Measurement systems and associated techniques for sensing electrical characteristics of a sensor

Abstract

Systems, devices, and methods of sensing electrical characteristics of a sensor are generally provided. Measurement devices described herein employ techniques for improved sensitivity when sensing electrical characteristics of a sensor. In some aspects, measurement devices described herein may be configured to reduce the impact of current noise generated in components of a measurement system when sensing electrical characteristics of the sensor. The techniques described herein may facilitate the inclusion of larger sense resistors in measurement devices, which increases the sensitivity of the system. In some aspects, such techniques may also facilitate coupling the sensor between the measurement device and ground when sensing the electrical characteristics for improved protection against overvoltage events such as electrostatic discharge (ESD).

Description

[0112] It should be appreciated that, in some embodiments, TIA 510 and / or sense amplifier 530 and controller 102 may be positioned on different PCBs and / or in different enclosures. Alternatively or additionally, in some embodiments, TIA 510 and / or sense amplifier 530 may be coupled to controller 102 using one or more electrical connectors. Alternatively or additionally, in some embodiments, second input 516 may be coupled to sensor 106 by other means, such as conductive traces on one or more PCBs.

[0113] FIG. 9 shows a graph 900 of SNR of a voltage at the output of a measurement device versus voltage Vappl applied by the measurement device across a sensor, in accordance with some embodiments. A measurement device, including components configured in the manner described herein in connection with FIG. 5, was placed in a system with a sensor configured in the manner described herein for sensor 206 in connection with FIG. 2. In order to evaluate noise intrinsic to the measurement system, the nanowire 220 in sensor 206 was modelled by a thin-film resistor with an indicated resistance value.

[0114] As shown in FIG. 9, the measurement device applied voltages Vappl between 10 mVRMS and 100 mVRMS to the sensor 206 (via input 516 of TIA 510). In response to applying the voltages Vappl to the sensor 206, the measurement device generated an output voltage (at the output 538 of the sense amplifier 530). The output voltage corresponded to a sensed resistance of the sensor 206 and included signal content and noise content, the signal content including voltage caused by the resistance of the sensor and the noise content including voltage caused by noise in the system.

[0115] The ratio of signal content to noise content in the output voltage was determined by converting the output voltage to a digital signal using 24-bit ADC circuitry and calculating an amplitude of the output voltage by executing a lock-in amplifier process on the digital signal using a processor. Once the output voltage amplitude was calculated, the noise content in the output voltage was determined by calculating the standard deviation of the signal. The signal content was calculated as a mean value of the signal. In a first set of measurements, labeled in FIG. 9 with circular dots (•), the nanowire 220 of the sensor 206 had an indicated resistance of 10 MQ. In a second set of measurements, labeled in FIG. 9 with triangles (A), the nanowire 220 had an indicated resistance of 1 MQ.

[0116] As shown in FIG. 9, the measurement device achieved an SNR of over 20,000 for voltages Vappl between 10 mVRMS and 100 mVRMS applied to the sensor 206 having a resistance of 1 MQ. The measurement device achieved an SNR of over 5,000 for voltages Vappl between 10 mVRMS and 100 mVRMS applied to the sensor 206 having a resistance of 10 MQ, including an SNR over 10,000 for voltages Vappl between 30 mVRMS and 100 uiVrms and an SNR over 20,000 for a voltage Vappl of 100 mVRMS.

[0117] While several embodiments of the present technology have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the present application.

[0118] For example, while measurement devices having analog components have been described herein, it should be appreciated that digital components may be used as alternative or additional components of measurement devices described herein. Also, while discrete FET components of amplifiers have been described herein, such discrete components may alternatively or additionally include bipolar components and / or high electron mobility transistors, in accordance with various embodiments. Also, while nanowire sensors are described as one example of a sensor that may be used in accordance with the technology described herein, other sensors may be used such as nanotube sensors.

[0119] For example, in general, a plurality of nanowires comprises nanowires having a chemical composition that is desirable. By way of example, the nanowires may be formed from and / or comprise a material that is capable of being functionalized with one or more chemistries of interest (e.g., one or more chemistries having a desirable interaction with an analyte of interest and / or which can further react with a molecule having a desirable interaction with an analyte of interest). As another example, the nanowires may be formed from and / or comprise a material having a desirable electrical conductivity and / or equivalent surface potential (e.g., from a semiconductor, from a material that exhibits a change in electrical conductivity upon exposure to an analyte of interest, and / or from a material that exhibits a change in equivalent surface potential upon exposure to an analyte of interest). Non-limiting examples of materials having this property include selected elements (e.g., silicon), ceramics (e.g., gallium nitride, gallium arsenide, indium oxide, indium phosphide, molybdenum disulfide, tungsten disulfide), polymers (e.g., semiconducting polymers), onedimensional materials (e.g., carbon nanotubes, one-dimensional materials comprising one or more of the above-referenced materials), and two-dimensional materials (e.g., graphene, twodimensional materials comprising one or more of the above-referenced materials). In some embodiments, the nanowires are formed from and / or comprise one or more of the abovereferenced materials in single-crystalline form (e.g., single-crystalline silicon). Additional characteristics of nanowires and sensors are provided in U.S. Application No. 62 / 953,140 filed December 23, 2019, entitled Sensor System and Methods, which is incorporated herein by reference in its entirety for all purposes.

[0120] More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teachings of the present disclosure is / are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the technology described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the aspects of the technology may be practiced otherwise than as specifically described and claimed. The present application is directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent, is included within the scope of the present application.

[0121] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0122] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0123] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0124] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0125] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0126] It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

[0127] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

1. A device for sensing electrical characteristics of a sensor, the device comprising: a sense amplifier comprising a first input, a second input, and an output, the sense amplifier configured to generate a voltage indicative of the electrical characteristics at the output; anda transimpedance amplifier (TIA), comprising:a first input coupled to the second input of the sense amplifier;a second input configured for coupling to the sensor; and an output coupled to the first input of the sense amplifier.

2. The device of claim 1, wherein the TIA comprises:a sense resistor configured for coupling to the sensor; anda first amplifier having the first input, the second input, and the output, with the sense resistor coupled between the second input and the output.

3. The device of claim 2, wherein the sense resistor is configured to generate a sense voltage indicative of a current flowing through the sensor.

4. The device of any one of claims 1 to 3, wherein the electrical characteristics include a conductance of the sensor.

5. A system, comprising:the device of claim 4; andthe sensor, wherein the sensor is configured such that the conductance indicates a presence of one or more analytes at a surface of the sensor.

6. The system of claim 5, wherein the surface of the sensor comprises a binding entity for one or more of:a biomarker for brain injury, the biomarker selected from a group comprising: GFAP;2021237492   25 Sep 2026UCH-L1;S100P;ICH; andNFL-1; anda biomarker for one or more infectious disease agents comprising sepsis.

7. The system of any one of claims 5 or 6, wherein the sensor is configured to generate an impedance greater than 0.5 MQ when at least some analytes are disposed at the surface of the sensor.

8. The system of claim 7, wherein the impedance is greater than 50 MQ.

9. The system of claim 7, wherein the impedance is greater than 75 MQ.

10. The system of claim 7, wherein the impedance is greater than 100 MQ.

11. The system of any one of claims 5 to 10, wherein the sensor comprises a nanowire sensor.

12. The device of any one of claims 1 to 4 or the system of any one of claims 5 to 11 wherein:the TIA is configured to generate a sense voltage indicative of a current flowing through the sensor;the TIA is contained in a single integrated circuit package; andthe TIA comprises a plurality of discrete components comprising a field-effect transistor (FET).

13. The device of any one of claims 1 to 4 or the system of any one of claims 5 to 11, wherein the sense amplifier comprises at least one member of a group comprising:an instrumentation amplifier;a difference amplifier; andan operational amplifier.2021237492   25 Sep 202614. A system comprising:a printed circuit board (PCB) having the device of any one of claims 1 to 4 and at least one electrical connector mounted thereon, wherein the at least one electrical connector is configured for removably electrically coupling the device to the sensor.

15. The device of any one of claims 1 to 4, wherein the TIA is further configured to receive an input voltage signal at the first input of the TIA and to apply the input voltage signal to the sensor via the second input of the TIA.

16. A system for sensing electrical characteristics of a sensor, comprising:the device of any one of claims 1 to 4, wherein:the transimpedance amplifier (TIA) is configured to provide an alternating current(AC) voltage to the sensor; andthe sense amplifier is configured to generate a voltage indicative of the electrical characteristics responsive to detecting a current flowing between the sensor and ground.

17. The system of claim 16, wherein the TIA is configured to receive the AC voltage from an AC voltage source having a frequency between 0.1 Hz and 1 kHz and provide the AC voltage to the sensor.

18. The system of claim 16, wherein the TIA is configured to receive the AC voltage from an AC voltage source having a frequency between 500 Hz and 700 Hz and provide the AC voltage to the sensor.

19. The device of any one of claims 1 to 4, wherein the second input is configured to provide an alternating current (AC) voltage to the sensor.

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