Analog event detection circuit for a nanopore array

Abstract

The present disclosure relates to nanopore arrays. A readout device for a nanopore array is provided, as well as an analog detection circuit for the readout device. The detection circuit is connectable to a readout electrode of a nanopore array and, in a detection mode, applies a bias voltage to the readout electrode. When the bias voltage is applied, it extracts a baseline current from an input current flowing through the readout electrode and, if the input current changes compared to the baseline current by a predetermined threshold, outputs a digital signal indicating the occurrence of a current event. The readout device comprises the detection circuit and a logic device. The logic device determines, based on the digital signal, whether a translocation event has occurred in the nanopore. In this case, it provides an instruction signal to the detection circuit to switch from the detection mode to a readout mode.

Description

Technical Field

[0001] This disclosure relates to nanopores and nanopore arrays. In particular, this disclosure provides a readout device for a nanopore array, and an analog detection circuit for the readout device. The readout device including the detection circuit can detect translocation events in the nanopore array. Background Technology

[0002] Nanopores are promising technologies for next-generation sequencing and / or proteomics. For example, solid-state nanopores are a method of fabricating nanopore devices on a solid (or similar) substrate using photolithography. To electrically record signals from such a solid-state nanopore, a constant bias voltage can be applied across the nanopore. This generates a current through the nanopore, and this current is modulated as (charged) molecules pass through it. A current amplifier can record the modulated current, and molecules passing through the nanopore can be identified based on this. This method is known as current-based detection.

[0003] Translocation events occur as a random process. Nanopores cannot be continuously filled by molecules, and therefore, typical nanopore signals are quite sparse. This means that most (mostly) of the signal from any single nanopore will contain uncorrelated baseline currents, while the actual translocation event signal is only a very small fraction of the entire recorded signal. However, since translocation events can occur at any point in time, nanopore signals are typically recorded continuously, and then useful portions of the signal are identified offline in post-processing.

[0004] Figure 1 A conceptual diagram of a nanopore array 11 and a conventional readout device 10 is shown. The nanopore array 11 comprises multiple nanopores with corresponding fluid channels (not shown). Each nanopore has its own readout chain in the readout device 10, which typically includes a transimpedance amplifier and a high-speed analog-to-digital converter. The raw digital output signal stream enters a signal processing block, which identifies translocation events in the signal stream and then analyzes them further (e.g., using a base call algorithm).

[0005] Because the original signal flow in an individual nanopore is sparse, it has only a small fraction (“current event 1”, caused by…) Figure 1The dropout in the exemplary signal shown may be related to the actual translocation event, and requires a significant amount of silicon area and power due to the need for numerous readout chains and analog-to-digital converters. However, most of these circuit building blocks will be processing irrelevant data most of the time. This creates a data bottleneck, especially for large nanopore arrays. For example, a nanopore array with 50,000 nanopores, each read at 1 Msps, with a typical resolution of 10 bits, would produce a raw signal stream of 500 Gbps. However, typical translocation rates can range from a few percent to at most tens of percent, meaning that only a very small fraction of this 500 Gbps contains actual data related to the translocation event. Summary of the Invention

[0006] In view of the above, this disclosure aims to provide an improved readout solution for nanopore arrays. The goal is to reduce the amount of data to be processed, thereby eliminating the aforementioned data bottleneck. Ideally, only data related to translocation events should be processed, while irrelevant data should be avoided.

[0007] As described in the independent claims, these and other objectives are achieved through the solutions disclosed herein. Advantageous embodiments are described in the dependent claims.

[0008] A first aspect of this disclosure provides a detection circuit for detecting translocation events in a nanopore array, wherein the detection circuit is connectable to a readout electrode of a nanopore in the nanopore array and is configured to, in a detection mode: apply a bias voltage to the readout electrode; extract a baseline current flowing through the readout electrode into the detection circuit when the bias voltage is applied from the input current; and output a digital signal indicating the occurrence of a current event if the input current changes by at least a predetermined threshold compared to the baseline current.

[0009] The detection circuit of the first aspect is capable of indicating that the input current deviates from the baseline current. This makes it possible to process only the data provided by the nanopore in the case of current events, where the data may correspond to a translocation event. In this respect, in the exemplary method of this disclosure, a current event can be used as an equivalent of a translocation event; that is, any current event can be considered a translocation event. In another approach, "false positives" of current events can be further analyzed to identify translocation events. As a result of using the detection circuit, only translocation events can be processed, but no irrelevant data must be processed. Therefore, the detection circuit of the first aspect is able to reduce the amount of data to be processed, thereby eliminating the aforementioned data bottleneck.

[0010] In the implementation of the detection circuit, the detection circuit can also be connected to the logic device and the readout chain respectively, and is also configured to: receive a first instruction signal from the logic device in detection mode; switch from detection mode to readout mode in response to the first instruction signal; and directly provide input current to the readout chain in readout mode.

[0011] Therefore, in readout mode, the readout chain receives data. In readout mode, the detection circuit structure of the detection circuit can be disconnected; that is, the detection circuit will not perform baseline current extraction and current comparison, whereas it is configured to perform these operations in detection mode. In detection mode, the readout chain can be disconnected from the nanopore, i.e., the detection circuit only detects current events without performing readout. Therefore, the detection circuit can be triggered to enable readout of the nanopore only in response to detected current events. This reduces the amount of readout data that must be processed.

[0012] In the implementation of the detection circuit, the detection circuit is further configured to: receive a second instruction signal from the logic device in readout mode; and switch from readout mode to detection mode in response to the second instruction signal.

[0013] In the implementation of the detection circuit, the detection circuit includes: a bias circuit configured to apply a bias voltage to a readout electrode and receive an input current; a current mirror circuit connected to the bias circuit, wherein the current mirror circuit includes a low-pass filter configured to extract a baseline current and configured to provide a current comparator circuit with the difference between the extracted baseline current and the input current; and the current comparator circuit is configured to compare the difference between the baseline current and the input current with a predetermined threshold; wherein the detection circuit is configured to output a digital signal indicating that a current event has occurred if the difference between the baseline current and the input current exceeds the predetermined threshold.

[0014] The mirror circuit can therefore have two paths. One path provides the input current through a low-pass filter to extract the baseline current, while the other path provides the real-time input current. In this case, the output of the mirror circuit is the difference between the real-time current signal and the baseline current. A current comparator compares this difference current with a threshold current, and when the difference current exceeds the threshold, a current event is "marked".

[0015] In the implementation of the detection circuit, the detection circuit further includes: a first switch configured to disconnect the bias circuit from the readout electrode in response to receiving a first instruction signal, and to connect the bias circuit to the readout electrode in response to receiving a second instruction signal; and a second switch configured to directly connect the readout electrode to the readout chain in response to receiving the first instruction signal, and to disconnect the readout electrode from the readout chain in response to receiving the second instruction signal.

[0016] The first and second switches are based on digital output signals, which is a simple and fast way to operate the detection circuit based on whether a current event is detected.

[0017] A second aspect of this disclosure provides a readout device for a nanopore array, wherein the readout device includes: a plurality of detection circuits according to the first aspect and any implementation thereof, and logic devices connected to the detection circuits, wherein each detection circuit is connectable to a corresponding readout electrode of one of a plurality of nanopores in the nanopore array; wherein the logic devices are configured to: receive from the corresponding detection circuit of the detection circuit a digital signal indicating the occurrence of one or more current events; determine, based on the digital signal, whether a translocation event has occurred in the corresponding nanopore to which the corresponding detection circuit is connected; and if a translocation event is determined to have occurred, provide a first instruction signal to the corresponding detection circuit to switch the corresponding detection circuit from a detection mode to a readout mode.

[0018] The readout device can identify translocation events in the current signal from the nanopore based on digital signals received from the detection circuit, and is configured to connect the nanopore only to the readout chain if it identifies a translocation event. Therefore, only data related to the translocation event of that nanopore can be processed in or after the readout chain, rather than irrelevant data. Thus, the readout device of the second aspect can reduce the amount of data to be processed, thereby eliminating the aforementioned data bottleneck.

[0019] In the implementation of the readout device, the logic device is also configured to provide a second instruction signal to the corresponding detection circuit to switch the corresponding detection circuit back to detection mode.

[0020] In the implementation of the readout device, the logic device is configured to provide a second instruction signal after a predetermined time period has elapsed since the first instruction signal was provided, or in response to a second digital signal received from a corresponding detection circuit, the second digital signal indicating the end of one or more current events.

[0021] This may help ensure that no translocation events are missed.

[0022] In the implementation of the readout device, the logic device is configured to always determine that a translocation event has occurred if a current event has already occurred.

[0023] This is a simple implementation that ensures no transposition events are missed.

[0024] In the implementation of the readout device, the logic device is configured to determine that a translocation event has occurred if multiple current events exhibit a predetermined occurrence pattern.

[0025] In the implementation of the readout device, a translocation event is associated with a specific patterned molecule through a nanopore, and logic devices are configured to determine that a translocation event has occurred if one or more current events are similar to one or more predetermined current events associated with the specific patterned molecule.

[0026] This more sophisticated implementation can help avoid the handling of "false positives" (i.e., current events are detected but do not correspond to actual translocation events). Furthermore, this implementation can also allow for the differentiation between translocation events of interest (e.g., attributed to a specific type of molecule) and irrelevant translocation events (e.g., attributed to other types of molecules that can also pass through nanopores but are not of interest).

[0027] In the implementation of the readout device, the readout device also includes one or more readout chains connected to the detection circuit and configured to read out all the nanopores of the nanopore array, which are connected to the detection circuit in readout mode.

[0028] In the implementation of the readout device, the corresponding group of detection circuits is multiplexed into each readout chain.

[0029] This implementation can reduce the area required for the read chain of the read device, and thus can help reduce the size of the read device.

[0030] In the implementation of the readout device, the readout device is configured to provide a first instruction signal to only one of the detection circuits in the group of detection circuits within a specific time period.

[0031] This may help avoid confusion in the readout chain of translocation events originating from different nanopores.

[0032] A third aspect of this disclosure provides a detection method for detecting translocation events in a nanopore array, the method comprising: applying a bias voltage to a readout electrode of a nanopore in the nanopore array; extracting a baseline current from an input current, the baseline current flowing through the readout electrode when the bias voltage is applied; determining that a current event has occurred if the input current changes by at least a predetermined threshold compared to the baseline current; determining, based on the current event, whether a translocation event has occurred in the nanopore; and if a translocation event is determined to have occurred, directly providing the input current to the readout chain.

[0033] The method of the third aspect achieves the same advantages as the readout device of the second aspect, and can be extended by the corresponding implementations of the detection circuit for the first aspect and the readout device for the second aspect as described above.

[0034] In summary, the solution disclosed herein is based on a novel detection circuit that detects current events (potentially involving translocation events) in the current signal of a nanopore, specifically directly on the nanopore side and before any analog signal amplification or analog-to-digital conversion. Only nanopores exhibiting current events are connected in this manner to a readout chain, such as that including amplifiers and analog-to-digital converters. Therefore, ideally, only data related to translocation events is processed and sent off-chip, significantly increasing the usable data throughput achievable on large-scale nanopore arrays.

[0035] Furthermore, the detection circuitry of this disclosure supports multiplexing multiple nanopores into a single readout chain. Since adjacent nanopores are unlikely to undergo translocation events simultaneously, it may not be necessary to physically provide a complete signal amplification and analog-to-digital conversion chain for each nanopore in the nanopore array. This means that in large nanopore arrays, the readout device may require less silicon area, further enhancing scalability. Attached Figure Description

[0036] The above aspects and implementations are explained in the following specific embodiments with reference to the accompanying drawings: Figure 1 A conventional readout device for nanopore arrays is shown.

[0037] Figure 2 A detection circuit for a nanopore array according to the present disclosure is shown.

[0038] Figure 3 A readout device for a nanopore array according to the present disclosure is shown.

[0039] Figure 4 Another readout device for nanopore arrays according to this disclosure is shown.

[0040] Figure 5 An exemplary detection circuit for a nanopore array according to the present disclosure is shown.

[0041] Figure 6 Details of an exemplary detection circuit for a nanopore array according to this disclosure are shown.

[0042] Figure 7 A flowchart of a method for detecting translocation events in a nanopore array according to the present disclosure is shown. Detailed Implementation

[0043] Figure 2A detection circuit 20 according to this disclosure is shown, which can be used with or in conjunction with the nanopore array 11. The detection circuit 20 can be used, in particular, to detect a current event 1 in the nanopore array 11, which can be correlated with a translocation event in the nanopore array 11. Therefore, the detection circuit 20 can be used to detect translocation events in the nanopore array 11. For example, the detection circuit 20 can be part of a readout device 30 (see...). Figure 3 The readout device 30 can be used to read out the nanopore array 11, and in particular, to determine translocation events within the nanopore array 11. For use of the detection circuit 20 in the aforementioned manner, it can be connected to the readout electrodes 12 of the nanopores in the nanopore array 11. The readout electrodes 12 of the nanopore array 11 can be "trans" electrodes, but can also be "cis" electrodes (it is worth noting that in...). Figure 2 (Not drawn to scale). For example, nanopore array 11 may include solid nanopores, but any conventional nanopore array may be used as long as it includes readout electrodes and allows current-based sensing.

[0044] The detection circuit 20 may include a circuit ( Figure 2 (Not shown in the image), this circuit is configured to perform, guide, or initiate various operations of the detection circuit 20 described below. This circuit may include hardware and / or may be controlled by software. The hardware may include analog or digital circuitry, or both. Analog circuitry may include transistors, diodes, amplifiers, capacitors, filters, etc. Digital circuitry may include components such as application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), digital signal processors (DSPs), or multi-purpose processors.

[0045] Specifically, the detection circuit 20 can be configured to operate in a detection mode, in which it is configured to apply a bias voltage 21 to the readout electrode 12 and extract a baseline current 23 from the input current 22 flowing through the readout electrode 12 into the detection circuit 20 when the bias voltage 21 is applied. Furthermore, the detection circuit 20 is configured in the detection mode to output a digital signal 24 indicating the occurrence of current event 1 if the input current 22 changes by at least a predetermined threshold 25 compared to the baseline current 23. The digital signal 24 can be a flag indicating current event 1. As described below, the detection circuit 20 can also operate in a readout mode.

[0046] Figure 3 A readout device 30 according to the present disclosure is shown, which is configured to read out a nanopore array 11. The readout device 30 may include one or more detection circuits 20, as shown in the reference numeral 11. Figure 1As described above. For example, the readout device 30 may include a plurality of such detection circuits 20. In this case, each detection circuit 20 may be connected to a corresponding readout electrode 12 of one of the plurality of nanopores of the nanopore array 11, that is, each detection circuit 20 may be associated with one of the nanopores of the nanopore array 11.

[0047] The readout device 30 may include a logic device 31 connected to one or more detection circuits 20. The logic device 30 may be a processor or a controller. The logic device 30 may include multiple logic units, such as sub-controllers or sub-processors, one of which may be associated with each corresponding detection circuit 20.

[0048] Logic device 30 may include processing circuitry (e.g., one or more processors, not shown) configured to execute, bootstrap, or initiate operations of logic device 30 as described below. The processing circuitry may include hardware and / or may be software-controlled. The hardware may include analog or digital circuitry, or both. Digital circuitry may include components such as application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), digital signal processors (DSPs), or multi-purpose processors. Logic device 30 may also include storage circuitry storing one or more instructions executable by the processing circuitry, particularly under software control. For example, the storage circuitry may include a non-transitory storage medium storing executable software code that, when executed by the processing circuitry, causes various operations of the logic device to be performed.

[0049] Specifically, logic device 31 is configured as (see...) Figure 3 The amplification region in the circuit receives a digital signal 24 from a corresponding detection circuit 20 of one or more detection circuits 20, the digital signal 24 indicating that one or more current events 1 have occurred. The logic device 31 is then configured to determine, based on the digital signal 24, whether a translocation event has occurred in a corresponding nanopore connected to the corresponding detection circuit 20. For example, the logic device 31 can be configured to always determine that a translocation event has occurred if a current event 1 has already occurred. In this case, the current event 1 detected by the detection circuit 20 corresponds to the translocation event identified by the logic device 31. The logic device 31 can simply evaluate the digital signal 24, which may correspond to a flag indicating the presence of a current event 1. However, it is also possible to configure the logic device 31 in a more complex manner, for example, determining that only one translocation event has occurred if multiple current events 1 occur according to a predetermined occurrence pattern. For example, if multiple current events 1 occur within a certain time period, or if multiple current events 1 follow a certain predetermined event pattern.

[0050] If logic device 31 determines that a translocation event has occurred, it is configured to provide a first instruction signal 33 to the corresponding detection circuit 20. The first instruction signal 33 instructs the corresponding detection circuit 20 to switch from its detection mode to its readout mode. Therefore, each detection circuit 20 of the readout device 30 can be configured to switch from detection mode to readout mode if it receives the first instruction signal 33 from logic device 31.

[0051] like Figure 3 As shown, the readout device 30 also includes one or more readout chains 32 connected to one or more detection circuits 20. Each readout chain 32 can be associated with a detection circuit 20, specifically as follows: Figure 3 As shown. In readout mode, or when the corresponding detection circuit 20 switches from detection mode to readout mode, the corresponding detection circuit 20 is configured to directly supply the input current 22 to the readout chain 32. In detection mode, the corresponding detection circuit 20 can be disconnected from the associated readout chain 32. Therefore, the readout chain 32 is configured to (only) read out all the nanopores of the nanopore array 11 that are connected to the detection circuit 20 in readout mode.

[0052] The logic device 31 is also configured to provide a second command signal 34 to the corresponding detection circuit 20, which instructs the corresponding detection circuit 20 to switch (return) to detection mode. Therefore, each detection circuit 20 of the readout device 30 can be configured to switch from readout mode to detection mode if it receives the second command signal 34 from the logic device 31. The logic device 31 can be configured to provide the second command signal 34 to the corresponding detection circuit 20 after a predetermined time period has elapsed since the first command signal 33 was provided. Alternatively, the logic device 31 can receive a second optional digital signal 35 from the corresponding detection circuit 20, which can indicate that a previously indicated current event 1 has ended. In response to receiving this second digital signal 35, the logic device 31 can send the second command signal 34 to the corresponding detection circuit 20.

[0053] In summary, this disclosure proposes an analog event detection circuit 20. This detection circuit 20 can be a relatively small circuit capable of detecting when a significant current deviation occurs from the baseline current 23 of the nanopores of the nanopore array 11. This is identified as current event 1 and can be identified as a translocation event by logic device 31. Only in the case of a translocation event can the corresponding nanopore of the nanopore array 11 be connected to a signal amplification and analog-to-digital conversion channel. The solution of this disclosure allows for a significant reduction in the raw signal flow, as only data after a rapid change in the baseline current 23 may need to be converted and further analyzed, for example, to determine whether it is a genuine translocation event, and if so, to perform appropriate analysis (e.g., base call or barcode detection).

[0054] Figure 4 Another readout device 30 according to this disclosure is shown, which is similar to Figure 3 The readout device 30 is shown. Therefore, Figure 3 and Figure 4 The same components are labeled with the same reference numerals and can be implemented similarly. Only the following description... Figure 3 and Figure 4 The difference between them.

[0055] As shown in the figure, the detection circuit 20 of the corresponding group is reused to Figure 4 In each read chain 32 of the read device 30. This means that, with Figure 3 Unlike the readout device 30, each readout chain 32 can be associated with more than one detection circuit 20. In this alternative implementation, multiple nanopores, each with its own detection circuit 20, can be multiplexed into a single readout chain 32. This can help further reduce the amount of hardware required. The number of nanopores that can be multiplexed into a single readout chain 32 can depend on the expected translocation rate. As a feasible example, the number of multiplexed nanopores can be in the range of 5-50 nanopores. Of course, two, three, or four nanopores can also be multiplexed into a single readout chain 32.

[0056] Figure 5 An exemplary detection circuit 20 according to the present disclosure is shown, which can implement the detection circuit 20 shown in the preceding figures. Figure 5 The same components as those in the previous diagrams are labeled with the same reference numerals and can be implemented similarly.

[0057] Figure 5The detection circuit 20 includes a bias circuit 51 configured to apply a bias voltage 21 to the readout electrode 12 and, when the bias voltage is applied, receive an input current 22 flowing through the readout electrode 12 into the detection circuit 20. The detection circuit 20 includes a first connection (“connection to nanopore sensor”) adapted to connect thereto to the nanopore array 11.

[0058] Figure 5 The detection circuit 20 also includes a current mirror circuit 52 connected to the bias circuit 51. The current mirror circuit 52 may include a low-pass filter 53 configured to extract the baseline current 23. The current mirror circuit 52 is configured to provide the difference between the extracted baseline current 23 and the received input current 22 to the current comparator circuit 54 of the detection circuit 20.

[0059] The current comparator circuit 54 is configured to compare the difference between the baseline current 23 and the input current 22 with a predetermined threshold 25. For example, the predetermined threshold 25 can be variable to account for different cases using the nanopore array 11. The threshold 25, as the threshold current, can be provided to the detection circuit 20.

[0060] The detection circuit 20 is then configured to output a digital signal 24 indicating whether a current event has occurred, for example, if the difference between the baseline current 23 and the input current 22 exceeds a predetermined threshold current 25, then it is a flag set to "1" in the event of a current event. The detection circuit 20 may output the digital signal 24 via a second connection adapted to connect it to a logic device ("Event_detected").

[0061] Figure 5 The detection circuit 20 also includes a third connection, which is also adapted to connect to the logic device 31 (“Enable_readout”). Specifically, the third connection is configured to receive a first or second instruction signal 33, 34 from the logic device 31. Figure 5 The detection circuit 20 also includes a first switch 55, which is configured to disconnect the bias circuit 51 from the readout electrode 12 in response to receiving a first command signal 33. The first switch 55 is also configured to connect the bias circuit 51 to the readout electrode 12 in response to receiving a second command signal 34. For example, the first and second command signals 33, 34 may have "high" and "low" values, which can open or close the corresponding switches 55, 56.

[0062] The detection circuit 20 also includes a fourth connection adapted to connect to the readout chain 32 associated with the detection circuit (“the connection to readout”). A second switch 56 is configured to directly connect the readout electrode 12 to the fourth connection of the readout chain 32 in response to receiving a first command signal 34. The second switch 56 is also configured to disconnect the readout electrode 12 from the readout chain 32 in response to receiving a second command signal 34.

[0063] Figure 5 A more abstract architecture of the detection circuit 20 and its sub-circuits 51, 52, 53, 54 and switches 55, 56 is shown. The operation of the detection circuit can be summarized as follows: 1. Switches 55 and 56: The nanopore associated with detection circuit 20 can be connected to readout chain 32 (in "readout mode," the first switch 55 is closed) or to event detection circuits 52, 53, and 54 (in "detection mode," the second switch 56 is closed). Switch control is handled by logic device 31 via a third connection. When the first switch 55 is closed, analog event detection circuits 52, 53, and 54 are disabled, and the nanopore signal can be amplified, digitized, and recorded normally.

[0064] 2. Nanopore Bias Circuit 51: The actual nanopore associated with the detection circuit 20 must be properly biased. More precisely, the recording electrode in the "reverse" chamber must be maintained at a suitable voltage. This is necessary to maintain proper nanopore operation and ensure that translocation events can occur. In the readout mode of the detection circuit 20, this can be accomplished by the readout chain 32. However, at least in the detection mode (second switch 56 closed, first switch 55 open), the dedicated nanopore bias circuit 51 can handle this situation.

[0065] 3. Baseline current extraction circuit 53: Extracts baseline current 23. Due to process variability, it can be expected that each nanopore will have a slightly different baseline current 23, and the baseline current 23 may drift over time.

[0066] 4. Comparator circuit 54: Compares the instantaneous nanopore current 22 with the event detection threshold current 25. The actual instantaneous nanopore current 22 can be subtracted from the extracted baseline current 23. When this instantaneous current exceeds a certain threshold 25 below the baseline current 23, the detection circuit 20 can trigger the digital output signal 24. The threshold 25 is advantageously chosen to be large enough that random nanopore noise will not cause triggering, but also small enough that a normal translocation event will be triggered. If desired, the threshold current 25 can be globally set or can be programmable per nanopore. A good rule of thumb is to choose the threshold 25 in the range of 3-9 times larger than the baseline root mean square noise to avoid too many false positive triggers. The threshold 25 is advantageously between 50% and 70% of the normal expected translocation current to avoid missing actual translocation events or detecting actual translocation events too late.

[0067] Output signal 24 is an indication that a translocation event may have begun, as it indicates current event 1. In this case, logic device 31 can disconnect analog event detection circuits 52, 53, and 54, and can connect the nanopore to signal readout chain 32, thereby allowing the translocation signal to be recorded. The end of recording can be at a fixed timing if the typical translocation event duration can be assumed to be predictable and reasonably constant, or it can be determined by another digital signal processing block (not shown) that detects the return of baseline current 23 in the recorded signal. Logic device 31 can also ignore triggering from some nanopore. This may occur if any of the following conditions are met: 1. If multiple nanopores are reused in a single readout chain 32 (e.g.) Figure 4 As shown, if a translocation event occurs on a nanopore, the nanopore will be connected to readout chain 32. If a translocation event occurs while readout chain 32 is already processing another event, the new event will be ignored.

[0068] 2. Dirty, broken, poorly wetted, or otherwise undesirable nanopores may appear in the large-scale nanopore array 11. It is conceivable that some nanopores will not function as intended. This could be because they are dirty, broken, not fully wetted, or for many other reasons. This could lead to continuous triggering, resulting in a large amount of useless data and potentially blocking the readout chain 32. Such undesirable nanopores can be ignored.

[0069] The logic device 31 can also be further configured to force normal recording from any particular nanopore at any given time by simply turning the connection "Enable_readout" high (first instruction signal 33) independent of the "Event_detected" state, i.e., the output signal 24. This is useful, for example, during initial calibration (i.e., recording baseline current) or performing standard quality control checks.

[0070] and Figure 5 on the contrary, Figure 6 A more detailed architecture of an exemplary detection circuit 20 according to this disclosure is shown, which is used for a nanopore array 11 having nanopores 61, and can implement the detection circuit 20 of the preceding figures. The loop formed by the amplifier and the common-gate stage MP1 can set the bias on the readout electrode 12 (here the detection circuit 20 is exemplary connected to the "reverse" electrode) to a voltage V. ref That is, it can be used as a bias circuit 51. The input current signal 22 from the readout electrode 12 is then replicated through a current mirror to two blocks called the "real-time signal" and the "low-pass filter". The low-pass filter 53 is implemented by resistors and capacitors and is used to extract the baseline current 23 of the input current 22 received from the readout electrode 12. This is subtracted from the real-time signal replicated from the upper block. This difference propagates to the next stage. At this node, a threshold current 25 is added, causing the current comparator circuit 54 to compare the difference current with the threshold current. When the difference current changes to below the threshold current value 25, the current comparator circuit 54 sends an event flag as a digital signal 24 to the logic device 31. This may occur in the case of a translocation event, i.e., when the molecule 62 passes through the nanopore 61. The flag can be reset when the input current 22 returns to the baseline current 23.

[0071] Figure 7 A flowchart of a method 70 for detecting a translocation event in a nanopore array 11 according to the present disclosure is shown. Method 70 can be performed by a readout device 30 to detect a translocation event. Method 70 includes steps 71 of applying a bias voltage 21 to readout electrodes 12 of the nanopores of the nanopore array 11, and steps 72 of extracting a baseline current 23 from an input current 22, which flows through the readout electrodes 12 when the bias voltage 21 is applied. Method 70 further includes a step 73 of determining that a current event 1 has occurred if the input current 22 changes by at least a predetermined threshold 25 compared to the baseline current 23. Method 70 then includes a step 74 of determining whether a translocation event has occurred in the nanopore based on the current event 1, and a step 75 of directly supplying the input current 22 to a readout chain 32 if a translocation event is determined to have occurred.

[0072] In summary, this disclosure presents an analog event detection circuit 20 capable of identifying potential translocation events through the nanopores of the nanopore array 11 before any signal amplification and digitization. The output of the analog detection circuit 20 can allow only the amplification and digitization of data related to the actual translocation event, ultimately resulting in far less data that must be recorded and processed.

[0073] In the claims and in the description of this disclosure, the word "a" does not exclude other elements or steps, and the indefinite article "a" ("a" or "an") does not exclude plural. A single element may perform the function of several entities or items recited in the claims. The mere fact that certain measures are stated in mutually different dependent claims does not imply that combinations of these measures cannot be used in an advantageous implementation.

Claims

1. A detection circuit (20) for detecting translocation events in a nanopore array (11), wherein the detection circuit (20) is connectable to a readout electrode (12) of a nanopore (61) of the nanopore array (11) and is configured to, in detection mode: A bias voltage (21) is applied to the readout electrode (12); Extract the baseline current (23) from the input current (22) flowing through the readout electrode (12) into the detection circuit (20) when the bias voltage (21) is applied; and If the input current (22) changes by at least a predetermined threshold (25) compared to the baseline current (23), a digital signal (24) indicating the occurrence of a current event (1) is output.

2. The detection circuit (20) according to claim 1, characterized in that, The detection circuit (20) can also be connected to the logic device (31) and the readout chain (32) respectively, and is also configured to, in the detection mode: Receive the first instruction signal (33) from the logic device (31); In response to the first instruction signal (33), switch from the detection mode to the readout mode; and In the readout mode, the input current (22) is directly supplied to the readout chain (32).

3. The detection circuit (20) according to claim 2, characterized in that, It is also configured that, in the readout mode: Receive a second instruction signal (34) from the logic device (31); and In response to the second instruction signal (34), the readout mode is switched to the detection mode.

4. The detection circuit (20) according to any one of claims 1 to 3, characterized in that, include: A bias circuit (51) is configured to apply the bias voltage (21) to the readout electrode (12) and receive the input current (22). A current mirror circuit (52) connected to the bias circuit (51) includes a low-pass filter (53) configured to extract the baseline current (23) and configured to provide the difference between the extracted baseline current (23) and the input current (22) to the current comparator circuit (54). and The current comparator circuit (54) is configured to compare the difference between the baseline current (23) and the input current (22) with the predetermined threshold (25); The detection circuit (20) is configured to output a digital signal (24) indicating that a current event (1) has occurred if the difference between the baseline current (23) and the input current (22) exceeds the predetermined threshold (25).

5. The detection circuit (20) according to claims 2, 3 and 4, characterized in that, Also includes: A first switch (55) is configured to disconnect the bias circuit (51) from the readout electrode (12) in response to receiving the first instruction signal (33) and to connect the bias circuit (51) to the readout electrode (12) in response to receiving the second instruction signal (34). and A second switch (56) is configured to connect the readout electrode (12) directly to the readout chain (32) in response to receiving the first instruction signal (33), and to disconnect the readout electrode (12) from the readout chain (32) in response to receiving the second instruction signal (34).

6. A readout device (30) for a nanopore array (11), wherein the readout device (30) comprises: The plurality of detection circuits (20) according to any one of claims 1 to 5, wherein each detection circuit (20) is capable of being connected to a corresponding readout electrode (12) of one of the plurality of nanopores (61) of the nanopore array (11); and Logic device (31) connected to the detection circuit (20); The logic device (31) is configured to: Receive a digital signal (24) indicating the occurrence of one or more current events (1) from one of the corresponding detection circuits (20); Based on the digital signal (24), it is determined whether a translocation event has occurred in the corresponding nanopore (61) to which the corresponding detection circuit (20) is connected; and If a translocation event is determined to have occurred, a first instruction signal (33) is provided to the corresponding detection circuit (20) to switch the corresponding detection circuit (20) from the detection mode to the readout mode.

7. The readout device (30) according to claim 6, characterized in that, The logic device (31) is also configured to provide a second instruction signal (34) to the corresponding detection circuit (20) to switch the corresponding detection circuit (20) back to the detection mode.

8. The readout device (30) according to claim 7, characterized in that, The logic device (31) is configured to provide the second instruction signal (34) after a predetermined time period has elapsed since the first instruction signal (33) was provided, or in response to a second digital signal (35) received from the corresponding detection circuit (20), the second digital signal (35) indicating the end of the one or more current events (1).

9. The readout device (30) according to any one of claims 6 to 8, characterized in that, The logic device (31) is configured to always determine that a translocation event has occurred if a current event (1) has occurred.

10. The readout device (30) according to any one of claims 6 to 8, characterized in that, The logic device (31) is configured to determine that a translocation event has occurred if the plurality of current events (1) exhibit a predetermined occurrence pattern.

11. The readout device (30) according to any one of claims 6 to 8, characterized in that, The translocation event is associated with a specific patterned molecule (62) through a nanopore, and the logic device (31) is configured to determine that a translocation event has occurred if the one or more current events (1) are similar to a predetermined one or more current events (1) associated with the specific patterned molecule (62).

12. The readout device (30) according to any one of claims 1 to 11, characterized in that, It also includes one or more readout chains (32) connected to the detection circuit (20) and configured to read out all the nanopores (61) of the nanopore array (11) connected to the detection circuit (20) in the readout mode.

13. The readout device (30) according to claim 12, characterized in that, The detection circuit (20) of the corresponding group is multiplexed into each readout chain (32).

14. The readout device (30) according to claim 13, characterized in that, The readout device (30) is configured to provide a first instruction signal (33) to only one of the detection circuits (20) in the group during a specific time period.

15. A detection method (70) for detecting translocation events in a nanopore array (11), wherein the detection method (70) comprises: A bias voltage (21) (71) is applied to the readout electrode (12) of the nanopore (61) of the nanopore array (11). The baseline current (23) is extracted (72) from the input current (22) flowing through the readout electrode (12) when the bias voltage (21) is applied. If the input current (22) changes by at least a predetermined threshold (25) compared to the baseline current (23), then it is determined (73) that a current event has occurred; Based on the current event (1), determine (74) whether a translocation event has occurred in the nanopore (61); and If a translocation event is determined to have occurred, the input current (22) is directly supplied (75) to the readout chain (32).

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