Description:FIELD OF THE INVENTION
[0001] Embodiments of the present disclosure relate to an L shaped device, and more particularly to an L-shaped Surface Neural Implant (SNI) for stimulation and electrophysiological signal acquisition and transmission.

BACKGROUND OF THE INVENTION
[0002] Generally, Brain machine interfaces (BMIs), or Brain Computer Interfaces (BCIs), are devices that act as a medium for communications between a brain and a computing device. This is an emerging field of research with numerous applications in domains of prosthetic devices, robotics, communication technology, gaming, education, security, etc., with interest persisting in areas such as neural signalling, microelectrode fabrication, signal classification algorithms etc. BMIs or BCIs are typically devices that connect a human/animal brain directly to a computing device such as computers, mobile phones etc. These are classified as intelligent systems that can be used to decipher brain signals using five consecutive stages: signal acquisition, pre-processing, feature extraction, classification, and control interface. BMIs can be either classified as motor, sensory, and sensorimotor, or they can be categorized as invasive or non-invasive depending upon which part of the brain they tap into or which part they are implanted in respectively.
[0003] Research in the past few decades have shown that people and animals can use brain signals to convey their intent to a computer using BCIs. BCI systems generally measure specific activities of the brain and translate these into control signals that may be used to drive an output. Sensor modalities most commonly used in BCI have been electroencephalographic (EEG) recordings from the scalp and single-neuron recordings from within the cortex. Over the past decade, the use of electrocorticographic (ECOG) activity recorded directly from the surface of the brain have been used, with ECOG attracting substantial interest, because it has been shown to reflect specific details of actual and imagined actions, and because its technical characteristics should readily support robust and chronic implementations of BCI systems in humans.
[0004] Generally, such ECOG devices are finding importance in bio-engineering and ECOG is referred to as the tracing of the brain waves made by a device, which is used for detecting and recording brain waves made with the electrodes in direct contact with the brain. Usually, neural implants for electrocorticography (ECOG) signal acquisition currently available have standard rectangular-shaped structures that prohibit the use of any other device in its vicinity. Additionally, the commercial implants, being general-purposed, consist of a higher number of electrodes, making the surgery-affected area, associated electronics, and subsequent computation complex. Usually, implantable electrodes for neural signal recording have great potentials to provide various diagnostic options and curing methods in diverse neuroscience and biomedical fields. Currently available, ECOG electrodes are suitable for recording large-scale neural signals and overcoming rigid electrodes' limitations. ECOG is an invasive technique that provides brain signals that have an exceptionally high signal-to-noise ratio, less susceptibility to artifacts than EEG, and a high spatial and temporal resolution (i.e., <1 cm/<1 millisecond, respectively), and has been gaining importance widely neuroscientific research. However, the area where the device is implanted is sensitive and special care needs to be taken not to damage neurons in the brain during the implant. It is therefore an object of the present disclosure to obliviate some or all disadvantages associated with current ECOG/neural implant devices.

SUMMARY OF THE INVENTION
[0005] Embodiments of the present disclosure relate to a device for recording and transmitting signals, a method for forming the device and a method of implanting the device. An embodiment of the present disclosure relates to a device for recording and transmitting electrical signals. In an exemplary embodiment, the device has a plurality of electrodes, plurality of contact pads wherein the plurality of electrodes and the plurality of contact pads are coupled via an interconnect. In an exemplary embodiment the interconnect includes a plurality of wires, wherein each of the plurality of wire of the interconnect is coupled to each of the plurality of electrodes at a first end of the interconnect. In an exemplary embodiment, each of the plurality of wires forming a plurality of contact pads at a second end of the interconnect. In an exemplary embodiment, each of the plurality of the contact pads is configured to read electrical signals from the electrodes and/or transmit electrical signals to the electrodes. Other embodiments are also disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The detailed description is described with reference to the accompanying figures. Features, aspects, and advantages of the subject matter of the present disclosure will be better understood with regard to the following description and the accompanying drawings. The figures are intended to be illustrative, not limiting, and are generally described in context of the embodiments, and it should be understood that it is not intended to limit the scope of the disclosure to these particular embodiments. In the figures, the same numbers may be used throughout the drawings to reference features and components. In order that the present disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figures. The figures together with detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages.
[0007] Figure 1A is an illustration of an exemplary L-shaped device in accordance with an embodiment of the present disclosure.
[0008] Figure 1B is an illustration of an exemplary L-shaped device with specific indicated in accordance with an embodiment of the present disclosure.
[0009] Figure 2 is an exemplary method of fabricating the L shaped device in accordance with a preferred embodiment of the present disclosure.
[0010] Figure 3A is an illustration of an exemplary method of fabricating the L shaped device in accordance with an embodiment of the present disclosure.
[0011] Figure 3B is an illustration of an exemplary method of fabricating the L shaped device in accordance with an embodiment of the present disclosure.
[0012] Figure 4 is an illustration of an exemplary time frequency analysis of the acquired ECOG signals in accordance with an embodiment of the present disclosure.
[0013] Figure 5 is an illustration of an exemplary histopathology study of vital organs of an animal implanted with the L shaped device, with H&E staining of extracted sections of: (a) Kidney (b) Liver (c) Lint (d) Large intestine and (e) Lungs in accordance with an embodiment of the present disclosure.
[0014] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical elements. The figures as disclosed herein are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings are meant to only be provided as examples and/or implementations consistent with the description, and the description may not be limited to the examples and/or implementations provided in the drawings.

DETAILED DESCRIPTION
[0015] The following describes technical solutions in exemplary embodiments of the subject matter of the present disclosure with reference to the accompanying drawings. In this application as disclosed herein, "at least one" means one or more, and "a plurality of" means two or more. The term "and/or" describes an association relationship for describing associated objects and represents that three relationships may exist. For example, A and/or B may represent the following cases: Only A exists, both A and B exist, and only B exists, where A and B may be singular or plural. The character "/" usually indicates an "or" relationship between the associated objects. "At least one item (piece) of the following" or a similar expression thereof means any combination of the items, including any combination of singular items (piece) or plural items (pieces). For example, at least one item (piece) of a, b, or c may represent a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c each may be singular or plural.
[0016] It should be noted that in this application articles “a”, “an” and “the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. The terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as “consists of only”. Throughout this specification defined above, unless the context requires otherwise the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated element or step or group of elements or steps but not the exclusion of any other element or step or group of elements or steps. The term “including” is used to mean “including but not limited to”. “Including” and “including but not limited to” are used interchangeably. In the structural formulae given herein and throughout the present disclosure, the following terms have been indicated meaning, unless specifically stated otherwise.
[0017] Unless otherwise defined, all terms used in the disclosure, including technical and scientific terms, have meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included for better understanding of the present disclosure. The term ‘about’ as used herein when referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of ±10% or less, preferably ±5% or less, more preferably ±1% or less and still more preferably ±0.1% or less of and from the specified value, insofar such variations are appropriate to perform the present disclosure. It is to be understood that the value to which the modifier ‘about’ refers is itself also specifically, and preferably disclosed.
[0018] It should be noted that in this application, the term such as "example" or "for example" or “exemplary” is used to represent giving an example, an illustration, or descriptions. Any embodiment or design scheme described as an "example" or "for example" in this application should not be explained as being more preferable or having more advantages than another embodiment or design scheme. Exactly, use of the word such as "example" or "for example" is intended to present a related concept in only a specific manner.
[0019] In the embodiments of the present subject matter that "B corresponding to A" indicates that B is associated with A, and B can be determined based on A. However, it should be further understood that determining B based on A does not mean that B is determined based on only A. B may alternatively be determined based on A and/or other information. In the embodiments of this application, "a plurality of" means two or more than two. Descriptions such as "first", "second" in the embodiments of this application are merely used for indicating and distinguishing between described objects, do not show a sequence, do not indicate a specific limitation on a quantity of devices in the embodiments of this application, and do not constitute any limitation on the embodiments of this application.
[0020] Exemplary embodiments of the present disclosure relate to a device for recording and transmitting signals, a method for forming the device and a method of implanting the device. An exemplary embodiment of the present disclosure relates to a device for recording and transmitting electrical signals. In an exemplary embodiment, the device has a plurality of electrodes and an interconnect. In an exemplary embodiment the interconnect includes a plurality of wires, wherein each of the plurality of wire of the interconnect is coupled to each of the plurality of electrodes at a first end of the interconnect. In an exemplary embodiment, each of the plurality of wires forming a plurality of contact pads at a second end of the interconnect. In an exemplary embodiment, each of the plurality of the contact pads is configured to read electrical signals from the electrodes and/or transmit electrical signals to the electrodes.
[0021] In an exemplary case the device may be placed in a region of interest in a human or animal. In a preferred embodiment, the region of interest may be the brain. In another exemplary case, the device may be placed at other areas of a human and/or animal body such as the pancreas or liver etc. In an exemplary case, electrical signal may be passed on from the device to the region of interest and electrical pulses or signals may be recorded from the region of interest. In an exemplary case, for a subject with Parkinson’s disease, the L shaped device may be implanted in the M2 region of the brain, wherein the subject may be an animal or human, and may be effectively used for controlling Parkinson’s by detecting an action, such as the shivering of hands and trigger another action to transmit a signal to the part of the part to control the shivering thereby providing a control for Parkinson’s disease. In an exemplary case, the same L shaped device may be used in other parts of the subject to control other forms of disorders such as diabetes etc. In an exemplary case, for human adaptation, the size of the L shaped device (reference to L shaped device may be read also as L shaped cortical surface implant in the present disclosure) may vary in dimensions and may be longer for humans than the L shaped device used for animals. In an exemplary case, when the Parkinson’s begins to take effect in a subject, i.e., the hand beings to tremble, an electrical signal is recorded via the L shaped device and instantaneously an electrical pulse may be sent to the region of the brain which would stop the trembling of the hand, thereby controlling the disorder.
[0022] In an exemplary embodiment, the number of electrodes may be at least five or more than five depending on the size of the electrode. In an exemplary embodiment, the shape of the electrode may vary and may be circular or triangular or square or rectangular or polygonal, such that maximum surface area may be covered in the region of interest where the device is operational. In an exemplary embodiment, the electrodes, the interconnect and the contact pads may be coated with a bio-compatible material and/or a non-reactive material. In a preferred embodiment the non-reactive material and/or biocompatible material may be a polyimide. It should be obvious to a person of ordinary skill in the art that different shapes for the electrodes may be designed and all such variations fall within the scope of the present disclosure. It should also be obvious to a person skilled in the art that various other non-reactive material may be used to coat the electrodes, interconnect and contact pad areas, and all such variations fall within the scope of the present disclosure.
[0023] In an exemplary embodiment, the electrodes may be exposed via an opening in the coating. In an exemplary embodiment, each of the plurality of contact pads may be exposed by a contact exposure area. In an exemplary embodiment, the interconnect may include a conductive non-reactive material. In an exemplary embodiment, the conductive material may include at least one of a noble metal and/or a biocompatible conductive material.
[0024] In an exemplary embodiment, the interconnect may be designed to be L shaped, wherein a first part of the interconnect coupled to the electrodes is smaller than a second part of the interconnect coupled to the contact pads. It should be obvious to a person of ordinary skill in the art that various other shapes may be designed, and all such shapes may be considered to be a part of a variation with respect to the present disclosure. In an exemplary embodiment, the entire interconnect may be zig-zag (serpentine) shaped, wherein the zig-zag shape refers to one of a series of short turns or curls, angles, or alterations in a course of the length of the interconnect, and has a form of a series, i.e., repetitive in nature for a certain path.
[0025] In an exemplary embodiment, the plurality of electrodes spans a range of 2800 to 3500 µm forming the first part of the L shaped device. In an exemplary embodiment, the plurality of electrodes may be arranged in a zig-zag orientation in the first part in a range of about 300-600 µm of the L shaped device. In an exemplary embodiment, a length of the plurality of contact pads may be about 2500 µm and a width of the contact pad area may be about 2700 µm. In an exemplary embodiment, the width of each of the plurality of contact pad may be about 300 µm. It should be obvious to a person of ordinary skill in the art that the ranges mentioned may vary in the L shaped device and all such variations fall within the scope of the present disclosure.
[0026] An exemplary case includes a method of forming the L shaped device as disclosed above. An exemplary case includes forming a polyimide layer on a silicon wafer, wherein the silicon wafer is a base, and the base is configured to provide mechanical support. In an exemplary case, the method includes depositing a conducting material on the polyimide layer. In an exemplary case, the method includes patterning the conducting material in a pre-determined manner, for example serpentine shape, for the electrodes the shape may be circular and for the contact pads the shape may be rectangular. It should be obvious that various other patterns may be formed for the electrodes, the interconnect and the contact pads and all such shapes and sizes with variations fall within the scope of the present disclosure. In the exemplary case, the method includes coating the patterned conducting material with a polyimide layer for passivation. In a exemplary case, the method includes etching to expose active electrodes and contact pad area. It should again be obvious to a person of ordinary skill in the art that various other techniques and methods may be used to expose the electrodes and contact pads and all such variations fall within the scope of the present disclosure. In an exemplary case, the method include realizing the L shaped device from the silicon wafer.
[0027] An exemplary embodiment includes an alternate method for forming an L shape device as disclosed above. An exemplary embodiment may include placing the electrodes in a zig-zag orientation, and the plurality of electrodes spanning an area of 300 – 600 µm on one arm of the L shaped device, which is the shorter arm or the first arm. An exemplary embodiment may include attaching each of the plurality of electrodes with an interconnect, the interconnect may include a plurality of wires, where each of the plurality of wires may be coupled to an electrode at one end and a contact pad at the other end, the interconnect having a zig-zag orientation bent at about 90 degrees forming an L shape, wherein a first part of the interconnect is coupled to the plurality of electrodes and a second part coupled to a plurality of contact pads. An exemplary embodiment may include coating the electrodes, the interconnect and the contact pads with a non-reactive material.
[0028] An exemplary embodiment may include creating an opening at each of the plurality of electrodes in the coating, thereby exposing the electrodes. In an exemplary embodiment, the interconnect may include a conductive non-reactive material, wherein the material comprises at least one of a noble metal and a biocompatible conductive material.
[0029] An exemplary embodiment may include forming an device with an L shape, where the interconnect in a zig-zag pattern, wherein a first part of the interconnect may be coupled to the electrodes, which is smaller than a second part of the interconnect coupled to the contact pads, which is longer than the first part, thereby forming a L shaped device. In an exemplary embodiment, an active electrode area for the plurality of electrodes may be in a range of 2800 to 3500 µm, forming the first part of the L shaped device. In an exemplary embodiment, a length of each of the plurality of contact pads may be about 2500 µm and a width of each of the plurality of contact pads may be about 2700 µm. In an exemplary embodiment, each contact pad has a width of about 300 µm. It should be obvious to a person of ordinary skill in the art as mentioned previously that the ranges disclosed herein are only indicative in nature and may be preferred, but several variations may be made to these ranges and all such variations fall within the scope of the present disclose that form a L shaped device.
[0030] An exemplary embodiment may include implanting the L shaped device in humans and/or animals. An exemplary embodiment may include identifying a region of interest for implanting the L shaped device. An exemplary embodiment may include placing the L shaped device in the identified region of interest, wherein electrical signals may be recorded from the region of interest where the L shaped device is located and/or electrical signals may be transmitting to the region of interest via the L shaped device. As disclosed previously the L shaped device may be advantageously placed in any region of interest identified in humans and/or animals. As mentioned previously, the dimensions of the device may vary according to the brain size of the animal or human. In an embodiment, placing the L shaped device in the region of interest may include performing a procedure on the human and/or animal at the identified region of interest. In an embodiment, once placed or collocated at the region of interest, the L shaped device may be operated by means of a battery to transmit signals to the region of interest. In an embodiment once placed or collocated at the region of interest, the L shaped device may record signals from the region of interest, which may be transmitted by a wired means or a wireless means or a combination thereof. In an embodiment, the recorded signals may be processed by means of a processor coupled to the L shaped device.
[0031] Reference is now made to Figure 1A, which is an illustration of an exemplary L-shaped device 100 in accordance with an embodiment of the present disclosure. Device 100 is designed in an L shaped, having two arms, first arm 122 and second arm 125. First arm 122 is shorter than second arm 125. First arm 122 and second arm 125 are bent at location 123, wherein location 123 forms a right angle between first arm 122 and second arm 125. It should be obvious to a person skilled in the art that location 123 as illustrated is roughly about 90 degrees, but location 123 may have a variation between about 70 degrees to about 120 degrees and such variation for location 123 between first arm 122 and second arm 125 fall within the scope of the present disclosure. First arm 122 has plurality of electrodes 100, wherein plurality of electrodes 100 are in contact with a region of interest (not shown in Figure) and used for communicating electricals signals to and/from the region of interest. Each of plurality of electrodes 110 is coupled to an interconnect 120 along first part 122 of interconnect 125. Interconnect 125 is designed to have a zig-zag shape along both first arm 122 and second arm 125. Interconnect 120 is made up of a non-reactive conducting material, and in an exemplary case, noble metals such as gold or platinum made be used to form the interconnect 120. First arm 122 having plurality of electrodes 110 is placed at a region of interest which may be monitored and on determining any disorders, and in the preferred case neurological disorders were addressed, where the region of interest may treat accordingly to address the discrepancies.
[0032] Second arm 125 of interconnect 120 is longer than first arm 122 and also has a zig-zag pattern as illustrated. Second arm 125 is coupled to plurality of contact pads 130, wherein plurality of contact pads 130 is coupled to the interconnect at joint 124. Each electrode of the plurality of electrodes has one wire coupled to it forming the interconnect 125 and coupled to each of the plurality of contact pads. In an exemplary case, if there are five electrodes, then each of the five electrodes has a connecting wire forming an L shape and then coupled to the five contact pads. Interconnect 125 is a conducting material as disclosed previously.
[0033] Plurality of electrodes 110, interconnect 125 and plurality of contact pads 130, i.e., the entire L shaped device is coated forming coating 140, wherein coating 140 is a non-reactive material and/or a biocompatible material. Plurality of electrodes 110 are exposed via opening 115 in coating 140, which may be formed by etching for example. It should be obvious that various other techniques may be used to expose the active electrodes and all such variation fall within the scope of the present disclosure. Plurality of contact pads 130 are exposed by contact exposure area 132, wherein contact pads 130 may be coupled to a connector (not shown in Figure), wherein the connector may be coupled to an external device for processing signals to and/or from the L shaped device. Again, contact pads may be exposed by etching and it should be obvious that various other techniques may be used and all such techniques fall within the scope of the present disclosure. Interconnect 125 coupling plurality of electrodes 110 and plurality of contact pads 130 are made of a non-reactive conducting material. In an exemplary case, the conductive material may include at least one of a noble metal and/or a biocompatible conductive material subsequently coated with conductive polymers.

[0034] Interconnect 120 is designed to be L shaped, wherein first part 123 of interconnect 120 coupled to the electrodes 110 is smaller than second part 125 of interconnect 120 coupled to contact pads 130. Entire interconnect 120, including first part 122 and second part 125 is zig-zag (serpentine) shaped. Contact par area 130 may also include chip 150, wherein chip 150 may include a processor for processing data, electrical signals, and transmitter for transmitting data/information to and/or from the L shaped device.

[0035] In a preferred embodiment, first a silicon wafer (carrier wafer) is taken as a base material, wherein the silicon wafer is required for mechanical support for forming the L shaped device. The silicon wafer is then coated with a polyamic acid solution and cured to form a polyimide layer. After formation of the polyimide layer a bio-compatible conducting material is deposited and the bio-compatible conducting material is patterned according to the desired shape, wherein optical lithography may be used. It should be obvious that deposition of the bio-compatible conducting layer and the patterning may be performed using various other techniques available to a person skilled in the art and all such variation fall within the scope of the present disclosure. Subsequent to patterning, another layer of polyimide is formed for passivation, followed by with active electrodes and contact pads exposure using etching techniques. It should be obvious that other techniques may be used instead of etching and all such variation fall within the scope of the present disclosure. The L shaped cortical surface implant is realized by separating it from the silicon wafer.
[0036] Reference is now made to Figure 1B, which is an illustration of an preferred L-shaped device 100B developed and tested in accordance with an embodiment of the present disclosure. As illustrated the preferred L shaped device 100B as devised in accordance with the present disclosure has three part, electrodes 110, interconnect 120 and contact area 130. Each of these components will be discussed in more details below as a preferred embodiment. However, a person skilled in the art may vary the dimensions indicated in the preferred embodiment to build a similar L shaped device and all such variation fall with the scope of the present disclosure.
[0037] Electrodes 110 (are of the L shaped device 100B having the electrodes) is expanded and indicated as active electrode area 111. Active electrode Area 111 has about 5 electrodes, each electrode having a dimension of about 400 µm. The five electrodes form the first part/first arm of the L shaped device. The first part of active electrode area is about 5492 µm in length on a longer side and about 3090 µm on a shorter side and is about 1950 µm in width, which encompasses all five electrodes. The longer side is preferably straight and the shorter side which is attached to the longer side is roughly C shaped. Each of the electrodes is coupled with a wire and the wires form a zig-zag pattern.
[0038] Interconnect 120 along with the first part is described above. The second part of the interconnect 120 is a longer arm which meets the first part forming the L shaped device. The length of the second part interconnect is about 27000 µm, excluding the contact pad area, an expanded view of the interconnect 120 is provided in the active interconnect area 121, wherein each wire in the interconnect 120 is about 50 µm, each of the wires are separated by a distance of 100 µm and the total width of interconnect 120 is about 1365 µm. In a preferred embodiment the second part of the interconnect is 25000 µm.
[0039] Interconnect 120 coupled to plurality of electrodes 110 at one end on first part/arm is coupled to of plurality of contact pads at second end, wherein second end of interconnect 120 is on second part/arm of L shaped device 100B. Contact pad area 131 expanded illustrates five contact pads as the number of electrodes is five and there are five wires from each electrode that will need to be connected to a connector forming the contact pad. Each of the connector in contact pad area has a dimension of about 300 µm, wherein the contact pad area is rectangular in shape with the length of the contact pad area being 2500 µm and the width of the contact pad area being 2700 µm. The total length of the L shaped device is about 29000 µm and the width of the device is roughly about 5500 µm, and as mentioned previously in a preferred embodiment the length of the L shaped device is about 25000 µm. It should be obvious that the dimensions of the L shaped device may vary, and all such variation fall within the scope of the present disclosure. The above built L shaped device as a preferred embodiment should be considered to be exemplary in nature and a number of variations may be made to this and all such variation fall within the scope of the present disclosure. The inset illustrates the size of the L shaped device built in the Laboratory. It should be obvious to a person of ordinary skill in the art that though the L shaped device illustrates five electrodes with five interconnects and five contact pads, within the given width of the L shaped device more or less than five electrodes may be placed and all such variations fall within the scope of the present disclosed, as long as the shape of the device is L or closer to L with the shorter arm deviation by about 20-30 degrees from the right angled shape. It should also be obvious to a, person of ordinary skill in the art that various other shapes for the electrode other than that illustrated may be used such as elliptical, triangular, rectangular, diamond, polygonal and all such shaped fall within the scope of the present disclosure.
[0040] Reference is now made to Figure 2, which is an exemplary method of fabricating the L shaped device in accordance with a preferred embodiment of the present disclosure. In step 210 first a silicon wafer (carrier wafer) is taken as a base material, wherein the silicon wafer is required for mechanical support. The silicon wafer is coated with a polyamic acid solution and cured to form a polyimide layer. In step 220, after formation of the polyimide layer bio-compatible conducting material is deposited and patterned according to the desired shape, wherein optical lithography may be used. It should be obvious that deposition of the bio-compatible conducting layer and the patterning may be performed using various other techniques available to a person skilled in the art and all such variation fall within the scope of the present disclosure. In step 230, subsequent to patterning, another layer of polyimide is formed for passivation, followed by with active electrodes and contact pads exposure using etching techniques. It should be obvious that other techniques may be used instead of etching and all such variation fall within the scope of the present disclosure. The L shaped cortical surface implant is realized by separating it from the silicon wafer.
[0041] Reference is now made to Figure 3A, which is an illustration of an alternate exemplary method of fabricating the L shaped device in accordance with an embodiment of the present disclosure. L shaped device may be formed by various methods and only an exemplary illustration of form the L shaped device in accordance with the present disclosure has been disclosed. It should be obvious to a person of ordinary skill in the art that other method used to form the L shaped device will fall within the scope of the present disclosure.
[0042] In step 310 long wires are taken and arranged in a zig-zag pattern bent preferably at 90 degrees or as mentioned previously from 70 degrees to about 120 degrees, wherein a first part/arm is smaller than a second part/arm. The wires form the interconnect coupling the electrodes and the contact pad area. Essentially the wires form an L shape or almost L shape. In step 320, on the shorter part/arm of the L shaped device electrodes are placed and coupled to the wire, which form an electrode area. The electrodes are also arranged in a zig-zag pattern. In step 330, the second part/arm of the L shaped device is provided with contact pads, which form the contact pad area. The number of electrodes, the number of wires connecting the electrodes and the contact pads, and the number of contact pads is constant. In an exemplary case, the L shaped device has five electrodes, five contact pads and five wires with each wire coupling one electrode to one contact pad. The electrodes, the wires and the contact pads are preferably made of a conducting material and/or biocompatible conducting materials which are non-reactive such as gold or the likes.
[0043] Reference is now made to Figure 3B, which is an illustration of an alternate exemplary method of fabricating the L shaped device in accordance with an embodiment of the present disclosure. Once the basic L shaped device is prepared in accordance with Figure 3A, in step 340, the entire L shaped device is coated with a non-reactive material such as a polyimide or any other non-reactive material. Once the device is coated with, in step 350 openings are formed on the shorter arm at the position of the electrodes, thereby exposing the electrodes. In step 360, openings are formed at the position of the contact pads, thereby exposing the contact pads. The electrodes are placed at a region of interest from where signals are recorded, and signals may be transmitted to take a corrective action. The contact pads may be coupled to a connector which may be coupled to a processor for further processing of the recorded signal and taking any corrective action. As discussed, the exemplary method of the L shaped device as indicated in Figure 1A and Figure 1B only details a few method steps and it should be obvious to a person skilled in the art that all material mentioned in the present disclosure and methods used to build such an L shaped device fall within the scope of the present disclosure.
[0044] In an exemplary case, the L shaped device formed using the methodology as described in Figure 2 was tested on rats under specific laboratory conditions in accordance with any statutory regulation that apply. In an exemplary case, for several anatomical reasons, the M2 area in the rat’s brain is predicted to be distinct from other regions. In an exemplary case, biocompatible microwires made from Tungsten, stainless-steel, platinum-iridium or metallic screws are typically used in neuroscience research to monitor the Motor cortex regions (M1 region and M2 region). In an exemplary case, these implanted screws or wires, normally pose significant damage because of the micromotion of the brain after implantation.
[0045] In an exemplary embodiment, the L shaped device a procedure may be performed to do a surface neural implant, wherein the shape of the neural implant may be uniquely designed for targeting the secondary motor region (M2 region). In an exemplary case, the five circular electrodes (diameter in the range of about 400 µm) spanning 1.95 mm x 3.09 mm optimally utilize the area in the brain without blocking a provision for analyzing other regions of the brain. In an exemplary case, any neural implant that records signals from other regions can be implanted with more ease compared to the commercially available rectangular grid-type of implants that are currently available for use. In an exemplary case, this allows progressing towards multi-site recording/stimulation to understand the spatiotemporal patterns across the brain regions. In an exemplary case, the L-shaped design of the neural implant can accommodate nearby deep neural probes without any obstruction. In an exemplary case, polyimide is proven to be an excellent biocompatible material, and may be chosen as a substrate material or covering material for the conducting material forming the device because of its low elastic modulus comparable to the brain tissue and high chemical resistance to the solvents used in the MEMS fabrication processes. In an exemplary case, simple spin coating techniques can easily achieve 15-20 µm thick Polyimide films. Other techniques may be used, and it should be obvious to a person of ordinary skill in the art that all such techniques fall within the scope of the present disclosure. In an exemplary case, the serpentine shaped (zig-zag) interconnect traces proposed in the design withstand higher strains.
[0046] In an exemplary case, the polyimide layer is used again as a passivation layer to insulate the interconnect area. In an exemplary case, the Polyimide layer around the five circular electrode areas and the corresponding contact pad area is etched using plasma-ashing, which is a process that may be used to remove photoresist. It should be obvious to a person of ordinary skill in the art that other techniques may be used to remove the photoresist and all such variation fall within the scope of the present disclosure. Other materials may be used to form the coating instead of polyamide and it should be obvious that all such materials that are non-reactive fall within the scope of the current disclosure. It should also be obvious to a person of ordinary skill in the art that other techniques may be used to expose the electrodes and contact pads and all such techniques fall with the scope of the present disclosure. In an exemplary case, the L-shaped neural implant optimizes the implantation area required in the brain, thereby reducing the chances of infections.
[0047] In an exemplary case, the contact pad area may be designed such that a simple, flexible printed circuit (FPC) connector can house the surface neural implant using a press-fit mechanism. In an exemplary case, this simplifies the Electrode Interface Board (EIB) design required for processing the signals. An advantage is that EIB can be reused by replacing neural implants with newer ones, and hence the cost of designing and manufacturing an EIB board can be significantly reduced.
[0048] Reference is now made to Figure 4, which is an illustration of an exemplary time frequency analysis of the acquired ECOG signals in accordance with an embodiment of the present disclosure. In an exemplary case, Surface Neural Implants (SNIs) may be fabricates as disclosed previously and in the current exemplary case was implanted in a rat for recording Electrocorticography (ECOG) signals from the M2 regions (right and left hemispheres)) after performing a bilateral craniotomy under regulated conditions confirming with all statutory regulations and norms. In an exemplary case, the SNIs are connected to the EIB board using FPC connectors. In an exemplary case, the rat after being implanted with the SNI is allowed to recover for about a week. In an exemplary case, the ECOG signals are acquired post the recovery. In the experimental case from Day 8, when the rat begins to perform various regular tasks such as sleeping, walking, holding the grill, etc. In an exemplary case, Open BCI Cyton Daisy Biosensing board has been used to perform the various measurements. In an exemplary case, the acquired biopotentials were preprocessed in a computational system (not shown in the Figure) coupled to the L shaped device and the time-frequency features were checked by performing a time-frequency analysis of the acquired ECOG signals on Day 8. In the exemplary case, lower neural activity were observed when the rat was in a sleep state compared to the rat being in an awake state. Additionally, a specific repetitive pattern with significantly higher electrical neural activity were observed while the rat was holding a grill and walking within the cage after perform the SNI.
[0049] Measurements include time versus voltage in (µV) for different states when the rat is sleeping, holding the grill and walking. In the sleep state, low frequency signals are dominant as seen in time frequency analysis. While the rat is holding onto the grill changes can be seen at certain time intervals, however, while the rat is walking or in motion variations are noticed. Next a power spectrum measurement is included versus frequency measured by the electrodes of the L shaped device for the same 3 states mentioned above. A heat map is indicated of frequency versus time measurement and time analysis is indicated for the three states.
[0050] In an exemplary case, to demonstrate the working of the L-shaped device, the L shaped device was implanted in the M2 region of a Wistar rat’s brain by performing a procedure on the rat in the Laboratory ensuring all statutory conditions and norms are strictly adhered to. In the exemplary case, post implantation of the L shaped device in the M2 region of the rats brain, the rat was allowed to undergo recovery for a period of about one week. In the exemplary case, the rat post recovery was placed in a cage for observation, study and signal acquisition. In the exemplary case, Electrocorticography (ECoG) signals were acquired from the rat via the L shaped device using a biopotential acquisition system. In the exemplary case, various different phases such as when the rat was sleeping, the rat was walking and the rat holding the grill were studied in order to demonstrated that the L shaped device is functional and non-toxic post implantation in an animal. It should therefore be obvious to a person of ordinary skill in the art, that L shaped device built the above mentioned methodology may be safe to use in other animals and/or humans.
[0051] In the exemplary case, measurements made using the L shaped device at various phases when the rat is sleeping, walking and holding the grill, where all activities are essentially being performed by the rat in a cage sufficiently large for the rat to survive in captivity. In the exemplary experimental case, the cage has a dimension of 4ft X 4Ft X 4Ft. In the exemplary illustration of Figure 4, the first column indicates time frequency plots of acquired neural data when the rat was sleeping, the second column indicates time frequency plots of acquired neural data when the rat was walking, third column indicates time frequency plots of acquired neural data when the rat was holding the grill. In the exemplary case, all measurements have been made post implementation of the L shaped device in the rat and full recovery of the rat post implantation.
[0052] In the exemplary plot, first row indicated a plot of time in seconds versus amplitude of the signal in µVolts measured from the L shaped device implanted in the rat during the three different phases. In the exemplary plot, second row indicated a plot of frequency in Hertz versus power spectrum in dB of the signal measured from the L shaped device implanted in the rat during the three different phases. In the exemplary plot, the third row is a heat map indicating time in seconds versus frequency in hertz for measurements made from the L shaped device, and the third row is an indicative plot of the heat map.
[0053] In the exemplary case, as illustrated from the heat map for the measurements made on the rat implanted with the L shaped device during the different phases, low frequencies may be dominant while the rat is sleeping till about 12 Hz, whereas while holding grill and while walking higher frequencies may be predominant, around the 60 Hz range, clearly indicating that electrodes of the L shaped device implanted in the rat are recording signals according to the neural activity.
[0054] Figure 5 is an illustration of an exemplary histopathology study of vital organs of an animal implanted with the L shaped device, with H&E staining of extracted sections of (a) Kidney, (b) Liver, (c) Lint, (d) Large intestine, and (e) Lungs in accordance with an embodiment of the present disclosure. In the exemplary experimental case, the ECOG signals were recorded for six weeks before euthanizing the rat in accordance with statutory norms and procedures. In the exemplary experimental case, the vital organs such as the kidney, liver, large intestine, small intestine, lungs, and heart were harvested to understand the toxicity induced by the neural implant or determine the amount of toxicity induced by such a neural implant. In the exemplary experimental case, the ultrastructural examination of the kidney reveals no renal necrosis (Error! Reference source not found.(a)). In the exemplary experimental case, almost all of the straight regions of the kidney's proximal tubules appeared to be normal. In the exemplary experimental case, histological findings regarding the liver were found to be normal, with clearly defined liver parenchyma composed of hepatic cords and sinusoids distributed radially around the central vein (Error! Reference source not found.(b)).
[0055] In the exemplary experimental case, the muscularis externa displayed a thick band of longitudinal muscles. In the exemplary experimental case, the rectum is composed of goblet cells and intestinal glands, as well as blood arteries that are more abundant than those of the caecum and colon. In the exemplary experimental case, these large intestinal structures are entirely normal (Error! Reference source not found.(c)). In the exemplary experimental case, the more widespread villi surface indicates that the jejunum has the largest absorptive capacity of any region of the small intestine. In the exemplary experimental case, payers patches can be found in the submucosa, and longitudinal muscles can be found in the tunica muscularis. In the exemplary experimental case, these histological characteristics are normal with no abnormalities (Error! Reference source not found.(d)). In an exemplary experimental case, H&E stained microscopic examinations of lung sections revealed normal tissue architecture of the lung alveolar, peribranchial, and perivascular areas, with uniform alveoli and clear bronchioles lumen. In the exemplary experimental case, in the lung parenchyma, there was no hyperplasia or cell infiltration (Error! Reference source not found.(e)). In the exemplaary experimental case, it is clear from the histopathology results that there is no visible evidence of toxicity induced by the SNI. It may therefore safely be concluded that the L shaped devices in accordance with the present disclosure may be used for clinical trials and further use in humans and animals, wherein depending on the animal and/or human the size of the L shaped device may vary. Also as indicated, tests were performed on the rat’s brain, but it should be obvious to a person of ordinary skill in the art that the L shaped device may be implanted in various other regions of the body targeting specific organs of humans and/or animals, like for example the pancreas, intestines, stomach etc.
[0056] Although the present disclosure has been described with reference to several preferred embodiments, it should be understood that the present disclosure is not limited to the preferred embodiments disclosed here. Embodiments of the present disclosure are intended to cover various modifications and equivalent arrangements within the spirit and scope of the appended claims. Although the foregoing disclosure has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practised within the scope of the appended claims. Examples of the present disclosure have been described in language specific to structural features and/or methods. It should be noted that there are many alternative ways of implementing both the process and apparatus of the present invention. Accordingly, embodiments of the present disclosure are to be considered illustrative and not restrictive, and the invention is not to be limited to the details given herein but may be modified within the scope and equivalents of the appended claims. It should be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed and explained as examples of the present disclosure.

, C , Claims:We Claim:
1. A device 100 for recording and transmitting signals, the device comprising:
a plurality of electrodes 110 and an interconnect 120;
the interconnect 120 comprising a plurality of wires, wherein each of the plurality of wire of the interconnect 120 is coupled to each of the plurality of electrodes 110 at a first end 122 of the interconnect 120;
each of the plurality of wires coupled to a plurality of contact pads 130 at a second end 124 of the interconnect 120;
and each of the plurality of the contact pads 130 is configured to read signals and/or transmit signals from the plurality of electrodes 110.

2. The device 100 as claimed in claim 1, wherein the signals comprise:
- an electrical signal, wherein the electrical signal is associated with a neuron activity.

3. The device 100 as claimed in claim 1, wherein the plurality of electrodes 110, the interconnect 120 and the contact pads 130 comprises:
- a coating with a non-reactive material and/or biocompatible material forming a covering 140.

4. The device as claimed in claim 1, wherein the plurality of electrodes 110, the interconnect 120 and the plurality of contact pads 130 comprises:
- a conductive non-reactive material and/or a conductive biocompatible material.

5. The device as claimed in claim 4, wherein the material comprises:
- at least one of a noble metal from the periodic table of elements and/or a biocompatible conductive material with an electropolymerized conducting polymer.

6. The device as claimed in claim 3, wherein the coating comprises a non-reactive material and/or biocompatible material.

7. The device as claimed in claim 6, wherein the non-reactive material and/or biocompatible material is a polyimide or polypropylene or nylon or parylene C or PDMS or a combination thereof.

8. The device as claimed in claim 1, wherein the plurality of electrodes 110 are exposed via an opening 115 in the coating 140.

9. The device as claimed in claim 1, wherein each of the plurality of contact pads 130 are exposed by a contact exposure area 132 in the coating 140.

10. The device as claimed in claim 1, wherein the interconnect 120 is L shaped, wherein a first part 123 of the interconnect 120 coupled to the electrodes 110 is smaller than a second part 125 of the interconnect 120 coupled to the contact pads 130.

11. The device as claimed in claim 10, wherein the interconnect 120 is zig-zag shaped or serpentine shaped.

12. The device as claimed in claim 10, wherein the plurality of electrodes 110 spans a range of 2800 to 3500 µm forming the first part 123 of the L shape.

13. The device as claimed in claim 10, wherein the plurality of electrodes 110 is arranged in a zig-zag orientation or serpentine orientation in the first part 123 in a range of about 300 to 600 µm

14. The device as claimed in claim 10, wherein a length of the plurality of contact pads 130 on the second part 125 of the interconnect 120 is about 2500 µm and a width of the contact pad area is about 2700 µm.

15. The device as claimed in claim 14, wherein the width of each of the plurality of contact pad is about 300 µm.

16. A method for forming a device 100, the method comprising:
- forming a polyimide layer on a silicon wafer, wherein the silicon wafer is chosen as a base, wherein the base is configured to provide mechanical support;
- depositing a conducting material on the polyimide layer;
- patterning the conducting material in a pre-determined manner, forming the electrodes, interconnect and the contact pads;
- coating the patterned conducting material with a polyimide layer for passivation;
- etching the polyimide layer to expose active electrodes and contact pad area;
- realizing the L shaped device from the silicon wafer.

17. The method as claimed in claim 16, the etching comprising:
- creating an opening at each of the plurality of electrodes, thereby exposing the electrodes; and
- creating an opening at each of the plurality of contact pads, thereby exposing the contact pads.

18. The method as claimed in claim 16, wherein the interconnect comprises a conductive non-reactive material and/or biocompatible material.

19. The method as claimed in claim 16, the method comprising:
- patterning the interconnect 120 in a zig-zag manner or a serpentine manner, wherein a first part 123 of the interconnect 120 coupled to the electrodes 110 is smaller than a second part 125 of the interconnect 120 coupled to the contact pads 130.

20. The method as claimed in claim 16, wherein an active electrode area comprising the plurality of electrodes is in a range of 2800 to 3500 µm, forming the first part 123.

21. The method as claimed in claim 15, wherein a length of each of the plurality of contact pads is about 2500 µm and a width of each of the plurality of contact pads is about 2700 µm.

22. The method as claimed in claim 15, wherein each contact pad has a width of about 300 µm.

23. A method for implanting the device as claimed in claims 1 to 15, the method comprising:
- identifying a region of interest for implanting the device;
- performing a procedure on an object to implant the device at the identified region of interest; and
- placing the device in a region of interest, wherein signals are recorded from the device and/or transmitting to the device targeting the region of interest.

24. The method as claimed in claim 23, wherein the signals comprise an electrical signal, wherein the electrical signal is related to a neuron activity.

Dated this 03rd day of April 2024 Indian Institute of Science
By their Agent & Attorney

Dr. Eric W B Dias/Reg No 1058
of Khaitan & Co