A self-bending cochlear implant and a method of manufacturing the same

Abstract

The application provides a self-bending cochlear implant and a preparation method thereof, which comprises an electrode body and an electrode support device connected with the electrode body; wherein: the electrode body comprises an electrode folding piece and a flexible thin film electrode layer, one end of the electrode folding piece is connected with the electrode support device, the flexible thin film electrode layer is laid on one side of the central axis of the electrode folding piece, and the flexible thin film electrode layer is used for generating electric current to stimulate cochlear wall neurons; the electrode folding piece comprises an initial shape and a temporary shape, the initial shape is in a curved and unfolded state, the temporary shape is in a flat and folded state, the size of the electrode folding piece in the initial shape is larger than the size of the electrode folding piece in the temporary shape, and the electrode folding piece can drive the flexible thin film electrode layer to bidirectionally transform between the initial shape and the temporary shape under external stimulation. The cochlear implant can be deformed under external stimulation to be combined with the cochlear wall, the cochlear structure is protected, and the hearing effect can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical medical devices, in particular to a self-bending cochlear implant and a preparation method thereof. BACKGROUND

[0002] Cochlear implantation is one of the effective means for treating sensorineural hearing loss. The most challenging component in a cochlear implant is the electrode array, which produces hearing by stimulating the auditory nerve. Most of the cochlear implants currently used in commercial production and clinical applications are manufactured by traditional methods, which involve manually assembling the electrode array, welding wires, and finally molding a silicone carrier around them. Due to the poor precision of manual assembly, the number of electrodes is limited to about 20, and the size of the produced electrode array is relatively large. The limited number of electrodes can provide limited frequency, which makes the cochlear implant provide poor sound richness. This traditional manufacturing method has many problems to be solved, such as high cost, long production process, and narrow frequency range of the product, etc.

[0003] In related art, there are two types of electrode array structures used in clinical applications, one is a straight electrode, and the other is a pre-bent electrode. Since the cochlea structure is spiral-shaped, the straight electrode cannot fit the cochlea and needs to be supported by the outer wall of the cochlea to maintain the curved shape, which makes it difficult to avoid damage to the cochlea during implantation. The pre-bent electrode can be closer to the inner wall of the cochlea due to its curved shape, but the curved shape makes the electrode tip easily damage the spiral ligament, causing the electrode to shift and damage the cochlea.

[0004] Therefore, based on the above problems, it is necessary to provide a self-bending cochlear implant and a preparation method thereof. SUMMARY

[0005] The present application provides a self-bending cochlear implant and a preparation method thereof, which can deform under external stimulation to fit the inner wall of the cochlea, thereby protecting the cochlea structure and effectively improving the hearing effect.

[0006] In a first aspect, the present application provides a self-bending cochlear implant, comprising an electrode body and an electrode support device connected to the electrode body; wherein:

[0007] The electrode body comprises an electrode folding piece and a flexible thin film electrode layer, one end of the electrode folding piece is connected to the electrode support device, and the flexible thin film electrode layer is laid on one side of the central axis of the electrode folding piece. The flexible thin film electrode layer is used to generate an electric current to stimulate cochlear wall neurons.

[0008] The electrode folding piece comprises an initial shape and a temporary shape, the initial shape is in a curved unfolded state, the temporary shape is in a flat folded state, the size of the electrode folding piece in the initial shape is larger than the size of the electrode folding piece in the temporary shape, and the electrode folding piece can drive the flexible thin film electrode layer to transform between the initial shape and the temporary shape under external stimulation.

[0009] Preferably, the electrode folding piece is composed of a plurality of foldable units; wherein each foldable unit is composed of two mutually parallel support plates and a paper folding bending segment between the two support plates;

[0010] Two adjacent foldable units share one support plate, the sizes of the two support plates in each foldable unit are different, and the size of the support plate close to one end of the electrode support device is larger than the size of the support plate far from the electrode support device, so that the size of the electrode folding piece changes in a gradient manner.

[0011] Preferably, the size of the electrode folding piece gradually decreases in the direction away from the electrode support device.

[0012] Preferably, in the electrode folding piece, each support plate close to the inner wall of the cochlea is provided with a plurality of groove structures, the bottom of the flexible thin film electrode layer is provided with a plurality of protruding structures, the positions of the protruding structures correspond to the positions of the groove structures, the sizes of the protruding structures are matched with the sizes of the groove structures, and the electrode folding piece is fixed with the electrode thin film layer through the groove structures and the protruding structures.

[0013] More preferably, the opening area of the groove structure is smaller than the internal area of the groove structure.

[0014] Preferably, the flexible thin film electrode layer comprises an electrode layer and a plurality of wire layers arranged in sequence from top to bottom; wherein the upper and lower surfaces of each wire layer are provided with an encapsulation layer, and the encapsulation layer is used for protecting the wire layer.

[0015] Preferably, the electrode layer comprises a plurality of arrayed metal contact electrodes, and each metal contact electrode is composed of a plurality of periodically arranged metal hollow units.

[0016] More preferably, each encapsulation layer is provided with a plurality of electrode channels, and the wires in each wire layer are connected with the metal contact electrodes in the electrode layer through the electrode channels.

[0017] Preferably, the electrode folding piece is further provided with a flexible electrode head, the flexible electrode head is located at the end far from the electrode support device, and is used for preventing the electrode folding piece from damaging the cochlea.

[0018] Preferably, at least one mark ring is further arranged on the electrode support device, and the mark ring is arranged at one end close to the electrode body, and is used for controlling the implantation depth of the electrode body.

[0019] More preferably, a wing-shaped handle is further arranged on the electrode support device, and the wing-shaped handle is arranged at one side of the central axis of the electrode support device and is opposite to the direction of the flexible thin film electrode layer, and is used for controlling the implantation direction of the electrode body.

[0020] Preferably, the electrode folding piece is prepared by using a bidirectional shape memory polymer material, and has bidirectional shape memory performance.

[0021] More preferably, the shape memory deformation rate of the electrode folding piece is 0.1-5 mm / s.

[0022] In a second aspect, the application provides a preparation method of the self-bending cochlear implant according to any one of the first aspect, and the preparation method comprises the following steps:

[0023] (1) constructing a three-dimensional structure model of the initial shape of the electrode folding piece according to the specific structure shape and size of the cochlea; wherein the initial shape of the electrode folding piece is in a curved and unfolded state, and the temporary shape is in a flat and folded state;

[0024] (2) using a bidirectional shape memory polymer as a printing line, and performing 4D printing according to the constructed three-dimensional structure model to obtain the electrode folding piece in the initial shape;

[0025] (3) preparing a flexible thin film electrode layer, smearing medical epoxy resin on the protruding structure of the flexible thin film electrode layer, aligning the protruding structure of the flexible thin film electrode layer with the groove structure in the electrode folding piece, and then fixing and curing by using a clamp to obtain the electrode body;

[0026] (4) heating the electrode body in the initial shape to above the glass transition temperature, applying a load, and cooling and setting to obtain the electrode body in the temporary shape;

[0027] (5) fixing one end of the electrode body to the electrode support device to obtain the self-bending cochlear implant; wherein the size of the electrode folding piece gradually decreases in the direction away from the electrode support device.

[0028] Compared with the prior art, the application has at least the following beneficial effects:

[0029] (1) In the present application, by designing the electrode body as an electrode folding piece and a flexible thin film electrode layer, the electrode folding piece is printed by using a bidirectional shape memory polymer, has bidirectional shape memory performance, and by designing the initial shape of the electrode folding piece as a curved unfolded state and the temporary shape as a flat folded state, the electrode folding piece can drive the flexible thin film electrode layer to bidirectionally transform between the initial shape and the temporary shape under external stimulation; in the early stage of cochlear implantation, the electrode body is in a flat folded state and has a small volume, which facilitates initial implantation, and after implantation, by applying appropriate external stimulation, the electrode folding piece in the electrode body produces shape memory performance, changes from the flat folded state to the curved unfolded state, so that the electrode body can be well fitted with the inner wall of the human cochlea, so that the flexible thin film electrode layer is close to the cochlea wall or the basilar membrane, thereby effectively reducing local nerve cell stimulation and exciting current, while protecting the cochlea structure and effectively improving hearing effect. At the same time, when the cochlear implant needs to be removed, by applying appropriate stimulation again, the electrode folding piece in the electrode body produces shape memory performance, changes from the curved unfolded state to the flat folded state;

[0030] (2) The electrode body in the present application has bidirectional shape memory performance, the shape transformation process can be carried out without external force, and the shape memory deformation rate is controllable, so as to reduce the complexity and difficulty of cochlear implantation surgery, realize non-invasive cochlear implantation, completely retain the inner ear structure and physiological function, and at the same time, realize non-invasive removal, avoid secondary damage to the cochlea during removal. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0032] Fig. 1 is a temporary shape structure schematic diagram of an electrode body in a self-bending cochlear implant provided by an embodiment of the present application;

[0033] Figs. 2-3 is an initial shape structure schematic diagram of a support body in a self-bending cochlear implant provided by an embodiment of the present application;

[0034] Fig. 4 is a structure schematic diagram of a foldable unit in a self-bending cochlear implant provided by an embodiment of the present application;

[0035] Fig. 5is a structure diagram of a foldable unit in a self-bending cochlear implant according to another embodiment of the present application;

[0036] Fig. 6 is a structure diagram of a flexible thin film electrode layer in a self-bending cochlear implant according to an embodiment of the present application;

[0037] Fig. 7 is a structure diagram of several metal contact electrodes in a flexible thin film electrode in a self-bending cochlear implant according to an embodiment of the present application;

[0038] Fig. 8 is a structure diagram of the arrangement of a wire layer in a flexible thin film electrode in a self-bending cochlear implant according to an embodiment of the present application;

[0039] In the figure, 100 is an electrode body, 200 is an electrode support device, 101 is an electrode folding piece, 102 is a flexible thin film electrode layer, 103 is a flexible electrode head, 104 is a marker ring, 105 is a wing-shaped handle, 1011 is a foldable unit, 1012 is a support plate, 1013 is a paper folding bending section, 1014 is a groove structure, 1021 is an electrode layer, 1022 is a wire layer, 1023 is an encapsulation layer, 1024 is an adhesive layer, 1025 is a protruding structure, and 1026 is a metal contact electrode. DETAILED DESCRIPTION

[0040] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0041] As described above, the electrode array of the currently clinically used cochlear implant has poor adhesion to the inner wall of the cochlea, and it is difficult to effectively improve the hearing effect, and it is easy to cause damage to the cochlear structure during implantation. Considering that the thin film electrode array (TFEA) has higher manufacturing precision, can provide more electrode quantity under the condition of keeping smaller size, and can be mass-produced through a micro-electro-mechanical system (MEMS) process to reduce cost and increase efficiency. In the embodiments of the present application, the thin film electrode array is considered to be applied to the cochlear implant to improve the hearing effect. However, due to the shortcomings of the mechanical performance of the TFEA, it cannot be directly applied to the cochlear implant, such as the higher stiffness value leading to the electrode being easy to damage the cochlear structure during implantation, or the higher flexibility leading to the electrode being excessively bent during implantation.

[0042] Therefore, in the embodiment of the present application, by first designing a self-bending electrode folding piece, and by designing a thin film electrode array as a flexible thin film electrode layer, the flexible thin film electrode layer is deformed by the electrode folding piece as a carrier of the thin film electrode array. Since the initial shape and the temporary shape of the electrode folding piece are different in size, the flexible thin film electrode layer can be conveniently implanted in the initial stage, and after deformation in the later stage, the flexible thin film electrode layer can be better attached to the inner wall of the cochlea, so that the hearing effect can be effectively improved while the cochlea structure is protected.

[0043] The above concept will be described in detail below.

[0044] As shown in Figs. 1-2 The present application provides a self-bending cochlear implant, comprising an electrode body 100 and an electrode support device 200 connected to the electrode body 100; wherein:

[0045] The electrode body 100 comprises an electrode folding piece 101 and a flexible thin film electrode layer 102, one end of the electrode folding piece 101 is connected to the electrode support device 200, and the flexible thin film electrode layer 102 is laid on one side of the central axis of the electrode folding piece 101, and the flexible thin film electrode layer 102 is used to generate electric current to stimulate cochlear wall neurons;

[0046] The electrode folding piece 101 comprises an initial shape and a temporary shape, the initial shape is in a curved and unfolded state, the temporary shape is in a flat and folded state, and the size of the electrode folding piece in the initial shape is greater than the size of the electrode folding piece in the temporary shape, and under external stimulation, the electrode folding piece can drive the flexible thin film electrode layer to bidirectionally transform between the initial shape and the temporary shape.

[0047] In the embodiment of the present application, as Figs. 1-2As shown, by designing the electrode body 100 as the electrode folding piece 101 and the flexible thin film electrode layer 102, the electrode folding piece 101 is printed by using a bidirectional shape memory polymer, has a bidirectional shape memory performance, and by designing the initial shape of the electrode folding piece 101 as a curved unfolded state and the temporary shape as a flat folded state, the electrode folding piece 101 can drive the flexible thin film electrode layer 102 to bidirectionally transform between the initial shape and the temporary shape under external stimulation; in the early stage of cochlear implantation, the electrode body 100 is in a flat folded state and has a small volume, which is convenient for initial implantation, and after implantation, by applying appropriate external stimulation, the electrode folding piece 101 in the electrode body 100 generates shape memory performance, and transforms from the flat folded state to the curved unfolded state, so that the electrode body 100 can be well fitted with the inner wall of the human cochlea, so that the flexible thin film electrode layer 102 is close to the cochlea wall or the basilar membrane, thereby effectively reducing the stimulation of local nerve cells and exciting current, while effectively improving the hearing effect while protecting the cochlea structure. At the same time, when the cochlear implant needs to be removed, by applying appropriate stimulation again, the electrode folding piece 101 in the electrode body 100 generates shape memory performance, and transforms from the curved unfolded state to the flat folded state.

[0048] The electrode body 100 in the present application has bidirectional shape memory performance, and the shape transformation process can be performed without external force, and the shape memory deformation rate is controllable, so as to reduce the complexity and difficulty of cochlear implantation surgery, and to realize non-invasive cochlear implantation to completely preserve the inner ear structure and physiological function, and at the same time, non-invasive removal can be realized, avoiding secondary damage to the cochlea during removal.

[0049] According to some preferred embodiments, the shape memory deformation rate of the electrode folding piece 101 is 0.1-5mm / s (for example, it can be 0.1mm / s, 0.3mm / s, 0.5mm / s, 0.8mm / s, 1mm / s, 2mm / s, 3mm / s, 4mm / s or 5mm / s).

[0050] In the embodiment of the present application, by using a bidirectional shape memory polymer material (such as a thermosetting acrylic resin) as the main raw material of the electrode folding piece 101 and using 4D printing technology to print the electrode folding piece 101, the electrode folding piece 101 has bidirectional shape memory performance, that is, under two external stimulations, the electrode folding piece can transform between the initial shape and the temporary shape, and by controlling the shape memory deformation rate of the electrode folding piece within the above range, controllable control of the electrode body 100 can be realized during the implantation or removal of the cochlear implant, avoiding damage to the inner wall of the cochlea during the deformation process of the cochlear implant.

[0051] As shown in FIG. 6, the electrode body 100 is in a flat folded state, and the flexible thin film electrode layer 102 is in a flat folded state. Figs. 1-2As shown, according to some preferred embodiments, the electrode folding piece 101 is composed of several foldable units 1011; wherein each foldable unit 1011 is composed of two mutually parallel support plates 1012 and a paper-folding bending segment 1013 between the two support plates 1012;

[0052] Two adjacent foldable units 1011 share one support plate 1012, the two support plates 1012 in each foldable unit 1011 are of different sizes, and the size of the support plate 1012 close to one end of the electrode support device 200 is different from the size of the support plate 1012 far from one end of the electrode support device 200, so that the size of the electrode folding piece 101 changes in a gradient manner.

[0053] According to some preferred embodiments, the size of the electrode folding piece 101 gradually decreases in the direction away from the electrode support device 200.

[0054] Continuing to refer to Figs. 1-3 , several foldable units 1011 constitute the electrode folding piece 101 in the embodiment of the application, and by designing the size of the support plate 1012 in the electrode folding piece 101, the size of the electrode folding piece 101 gradually decreases in the direction away from the electrode support device 200, so that the electrode body 100 has a conical structure, the end close to the cochlear structure is thin, and the end close to the electrode support device 200 is thick, thereby making the size structure of the electrode body 100 more in line with the internal structure of the human cochlea, and further avoiding damage to the inner wall of the human cochlea by the electrode body 100.

[0055] In a specific embodiment, as shown in Fig. 4 , the two support plates 1012 in the foldable unit 1011 are different-sized quadrilateral support plates 1012, and the two quadrilateral support plates 1012 are connected to each other by two foldable quadrilateral paper-folding bending segments 1013, respectively. By adjusting the unfolded and folded states of the two paper-folding bending segments 1013 between the support plates 1012 in the foldable unit 1011, the electrode body 100 can achieve the effects of flat unfolding and curved unfolding, and the angle of curvature is controllable, thereby regulating the state and shape of the entire cochlear flexible thin-film electrode. Based on this characteristic, the unfolding and bending of each foldable unit 1011 can be adjusted according to the cochlear morphological structure of different patients, so that the cochlear flexible thin-film electrode is close to the central part of the scala tympani, thereby further avoiding damage to the fine structure of the cochlea.

[0056] In a specific embodiment, as shown in Fig. 5As shown, the two support plates 1012 in the foldable unit 1011 are two different sizes of regular hexagonal support plates 1012, and the two regular hexagonal support plates 1012 are connected to each other through the Kresling origami bending segment 1013. The Kresling origami bending segment 1013 between the support plates 1012 in the foldable unit 1011 is twisted to achieve the unfolded and folded states. Different torques applied to the Kresling origami segment can achieve the effects of flat unfolding and curved unfolding, and the angle of curvature is controllable, thereby adjusting the state and shape of the flexible thin film electrode of the artificial cochlea. Based on this characteristic, the unfolding and curvature of each foldable unit 1011 can be adjusted according to the cochlear morphology of different patients, so that the artificial cochlea is close to the central part of the cochlea, and the damage to the fine structure of the cochlea is reduced.

[0057] As shown in Fig. 4 and Fig. 6 According to some preferred embodiments, in the electrode folding piece 101, one end of each support plate 1012 close to the inner wall of the cochlea is provided with a plurality of groove structures 1014, the bottom of the flexible thin film electrode layer 102 is provided with a plurality of protruding structures 1025, the positions of the protruding structures 1025 correspond to the positions of the groove structures 1014, the sizes of the protruding structures 1025 are adapted to the sizes of the groove structures 1014, and the electrode folding piece 101 is fixed to the electrode thin film layer through the groove structures 1014 and the protruding structures 1025. The opening area of the groove structure 1014 is smaller than the internal area of the groove structure 1014.

[0058] Continuing to refer to Fig. 4 In the embodiment of the present application, a plurality of groove structures 1014 are arranged on each support plate 1012 on one side of the electrode folding piece 101 in the bending direction of the electrode folding segment, and further a corresponding protruding structure 1025 is arranged on the bottom of the flexible thin film electrode layer 102 at a position corresponding to each support plate 1012, so that mechanical interlocking is formed between the electrode folding segment and the flexible thin film electrode layer 102, and an organic adhesive is additionally applied at the groove structure 1014 and the protruding structure 1025. In this way, the fixation between the electrode body 100 and the flexible thin film electrode layer 102 is more firm, which not only facilitates the electrode body 100 to better drive the flexible thin film electrode layer 102 to change shape, but also effectively avoids the phenomenon of falling off of the flexible thin film electrode.

[0059] Further, the opening area of the groove structure 1014 is less than the internal area of the groove structure 1014, and the convex structure 1025 is matched with the groove structure 1014, so that the electrode body 100 is more firm and stable when being bonded with the flexible thin film electrode layer 102. In the embodiment of the present application, the shape of the groove structure 1014 is not limited, for example, it can be a regular polygonal platform or a hemisphere.

[0060] As shown in the figure, according to some preferred embodiments, the flexible thin film electrode layer 102 comprises an electrode layer 1021 and a plurality of wire layers 1022 arranged in sequence from top to bottom; wherein the upper and lower surfaces of each wire layer 1022 are provided with an encapsulation layer 1023, and the encapsulation layer 1023 is used for protecting the wire layer 1022. Fig. 6

[0061] According to some preferred embodiments, the flexible thin film electrode layer 102 further comprises an adhesive layer 1024, which is located below the encapsulation layer 1023 away from the electrode layer 1021, and the bottom of the adhesive layer 1024 is provided with a plurality of convex structures 1025 matched with the groove structure 1014, and the flexible thin film electrode layer 102 and the electrode folding piece 101 are fixedly connected through the groove structure 1014 and the convex structure 1025.

[0062] According to some preferred embodiments, the electrode layer 1021 comprises a plurality of arrayed metal contact electrodes 1026, each of which is composed of a plurality of periodically arranged metal hollow units; each encapsulation layer 1023 is provided with a plurality of electrode channels, and the wires in each wire layer 1022 are connected with the metal contact electrodes 1026 in the electrode layer 1021 through the electrode channels.

[0063] In the embodiment of the present application, the base material of the flexible thin film electrode layer 102 can be polyimide, and the electrode layer 1021 in the flexible thin film electrode layer 102 is designed as a plurality of arrayed metal contact electrodes 1026, each of which is composed of a plurality of periodically arranged metal hollow units, so that each metal contact electrode 1026 presents a hollow paper-cut pattern (for example, it can be as shown in the figure). Fig. 7 ​The flexible thin film electrode layer 102 is designed by the distance between each metal contact electrode 1026 and the structure of the metal contact electrode 1026, so that the stretchability, foldability and flexibility of the flexible thin film electrode layer 102 are enhanced, the flexible thin film electrode can be better attached to the electrode body 100 during deformation, the performance of the flexible thin film electrode is prevented from being damaged during deformation, the overall function and effect of the artificial cochlea are further improved, and the service life of the flexible thin film electrode layer 102 in the artificial cochlea is prolonged and the long-term use reliability is improved.

[0064] In the embodiment of the present application, with reference to Fig. 6 and Fig. 8 , the multi-layer wire layer 1022 is designed, and the adjacent two layers of wire layers 1022 are separated by the packaging layer 1023 (polyimide) and do not interfere with each other. Further, a plurality of electrode channels are arranged on the central region of the packaging layer 1023. The metal wires in each wire layer 1022 are arranged as shown in Fig. 8 , that is, each layer of metal wires is arranged on both sides of the wire layer 1022 in the width direction (electrode channel), so that the metal wires in each wire layer 1022 are sequentially wired from inside to outside to the middle electrode channel, and the electrode channel penetrates to the electrode layer 1021 so that each metal wire is connected to each metal contact electrode 1026. In this way, the number of channels of the artificial cochlea electrode is increased, the audio resolution is improved, the patient can recognize more complex sounds, including speech and music, the hearing experience is improved, and the area of the electrode can be larger because it is not restricted by the wire, and the stimulation effect is better.

[0065] According to some preferred embodiments, the electrode folding piece 101 is further provided with a flexible electrode head 103 located at one end away from the electrode support device 200, which is used to prevent the electrode folding piece 101 from damaging the cochlea.

[0066] In the embodiment of the present application, with reference to Fig. 3 , the flexible electrode head 103 is further arranged on the open end of the electrode folding piece 101. The flexible electrode head 103 can be made of silicone, for example, which can effectively prevent damage to the inside of the cochlea when the electrode folding piece 101 changes from a flat shape to a curved spiral shape as shown in Fig. 3 .

[0067] It should be noted that in the embodiment of the present application, the electrode body 100 can be changed by different external stimulation methods, and different driving methods include but are not limited to thermal driving or magnetic driving.

[0068] In the examples of the present application, when thermal driving is performed, for example, a copolymer network of butyl acrylate and polycaprolactone prepared by a chemical crosslinking agent can be selected as the printing material of the electrode folding piece 101, and the glass transition temperature (T g ) and the response temperature (T high , T low ) of the electrode folding piece 101 are adjusted by adjusting the mass fraction and the molecular weight of the three different components in the copolymer network. When magnetic driving is performed, the driving mode of the material of the electrode folding piece 101 is changed to magnetic driving by introducing magnetic particles (such as Fe3O4) in the copolymer network.

[0069] According to some preferred embodiments, at least one marker ring 104 is further arranged on the electrode support device 200, which is located close to one end of the electrode body 100, and is used to control the implantation depth of the electrode body 100.

[0070] A wing-shaped handle 105 is further arranged on the electrode support device 200, which is located on one side of the central axis of the electrode support device 200 and opposite to the direction of the flexible thin film electrode layer 102, and is used to control the implantation direction of the electrode body 100.

[0071] With reference to Figs. 1-3 , in the examples of the present application, the wing-shaped handle 105 is arranged on the electrode support device 200, so that the electrode body 100 can be implanted conveniently, and the direction of the electrode contact in the electrode body 100 in the cochlea can also be indicated, ensuring that the electrode contact implanted in the cochlea is directed to the modiolus side. At the same time, at least one marker ring 104 is arranged, and the depth of the cochlea entered by the cochlear implant can be determined according to the arrangement position of the marker ring 104, which plays a depth identification role and facilitates the fixation of the cochlear implant. After the cochlear implant electrode is fixed at a certain depth position, the electrode folding section starts to actively expand and bend. The cochlear implant electrode has the properties of autonomous programming and controllability due to the control of the shape memory polymer structure of the electrode folding piece 101, and almost occupies the central part of the scala tympani after being implanted in the cochlea, without contacting the modiolus and the lateral wall of the scala tympani, which can minimize the damage to the intracochlear structure.

[0072] With reference to Fig. 3 , in the examples of the present application, when the thin film electrode layer 1021 is located on one side of the central axis of the electrode folding piece 101, there is a certain gap between the thin film electrode layer 1021 and the electrode support device 200, which can form an insulation section between the electrode body 100 and the electrode support device 200, so as to avoid the current generated by the electrode contact in the electrode body 100 from stimulating the spiral ganglion cells at a non-target position, and play a buffering protection role.

[0073] The embodiment of the present application also provides a preparation method of the self-bending cochlear implant.

[0074] (1) constructing a three-dimensional structure model of the initial shape of the electrode folding piece 101 according to the specific structure shape and size of the cochlea; wherein the initial shape of the electrode folding piece 101 is a curved unfolded shape, and the temporary shape is a straight folded shape;

[0075] (2) taking a bidirectional shape memory polymer as a printing line, and performing 4D printing according to the constructed three-dimensional structure model to obtain the electrode folding piece 101 in the initial shape;

[0076] (3) preparing a flexible film electrode layer 102, smearing medical epoxy resin on the protruding structure 1025 of the flexible film electrode layer 102, aligning the protruding structure 1025 of the flexible film electrode layer 102 with the groove structure 1014 in the electrode folding piece 101 respectively, and then fixing and curing by using a clamp to obtain the electrode body 100;

[0077] (4) heating the electrode body 100 in the initial shape to above the glass transition temperature, applying a load, and then cooling and shaping to obtain the electrode body 100 in the temporary shape;

[0078] (5) fixing one end of the electrode body 100 to the electrode support device 200 to obtain the self-bending cochlear implant; wherein the size of the electrode folding piece 101 gradually decreases in the direction away from the electrode support device 200.

[0079] In the embodiment of the present application, after the electrode folding piece 101 in the initial shape (curved unfolded shape) is obtained by printing, the electrode folding piece 101 is heated to the glass transition temperature T g (about 40-45℃), the electrode folding piece 101 is compressed and folded to deform into the temporary shape (straight folded shape), and then the electrode folding piece 101 is cooled to below the response temperature T low (about 20℃), while the material is deformed, at this time, the electrode folding piece 101 can maintain the stable straight folded shape, and the shaping process is completed. Subsequently, the response temperature (T high and T low ) of the electrode folding piece 101 is controlled to control the bidirectional deformation of the electrode folding piece 101. Specifically, when the electrode folding piece 101 in the temporary shape (straight folded shape) is heated to the response temperature T high (about 37℃), the electrode folding piece 101 is converted into the initial shape (curved unfolded shape), and the shape memory process is completed. When the electrode folding piece 101 in the initial shape (curved unfolded shape) is cooled to T lowAt this time, the electrode folding piece 101 reversibly transforms into a temporary shape (straight folding shape), and the two-way shape memory process is completed.

[0080] Before the cochlear implant electrode is implanted into the cochlea, the temperature of the electrode body 100 of the cochlear implant is controlled to increase to T g The electrode folding piece 101 is formed into a temporary shape (straight folding shape), and when the cochlear implant electrode is implanted into the cochlea, the temperature of the electrode folding piece 101 of the cochlear implant is increased to T high At this time, even if no external force is applied, the electrode folding piece 101 can restore to its initial curved unfolded shape, realize the shape memory effect, and complete the self-bending process. low At this time, the electrode folding piece 101 can again generate the shape memory effect, self-fold, and transform from the curved unfolded shape to the straight folding shape, and the process can be performed without external force, and the rate is controllable, so that the non-invasive removal can be realized, and secondary damage to the cochlea during the removal process can be avoided.

[0081] In the embodiment of the application, the flexible thin film electrode layer is prepared by a micro-electro-mechanical system process, and the specific preparation method of the process is not described in detail in the embodiment.

[0082] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A self-flexible cochlear implant, characterized in that, It includes an electrode body and an electrode support device connected to the electrode body; wherein: The electrode body includes an electrode folding component and a flexible thin-film electrode layer. One end of the electrode folding component is connected to the electrode support device. The flexible thin-film electrode layer is laid on one side of the central axis of the electrode folding component. The flexible thin-film electrode layer is used to generate current to stimulate neurons in the inner wall of the cochlea. The electrode folding component is printed using bidirectional shape memory polymer. The electrode folding component is composed of several foldable units; each foldable unit consists of two parallel support plates and a paper bending section located between the two support plates; the electrode body can be folded flat and bent open by adjusting the unfolding and folding state of the paper bending section between the support plates. Two adjacent foldable units share a support plate. The two support plates in each foldable unit have different sizes. The size of the support plate closer to the electrode support device is larger than the size of the support plate farther away from the electrode support device, so that the size of the electrode folding part changes in a gradient. The electrode folding component includes an initial shape and a temporary shape. The initial shape is curved and unfolded, and the temporary shape is flat and folded. The size of the electrode folding component with the initial shape is larger than the size of the electrode folding component with the temporary shape. Under external stimulation, the electrode folding component can drive the flexible thin film electrode layer to change bidirectionally between the initial shape and the temporary shape.

2. The cochlear implant according to claim 1, characterized in that, The size of the electrode fold gradually decreases in the direction away from the electrode support device.

3. The cochlear implant according to claim 1, characterized in that, In the electrode folding component, each support plate near the inner wall of the cochlea has several groove structures at one end, and the bottom of the flexible thin film electrode layer has several protrusion structures. The protrusion structures correspond to the groove structures in position, and the size of the protrusion structures matches the size of the groove structures. The electrode folding component is fixed to the flexible thin film electrode layer through the groove structures and the protrusion structures. The opening area of ​​the groove structure is smaller than the internal area of ​​the groove structure.

4. The cochlear implant according to claim 1, characterized in that, The flexible thin-film electrode layer includes an electrode layer and several conductive layers arranged sequentially from top to bottom; wherein, each conductive layer has an encapsulation layer on its upper and lower surfaces, and the encapsulation layer is used to protect the conductive layer.

5. The cochlear implant according to claim 4, characterized in that, The electrode layer includes a plurality of arrayed metal contact electrodes, each metal contact electrode being composed of a plurality of periodically arranged metal hollow units; and / or Each encapsulation layer has several electrode channels, and the wires in each wire layer are connected to the metal contact electrodes in the electrode layer through the electrode channels.

6. The cochlear implant according to claim 1, characterized in that, The electrode folding component is also provided with a flexible electrode head, which is located at the end away from the electrode support device, in order to prevent the electrode folding component from damaging the cochlea.

7. The cochlear implant according to claim 1, characterized in that, The electrode support device is also provided with at least one marking ring, which is located at one end close to the electrode body and is used to control the implantation depth of the electrode body; The electrode support device is also provided with a wing-shaped handle, which is located on one side of the central axis of the electrode support device and opposite to the direction of the flexible thin film electrode layer, for controlling the implantation direction of the electrode body.

8. The cochlear implant according to claim 1, characterized in that, The shape memory deformation rate of the electrode folding component is 0.1-5 mm / s.

9. The method for preparing a self-flexible cochlear implant according to any one of claims 1 to 8, characterized in that, The preparation method includes the following steps: (1) Construct a three-dimensional structural model of the initial shape of the electrode folding component based on the specific structural shape and size of the cochlea; wherein the initial shape of the electrode folding component is curved and unfolded, and the temporary shape is flat and folded. (2) Using bidirectional shape memory polymer as the printing line, 4D printing is performed according to the constructed three-dimensional structural model to obtain the electrode folding part of the initial shape; (3) Prepare a flexible thin film electrode layer. After applying medical epoxy resin to the protruding structure of the flexible thin film electrode layer, align the protruding structure of the flexible thin film electrode layer with the groove structure in the electrode folding part, fix and cure it with a clamp to obtain the electrode body. (4) After heating the electrode body of the initial shape to above the glass transition temperature, a load is applied, and after cooling and shaping, a temporary shape of electrode body is obtained; (5) Fix one end of the electrode body to the electrode support device to obtain the self-bending cochlear implant; wherein, along the direction away from the electrode support device, the size of the electrode folding part gradually decreases.

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