Probe devices for interfacing with cells such as neurons, as well as related devices, methods, and uses

Abstract

A probe device for interfacing with individual neurons, such as neurons within brain tissue, preferably cells, comprising a support structure having a longitudinal axis and a set of neuron interface electrodes disposed and configured on the support structure, the set of neuron interface electrodes being arranged and adapted to be movable between a first insertion configuration and a second expanded configuration, the first configuration being different from the second configuration, the first configuration being adapted to reach a predetermined target region within the brain while minimizing damage to the brain, and the second configuration corresponding to a predetermined regular three-dimensional lattice configuration corresponding to a cubic, face centered cubic (fcc), body centered cubic (bcc), or hexagonal lattice configuration.

Description

Technical Field

[0001] The present disclosure relates to the field of medical probes such as neural probes.

Background Art

[0002] A complete understanding of brain function is a global scientific challenge. Neuroelectrophysiological knowledge is extended by increasing the ability to record large-scale single-unit activities in isolation. For this purpose, 3D electrode arrays are considered to provide the best yield of units due to their relatively large monitoring volume and relatively increased monitoring volume. The increase in the monitoring volume can improve neuron localization, increase the number of neurons detected, and result in robust spike sorting.

[0003] Most state-of-the-art neural probes that include a single shaft or multiple shafts containing one or more electrodes sample only in one-dimensional (1D) or two-dimensional (2D) space. They are limited to measurements along a small cylindrical volume around the probe shaft, which is not sufficient to measure all neurons within a cortical column. Three-dimensional (3D) rigid silicon neural probes (by stacking several 2D silicon probes) are commercially available, but they cause significant tissue damage and are difficult to insert into the brain. The high density of the penetrating probe shaft results in large tissue depressions during implantation and causes cell loss. Also, their 3D probe arrays have a limited depth and cannot reach deep brain regions beyond 10 mm in depth.

[0004] There is a need for neural probes that use a limited number of electrodes and have better neuron localization and increased neuron identification and / or reduced tissue damage during localization, which can provide new therapeutic insights in solving brain-related diseases and disorders.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide a probe device for interfacing with a neuron cell, preferably an individual cell or a small set of cells (e.g., 2, 3, 4, 5 cells), preferably a neuron cell, as claimed in claim 1, a related composite probe device, the use of a probe device or a probe composite device, a method for determining the position of an individual neuron in brain tissue, a method for measuring neuron activity in brain tissue, a method for stimulating neurons in brain tissue, and a method for manufacturing a probe device for interfacing with neurons in the brain.

Means for Solving the Problems

[0006] In a first aspect of the present disclosure, there is disclosed a probe device for interfacing with cells, preferably neuron cells, preferably individual cells or neurons, alternatively a plurality of cells or neurons in brain tissue, such as a neural probe, comprising a support structure having a longitudinal axis and a set of cell or neuron interface devices arranged and configured on the support structure. The set of cell or neuron interface devices is arranged and adapted to be movable between a first insertion configuration and a second expansion configuration, the first configuration being different from the second configuration. The first configuration is preferably adapted to reach a predetermined target region in the brain while minimizing damage to the brain. The second configuration preferably corresponds to a predetermined regular three-dimensional lattice configuration of one of cubic, face centered cubic (fcc), body centered cubic (bcc), or hexagonal lattice configurations. Alternatively, the second configuration preferably corresponds to a predetermined regular three-dimensional lattice configuration of a tetrahedral type.

[0007] A neural probe comprising a cell / neuron interface device of any of these configurations is advantageous in that it enables much better individual cell / neuron discrimination and / or localization, for example, when compared to a cell / neuron interface device of a random configuration, for the same amount of cell / neuron interface device per volume.

[0008] According to a preferred embodiment, the probe device is configured such that, for example, the electrode detection radius (defining the detection sphere) in brain tissue is in the range of 75 microns to 150 microns, and the electrode pitch (or minimum electrode distance or electrode spacing) is in the range of 45 microns to 150 microns. Typically, as is known in the art, the electrode pitch is measured from electrode center to electrode center.

[0009] As used herein, the electrode pitch is the minimum electrode distance of each predetermined regular 3D lattice configuration. A predetermined type of three-dimensional lattice configuration (one of cubic, face centered cubic (fcc), body centered cubic (bcc), tetrahedral, or hexagonal lattice) is further fully defined by the value of the pitch.

[0010] The electrode detection radius is more typically determined by the electrode impedance. According to a preferred embodiment, the electrode pitch is less than 150 microns, or less than 125 microns, or less than 100 microns, or less than 75 microns.

[0011] Preferably, the overlapping detection spheres of at least four adjacent electrodes form a significant volume within a predetermined regular three-dimensional lattice configuration (cubic, face centered cubic (fcc), body centered cubic (bcc), hexagonal or tetrahedral shape).

[0012] Such a significant volume is required for cell / neuron identification (e.g., by using known positioning techniques such as triangulation techniques), whereby four or more electrodes can detect neural spike signals simultaneously generated by the same cell / neuron.

[0013] According to a preferred embodiment, the electrode pitch is less than 150 microns, obtaining a larger significant volume for much better individual cell / neuron identification (e.g., using triangulation). Preferably, the electrode detection radius is 150 microns or less, or about 150 microns or less. In some embodiments, this combination of ranges is applied to a predetermined regular three-dimensional lattice structure corresponding to a cubic, fcc or bcc configuration.

[0014] According to a preferred embodiment, the electrode pitch is less than 100 microns, obtaining a larger significant volume for much better individual cell / neuron identification (e.g., using triangulation). Preferably, the electrode detection radius is 100 microns or less, or about 100 microns or less. In some embodiments, this combination of ranges is applied to a predetermined regular three-dimensional lattice structure corresponding to a cubic, fcc or bcc configuration.

[0015] According to a preferred embodiment, the predetermined regular three-dimensional lattice structure corresponds to a cubic, fcc or bcc configuration, the electrode pitch is 60 microns to 85 microns, and when the electrode detection radius is 75 microns or about 75 microns (e.g., 75 ± 12.5 microns, etc.), the largest significant volume for much better individual cell / neuron identification is obtained.

[0016] According to a preferred embodiment, the predetermined regular three-dimensional lattice structure corresponds to a cubic, fcc or bcc configuration, the electrode pitch is 85 microns to 100 microns, and when the electrode detection radius is 100 microns or about 100 microns (e.g., 100 ± 12.5 microns, etc.), the largest significant volume for much better individual cell / neuron identification is obtained.

[0017] According to a preferred embodiment, a predetermined regular three-dimensional lattice configuration corresponds to a cubic, fcc or bcc configuration, the electrode pitch is from 100 microns to 125 microns, and when the electrode detection radius is 125 microns or about 125 microns (such as 125±12.5 microns, etc.), a much better maximum significant volume for individual cell / neuron discrimination is obtained.

[0018] According to a preferred embodiment, a predetermined regular three-dimensional lattice configuration corresponds to a cubic, fcc or bcc configuration, the electrode pitch is from 125 microns to 150 microns, and when the electrode detection radius is 150 microns or about 150 microns (such as 150±12.5 microns, etc.), a much better maximum significant volume for individual cell / neuron discrimination is obtained.

[0019] Preferably, the neuron interface device is an electrode. Alternatively, the neuron interface device is an optical interaction device comprising a light source (e.g., an LED) and / or an optical sensor. According to a preferred embodiment, the neuron interface device is an electrode, and some or all of the electrodes can be adjacent to and provide a corresponding optical interaction device. The latter can not only identify individual neurons and provide electrical stimulation or its readout, but also enable the identified neurons to be stimulated by a light beam or signal. For example, different types of neurons can be labeled such that each type of neuron is sensitive to, i.e., activated and inactivated by, a specific type of light wave, such as a specific wavelength, and thus a specific type of LED.

[0020] According to a preferred embodiment, the support structure comprises a flexible material such as a flexible biocompatible polymer. The support structure is sufficiently rigid in the inserted configuration to penetrate tissue. The support structure is suitable for positioning the electrodes within the tissue. Preferably, the flexible biocompatible polymer includes polyimide, parylene, epoxy, PEEK, Ultem, SU-8, PDMS, silicone. Alternatively, a dissolvable material that is rigid during implantation and dissolves over time when implanted, for example, in the environment of brain tissue, can be used.

[0021] According to a preferred embodiment, the support structure generally defines a longitudinal probe shape defining a peripheral wall comprising a cylindrical mantle portion that depicts an angular section of a cylindrical surface, and the neuron interface device abuts and / or is positioned on the cylindrical mantle portion when in a first configuration.

[0022] The support structure can preferably include a circular cross-section in a direction perpendicular to its longitudinal axis. Such a circular cross-section support structure is typically more advantageous than a silicon-based probe with a rectangular cross-section because substantially less tissue damage occurs during insertion of the probe into brain tissue. Tissue damage results in the formation of scar tissue, further endangering the recording and stimulation functions of the neural probe.

[0023] According to a preferred embodiment, the support structure comprises a longitudinal central portion and a plurality of sets of at least one (e.g., one) (or at least two (e.g., two), or at least three (e.g., three), or at least four (e.g., four)) flexible arms, each arm generally extending from a respective first end of the central portion of the support structure to a second end that is an independent distal end, forming, for example, a 3D lattice. Preferably, each arm comprises at least one neuron interface device, and the arm is adapted and arranged to position the neuron interface device in a predetermined regular lattice configuration by bending radially outwardly to a predetermined extent when in a second configuration (corresponding to the second configuration of the arm). Preferably, each of the flexible arms has a tip suitable for insertion into brain tissue.

[0024] According to an alternative preferred embodiment, the support structure comprises a longitudinal central portion and a plurality of sets of flexible arms, each arm generally extending from a respective first end of the central portion of the support structure to a second end that is an independent distal end. Preferably, each arm comprises at least one neuron interface device, such as an electrode, and the central portion comprises one or more neuron interface devices, such as electrodes, and the central portion and the flexible arms are adapted and arranged to position the neuron interface devices in a predetermined regular lattice configuration by bending the flexible arms radially outwardly to a predetermined extent when in a second configuration.

[0025] According to a preferred embodiment, the predetermined extent is determined by a predetermined internal stress within the arm that causes a radially outward biasing of the distal end relative to the first end of the arm, and a predetermined movement of the device along a direction corresponding to its longitudinal axis within the brain tissue.

[0026] According to a preferred embodiment, a probe device for interfacing with neurons within brain tissue includes a flexible 2D substrate that is at least partially or fully rolled up, preferably processed and patterned. As is known in the art, the term "processing" is used to perform microfabrication or microelectronics processing steps. The microfabrication processing steps can include, for example, steps of forming one or more layers such as a connection layer and a dielectric layer on the 2D substrate, patterning these layers, and providing microelectronic structures or components on the substrate. The step of patterning the flexible 2D substrate following the (microfabrication) processing steps can include patterning of the substrate itself to provide, for example, a 2D template that provides respective arms when rolled up.

[0027] This provides a very sophisticated and low-cost manufacturing of the neural probe. According to a preferred embodiment, the arms are patterned within the 2D substrate such that they are arranged in a direction substantially parallel to the longitudinal axis.

[0028] According to a preferred embodiment, the neuron interface device has a tip portion for inserting the device into brain tissue, and the arms face outward from the tip portion in a first configuration of the neuron interface device (corresponding to the first configuration of the arms).

[0029] According to an alternative preferred embodiment, the neuron interface device has a tip portion for inserting the device into brain tissue, and the arms face towards the tip portion in a first configuration of the neuron interface device (corresponding to the first configuration of the arms).

[0030] According to a preferred embodiment, the arms are patterned within the 2D substrate such that they are arranged in a direction substantially perpendicular to the longitudinal axis, and the arms are wound or rolled up around the longitudinal axis.

[0031] In a second aspect of the present disclosure, a composite probe device for interfacing with neurons within brain tissue, the device comprising a tubular guide structure having a longitudinal inner bore for receiving and guiding a device according to any of the embodiments of the first aspect for insertion into the brain tissue, the tubular structure comprising a set of openings having a predetermined configuration arranged and adapted to guide a set of neuron interface devices toward a predetermined regular lattice configuration, is disclosed.

[0032] This provides the advantage that the neural probe can be inserted into the brain in a more controlled manner, also reducing potential damage to the brain tissue.

[0033] According to a preferred embodiment, the composite device is adapted to guide a neuron interface device comprising a support structure, the support structure comprising a longitudinal central portion and a set of at least one (e.g., one) (or at least two (e.g., two), or at least three (e.g., three), or at least four (e.g., four)) flexible arms, each arm generally extending from a respective first end of the central portion of the support structure to a second end that is an independent distal end, each arm comprising at least one neuron interface device, the arms being adapted and arranged to position the neuron interface devices in a predetermined regular lattice configuration by bending radially outwardly according to a predetermined degree when in a second configuration, the openings being arranged and adapted to allow each arm to pass through a respective opening of the set of openings when the device is moved along the inner bore (or in the direction of its axis).

[0034] According to a preferred embodiment, the arms are patterned in a 2D substrate so as to be arranged in a direction substantially perpendicular to the longitudinal axis, the arms are wound or rolled up around the longitudinal axis, and the openings are arranged and adapted so that when the device rotates around its axis within the bore, each arm can penetrate each opening of the set of openings.

[0035] According to a preferred embodiment, each of the arms comprises at least one neuron interface device such as an electrode. According to a further preferred embodiment, a light source / LED is provided adjacent to or below some electrodes, adjacent to or below a plurality of electrodes, or adjacent to or below each electrode. The distance between the light source or LED and each electrode is preferably less than 500 microns. When a light source is provided below the electrode, the electrode is preferably embodied as a transparent electrode.

[0036] According to a preferred embodiment, the neuron interface devices of at least one arm are arranged on opposite sides of the arm, for example, on opposite sides of the planar substrate from which the neuron interface device is formed. According to a preferred embodiment in which the arm is patterned on a flexible substrate, one or more neuron interface electrodes or neuron interface devices are provided on one side of the substrate, while one or more neuron interface electrodes or neuron interface devices are provided on the other side of the substrate.

[0037] In a third aspect of the present disclosure, the use of a probe device according to any of the embodiments of the first or second aspect is disclosed, wherein the neuron interface device is an electrode for identifying individual neurons within brain tissue.

[0038] In a fourth aspect of the present disclosure, there is provided a method for determining the position of individual neurons within brain tissue, the method comprising implanting a probe device according to any of the embodiments of the first or second aspect, the probe device comprising electrodes as a neuron interface device, into the brain tissue, and reading signals from a set of electrodes.

[0039] According to a preferred embodiment, the method further comprises performing a positioning technique, such as triangulation, for determining a specific neuron position based on the reading of neural signals, such as spikes or spike signals, from a set of electrodes. An example of such a method is disclosed in Boussard et al. (DOI: 10.1101 / 2021.11.05.467503).

[0040] In a fifth aspect of the present disclosure, there is provided a method for measuring neuron activity within brain tissue, the method comprising implanting a probe device according to any of the embodiments of the first or second aspect, the probe device comprising electrodes as a neuron interface device, into the brain tissue, and reading signals from a set of neuron interface devices.

[0041] In a sixth aspect of the present disclosure, there is provided a method for stimulating neurons within brain tissue, the method comprising implanting a probe device according to any of the embodiments of the first aspect, or a composite device or a set of devices according to any of the embodiments of the second aspect, into the brain tissue, comprising electrodes as a neuron interface device, and providing an electrical stimulation signal to a set of electrodes. Preferably, the electrical stimulation signal is provided based on a measurement signal obtained by the method according to the fifth aspect. According to a preferred embodiment, the stimulation signal for a given neuron can be provided by one or a plurality of adjacent electrodes to that neuron. Although not necessarily so, preferably, the adjacent electrodes used for stimulating the neuron are the same or selected from the electrodes used in a positioning technique, such as triangulation, used in the fourth aspect.

[0042] In a seventh aspect of the present disclosure, a method for manufacturing a probe device for interfacing with neurons in brain tissue, according to any of the embodiments of the first or second aspects, comprising: - providing a flexible biocompatible planar (2D) substrate; - patterning the planar substrate to define a set of at least one (e.g., one) (or at least two (e.g., two), or at least three (e.g., three), or at least four (e.g., four)) flexible arms; - processing the planar substrate to provide at least one electrically connected neuron interface device, preferably an electrode, for each flexible arm; - at least partially winding up the planar substrate into a tubular configuration.

[0043] In an eighth aspect of the present disclosure, when a device according to any of the embodiments of the first aspect, or a composite device or set of devices according to any of the embodiments of the second aspect, is implanted in brain tissue, a method for exchanging signals with, or interfacing or interacting with, brain tissue by a set of electrodes from the device or composite device is disclosed.

[0044] In a preferred embodiment, exchanging signals with brain tissue includes determining the positions of individual neurons in the brain tissue by reading signals from the set of electrodes.

[0045] In a preferred embodiment, exchanging signals with brain tissue includes measuring the activities of individual neurons in the brain tissue, preferably by reading signals from the set of electrodes.

[0046] In a preferred embodiment, exchanging signals with brain tissue includes stimulating individual neurons in the brain tissue, preferably by providing an electrical stimulation signal to the set of electrodes.

[0047] In a ninth aspect, there is disclosed a device for exchanging signals with or interfacing or interacting with brain tissue by means of a set of electrodes, the device comprising a device according to any of the embodiments of the first aspect, or a composite device or set of devices according to any of the embodiments of the second aspect.

[0048] In a preferred embodiment, the device is adapted to determine the individual neuron positions within the brain tissue by reading signals from the set of electrodes.

[0049] In a preferred embodiment, the device is adapted to measure the individual neuron activity within the brain tissue, preferably by reading signals from the set of electrodes.

[0050] In a preferred embodiment, the device is adapted to stimulate preferably the individual neurons within the brain tissue by providing preferably electrical stimulation signals to the set of electrodes.

[0051] The features and advantages disclosed for one of the above aspects of the present disclosure are implicitly disclosed herein for other aspects as well, with the necessary modifications, as will be recognized by those skilled in the art.

[0052] The present disclosure is further illustrated by the following description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0053]

Figure 1

Figure 2

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Figure 3(c)

Figure 3(d)

Figure 3(e)

Figure 3(f)

Figure 3(g)

Figure 4(a)

Figure 4(b)

Figure 4(c)

Figure 4(d)

Figure 5(a)

Figure 5(b)

Figure 6(a)

Figure 6(b)

Figure 6(c)

Figure 6(d)

Figure 7(a)

Figure 7(b)

Figure 7(c)

Figure 7(d)

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Figure 9(a)

Figure 9(b)

Figure 9(c)

Figure 9(d)

[0054] The present disclosure is described with respect to specific embodiments and with reference to specific drawings, but the present disclosure is not limited thereto and is limited only by the claims. The described drawings are merely schematic and not limiting. In the drawings, the sizes of some elements may be exaggerated for illustrative purposes and may not be drawn to scale. Dimensions and relative dimensions do not necessarily correspond to actual reductions in the practice of the present disclosure.

[0055] Furthermore, terms such as first, second, third, etc. in the specification and claims are used to distinguish similar elements and are not necessarily for describing a sequential or temporal order.

[0056] Various embodiments are referred to as "preferred" but are not to be construed as limiting the scope of the present disclosure and should be construed as examples in which the present disclosure can be implemented.

[0057] FIG. 1 is a graph showing simulation results for different spatial configurations of a neuron interface electrode.

[0058] Significant volume (y-axis, square microns (microns 3)) is plotted as a function of the pitch (x-axis, in microns) between neuron interface electrodes for different spatial configurations in the form of a regular 3D lattice structure and a linear array of electrodes (1D). The significant volume is the overlapping monitoring volume of four adjacent electrodes covering the 3D volume for each normal lattice configuration. It is assumed that one electrode can detect activity within a radius of 75 μm (microns). The graph shows which spatial electrode configuration (BCC, FCC, etc.) covers the maximum volume (using a total of 384 electrodes) for increasing electrode pitch. However, it is important to note that this is with respect to four adjacent electrodes that can sample the 3D volume. This means that only two of the four electrodes can be located on the same axis. Since at least four electrodes are required to define the location of neurons within the 3D volume, a minimum of four electrodes are used. The graph shows a general trend that if the electrode pitch is too small, there are too many overlapping redundant volumes, limiting the overall volume. If the electrode pitch is too large, the amount of overlap is too small to localize neurons within that particular spatial configuration. It can be concluded that the linear configuration is the least efficient in sampling the volume. Along with Figure 2, the FCC and BCC configurations can sample the maximum volume for a particular electrode pitch, considering that the electrodes can detect within a radius of 75 μm to 150 μm. At this time, the simple cubic, tetrahedral, or hexagonal lattice captures the third to fifth largest volumes for a particular electrode pitch with an electrode detection radius of 75 μm to 150 μm. Finally, electrodes configured in 2D at an electrode pitch of 45 μm to 15 μm and an electrode detection radius of 75 μm to 150 μm obtain a relatively smaller volume than any of the 3D lattice configurations.

[0059] Representations of different spatial configurations are shown in FIG. 3. It also shows the definition of the electrode pitch P for each configuration (i.e., the minimum electrode distance of each predetermined regular 3D lattice configuration) as a function of the respective lattice constant X. FIG. 3(a) shows a tetrahedral configuration with four electrodes. FIG. 3(b) shows a simple cubic configuration with eight electrodes. FIG. 3(c) shows a body centered cubic (BCC) configuration with nine electrodes. FIG. 3(d) shows a face centered cubic (FCC) configuration with 14 electrodes. FIG. 3(e) shows a hexagonal configuration with 12 electrodes.

[0060] FIGS. 3(f) and 3(g) show the overlapping fields of the electrodes for the tetrahedral and simple cubic configurations, assuming that the detection radius of the electrodes is about 2 / 3 of the electrode pitch P.

[0061] FIGS. 4(a) to 4(d) show the electrode configuration of the neural probe 100 according to an embodiment of the present disclosure. The neural probe 100 can consist of a support structure 1, or can be a composite device comprising a support structure 1 and a tubular guide structure 4 (not shown in FIGS. 4(a) to 4(d)).

[0062] The probe 100 preferably comprises a support structure 1 made of a flexible biocompatible material such as, for example, polyimide, parylene, epoxy, PEEK, Ultem, SU-8, PDMS or silicone. It is adapted to interface with neurons in the brain tissue such that the material does not damage the cells and the cells do not damage the structural material. It comprises a support structure 1 having a longitudinal axis and a set of neuron interface electrodes 3 disposed and configured on the support structure 1.

[0063] The set of neuron interface electrodes 3 is arranged and adapted to be movable between a first insertion configuration and a second expansion configuration. The first configuration is different from the second configuration. The first configuration (the left side of each pair in related FIGS. 4(a), 4(b), 4(c), 4(d)) is adapted to reach a predetermined target area in the brain while minimizing the damage imparted to the brain. The second configuration corresponds to a simple cubic (or cubic), face-centered cubic, body-centered cubic, hexagonal, or tetrahedral lattice configuration.

[0064] The support structure 1 defines a longitudinal probe shape defining a peripheral wall having a cylindrical mantle portion that depicts an angular section of, for example, 180° to 360° of a cylindrical surface, and the neuron interface electrode 3 is in contact with the cylindrical mantle portion when in the first configuration. The support structure 1 includes a longitudinal central portion and a set of flexible arms 2, each arm 2 generally extending from a respective first end of the central portion of the support structure 1 to a second end that is an independent distal end, and each arm 2 includes at least one electrode 3. The arm 2 moves towards the second configuration of the electrode (the right of each pair of related drawings corresponding to the second configuration of the arm) and, when terminating in that configuration, is adapted and arranged to position the electrode 3 in a predetermined regular lattice configuration by bending radially outwards according to a predetermined extent. The arm has a distal tip for insertion into brain tissue.

[0065] In FIG. 4(a), the second configuration of the electrode corresponds to a cubic configuration. In FIG. 4(b), the second configuration of the electrode corresponds to a body-centered configuration.

[0066] In FIG. 4(c), the second configuration of the electrode corresponds to a face-centered configuration. In FIG. 4(d), the second configuration of the electrode corresponds to a hexagonal lattice configuration.

[0067] Preferably, as shown in FIG. 5, the support structure 1 comprises a tubular guide structure 4 for insertion into the brain tissue and is part of a composite device or probe 100(1,4) that has a longitudinal inner bore or cylindrical volume for receiving and guiding the support structure 1. The tubular guide structure has a sharp insertion tip 44 at a first end for penetrating the brain tissue. The support structure 1 can be positioned within the tubular guide structure 4 when the guide structure is inserted into the brain. Alternatively, the support structure 1 may be received by the guide structure 4 after the guide structure is inserted into the brain. The material of the tubular guide structure is assumed to be rigid enough to penetrate the brain tissue and can be made from a biocompatible polymer material or a rigid material using microfabrication techniques. The tubular structure 4 comprises a set of openings 40 that are arranged and configured to guide the set arms 2, and thus the neuron interface electrodes 3, into a predetermined regular lattice configuration. The openings 40 are arranged and configured such that the support structure 1 can move relative to the guide structure 4 and into its inner bore such that each arm 2 can pass through a respective opening of the set of openings 40, for example, by sliding it along the direction of the bore (or the axis of the cylindrical volume) towards or away from the insertion tip 44 of the tubular structure 4, or by rotating the support structure 1 about the axis of the support structure 1 within the bore or cylindrical volume.

[0068] The support structure 1 or probe 100 (in the case where there is no tubular guide structure 4) is manufactured by partially or fully winding up a processed and patterned flexible 2D substrate 10. The arms 2 are patterned in the 2D substrate in a predetermined pattern before the substrate 10 is wound up. The arms 2 extend in a direction substantially parallel to the longitudinal axis in a first configuration of the electrodes corresponding to the first configuration of the arms 2.

[0069] In the illustrated embodiments of FIGS. 4(a) to 4(d), the neural probe 100 (or the support structure 1 when there is no tubular guide structure 4) has a tip portion 14 for inserting the device into the brain tissue. In the first configuration of the electrodes (and the arms), the arms 2 face outward from the tip portion 14. When the probe is slightly withdrawn outward from the brain, the arms open and they penetrate the brain tissue radially outward.

[0070] The embodiments of FIGS. 4(a) to 4(d) can be used, for example, independently or in a configuration having the tubular guide structure 4 described in connection with FIG. 5. In the latter case, the arms face outward from the tip portion 44 in their first configuration (corresponding to the first configuration of the electrodes).

[0071] FIGS. 9(a) to 9(d) are similar to FIGS. 4(a) to 4(d) and show embodiments of the support structure 1 that can be used in combination with the tubular guide structure 4. The support structure of FIGS. 9(a) to 9(d) does not include a tip portion 14.

[0072] Alternatively, as shown in FIGS. 6(a) to 6(d), the support structure 1 is used in combination with a tubular guide structure 4 having a tip portion 44 at its lower end (not shown), and the arms 2 can face the tip portion 44 of the tubular guide structure 44.

[0073] When the support structure 1 is axially moved along the longitudinal axis of the bore (outward from the tip portion 44 or toward the tip portion depending on the embodiment), the arms 2 meet the respective openings 40 of the tubular guide structure 4 and extend through them into the brain tissue, thereby exposing the electrodes 3 to the brain tissue. Alternatively, or in combination therewith, the arms 2 can also be deployed as shown in FIG. 8 due to the guide 45 being arranged inside the tubular guide structure 4. The guide 45 can include, for example, a rounded surface suitable for guiding the arms toward the respective openings of the tubular guide structure 4.

[0074] In the embodiments shown in FIGS. 7(a) to 7(d), the arm is patterned in a 2D substrate so as to be initially arranged in a direction substantially perpendicular to the longitudinal axis of the probe or more preferably the composite probe, and the arm 2 is wound along the longitudinal axis. By rotating the support structure 1 within the bore about its longitudinal axis to unwind the winding of the arm 2, the arm 2 meets each opening 40 of the tubular guide structure 4 and extends through it into the brain tissue, thereby exposing the electrode 3 to the brain tissue.

[0075] For all of the foregoing embodiments, each of the arms comprises at least one electrode 3. According to a preferred embodiment, each arm comprises one or two electrodes 3.

[0076] In a particular embodiment, at least one of the plurality of arms 2 comprises at least two electrodes 3, and the electrodes 3 can be provided on opposite sides of the arm 2 corresponding to opposite sides of the substrate 10.

[0077] For all embodiments, the electrode 3 or other neuron interface device such as a light interaction device is connected to a readout or stimulation circuit by appropriate electrical connections, as is known in the art.

[0078] Those skilled in the art will understand the following. - The disclosed neural implant or probe 100 can be used efficiently to identify individual neurons within the brain tissue and in particular to measure the neuronal activity of a given, for example identified, neuron and to stimulate one or more given, for example identified, neurons within the brain tissue.

[0079] - The neural probe 100 can be implanted into the brain tissue and signals can be read from the electrode 3.

[0080] To determine a specific neuron position based on signals read from a set of electrodes of a disclosed neural implant, positioning techniques such as triangulation can be used. An example of a triangulation method that can be used is described by Boussard et al. (DOI: 10.1101 / 2021.11.05.467503). For example, in the devices disclosed in U.S. Patent Application Publication No. 2013-0281811, U.S. Patent Application Publication No. 20060173263, U.S. Patent Application Publication No. 20150119673, U.S. Patent Application Publication No. 20170080210, U.S. Patent Application Publication No. 2020359965, U.S. Patent Application Publication No. 20070088417, U.S. Patent Application Publication No. 20100114272, and U.S. Patent Application Publication No. 20170105641, the electrode pitch is too large and it is impossible to use triangulation.

[0081] The disclosed embodiments of the probe device for interfacing with neurons within brain tissue can be manufactured by a method that includes the following steps.

[0082] - Providing a flexible biocompatible planar (2D) substrate 10. For example, the material can be deposited on a carrier substrate by spin coating or other MEMS deposition techniques. The substrate can be photosensitive or non-photosensitive for patterning purposes.

[0083] - Patterning the planar substrate 10 to define a set of at least two, for example two, three, or four flexible arms 2, by using micromachining techniques such as dry etching techniques or wet etching techniques, or by photolithography of the material itself.

[0084] - For example, by using a lift-off technique, or a dry or wet etching technique, or by patterning the metal, for example, by plating, using a metal deposition technique such as PECVD or sputtering coating technique, processing the planar substrate 10 to provide at least one electrically connected neuron interface electrode 3 to each flexible arm 2. For very small feature sizes on the order of nanometers, for example, less than 5 nm, or less than 3 nm, for example, a focused ion beam technique can be used.

[0085] - For example, by using a mold and a micromanipulator, winding up the planar substrate into a tubular configuration.

[0086] Some advantages of the embodiments and aspects of the present disclosure are as follows. - The disclosed probe 100 can identify more neurons (10 times) than a probe having the same number of microelectrodes used in a standard linear electrode array.

[0087] - Reduction of tissue damage in the case of a composite device, where the tissue damage is generally limited to the damage induced by the tubular guide structure 4, but the recording is performed from electrodes on the thin flexible polymer arm 2 (the substrate and the polymer arm have a typical thickness of 1 to 30 microns).

[0088] - The configuration of the electrodes 3 is such that they capture most of the 3D spatial features of the spike waveform, enabling better discrimination and localization of neurons compared to conventional linear electrode arrays.

[0089] - The disclosed probe 100 having the claimed electrode configuration can also reach deep brain regions located deeper than 10 mm from the brain surface. This is impossible using the prior art stacked 2D probe arrays or matrices of 1D linear probes.

[0090] What is claimed is as follows. 1. A probe device (100) for interfacing with cells, preferably neurons, within brain tissue, comprising a support structure (1) having a longitudinal axis and a set of cell or neuron interface electrodes (3) disposed on the support structure (1), the set of cell or neuron interface electrodes (3) being arranged and adapted to be movable between a first inserted configuration and a second expanded configuration, the first configuration being different from the second configuration, the first configuration being adapted to reach a predetermined target region within the brain while minimizing damage to the brain, and the second configuration corresponding to a predetermined regular three-dimensional lattice configuration corresponding to a cubic, face centered cubic (fcc), body centered cubic (bcc), hexagonal or tetrahedral lattice configuration, the probe device (100).

[0091] 2. The probe device (100) according to claim 1, wherein the neuron interface electrodes have a sensing radius in the range of 75 microns to 150 microns and the electrode pitch of the neuron interface electrodes is in the range of 45 microns to 150 microns.

[0092] 3. The probe device (100) according to claim 1 or 2, wherein the predetermined regular three-dimensional lattice configuration corresponds to a cubic, face centered cubic (fcc), body centered cubic (bcc) configuration.

[0093] 4. The device according to any of the preceding claims, wherein the support structure comprises a flexible material such as a flexible biocompatible polymer.

[0094] 5. The device according to any of the preceding claims, wherein the support structure generally defines a longitudinal probe shape defining a peripheral wall comprising a cylindrical mantle portion depicting an angular section of a cylindrical surface, and the neuron interface electrodes, when in the first configuration, abut against the cylindrical mantle portion.

[0095] 6. The support structure comprises a central longitudinal portion and a set of at least four flexible arms (2), each arm generally extending from a respective first end of the central portion of the support structure to a second end which is a free distal end, each arm (2) comprising at least one electrode, the arms being adapted and arranged such that, in a second configuration, the electrodes are positioned in a predetermined regular lattice configuration by bending radially outwards according to a predetermined degree, the device according to any of the preceding claims.

[0096] 7. The predetermined degree is determined by a predetermined internal stress within the arm which causes a radially outwards biasing of the distal end relative to the first end of the arm, and a predetermined movement of the device along a direction corresponding to its longitudinal axis within the brain tissue, the device according to claim 6.

[0097] 8. The device according to claim 6 or 7, comprising a flexible 2D substrate (10) which is at least partially or fully rolled up, processed and patterned.

[0098] 9. The device according to claim 8, wherein the arms are patterned within the 2D substrate (10) such that they are arranged in a direction substantially parallel to the longitudinal axis.

[0099] 10. The device according to claim 9, having a tip portion (14) for inserting the device into the brain tissue, the arms (2) being directed outwards from the tip portion (14) in a first configuration of the electrodes.

[0100] 11. The device according to claim 9, having a tip portion (14) for inserting the device into the brain tissue, the arms (2) being directed towards the tip portion (14) in a first configuration of the electrodes.

[0101] 12. The device according to claim 8 or 9, wherein the arms (2) are patterned within the 2D substrate (10) such that they are arranged in a direction substantially perpendicular to the longitudinal axis, and the arms (2) are wound along the longitudinal axis.

[0102] 13. The device according to any one of claims 6 to 12, wherein the arm comprises at least one electrode (3).

[0103] 14. The device according to claim 13, comprising at least one arm having at least two electrodes (3), wherein the electrodes of at least one arm (2) are arranged on opposite sides of the arm.

[0104] 15. A composite device or set of devices comprising a tubular guide structure (4) for insertion into brain tissue and having a longitudinal inner bore for receiving and guiding the device according to any of the preceding claims, wherein the tubular structure (4) comprises a set of openings (40) having a predetermined configuration arranged and adapted to guide a set of neuron interface electrodes (3) in a predetermined regular lattice configuration.

[0105] 16. The composite device or set of devices according to claim 15, for guiding the device according to any one of claims 1 to 14, wherein the openings (40) are arranged and adapted such that when the device moves along the inner bore, each arm (2) can pass through each opening of the set of openings (40).

[0106] 17. The composite device or set of devices according to claim 15, for guiding the device according to any one of claims 1 to 14, wherein the openings (40) are arranged and adapted such that when the device rotates about its axis within the bore, each arm (2) can pass through each opening of the set of openings.

[0107] 18. Use of the device according to any one of claims 1 to 14 or the composite device or set of devices according to any one of claims 15 to 17 for identifying individual neurons in brain tissue.

[0108] 19. A method for determining the position of individual neurons within brain tissue, comprising implanting the device according to any one of claims 1 to 14, or the composite device or set of devices according to any one of claims 15 to 17, into the brain tissue, and reading signals from the set of electrodes (3).

[0109] 20. The method according to claim 19, further comprising performing a positioning technique, such as triangulation, for determining a specific neuron position based on the read signals from the set of electrodes (3).

[0110] 21. A method for measuring neuron activity within brain tissue, comprising implanting the device according to any one of claims 1 to 14, or the composite device or set of devices according to any one of claims 15 to 17, into the brain tissue, and reading signals from the set of electrodes (3).

[0111] 22. A method for stimulating neurons within brain tissue, comprising implanting the device according to any one of claims 1 to 14, or the composite device or set of devices according to any one of claims 15 to 17, into the brain tissue, and preferably providing an electrical stimulation signal to the set of electrodes (3).

[0112] 23. A method for manufacturing a probe device 100 for interfacing with neurons within brain tissue, comprising: - providing a flexible biocompatible planar (2D) substrate (10); - patterning the planar substrate (10) to define a set of at least one (e.g., one), or at least two (e.g., two), or at least three (e.g., three), or at least four (e.g., four) flexible arms (2); - processing the planar substrate to provide at least one electrically connected neuron interface electrode (3) for each flexible arm (2); - rolling up the planar substrate into a tubular configuration and including.

Claims

**Claim 1** A probe device (100) for interfacing with cells, preferably neurons within brain tissue, comprising a support structure (1) having a longitudinal axis and a set of cell or neuron interface electrodes (3) disposed on said support structure (1), said set of cell or neuron interface electrodes (3) being arranged and adapted to be movable between a first insertion configuration and a second expansion configuration, said first configuration being different from said second configuration, said first configuration being preferably adapted to reach a predetermined target area within the brain while minimizing damage to the brain, said second configuration corresponding to a predetermined regular three-dimensional lattice configuration corresponding to a cubic, face centered cubic (fcc), body centered cubic (bcc), or hexagonal lattice configuration, said neuron interface electrodes having a sensing radius in brain tissue in the range of 75 microns to 150 microns, and the electrode pitch of said neuron interface electrodes (3) being in the range of 45 microns to 150 microns, probe device (100). **Claim 2** The device according to any of the preceding claims, wherein said support structure (1) comprises a flexible material such as a flexible biocompatible polymer. **Claim 3** The device according to any of the preceding claims, wherein said support structure (1) generally defines a longitudinal probe shape defining a peripheral wall comprising a cylindrical mantle portion depicting an angular partition of a cylindrical surface, and said neuron interface electrodes, when in said first configuration, abut against said cylindrical mantle portion. **Claim 4** The device according to any of the preceding claims, wherein said support structure (1) comprises a longitudinal central portion and a set of at least one flexible arm (2), each arm generally extending from a respective first end of the central portion of said support structure to a second end which is an independent distal end, each arm (2) comprising at least one electrode (3), said arms being adapted and arranged to position said electrodes (3) in said predetermined regular lattice configuration by bending radially outwards according to a predetermined degree when in said second configuration. **Claim 5** The device according to claim 4, comprising a flexible 2D substrate (10) that is at least partially or fully wound up, processed, and patterned.

6. The device according to claim 4 or 5, wherein the arms (2) are patterned in the 2D substrate (10) such that they are arranged in a direction substantially parallel to the longitudinal axis.

7. The device according to claim 6, wherein the arms (2) are patterned in the 2D substrate (10) such that they are arranged in a direction substantially perpendicular to the longitudinal axis, and the arms (2) are wound along the longitudinal axis.

8. A composite device or set of devices comprising a tubular guide structure (4) for insertion into brain tissue and having a longitudinal inner bore for receiving and guiding a device according to any of the preceding claims, wherein the tubular guide structure (4) comprises a set of openings (40) having a predetermined configuration arranged and adapted to guide the set of neuron interface electrodes (3) into the predetermined regular lattice configuration.

9. The composite device or set of devices according to claim 8, for guiding a device according to any of claims 1 - 8, wherein the openings (40) are arranged and adapted such that when the device moves along the inner bore, each arm (2) can pass through a respective opening of the set of openings (40).

10. The composite device or set of devices according to claim 8, for guiding a device according to any of claims 1 - 8, wherein the openings (40) are arranged and adapted such that when the device rotates about its axis within the bore, each arm (2) can pass through a respective opening of the set of openings (40).

11. A method for exchanging signals with brain tissue by means of the set of electrodes from the device according to any of claims 1 - 7 or the composite device or set of devices according to any of claims 8 - 10 when the device or the composite device is implanted in the brain tissue.

12. The method according to claim 11, wherein exchanging signals with the brain tissue includes determining preferably the positions of individual neurons within the brain tissue by reading signals from the set of electrodes. **Claim 13** The method according to claim 11, wherein exchanging signals with the brain tissue includes measuring preferably the activity of individual neurons within the brain tissue by reading signals from the set of electrodes. **Claim 14** The method according to claim 11, wherein exchanging signals with the brain tissue includes stimulating preferably individual neurons within the brain tissue by providing preferably electrical stimulation signals to the set of electrodes. **Claim 15** A device for exchanging signals with brain tissue by means of a set of electrodes, the device comprising a device according to any one of claims 1 to 7 or a composite device or a set of devices according to any one of claims 8 to 10.

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