Patent Description:
Current nanopipette sensors fashioned from quartz glass capillary tubes suffer from significant shortcomings. They are difficult to fabricate and manufacture at scale. They are also fragile and easily broken. In addition, individual nanopipettes are highly variable and must be individually calibrated for accurate results. Nanopipette tips also show chemical and electrical degradation after repeated use, which seriously compromises performance and limits reuse. <CIT> describes devices containing freestanding, ultra thin (<<NUM> thick) membranes and methods of making such devices.

A nanosensor chip for detecting or quantifying target molecules in a liquid sample is the first aspect of the present invention and is provided in claim <NUM>. A method for detecting or quantifying target molecules in a liquid sample is the second aspect of the present invention and is provided in claim <NUM>. Preferred embodiments are provided in the dependent claims. Any embodiments of the disclosure below which are not encompassed by the claims are provided for reference only. A nanosensor chip for detecting and/or quantifying target molecules In a liquid sample is disclosed herein. The nanosensor chip includes a semiconductor substrate with one or more compound nanopores formed in the semiconductor substrate. Each compound nanopore is an aperture that includes multiple nanopores, each of which is functionalized with immobilized probe molecules. The probe molecules are used to detect the target molecules in the liquid sample. A compound nanopore is referred to herein as a "compore.

Each compore has a corresponding electrode structure on the semiconductor substrate. The electrode structure has a shape and position relative to the compore that enable the electrode structure to apply an electric field across all of the nanopores in the compore. The electrode structure also provides a conductive path for detecting an aggregate current through all of the nanopores in the compore. The detected aggregate current changes in response to target molecules in the liquid sample binding to the probe molecules, which binding is a function of the applied electric field.

For example, if the liquid sample includes some of the target molecules (e.g., a particular viral protein in a biofluid sample), when a specific electric field (or voltage) is applied across the compore, the target molecules bind to probe molecules in the nanopores. The probe molecules that functionalize the compore are selected to bind to the particular target molecule when a specific electric field is applied. The binding of the target molecules to the probe molecules changes the electrical characteristics of the nanopore openings, which creates a change in the aggregate current through the compore. A given probe molecule-target molecule pairing binds in the presence of a particular electric field strength or range of electric field strengths. If the liquid sample does not include the target molecule and the electric field is applied, there will be no aggregate current change. In addition, if an electric field different from the particular electric field strength or range is applied, the target molecules do not bind to the probe molecules and there is no aggregate current change.

The compore structure provides a greater level of reliability than prior nanopipette sensors. For example, if one of the nanopores in the compore is blocked or clogged, an aggregate current change is detected based on the binding of the target molecules to the probe molecules in the other, unblocked nanopores. Furthermore, if the nanopores in a given compore are not uniformly functionalized with the probe molecules, e.g., some nanopores have a higher concentration of probe molecules and other nanopores have a lower concentration of probe molecules, the change in aggregate current across all of the nanopores averages out the variations in concentration when detecting the presence of target molecules in liquid sample. Because of this greater reliability, the compore sensor is more accurate and reliable than prior nanopipette sensors.

Nanosensor chips may have other advantages over nanopipette technology. In particular, nanosensor chips can be efficiently and inexpensively manufactured at scale. An entire wafer of chips may be functionalized with probe molecules simultaneously, where the prior nanopipettes are indivudally functionalized. Due to improved consistency, a single chip can be used to calibrate an entire wafer of chips, instead of individually calibrating the nanopipettes.

Other aspects include components, devices, systems, improvements, methods, processes, applications, and other technologies related to any of the above.

The Figures (FIGs. ) and the following description relate to preferred embodiments by way of illustration only. It should be noted that from the following discussion, alternative embodiments of the structures and methods disclosed herein will be readily recognized as viable alternatives that may be employed without departing from the principles of what is claimed.

The figures depict embodiments of the disclosed nanosensor chip for purposes of illustration only.

Figure (<FIG> is a top view of a nanosensor chip <NUM> with multiple conical compound nanopores <NUM>, also referred to as compores <NUM>. The nanosensor chip <NUM> is formed from a semiconductor substrate <NUM>, e.g., a silicon or gallium arsenide (GaAs) substrate. Alternative substrates can be used instead, such as glass, plastic, film and other materials. One or more compores <NUM> are formed in the semiconductor substrate <NUM>. A compore <NUM> is an aperture formed in the semiconductor substrate <NUM> that includes multiple nanopores <NUM>. The nanopores <NUM> form holes extending through the semiconductor substrate <NUM>. The nanopores <NUM> have openings at a top of the compore <NUM> (shown in <FIG>) and at a bottom of the compore <NUM> on the reverse side of the nanosensor chip <NUM> (not visible in <FIG>). The nanopores <NUM> of the compore <NUM> are functionalized with immobilized probe molecules and collectively form an aperture through the semiconductor substrate <NUM>. The compore <NUM> may have a maximum width between <NUM> micron and <NUM> microns. The compore <NUM> is brought into contact with a liquid sample, for example it may be positioned vertically between sample and buffer reservoirs. It can be used to detect whether or not one or more target molecules are present in the liquid sample and/or to quantify the concentration of target molecules in the liquid sample, based on binding of the target molecules to the probe molecules.

The compore <NUM> can be used to assay any liquid sample, e.g., a sample of blood, saliva, spinal liquid, urine, food, beverage, water, etc., in which a target molecule of interest may be present. Different nanosensor chips <NUM>, and different compores <NUM> within a single nanosensor chip <NUM>, may be configured to assay different types of liquid samples and to detect one or more types of target molecules within the liquid sample. For example, one nanosensor chip <NUM> may be configured to test for a set of antibodies in blood samples, while another nanosensor chip <NUM> is configured to test for a set of contaminants in water samples.

Each of the nanopores <NUM> in a compore <NUM> is functionalized with immobilized probe molecules. Each nanopore <NUM> has a sidewall extending between the two openings, and probe molecules are affixed to the sidewall of the nanopore <NUM>. An example arrangement of probe molecules within a nanopore <NUM> is shown in <FIG>. The probe molecules may be selected for detecting a particular type of target molecule or set of target molecules in a liquid sample, e.g., to detect a particular antibody or set of antibodies in a blood sample, or to detect a particular contaminant in water. The probe molecules have a binding affinity to the target molecules, such that in the presence of a specific electric field, target molecules in a sample bind to the probe molecules. The target molecules may reversibly bind to the probe molecules, so that when the electric field is removed, the target molecules release from the probe molecules. Examples of probe molecules include antibodies, antibody analogs, proteins, aptamers, polymers, oligonucleotides, and nanobodies.

Each compore <NUM> has a corresponding electrode structure <NUM> laid out on the semiconductor substrate <NUM>. The electrode structure <NUM> has a shape and a position relative to the compore <NUM> suitable to apply an electric field across all of the nanopores <NUM> in the compore <NUM>. The electrode structure <NUM> also provides a conductive path for conducting an aggregate current that passes through the nanopores <NUM> in the compore <NUM>. For example, the electrode structure <NUM> may include one or more electrodes on the top of the compore <NUM> (as shown in <FIG>) and one or more electrodes on the reverse side of the compore <NUM> (not visible in <FIG>). Exemplary electrode structures are shown in <FIG> and <FIG>. The electrode structure <NUM> may connect to circuitry located on the nanosensor chip <NUM> for supplying a voltage source for the electric field and/or detecting the aggregate current. Alternatively, the electrode structure <NUM> may connect to an off-chip source and/or detector.

When the liquid sample includes the target molecule and the correct electric field is applied across the compore <NUM>, the target molecules bind to the immobilized probe molecules in the nanopores <NUM>. This binding changes an aggregate current that passes through the compore <NUM>. The aggregate current flows through the electrode structure <NUM> to a current detector on the nanosensor chip <NUM> or connected to the nanosensor chip <NUM>. A change in the aggregate current through all of the nanopores <NUM> of a compore <NUM> indicates the presence of the target molecules in the liquid sample. An amount by which the aggregate current changes may be used to determine a concentration or quantity of the target molecules in the liquid sample. By contrast, if the particular electric field is applied to the compore <NUM> but no aggregate current change is detected, this indicates that the target molecules are not present in the liquid sample.

Because each compore <NUM> includes multiple nanopores <NUM> that experience the same electric field and the aggregate current through all of the nanopores is detected, the compore <NUM> has a greater reliability than previous nanosensors. For example, even if one or a few of the nanopores <NUM> are blocked or clogged, the aggregate current through the set of nanopores <NUM> in the compore <NUM> still changes in response to the target molecules in the liquid sample binding to the probe molecules in the presence of the electric field. Similarly, the change in aggregate current through the set of nanopores <NUM> can still be detected even if the nanopores are not uniformly functionalized, e.g., if some nanopores have more immobilized probe molecules than other nanopores. In addition, using multiple nanopores <NUM> increases the number of different types of target molecules that a single compore <NUM> can be used to detect, because the nanopores <NUM> can be functionalized with multiple different types of probe molecules. Configurations with multiple types of probe molecules are described further in relation to <FIG>.

The nanosensor chip <NUM> depicted in <FIG> includes four compores <NUM>. In other arrangements, the nanosensor chip <NUM> may include any number of compores, e.g., one, four, sixteen, or many hundreds or even thousands of compores. Two compores <NUM> on the nanosensor chip <NUM> may test the same liquid sample or different liquid samples. The compores on the nanosensor chip <NUM> may be identical, or some or all of the compores may be different from each other. For example, two compores <NUM> on a single nanosensor chip <NUM> may have different sizes, different shapes, different numbers of nanopores, nanopores with different sizes or shapes, or nanopores with different probe molecules. Including different compores on a single nanosensor chip <NUM> enables a single nanosensor chip <NUM> to perform multiple different tests, e.g., to test for multiple different target molecules, to test with different sensitivities, or to include controls to verify the accuracy and to authenticate the nanosensor chip <NUM>. Including multiple identical compores on a single nanosensor chip <NUM> may be used to improve the accuracy and reliability of a single nanosensor chip <NUM>.

In <FIG>, each compore <NUM> on the nanosensor chip <NUM> may be individually addressed using its respective electrode structure <NUM>. Because each compore <NUM> has a separate electrode structure <NUM>, the aggregate current through each compore <NUM> can be individually measured by a current detector connected to the electrode structure <NUM>. In some embodiments, each electrode structure <NUM> is also used to individually apply an electric field across each respective compore <NUM>. In other embodiments, the electrode structure for applying the electric field across a compore is distinct from the electrode structure used to measure the aggregate current through a compore. In such embodiments, the electrode structures for applying the electric fields may be connected for two or more compores, so that the same electric field or voltage can be applied to multiple compores simultaneously.

<FIG> is a perspective view of an individual compore <NUM>, but not showing the electrode structure. <FIG> shows the structure of the compore <NUM> in greater detail. The compore <NUM> has a central region <NUM> that is thinner than the semiconductor substrate <NUM>. The nanopores <NUM> are formed within this thinned central region. For example, the central region <NUM> may be thinned to a thickness of less than <NUM> micron. The thickness of the central region <NUM> is also the height of the nanopores <NUM> formed within the compore <NUM>. In a nanosensor chip with multiple compores, such as the nanosensor chip <NUM> shown in <FIG>, the thinned regions of the compores are separated from each other by unthinned regions. If desired, this may be used to maintain separation between the liquid samples of different compores and to maintain isolation between the voltages and currents of different compores.

Between the top of the central region <NUM> and the top of the semiconductor substrate <NUM>, the compore <NUM> has a compore sidewall <NUM>. The compore sidewall <NUM> is depicted as being sloped, but it may be straight, curved, or have some other arrangement. In some embodiments, the liquid sample may be placed in the depression formed by the central region <NUM> and the compore sidewall <NUM>, with a buffer solution on the other side of the compore <NUM>. In other embodiments, the nanosensor chip <NUM> may be positioned vertically between two reservoirs, one containing buffer solution and the other containing the liquid sample.

Various other configurations for applying a liquid sample to the compore <NUM> may be used. For example, the opposite side of the compore <NUM> may be exposed to the liquid sample instead. In such embodiments, the portion of the compore <NUM> surrounded by the compore sidewall <NUM> may receive a liquid buffer.

<FIG> is a top view of an individual compore <NUM>. <FIG> shows an exemplary arrangement of nanopores <NUM> in a compore <NUM>. Adjacent nanopores <NUM> are separated by some spacing <NUM>. The spacing distance <NUM> between two adjacent nanopores in a single compore <NUM> may be, for example, between <NUM> nanometer and <NUM> microns. In the example shown in <FIG>, the compore <NUM> has ten nanopores <NUM>. In other embodiments, a compore <NUM> may have a different number of nanopores <NUM>, e.g., from two to several hundred nanopores. While the nanopores <NUM> in <FIG> shows the nanopores <NUM> being arranged in three rows, in other embodiments, the nanopores <NUM> may have a different arrangement.

<FIG> is a cross section of the compore <NUM> through line A-A' shown in <FIG>. The compore cross-section includes three nanopores 130a, 130b, and 130c that pass through the semiconductor substrate <NUM>. In this embodiment, one side of the nanopore structure is characterized by a depression formed by the top of the thinner central region and the compore sidewalls. For convenience, this side will be referred to as the top side, and the reverse side will be referred to as the bottom side. Either the top side or the bottom side may be exposed to the liquid sample, and the other side is typically exposed to a buffer. In <FIG>, an upper electrode <NUM> is formed on the top surface of the compore <NUM> and a lower electrode <NUM> is formed on the bottom surface. However, one or both of these electrodes may be mounted externally to the chip, e.g. in the chip receptacle, in alternative embodiments.

The upper electrode <NUM> and lower electrode <NUM> form the electrode structure for applying the electric field to the compore <NUM> and for conducting the aggregate current through the nanopores <NUM>. Because all of the nanopores <NUM> in the compore <NUM> are in close proximity to each other, the electrode structure comprising the upper electrode <NUM> and lower electrode <NUM> located to the side of the nanopores <NUM> may be sufficient to apply an electric field across all of the nanopores <NUM> and to detect an aggregate current through all of the nanopores <NUM>. In alternative embodiments, the electrode structure may be more complex. For example, the upper electrode <NUM> may have a portion to the left of the nanopore 130a or encircling all of the nanopores (as shown in <FIG>). The upper electrode <NUM> may also extend into the areas between the nanopores 130a-130c. Similarly, the lower electrode <NUM> may have an additional portion formed to the left of the nanopore 130a, encircling the nanopores, and/or extending into the areas between the nanopores 130a-130c.

The upper electrode <NUM> and lower electrode <NUM> are connected to a voltage source <NUM> and a current detector <NUM>. The voltage source <NUM> supplies a selected voltage to the upper and lower electrodes <NUM>, which creates the electric field across all of the nanopores <NUM> in the compore <NUM>. The current detector <NUM> detects the aggregate current flowing through all the nanopores <NUM> in the compore <NUM>. The voltage source <NUM> and the current detector <NUM> may use different electrodes.

In some embodiments, the voltage source <NUM> and/or current detector <NUM> are incorporated into the nanosensor chip <NUM>. In such embodiments, the nanosensor chip <NUM> may further include a controller for controlling the voltage source <NUM> and the current detector <NUM>. For example, the controller may control the voltage source <NUM> to vary the applied voltage, in amplitude or frequency. Different patterns of applied voltages (i.e., electric fields) may be used to probe for different target molecules. From the current detector <NUM>, the controller may determine whether there is a change in the measured aggregate current through the compore <NUM> as a function of the applied voltage. For example, the controller may instruct the voltage source <NUM> to apply a series of different voltages across the compore <NUM> and, for each voltage, detect a level of change in the measured aggregate current. The controller may generate a signal indicating the current detected by the current detector <NUM> or indicating the determined change in detected current and transmit this signal to an off-chip processor for further processing. The controller may be implemented on the nanosensor chip and/or as part of an external device or component.

<FIG> is a cross-section of a single nanopore <NUM> of the compore <NUM>. The compore <NUM> has an upper opening <NUM> at the top of the nanopore <NUM> and a lower opening <NUM> at the bottom of the nanopore <NUM>. The upper opening <NUM> has an upper diameter <NUM>, and the lower opening <NUM> has a lower diameter <NUM>. The upper diameter <NUM> may be in the range of <NUM> nanometers to <NUM> nanometers. In this example, the lower diameter <NUM> is smaller than the upper diameter <NUM>, and may be less than <NUM> nanometers. However, in other embodiments, the nanopore may be "flipped" so that the upper opening is smaller. The nanopore <NUM> has a height <NUM>, which is the same as the height of the thinned central region <NUM> of the nanopore. The height <NUM> of the nanopore may be <NUM> micron or less. The nanopore has a sidewall extending between the upper opening <NUM> and the lower opening <NUM>. The sidewall slope is defined by the angle θ, which may be between <NUM>° and <NUM>°. In other embodiments, the sidewall is not straight as shown in <FIG>, but may be curved or have some other shape.

<FIG> are cross-sections that show operation of a nanopore. <FIG> shows a nanopore <NUM> having probe molecules <NUM> affixed to the sidewall. As shown in <FIG>, the probe molecules are affixed to the sidewall near the smaller opening, i.e., the lower opening <NUM> shown in <FIG>. The probe molecules <NUM> may extend up the entire sidewall, or may be concentrated in a portion of the sidewall, e.g., along a lower portion of the sidewall near the lower opening <NUM>. The probe molecules <NUM> may be attached to the sidewall of the nanopore <NUM> by covalent binding, non-covalent binding, or physisorption.

In the example shown in <FIG>, the nanopore <NUM> is exposed to a liquid sample that includes a target molecule <NUM>. In the example shown in <FIG>, the sample with the target molecule is located below the nanopores <NUM>. As described above, in other embodiments, the sample containing the target molecule may be located on the other side of the nanopores <NUM>. <FIG> shows the nanopore without the proper electric field applied. In this condition, the target molecules <NUM> remain separated from the probe molecules <NUM>.

<FIG> shows the same nanopore after a specific electric field has been applied across the compore. In the presence of this electric field, the target molecules <NUM> are attracted inside the nanopore, and individual target molecules <NUM> bind to corresponding probe molecules <NUM> to form probe/target bonds <NUM>. This binding creates an ionic current change in current across the nanopore <NUM>. The other nanopores in the compore are also functionalized with the same probe molecules <NUM> and exposed to the same sample and electric field, so other target molecules <NUM> in the sample flow into the other nanopores to form additional probe/target bonds <NUM> across the compore. The probe/target bonds <NUM> across the nanopores of the compore create an aggregate ionic current change that is measurable by the current sensor.

When the electric field is removed or changed, the target molecules <NUM> release from the probe molecules <NUM>. The target molecules <NUM> may flow out the nanopore <NUM>, reverting to the arrangement shown in <FIG>. The probe/target bond <NUM> is reversible, so that when the compore is subjected to a varying voltage, the target molecules <NUM> continually bind and release from the probe molecules <NUM>. The probe molecules <NUM> remain affixed to the sidewalls of the nanopores after use of the compore <NUM>, e.g., after the target molecules <NUM> bind and then release, and through resetting the compore <NUM> with a buffer liquid. Because the probe molecules <NUM> remain affixed after use, the compore <NUM> can be reused for multiple samples.

For some applications, the nanopores of a single compore <NUM> are functionalized with two or more different probe molecules. The probe molecules may be a same category of molecule (e.g., two antibodies) or different categories of molecules (e.g., one antibody and one protein). This allows a single compore <NUM> to be used to detect multiple different types of target molecules. In one exemplary application, a first probe molecule pairs with a first target molecule at a first electric field strength (e.g., +<NUM> volts), a second probe molecule pairs with a second target molecule at a second electric field strength (e.g., +<NUM> volts), and a third probe molecule pairs with a third target molecule at a third electric field strength (e.g., +<NUM> volts). A sequence of different electric fields can be applied to the compore <NUM> to determine if any of the three target molecules are present in the sample. This allows the compore <NUM> to be used to efficiently perform multiple tests simultaneously on a single sample with a single sensor.

For other applications, the probe molecules may be selected so that multiple target-probe pairings are able to bind at the same range of voltages. This configuration may be used to detect the presence of any of a set of target molecules, e.g., a set of multiple potential contaminants within a food product, or a set of target antibodies in a blood sample. By using multiple target-probe pairings that bind at the same voltage, the compore <NUM> can efficiently identify a negative result for a sample. For some applications, if a positive result is obtained, further testing may be performed to determine which target molecule is present after an initial positive result is obtained.

Including multiple nanopores <NUM> in a single compore <NUM> allows the compore <NUM> to be functionalized with more types of probe molecules than prior sensors. An entire wafer of nanosensor chips may be accurately spotted in parallel with probe molecules using a specialized high-resolution printer. This enables production of multiplex tests and test panels at low cost. Additionally, compores <NUM> may be functionalized to detect positive and negative controls for validation and calibration, as well as markers to authenticate and verify the integrity of the nanosensor chip and reagents.

<FIG> are graphs that illustrate operation of a compore. <FIG> is a graph showing the behavior of the compore when there are no target molecules present and <FIG> shows the response with target molecules. In this example, the voltage source <NUM> generates a square-wave current first at a voltage of -<NUM> millivolts (mV), then at -<NUM> mV, at <NUM> mV, and at +<NUM> mV. Each specific pair of probe and target molecule will have a specific voltage at which they will bind. This changes the electrical characteristics of the nanopore <NUM> opening, which alters the current, as shown in <FIG> where the specific voltage is -<NUM> mV. Compared to <FIG>, the strength of the output current changes. This indicates that the target molecules are binding to the probe molecules in the presence of the -<NUM> mV electric field, so the target molecules that bind to probe molecules at -<NUM> mV are present in the sample. The magnitude of the change in current may also indicate the concentration of target molecules in the sample. If a variable voltage is used, the target molecules may bind and release from the probe molecules. Certain target molecules may not bind and release. Instead, these may bind and remain bound.

While the compore <NUM> depicted in <FIG> has a circular shape and circular nanopores <NUM>, in other embodiments, the compore <NUM> and/or nanopores <NUM> may have different shapes and the nanopores may be arranged differently within the compore. <FIG> is a top view showing a first alternative arrangement of nanopores within a compore. <FIG> depicts a square compore <NUM> that has square nanpores <NUM>. In other embodiments, the compore <NUM> may be shaped as an oval, a rectangle, another polygon, or some other shape. Similarly, the nanopores <NUM> may be oval, rectangular, some other polygon, or have some other shape. The shape of the nanopores <NUM> may be different from the shape of the compore <NUM>.

<FIG> is a top view showing a second alternative arrangement of nanopores within a compore. While the compores <NUM> and <NUM> had nanopores of a consistent size, in other embodiments, the nanopores in a single compore may have different sizes. <FIG> depicts a compore <NUM> that has nanopores <NUM> of multiple different sizes, including a small nanopore 830A and a large nanopore 830B. The differently-sized nanopores <NUM> may have sloped sidewalls with the same angle (e.g., each has a sidewall angle of <NUM>°) or different angles. In some embodiments, using multiple different sized nanopores can improve the sensitivity and dynamic range of the nanosensor.

<FIG> is a cross-section of a compore <NUM> fabricated using semiconductor technology. The structure of the compore <NUM> is similar to the compore shown in <FIG>. The compore <NUM> includes a layer of silicon <NUM>, which is an example of the semiconductor substrate <NUM>. In other embodiments, other semiconductor materials may be used in place of silicon <NUM>. Alternatively, the nanosensor can be implemented on a substrate of glass, plastic, film or other non-conducting or semiconducting material. Various etching processes may be used to thin the substrate to form the compore central regions in the silicon <NUM>, e.g., wet etching or dry etching. A separate process such as ion-beam lithography may be used to form the nanopores. While only one compore <NUM> is shown in <FIG>, multiple compores may be formed and an electrode structure laid out, as shown in <FIG>.

Two layers of silicon nitride <NUM> and <NUM> are deposited on the top and bottom, respectively, of the silicon <NUM>. Various deposition processes for silicon nitride may be used to deposit the two layers of silicon nitride <NUM> and <NUM>, e.g., chemical vapor deposition or plasma-enhanced chemical vapor deposition. While layers of silicon nitride <NUM> and <NUM> for only one compore <NUM> are shown in <FIG>, the layers of silicon nitride <NUM> and <NUM> may extend across the nanosensor chip for each of the compores included in the nanosensor chip.

Two layers of electrodes <NUM> and <NUM> are deposited on the upper layer of silicon nitride <NUM> and the lower layer of silicon nitride <NUM>, respectively. The electrode layers <NUM> and <NUM> may be formed from any conductive material, e.g., copper, silver or platinum. Various deposition process for depositing the conductive material may be used to deposit the two layers of electrodes <NUM> and <NUM>, e.g., evaporation or chemical vapor deposition. In this embodiment, the layers of electrodes <NUM> and <NUM> are arranged on either side of the compore <NUM>. In other embodiments, the electrodes <NUM> and <NUM> may be laid out differently on the compore <NUM>, as described with respect to <FIG>. For example, in other embodiments, the electrode <NUM> may also be formed on the silicon sidewalls and/or on the surface of the thinned silicon. Each compore included in the nanosensor chip may have a similar electrode structure. In other embodiments, any of the electrodes may be located off-chip, in a separate component such as the chip receptacle in which the chip is mounted.

<FIG> is a block diagram of a detection system <NUM> that includes a nanosensor chip. The detection system <NUM> includes a nanosensor chip <NUM>, a chip receptacle <NUM>, a voltage source <NUM>, a current detector <NUM>, a controller <NUM>, a user interface <NUM>, a display <NUM>, and a communications interface <NUM>. Other components (not shown) may include processors, memory, digital-to-analog converters, and analog-to-digital converters. In other embodiments, the detection system <NUM> has additional, alternative, or fewer components than shown in <FIG>.

The nanosensor chip <NUM>, as described with respect to <FIG>, has one or more compores. The chip receptacle <NUM> is configured to receive and hold the nanosensor chip <NUM> and form electrical connections between components of the nanosensor chip <NUM> and other components of the detector system <NUM>. For example, the chip receptacle <NUM> may include electrodes configured to connect to the electrode structures <NUM> shown in <FIG>. The chip receptacle <NUM> may also have one or more fluid connections to the nanosensor chip <NUM>, e.g., to transfer one or more liquid samples to the compores of the nanosensor chip <NUM>, or to transfer a buffer liquid to the compores of the nanosensor chip <NUM>.

The voltage source <NUM> generates the electric field supplied by the electrodes to the compores. The voltage source <NUM> may be a variable voltage source that generates a varying current at a range of voltages to one or more compores. In some embodiments, the voltage source <NUM> is integrated into the nanosensor chip <NUM>. The detection system <NUM> may have one voltage source <NUM> or multiple voltage sources, e.g., one voltage source for each compore included in the nanosensor chip <NUM>. If the detection system <NUM> has fewer voltage sources than compores, the nanosensor chip <NUM> may have a switching mechanism to apply the voltage to one compore at a time, or the nanosensor chip <NUM> may be configured to apply the same voltage to two or more compores simultaneously.

The current detector <NUM> detects a current through a compore. In some embodiments, the current detector <NUM> is integrated into the nanosensor chip <NUM>. The detection system <NUM> may have one current detector <NUM>, e.g., one current detector for each compore included in the nanosensor chip <NUM>. Alternatively, it may have multiple current detectors. If the detection system <NUM> has fewer current detectors than compores, the nanosensor chip <NUM> may include a switching mechanism that allows the current detector to individually address a selected compore.

The controller <NUM> controls the voltage source <NUM> and the current detector <NUM>. The controller <NUM> may be similar to the controller described with respect to <FIG>. The controller <NUM> may be integrated into the nanosensor chip <NUM>, or may be part of a separate component or device. The detection system <NUM> may have one controller <NUM> for controlling all of the voltage sources, current detectors, and any switching mechanisms included in the detection system <NUM>. Alternatively, the detection system <NUM> may have multiple controllers <NUM>, e.g., one for each compore. In addition to controlling the voltage source <NUM> and current detector <NUM>, the controller <NUM> is also configured to interact with other components of the detection system, e.g., the user interface <NUM>, the display <NUM>, and the communications interface <NUM>.

The user interface <NUM> is configured to receive user input, e.g., a command from a user to start an analysis of a sample, or parameters for analyzing a sample. For example, the user interface <NUM> may receive parameters describing one or more voltages to be applied to a compore, or an indication of a testing procedure that is pre-programmed with a set of voltages to be run on the compore. The user interface <NUM> passes these commands or parameters to the controller <NUM>. The user interface <NUM> may include buttons, a keyboard, a touch screen, a microphone and voice recognition software, or any other suitable mechanism for receiving input from a user. Alternately, the detection system <NUM> may receive commands and parameters from a mobile phone app, tablet, PC, or web application, or from an automated external control system.

The display <NUM> provides visual output to a user regarding tests run by the detection system <NUM>. For example, the display <NUM> may be used in conjunction with the user interface <NUM> and the controller <NUM> to display options to a user, which can be selected by the user. The display <NUM> may also output test results generated by the controller <NUM>, e.g., whether a given target molecule is detected in a sample, or a concentration of a target molecule detected in a sample.

The communications interface <NUM> may allow the detection system <NUM> to communicate with one or more other devices over a network, e.g., a local network or the Internet, or by means of a serial or parallel, wireless or wired, interface such as Bluetooth, USB or other communication protocols. For example, the communications interface <NUM> may upload results of a test performed by the detection system <NUM> to another device or component for further processing, or may upload test results to a database.

Claim 1:
A nanosensor chip (<NUM>) for detecting or quantifying target molecules (<NUM>) in a liquid sample, the nanosensor chip (<NUM>) comprising:
a substrate (<NUM>) with one or more compound nanopores ("compores", <NUM>), wherein each compore (<NUM>) comprises an aperture formed in the substrate (<NUM>) with a central region (<NUM>) that is thinner than the surrounding substrate (<NUM>) and comprises therein a plurality of nanopores (130a, 130b, 130c),
characterized in that each of the nanopores (130a, 130b, 130c) has a larger opening (<NUM>) and a smaller opening (<NUM>), and each of the nanopores (130a, 130b, 130c) is functionalized with a plurality of immobilized probe molecules (<NUM>) affixed to a sidewall of the nanopore; and
for each compore (<NUM>), a corresponding electrode structure (<NUM>) having a shape that surrounds the plurality of nanopores (130a, 130b, 130c) and is arranged to conduct an aggregate current through the plurality of nanopores (130a, 130b, 130c), whereby the aggregate current changes in response to binding of target molecules (<NUM>) in the liquid sample to the probe molecules (<NUM>).