Electrochemical sensor systems and methods for sensing and analyzing reactions and biological processes.

Abstract

An electrochemical sensor system for sensing and analyzing reactions and biological processes is provided. The electrochemical sensor system includes: a current-measuring sensor comprising two electrodes, wherein the electrodes include a working electrode and a reference electrode, wherein the current-measuring sensor does not include other electrodes; and a potential-measuring sensor comprising the working electrode and the reference electrode, wherein the potential-measuring sensor does not include other electrodes, wherein the reference electrode of the potential-measuring sensor is connected to ground, wherein the working electrode of the current-measuring sensor is electrically connected to the reference electrode of the potential-measuring sensor, wherein the current-measuring sensor is configured to receive an excitation voltage between the working electrode and the reference electrode of the current-measuring sensor, such that the received excitation voltage is used as a reference voltage of the potential-measuring sensor via the reference electrode.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of European patent application 20382702.7, filed on July 30, 2020. Technical Field

[0003] This invention relates to electrochemical sensor systems for sensing and analyzing reactions and biological processes. The invention also relates to methods for sensing and analyzing reactions and biological processes. Background Technology

[0004] Electrochemical sensor systems using current-measuring sensors and potential-measuring sensors are generally known.

[0005] There are basically two types of current and potential sensors: those using two electrodes and those using three electrodes. Two-electrode sensors use a working electrode and a reference electrode. Three-electrode sensors use a working electrode, a reference electrode, and a reverse electrode.

[0006] In a potentiometric sensor with two electrodes, the potential between the working electrode and the reference electrode is measured. This potential is proportional to the concentration or activity of the analyte in the measurement medium.

[0007] In a current-measuring sensor with two electrodes, current is measured. This current is the result of an electroactive substance losing (oxidizing) or gaining (reducing) one or more electrons on the surface of the working electrode, which is at a constant operating potential relative to a reference electrode. The current is proportional to the concentration or activity of the analyte in the measurement medium.

[0008] However, in electrochemical sensor systems that include current-measuring sensors and potential-measuring sensors, there is interference or crosstalk between current-measuring and potential-measuring techniques, especially when the measurements of the current-measuring and potential-measuring sensors are performed substantially simultaneously and relatively close to each other.

[0009] The examples disclosed herein seek to at least partially reduce one or more of the aforementioned problems. Summary of the Invention

[0010] In a first aspect of the invention, an electrochemical sensor system for sensing and analyzing reactions and biological operations is provided. The electrochemical sensor system includes: a current-measuring sensor comprising two electrodes, wherein the electrodes include a working electrode and a reference electrode, wherein the current-measuring sensor does not include other electrodes; and a potential-measuring sensor comprising two electrodes, wherein the electrodes include a working electrode and a reference electrode, wherein the potential-measuring sensor does not include other electrodes, wherein the reference electrode of the potential-measuring sensor is electrically connected to ground, wherein the working electrode of the current-measuring sensor is electrically connected to the reference electrode of the potential-measuring sensor, wherein the current-measuring sensor is configured to receive an excitation voltage between the working electrode of the current-measuring sensor and the reference electrode of the current-measuring sensor, such that the received excitation voltage is used as a reference voltage of the potential-measuring sensor via the reference electrode of the potential-measuring sensor.

[0011] According to this first aspect, current-measuring sensors and potential-measuring sensors, each with two electrodes, are provided. This allows for the use of sensors that are relatively small in size and relatively inexpensive. Specifically, in such sensors with two electrodes, the use of a counter electrode is avoided. Counter electrodes are typically made of platinum, and their diameter can be relatively large, for example, 125 μm. Such use could imply additional cost and weight for the electrochemical sensor system.

[0012] In summary, in contrast to electrochemical sensor system solutions involving the use of current-measuring and potential-measuring sensors with three electrodes, the use of electromechanical sensor systems, including current-measuring and potential-measuring sensors with only two electrodes, facilitates more compact and cost-effective electromechanical sensor system solutions.

[0013] Furthermore, the working electrode of the current measuring sensor is electrically connected to the reference electrode of the potential measuring sensor, such that during use, the excitation voltage provided between the working electrode and the reference electrode of the current measuring sensor (via the reference electrode of the potential measuring sensor) serves as the reference voltage for the potential measuring sensor. Through this arrangement, and by grounding the reference electrode of the potential measuring sensor, a ground potential or virtual zero point is introduced in the working electrode of the current measuring sensor.

[0014] In use, when an excitation voltage is applied between the working electrode and the reference electrode of the current measuring sensor, a current is generated at the working electrode of the current measuring sensor. This current corresponds to the voltage drop caused by the excitation voltage of the current measuring sensor (and the ground potential or virtual zero introduced by the grounded reference electrode of the potential measuring sensor). This voltage drop corresponding to the excitation voltage between the working electrode and the reference electrode of the current measuring sensor is used as a reference voltage by the potential measuring sensor via its reference electrode. Therefore, interference between the measurement results of the current measuring sensor and the potential measuring sensor is avoided. Furthermore, current measurement and potential measurement can be performed substantially simultaneously.

[0015] In a second aspect of the invention, a method is provided for sensing analytical reactions and biological operations that can be executed by a control module. The method includes: receiving a filtered offset potential measurement voltage from a potential measurement sensor circuit; and substantially simultaneously receiving an output current measurement voltage signal from a current measurement sensor circuit. Then, substantially simultaneously, determining a current measurement result related to the received output current measurement sensor voltage from the current measurement sensor circuit and a voltage measurement result related to the received filtered offset potential measurement voltage from the potential measurement sensor circuit.

[0016] According to this second aspect, the control module receives a first voltage (from the current-measuring sensor) and a second voltage (from the potential-measuring sensor circuit) substantially simultaneously. Such a control module can also determine, substantially simultaneously, the current measurement result related to the output current-measuring sensor voltage received from the current-measuring sensor circuit and the voltage measurement result related to the filtered offset potential-measuring voltage received from the potential-measuring sensor circuit. Therefore, it is evident that measurements for both the current-measuring sensor and the potential-measuring sensor can be performed (almost) simultaneously, and all of these measurements are free from interference or crosstalk between them. Attached Figure Description

[0017] The following description, with reference to the accompanying drawings, illustrates a non-limiting example of this disclosure, wherein:

[0018] Figure 1 An example of an excitation circuit is shown; and

[0019] Figure 2a An example of a current-measuring sensor circuit is shown, wherein the current-measuring sensor circuit can be connected to an excitation circuit, which can be connected to... Figure 1 The excitation circuits shown are the same or similar;

[0020] Figure 2b Showing the formation Figure 2aAn example of a gain resistor circuit for a transimpedance amplifier (TIA) as part of a current measuring sensor circuit.

[0021] Figure 2c An example of a reference electrode circuit for a current-measuring sensor is schematically shown.

[0022] Figure 3 An example of a potential measuring sensor circuit based on an example potential measuring sensor is shown;

[0023] Figure 4 A block diagram of a control module for an electrochemical sensor system, based on some examples, is shown. Detailed Implementation

[0024] Throughout this disclosure, the term "electrochemical sensor system for sensing analytical reactions and biological operations" encompasses operations such as detecting local ischemia and hypoxia, and generally includes measurements related to oxygen levels and pH values.

[0025] Throughout this disclosure, the term "current measuring sensor excluding other electrodes" means that the current measuring sensor comprises only two electrodes. Similarly, the term "potential measuring sensor excluding other electrodes" means that the potential measuring sensor comprises only two electrodes.

[0026] Figure 1 An example of an excitation circuit 100 is schematically shown. The excitation circuit is configured to provide a voltage change as a function of time between the working electrode and the reference electrode of a current-measuring sensor. Therefore, a current may appear between such electrodes, specifically at the working electrode. This current can be measured using a current-measuring sensor, as will be explained later.

[0027] Circuit 100 may include a low-pass filter 101. The low-pass filter 101 may include a resistor 102 having two terminals 102a and 102b, a resistor 103 having two terminals 103a and 103b, a capacitor 104 having two terminals 104a and 104b, a capacitor 105 having two terminals 105a and 105b, and a capacitor 106 having two terminals 106a and 106b, as well as an operational amplifier 107. Operational amplifier 107 includes a negative input terminal 107a, a positive input terminal 107b, and an output terminal 107c.

[0028] Terminal 102b of resistor 102 can be connected to terminal 105a of capacitor 105. Terminal 102b of resistor 102 can also be connected to terminal 103a of resistor 103. Terminal 103b of resistor 103 can be connected to the positive input terminal 107b of amplifier 107. Terminal 103b of resistor 103 can also be connected to terminal 104a of capacitor 107. Terminal 104b of capacitor 103 can be grounded 180°.

[0029] According to the example, terminal 105b of capacitor 105 can be connected to the negative input terminal 107a of operational amplifier 107, and it can also be connected to the output terminal 107c of operational amplifier 107. The output terminal 107c of operational amplifier 107 can be connected to terminal 106a of capacitor 106. Terminal 106b of capacitor 106 can be grounded 180°.

[0030] Terminal 102a of resistor 102 can be connected to a pulse width modulator (PWM), such as a microcontroller (not shown). The microcontroller (e.g., a PIC32MX microcontroller) provides a pulse width modulation (PWM) output. The microcontroller is configured to provide a PWM duty cycle to the PWM output, such that the desired voltage can be supplied to terminal 102a of resistor 102. The aforementioned low-pass filter 101 is configured to remove alternating signals (pulses) and / or noise from the voltage supplied by the microcontroller, in order to provide a noise-free voltage (e.g., a noise-reduced voltage) to the current-sensing sensor circuit between the working and reference electrodes of such current-sensing circuit, as will be explained later.

[0031] It should be noted that the operational amplifier 107 can be configured to operate as an inverter amplifier providing a negative voltage to the current measuring circuit or as a voltage follower to provide a positive voltage to the current measuring circuit (specifically, between the working electrode and the reference electrode). The voltage provided to the current measuring circuit can be between -3 volts and +3 volts.

[0032] Figure 2a An example of a current-measuring sensor circuit that can be connected to an excitation circuit is shown, the excitation circuit being compatible with... Figure 1 The excitation circuit shown is the same as or similar to that shown. The current measuring sensor circuit forms part of the current measuring sensor. The current measuring sensor circuit 200 may include: a transimpedance amplifier (TIA) 201 including a negative input terminal 201a, a positive input terminal 201b, and an output terminal 201c; a resistor 202 including two terminals 202a and 202b; a resistor 203 including two terminals 203a and 203b; a resistor 204 including two terminals 204a and 204b; a gain resistor 205 including two terminals 205a and 205b; and an operational amplifier 206. The operational amplifier 206 includes a negative input terminal 206a, a positive input terminal 206b, and an output terminal 206c.

[0033] The negative input terminal 201a of TIA 201 can be electrically connected to the working electrode 280 of the current-measuring sensor. The positive input terminal of TIA 201 can be grounded 180. An excitation voltage can be applied between the working electrode 280 and the reference electrode (not shown in this figure) via the excitation voltage circuit described above. Therefore, current appears at the working electrode. This current is sensed by the working electrode 280. It should be noted that, as mentioned above, the circuitry of the reference electrode, which forms part of the current-measuring sensor, is not shown in this figure. Reference will be made later. Figure 2c The circuit is described below.

[0034] In any case, the current appearing at the working electrode corresponds to the voltage drop caused by the excitation voltage provided by the excitation voltage circuit and the ground potential 180 or virtual zero introduced by the reference electrode (which is grounded) of the potentiometric sensor, as will be explained later. In this respect, the reference electrode of the potentiometric sensor is connected to the working electrode of the current sensor. It should be noted that this voltage drop, i.e., the excitation voltage provided between the working electrode and the reference electrode of the current sensor, will be used as the reference voltage of the potentiometric sensor (sensed by the reference electrode), as will also be explained later.

[0035] The TIA201 can be configured to convert the current sensed by the working electrode 280 of the current measurement sensor into a proportional output voltage.

[0036] According to the example, a gain resistor (not shown) can be connected between the negative terminal of TIA201 and the output terminal 201c of TIA201. Figure 2b As shown, a circuit is provided that is configured to select the gain resistor for TIA. The circuit may include eight resistors 250-257, each of which includes two terminals 250a-257a and 250b-257b. The circuit also includes eight capacitors 260-267, each of which includes two terminals 260a-267a and 260b-267b.

[0037] The circuit also includes a CMOS analog matrix switch 269. This switch has eight input terminals 270-277. Terminal 250b of resistor 250 and terminal 260b of capacitor 260 are connected to input terminal 270 of the switch. Terminal 251b of resistor 251 and terminal 261b of capacitor 261 are connected to input terminal 271 of the switch. Terminal 252b of resistor 252 and terminal 262b of capacitor 262 are connected to input terminal 272 of the switch. Terminal 253b of resistor 253 and terminal 263b of capacitor 263 are connected to input terminal 273 of the switch. Terminal 254b of resistor 254 and terminal 264b of capacitor 264 are connected to input terminal 274 of the switch. Terminal 255b of resistor 255 and terminal 265b of capacitor 265 are connected to input terminal 275 of the switch. Terminal 256b of resistor 256 and terminal 266b of capacitor 266 are connected to input terminal 276 of switch. Terminal 257b of resistor 257 and terminal 267b of capacitor 267 are connected to input terminal 277 of switch.

[0038] Resistors of 250-257 can be selected in the range of 1 KOhm to 33 MOhms. Further selection of capacitors of 260-267 is possible to avoid unwanted oscillations.

[0039] Switch 269 may include a power input 290, which can be operated by a power supply from, for example, 2.7 volts to 5.5 volts, particularly 3.3 volts. Such a power supply may also be connected to address inputs 290, 291. The switch may also include a grounded ground reference 180. The switch may also include a serial clock line input, which can be used in conjunction with a serial data line input to time data into an 8-bit input shift register.

[0040] Again in Figure 2a In this configuration, the output terminal 201c of TIA201 can also be connected to terminals 202a of resistor 202 and 203a of resistor 203. Terminal 202b of resistor 202 can be connected to the negative input terminal 206a of operational amplifier 206. The output terminal 203b of resistor 203 can be connected to the positive input terminal 206b of operational amplifier 206. Additionally, resistor 204 can be grounded 180° via terminal 204a and connected to the positive input terminal 206b of TIA via terminal 204b.

[0041] Terminal 205a of gain resistor 205 can be connected to the negative input terminal 206a of operational amplifier, and terminal 205b can be connected to the output terminal 206c of operational amplifier 206.

[0042] Operational amplifier 206 can be configured to operate as an inverter amplifier when the proportional voltage output from transimpedance amplifier 201 is negative, in order to convert the negative voltage to a positive voltage. In some other examples, operational amplifier 206 can be configured to operate as a follower amplifier when the proportional voltage output from transimpedance amplifier 201 is positive. The reason for this arrangement is that a control module, including, for example, an AC-DC converter (not shown in the figure), can be connected to the output terminals of operational amplifier 206, as will be explained later. The AC-DC converter can be configured to operate in a voltage range between 0 volts and 3.3 volts, and therefore, when the operational amplifier outputs a negative voltage, such a negative voltage may not be detected by the AC-DC converter. In any case, the gain of operational amplifier 206 can be 1.

[0043] Figure 2c An example of a reference electrode circuit for a current-measuring sensor is shown. The reference electrode circuit of the current-measuring sensor may include an operational amplifier 800, which includes a negative input terminal 800a, a positive input terminal 800b, and an output terminal 800c. The circuit also includes a resistor 801 having two terminals 801a and 801b.

[0044] The reference electrode 809 of the current-measuring sensor can be connected to the positive input terminal 800b of the operational amplifier 800. Terminal 801a of the resistor 800 can be connected to the negative input terminal 800a of the operational amplifier 800. Terminal 801b of the resistor can be connected to the output terminal 800c of the operational amplifier 800. In this example, the resistor 801 can have 0 ohms. The operational amplifier can be configured to act as a potentiometer.

[0045] Figure 3 An example of a potentiometric sensor circuit according to an example potentiometric sensor is shown. The potentiometric sensor is configured to measure the potential difference between a working electrode and a reference electrode forming part of such a potentiometric sensor. The potentiometric sensor circuit 300 may include: a voltage follower operational amplifier 301 including a negative input terminal 301a, a positive input terminal 301b, and an output terminal 301c; a resistor 302 including two terminals 302a and 302b; a resistor 303 including two terminals 303a and 303b; a resistor 304 including two terminals 304a and 304b; a resistor 305 including two terminals 305a and 305b; a resistor 306 including two terminals 306a and 306b; a resistor 307 including two terminals 307a and 307b; and an adder amplifier 308. The adder amplifier 308 includes a negative input terminal 308a, a positive input terminal 308b, and an output terminal 308c. The potential measurement sensor circuit also includes RC circuit 309.

[0046] The working electrode 400 of the potential measurement sensor can be connected to the positive input terminal 301b of the voltage follower operational amplifier 301. The reference electrode 401 of the potential measurement circuit is grounded 180, and it is also electrically connected to the working electrode of the current measurement sensor (which is not shown in the figure, but is present in the figure). Figure 2a (As shown in the image), as described above.

[0047] With this arrangement, in use, as described above, the excitation voltage provided between the working electrode and the reference electrode of the current measuring sensor is used as the reference voltage of the potential measuring sensor via the reference electrode 401. The potential measuring sensor can therefore measure the potential difference between the working electrode and the reference electrode, wherein the potential difference between the working electrode and the reference electrode of the current measuring sensor is provided to the reference electrode. Therefore, measurements can be performed substantially simultaneously using the current measuring sensor and the potential measuring sensor without crosstalk or interference.

[0048] According to the example, the voltage follower amplifier 301 is configured to convert the voltage sensed between the reference electrode and the working electrode 400 of the potentiometric sensor into a proportional potentiometric voltage.

[0049] The negative input terminal 301a of the voltage follower amplifier can be connected to the output terminal 301c of this type of voltage follower operational amplifier. The output terminal 301c can also be connected to the terminal 302a of the resistor 302. The terminal 302b of the resistor 302 can also be connected to the terminal 303b of the resistor 303, the terminal 304b of the resistor 304, and the positive input terminal 308b of the adder amplifier 308.

[0050] Furthermore, terminal 304a of resistor 304 can be grounded 180° and connected to terminal 305a of resistor 305. Terminal 305b of resistor 305 can be connected to terminal 306a of resistor 306. Terminal 306b of resistor 306 can also be connected to the negative input terminal 308a of adder amplifier 308 and to terminal 307a of resistor 307. Terminal 307b of resistor 307 can be connected to the output terminal 308c of amplifier 308.

[0051] Similar to a current-measuring circuit, adder amplifier 308 can be configured to operate as an inverter amplifier when the proportional voltage supplied to it is negative, in order to convert the negative voltage to a positive voltage. In some other examples, adder amplifier 308 can be configured to operate as a follower amplifier when the proportional voltage supplied to it is positive. The reason for this arrangement is that a control unit, including an AC-DC converter (not shown in the figure), can be connected to the output of the potentiometer circuit. The AC-DC converter can be configured to operate within a voltage range of 0 volts to 3.3 volts, and therefore, such a negative voltage might not be detected by the AC-DC converter if the operational amplifier outputs a negative voltage.

[0052] The output terminal 308c of the adder amplifier 308 can also be connected to the RC circuit 309. The RC circuit includes a resistor 311 with two terminals 311a and 311b, and a capacitor 312 with two terminals 312a and 312b.

[0053] Terminal 311a of resistor 311 can be connected to output terminal 308c of amplifier 308. Terminal 311b of resistor 311 can be connected to terminal 312a of capacitor 312 and to the aforementioned control module including the AC-DC converter (not shown in the figure), as explained later. Terminal 312b of capacitor 311 can be grounded 180°.

[0054] As described above, the reference electrode 401 of the potential measurement circuit is grounded 180 and it is also electrically connected to the working electrode of the current measurement sensor, as described above.

[0055] It should be noted that the current measuring sensor and the potential measuring sensor, as described above, can be positioned adjacent to each other at a distance between 1 micrometer and 5 centimeters. Optionally, the current measuring sensor and the potential measuring sensor are attached to the support substrate.

[0056] Figure 4 A block diagram of a control module for an electrochemical sensor system, based on some examples, is shown.

[0057] The system may include an electromechanical sensor (array) system 600 as described above, a reader module 601 (e.g., a Huzzah ESP8266 transceiver) and a control module 602.

[0058] The reader module 601 can be configured to receive voltages from both the current-measuring sensor circuit of the current-measuring sensor and the voltages from the potential-measuring sensor circuit of the potential-measuring sensor. These voltages can be received substantially simultaneously. The reader module 601 may have, for example, wireless functionality. With this arrangement, the reader module 601 can wirelessly extract voltages from both the current-measuring sensor and the potential-measuring sensor using standard operation.

[0059] In summary, the reader module 601 is configured to extract voltage (signals) from the current measuring sensor circuit and voltage (signals) from the potential measuring sensor circuit substantially simultaneously, and to provide such voltages to the control module 602 for simultaneous processing of these voltages.

[0060] The control module 602 can be, for example, a PIC32MX795 microcontroller.

[0061] The control module 602 may include or may be implemented by electronic devices, computing devices, or combinations thereof, such that the electronic devices or computing devices can be used interchangeably, such that a portion of the device may be an electronic device and another portion may be a computing device, or all of the device may be electronic devices or all of the device may be computing devices.

[0062] Examples of control modules 602 that include only electronic devices (i.e., purely electronic configurations) can be programmable electronic devices such as CPLDs (Complex Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), or ASICs (Application-Specific Integrated Circuits).

[0063] An example of a control module 602 that includes only a computing device may be a computer system (e.g., a laptop, server, desktop computer, embedded computer, or industrial computer), which may include a memory and a processor. The memory is adapted to store a set of computer program instructions, and the processor is adapted to execute the instructions stored in the memory in order to generate various events and actions that have been programmed for the control module 602.

[0064] The computer program may include program instructions for causing the control module 602 to perform methods for sensing and analyzing reactions and biological manipulations, which will be described later. The computer program may be embodied on a storage medium such as a ROM (e.g., a CD-ROM or semiconductor ROM), a magnetic recording medium (e.g., a hard disk), a solid-state drive (SSD), a USB flash drive (e.g., a pen drive); or a non-volatile memory card such as an SD, miniSD, or microSD card. Furthermore, the computer program may be carried on a transmissible medium such as electrical or optical signals, which may be transmitted via cable or optical fiber or via radio or other means.

[0065] When a computer program is embodied in a signal that can be directly transmitted via a cable or other device or apparatus, the carrier may be composed of such a cable or other device or apparatus.

[0066] Alternatively, the carrier may be an integrated circuit in which a computer program is embedded, the integrated circuit being adapted to perform or be used to perform the relevant methods.

[0067] Computer programs can be in the form of source code, object code, intermediate source code, and object code, such as partially compiled forms, or any other form suitable for implementing methods. A carrier can be any entity or device capable of holding a computer program.

[0068] Furthermore, the control module 602 may also have a hybrid configuration between a computing device and an electronic device. In this case, the control module may include a memory and a processor for a computing portion to perform its functions, as well as specific electronic circuitry to perform the remaining functions.

[0069] As described above, in this example, control module 602 may be a PIC32MX795 microcontroller. The microcontroller may include a 32-bit architecture comprising at least one USB port and at least one I2C port. Microcontroller 602 may be configured to receive at least one response voltage, for example, from a current-measuring sensor circuit (see [link to relevant documentation]). Figure 2a ) and potential measurement sensor circuit (see Figure 3 The voltage signal can be received substantially simultaneously (i.e., almost simultaneously) or with a time difference of less than, for example, one second. In this regard, the microcontroller can be configured to: generate parameters related to current measurement sensing and potential measurement sensing (via USB port), generate a power signal related to current measurement, perform analog-to-digital conversion related to the potential and current sensors substantially simultaneously, perform selection of the gain resistor in the current measurement circuit (via the I2C port connected to ADG728 as described above), and send and receive information via transceiver 601 (e.g., Huzzah WiFiESP8266).

[0070] In any case, the control module 602 can be configured to perform methods for sensing and analyzing reactions and biological operations, wherein the method includes:

[0071] - Receives the filtered offset potential measurement voltage from the potential measurement sensor circuit;

[0072] - Essentially, it simultaneously receives the output current measurement sensor voltage from the current measurement sensor circuit;

[0073] - Essentially, it simultaneously determines the current measurement result related to the voltage received from the current measuring sensor circuit and the voltage measurement result related to the voltage received from the potential measuring sensor circuit.

[0074] Although only a few examples are disclosed herein, other alternatives, modifications, uses, and / or equivalents thereof may be employed. Furthermore, all possible combinations of the examples are covered. Therefore, the scope of this disclosure should not be limited to the specific examples, but should be determined solely by a reasonable interpretation of the appended claims. If reference numerals relating to the drawings are placed in brackets within the claims, they are used only to attempt to improve the comprehensibility of the claims and should not be construed as limiting the scope of the claims.

Claims

1. An electrochemical sensor system for sensing analytical reactions and biological operations, wherein, The electrochemical sensor system comprises: a current measurement sensor comprising two electrodes, wherein the electrodes comprise a working electrode and a reference electrode, wherein the current measurement sensor does not comprise further electrodes; a potential measurement sensor comprising two electrodes, wherein the electrodes comprise a working electrode and a reference electrode, wherein the potential measurement sensor does not comprise further electrodes, wherein the reference electrode of the potential measurement sensor is electrically coupled to ground; wherein the working electrode of the current measurement sensor is electrically coupled to the reference electrode of the potential measurement sensor, and wherein the current measurement sensor is configured to receive an excitation voltage between the working electrode of the current measurement sensor and the reference electrode of the current measurement sensor, such that the received excitation voltage is used as a reference voltage for the potential measurement sensor via the reference electrode of the potential measurement sensor.

2. The system of claim 1, wherein, The potential measurement sensor is an ion-selective sensor.

3. The system of any one of claims 1-2, wherein, The current measurement sensor and the potential measurement sensor are positioned adjacent to each other at a distance between 1 micrometer and 5 centimeters.

4. The system of claim 1, wherein, The current measurement sensor is coupled to a pulse width modulator configured to provide the excitation voltage between the working electrode of the current measurement sensor and the reference electrode of the current measurement sensor.

5. The system of claim 4, further comprising a low pass filter placed between the pulse width modulator and the current-sense sensor, wherein, The low pass filter is configured to remove a noise voltage signal from the excitation voltage received by the pulse width modulator, such that a noise-free excitation voltage is provided between the working electrode and the reference electrode of the current measurement sensor.

6. The system of claim 5, wherein, The low pass filter comprises an operational amplifier operated as an inverter amplifier to achieve a negative noise-free excitation voltage or as a voltage follower to achieve a positive noise-free excitation voltage.

7. The system of claim 1, wherein, The current measurement sensor further comprises a current measurement sensor circuit comprising a transimpedance amplifier, wherein the transimpedance amplifier comprises a positive input terminal, a negative input terminal and an output terminal, wherein the positive input terminal is grounded, wherein the negative input terminal is connected to the working electrode of the current measurement sensor, wherein the transimpedance amplifier is configured to convert an input current sensed via the working electrode of the current measurement sensor to a proportional output voltage.

8. The system of claim 7, wherein, The transimpedance amplifier further comprises a gain resistor arranged between the negative input terminal of the transimpedance amplifier and the output terminal of the transimpedance amplifier, wherein the current measurement sensor circuit further comprises a resistor gain circuit configured to select the gain resistor in a range between 1 KOhm and 33 MOhm.

9. The system of claim 7, wherein, The amperometric sensor circuit further comprises an operational amplifier, wherein a positive input terminal and a negative input terminal of the operational amplifier are coupled to the output terminal of the transimpedance amplifier, wherein the operational amplifier is configured to operate as an inverter amplifier in case the proportional voltage output by the transimpedance amplifier is a negative voltage, or to operate as a follower amplifier in case the proportional voltage output by the transimpedance amplifier is a positive voltage, in order to obtain an output amperometric sensor voltage.

10. The system of claim 9, wherein, The amperometric sensor further comprises a reference electrode circuit, wherein the reference electrode circuit comprises an operational amplifier, wherein the reference electrode of the amperometric sensor is coupled to a positive input terminal of the operational amplifier of the reference electrode circuit.

11. The system of claim 10, wherein, The potentiometric sensor further comprises a potentiometric sensor circuit, the potentiometric sensor circuit comprising a voltage follower amplifier, wherein the voltage follower amplifier comprises a positive terminal, a negative terminal and an output terminal, wherein the positive terminal of the voltage follower amplifier is coupled to the working electrode of the potentiometric sensor, wherein the voltage follower amplifier is configured to convert the voltage sensed between the working electrode and the reference electrode of the potentiometric sensor into a proportional potentiometric voltage.

12. The system of claim 11, wherein, The potentiometric sensor circuit further comprises a summing amplifier, wherein the summing amplifier comprises an input positive terminal, an input negative terminal and an output terminal, wherein the output terminal of the voltage follower amplifier of the potentiometric sensor is coupled to the input positive terminal and the input negative terminal of the summing amplifier, wherein the summing amplifier is configured to apply an offset to the voltage received by the voltage follower amplifier, in order to obtain an offset potentiometric voltage.

13. The system of claim 11, wherein, The potentiometric sensor circuit further comprises an RC circuit, wherein the RC circuit is coupled to the output of the summing amplifier, in order to obtain a filtered offset potentiometric voltage.

14. A control module comprising: at least one electrochemical sensor system according to any one of claims 11 to 13; a reader module configured to receive at least one response voltage from the potentiometric sensor circuit comprised in the potentiometric sensor; and at least one response voltage from the amperometric sensor circuit comprised in the amperometric sensor; the control module being configured to: receive the filtered offset potentiometric voltage from the potentiometric sensor circuit; receive substantially simultaneously the output amperometric voltage from the amperometric sensor circuit; and determine substantially simultaneously a current measurement related to the received output amperometric voltage from the amperometric sensor circuit and a voltage measurement related to the received filtered offset potentiometric voltage from the potentiometric sensor circuit.

15. A method for sensing an analytical reaction and biological operation that can be performed by the module according to claim 14, the method comprising: - receiving the filtered offset potentiometric voltage from the potentiometric sensor circuit; - receiving the output amperometric sensor voltage from the amperometric sensor circuit substantially simultaneously; and - determining a current measurement related to the received output amperometric sensor voltage from the amperometric sensor circuit and a voltage measurement related to the received filtered offset potentiometric voltage from the potentiometric sensor circuit substantially simultaneously.

16. A method for sensing an analytical reaction and biological operation that can be performed by the module according to claim 14, the method comprising: - receiving the filtered offset potentiometric voltage from the potentiometric sensor circuit; - receiving the output amperometric sensor voltage from the amperometric sensor circuit substantially simultaneously; - determining a current measurement related to the received output amperometric sensor voltage from the amperometric sensor circuit and a voltage measurement related to the received filtered offset potentiometric voltage from the potentiometric sensor circuit substantially simultaneously; and - determining a concentration of an analyte in the sample based on the current measurement and the voltage measurement.

17. A method for sensing an analytical reaction and biological operation that can be performed by the module according to claim 14, the method comprising: - receiving the filtered offset potentiometric voltage from the potentiometric sensor circuit; - receiving the output amperometric sensor voltage from the amperometric sensor circuit substantially simultaneously; - determining a current measurement related to the received output amperometric sensor voltage from the amperometric sensor circuit and a voltage measurement related to the received filtered offset potentiometric voltage from the potentiometric sensor circuit substantially

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