluids are accessed in a minimally invasive manner, causing only negligible pain to the animal wearing the device, while the device is reliably leak-free and electronically robust.

[0135] The technology described herein can be applied for the continuous, pain-free monitoring of biomarkers, for example for monitoring haemoglobin and lactate in an individual, pain-free and continuous manner. The interface allows setting up the single-use microelectric platforms reliably and enables them to be reliably connected to the reusable electronics. The electronics is suited fortesting multichannel interconnections and the interconnections between components in addition to its primary function of monitoring the concentration of various biomarkers relevant for biomedical aspects. The interface is configured such that it assists the electronics in controlling several microelectrodes in a multipotentiostatic manner. The electronics allows the individual polling of the microelectrodes and the combination of their signals in various arrangements. These features allow for measuring several biomarkers on various microelectric platforms irrespective of the chosen platform. The interface must ensure that all the electrodes are connected to the electronics.

[0136] The interface described above has small size, possesses a reliable and reusable connection mechanism, and provides waterproof electric connections. Additionally, the electronics board is capable of multiplexed detection at the tip of the microelectrodes, continuously monitoring the biomarkers of interest. Furthermore, the manufacturing device that is for example applied for producing the microneedles may facilitate a micromachining technique with a reproducible real-world accuracy of 1 micron.

[0137] One of the preferred fields of application of the present technology is related to the enzymatic detection and / or immunodetection of important injury-related biomarkers in the interstitial fluid (ISF). The microneedles preferably have a resilient base or cushioning and can be anchored to the animal skin so they can withstand the mechanical stresses occurring during operation. The microneedles can be adapted to have various extraction and detection configurations, including the pinpoint-like configuration of carbon electrodes, and the column-like microneedles of metallic gold or platinum electrodes.

[0138] The invention is therefore a veterinary sensor device for the continuous individual monitoring of various animal biomarkers with the help of a microneedle “patch” (Veterinary Monitoring Patch: VMP) developed for invasive testing through animal skin, and a communication device adapted for the evaluation and transmission of the measurement data, the device comprising a pad having multiple rows of microneedles, with needles capable of recording for example hyaluronic acid biomarkers being located on one side of the tab together with electric sensors corresponding to each needle, and with a PCB circuit and the communication module being located on the other side.

[0139] The microneedles are preferably disposed in multiple rows and have a length that is required for surface penetration. The penetration does not reach the small blood vessels and nerves, so it is not painful for the animal, and, being configured with a special lancet technology creating small wounds and supporting fast tissue regeneration, it provides pain-free penetration through the skin. At the connection of the needles to the electric sensors the device comprises an evaluation unit that detects the biomarkers obtained from the animal being tested through their interaction with reagents disposed at the sensor endpoints.

[0140] The microneedle row of the device is adapted for detecting the levels of the biomarkers required for indicating the state of key organs, and, at the endpoint of the sensor, for evaluation, it indicates for example the levels of hormones, enzymes, and body fluids. The microneedle pad 10 preferably includes foil (film) layers, with the signals proceeding between these layers to the electronic unit comprising the printed circuit board 11. The electronic unit provided with the printed circuit board 11 preferably has “sleep” and “active” operating states of which the control is in the hands of a third party located at the other endpoint of the communications channel.

[0141] In contrast to prior art approaches that perform measurements using liquids fed to the interior of the needles with the application of hollow needles, the solution according to the invention utilises sensors disposed on the outer surface of the microneedles. This configuration is simpler, can be produced more cost-effectively, and has a response time that is by orders of magnitude shorter because the concentration variation of the biomarker immediately appears at the electrode, so it is not required to exchange the liquid in the needle cavity. The special needle geometry characteristic of the preferred embodiments of the invention has been developed for the non-destructive separation of the thick skin of farmed animals to provide faster wound healing. Instead of the known approaches applying patches, an ear-tag like anchoring or anchor needles forming a part of the needle pad are applied that exclusively have a mechanical anchoring function. This solves the problem of long-term stable wearability that is of key importance in livestock farming.

Claims

CLAIMS1. A sensor device for biomarker measurement through animal skin, the device comprising a microneedle pad (10), an electronic unit connected to the microneedle pad (10), and a communication module (13) that is connected to the electronic unit and is configured to transfer measurement data, characterised in that the microneedle pad (10) comprises- an arrangement consisting of microneedles, the arrangement comprising at least one reference electrode microneedle (20), at least one counter electrode microneedle (21), and at least as many working electrode microneedles (22) as the number of the biomarkers to be tested, wherein an electrochemical sensor specific to the given biomarker to be tested is disposed on a surface of each working electrode microneedle (22); and - an anchoring adapted to mechanically anchor the device to the animal skin.

2. The device according to claim 1 , characterised in that the electrochemical sensor is disposed- on an outer surface of the working electrode microneedle (22),- in a recess formed longitudinally in an outer surface of the working electrode microneedle (22), or- at a tip of the working electrode microneedle (22).

3. The device according to claim 1 or claim 2, characterised in that the microneedles (20, 21 , 22) are configured to have a height that reaches an interstitial fluid present in a dermis layer of the given animal but does not reach nerves and blood vessels, preferably a height between 750 pm and 1450 pm.

4. The device according to any of claims 1-3, characterised in that the microneedles (20, 21, 22) are configured to have lance-point shaped tips adapted to non-destructively separate columnar epithelial cells of the animal skin.

5. The device according to any of claims 1-4, characterised in that the microneedles (20, 21, 22) are arranged in groups of three in the microneedle pad (10), whereineach group is configured to sense a given biomarker, and each group comprises a reference electrode microneedle (20), a counter electrode microneedle (21) and a working electrode microneedle (22).

6. The device according to any of claims 1-4, characterised in that it comprises a single common reference electrode microneedle (20) and a single common counter electrode microneedle (21) for all the working electrode microneedles (22).

7. The device according to any of claims 1-6, characterised in that the anchoring comprises- anchor needles (23) without a sensing functionality, and / or- an ear-tag like anchor.

8. The device according to any of claims 1 -7, characterised in that the electronic unit is connected to the microneedle pad (10) with a releasable mechanical and electrical connector.

9. The device according to any of claims 1-8, characterised in that a diaphragm (30) adapted to be vibrated electrically and, by way of the vibration, to induce a flow of interstitial fluid of the animal skin in the vicinity of the working electrode microneedles (22), is disposed on the skin-facing side of the microneedle pad (10).

10. The device according to any of claims 1-9, characterised in that it comprises electrophoretic means adapted to induce a flow of interstitial fluid in the vicinity of the working electrode microneedles (22) utilising electrophoretic principle, the electrophoretic means comprising an electric field generation unit (40) adapted to generate an electric field between microneedles other than the working electrode microneedles (22).

11. The device according to claim 10, characterised in that the electric field generation unit (40) comprises a digital to analogue converter or a pulse-width modulated signal generator adapted to generate a voltage profile consisting of voltage pulses and gaps, and to periodically switch the roles of anode and cathode.

12. The device according to claims 10 or 11, characterised in that the electric field generation unit (40) is connected to microneedles (24) of the microneedle pad (10) that are dedicated for this purpose and do not perform any other function, to the anchor needles (23), and / or to the counter electrode microneedles (21).

13. The device according to any of claims 10-12, characterised in that the electric field generation unit (40) also comprises a multiplexer circuit adapted to select those connected microneedles that are actually taking part in the electrophoretic induction of flow.

14. The device according to any of claims 1-13, characterised in that the electrochemical sensor disposed on the surface of the working electrode microneedle (22) comprises a charge-transfer base layer (50), an enzyme or aptamer active layer (51) arranged on the base layer (50), and a protective layer (52) or protective mesh arranged on the active layer (51).

15. The device according to any of claims 1-14, characterised in that the electronic unit has a printed circuit board (11) and an evaluation unit (12) provided with electric contacts connected to the electric contacts of the microneedle pad (10).

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