Middle ear full-implantation artificial cochlea

Abstract

The invention relates to the technical field of biomedical engineering. A middle ear fully-implanted artificial cochlea comprises a sensing part and a stimulating electrode part, and the sensing part is directly connected with the stimulating electrode part. The sensing part comprises a supporting layer, and the supporting layer is made of silicon or silicon dioxide; the sensing part further comprises piezoelectric units fixed on the supporting layer, and each piezoelectric unit comprises an upper electrode layer, a piezoelectric sensing layer made of a piezoelectric material and a lower electrode layer which are stacked in the thickness direction; the resonant frequencies of the piezoelectric units are different; the stimulating electrode part comprises platinum electrode contacts which are arranged in one-to-one correspondence with the piezoelectric units, and the platinum electrode contacts are connected with the piezoelectric units through platinum wires; the stimulating electrode part further comprises an insulating sleeve connected with the supporting layer, and the platinum electrode contacts are sequentially arranged in the length direction of the insulating sleeve. A signal processing circuit between a traditional sensing part and a stimulating electrode part is omitted, meanwhile, external power supply and an active circuit are not needed, and sound-electricity conversion is achieved purely depending on the piezoelectric effect.

Description

Technical Field

[0001] This invention relates to the field of biomedical engineering technology, specifically to cochlear implants. Background Technology

[0002] Currently, cochlear implants on the market typically consist of two parts: an implant and an external unit. This design has several inconveniences: the external unit is not securely worn, especially for children, and is prone to falling out; it is aesthetically unappealing, making it easy for others to identify the patient as deaf, which may hurt the patient's self-esteem; and it is inconvenient to wear during exercise. Furthermore, both the implant and the external unit are electronic products with a limited lifespan, requiring replacement upon expiration. This not only increases costs, but the surgical removal and re-implantation of the implant also causes secondary harm to the patient. Summary of the Invention

[0003] In view of the problems existing in the prior art, the present invention provides a cochlear implant for the middle ear, which solves at least one of the above-mentioned technical problems.

[0004] The technical solution of the present invention is: a cochlear implant for the middle ear, comprising a sensing part and a stimulation electrode part, characterized in that the sensing part and the stimulation electrode part are directly connected;

[0005] The sensing unit includes a support layer, and the support layer is made of silicon or silicon dioxide.

[0006] The sensing unit also includes piezoelectric units fixed to the support layer. Each piezoelectric unit includes an upper electrode layer, a piezoelectric sensing layer made of piezoelectric material, and a lower electrode layer stacked along the thickness direction.

[0007] Each piezoelectric element has a different resonant frequency;

[0008] The stimulation electrode section includes platinum electrode contacts that correspond one-to-one with the piezoelectric units, and the platinum electrode contacts are connected to the piezoelectric units via platinum wires;

[0009] The stimulation electrode section also includes an insulating sleeve connected to the support layer, the platinum electrode contacts protruding from the insulating sleeve, and the platinum wires connected to the platinum electrode contacts one by one being separated from each other by the insulating sleeve.

[0010] The platinum electrode contacts are arranged sequentially along the length of the insulating sleeve, and the resonant frequency of the piezoelectric unit connected to the platinum electrode contacts decreases sequentially from the vicinity of the support layer to the distance from the support layer along the length of the insulating sleeve.

[0011] This invention achieves a direct connection between the sensing unit and the stimulation electrode unit, omitting the signal processing circuit between the traditional sensing unit and the stimulation electrode unit. At the same time, it does not require external power supply or active circuitry, and achieves sound-to-electric conversion purely by relying on the piezoelectric effect.

[0012] More preferably, the upper electrode layer is a platinum layer or a gold layer.

[0013] More preferably, the lower electrode layer is a platinum layer or a gold layer.

[0014] More preferably, the piezoelectric sensing layer is aluminum nitride or lead zirconate titanate.

[0015] More preferably, the thickness of the upper electrode layer is 0.001–10 μm;

[0016] The thickness of the lower electrode layer is 0.001–10 μm;

[0017] The thickness of the piezoelectric sensing layer is 0.001–0.2 mm;

[0018] The thickness of the support layer is 0.1–0.5 mm;

[0019] The platinum wire has a diameter of 50 μm.

[0020] More preferably, the volume of the piezoelectric unit is less than 2×2×2 mm³.

[0021] More preferably, during the assembly of the sensing unit, the piezoelectric unit is pressed into the support layer to form a human ear tympanic membrane structure, and the outer surface of the human ear tympanic membrane structure is covered with a 3–5 μm thick parylene-C coating by chemical vapor deposition.

[0022] More preferably, the resonant frequency of the piezoelectric unit is an integer multiple of 100 Hz;

[0023] Of all the piezoelectric units, the smallest resonant frequency is 200Hz and the largest resonant frequency is 8000Hz.

[0024] More preferably, all piezoelectric units include a first piezoelectric unit with a resonant frequency of 200Hz, a second piezoelectric unit with a resonant frequency of 300Hz, a third piezoelectric unit with a resonant frequency of 400Hz, a fourth piezoelectric unit with a resonant frequency of 500Hz, a fifth piezoelectric unit with a resonant frequency of 600Hz, a sixth piezoelectric unit with a resonant frequency of 800Hz, a seventh piezoelectric unit with a resonant frequency of 1000Hz, an eighth piezoelectric unit with a resonant frequency of 2000Hz, a ninth piezoelectric unit with a resonant frequency of 3000Hz, a tenth piezoelectric unit with a resonant frequency of 4000Hz, an eleventh piezoelectric unit with a resonant frequency of 5000Hz, and a twelfth piezoelectric unit with a resonant frequency of 6000Hz.

[0025] The first piezoelectric unit, the second piezoelectric unit, the third piezoelectric unit, the fourth piezoelectric unit, the fifth piezoelectric unit, the sixth piezoelectric unit, the seventh piezoelectric unit, the eighth piezoelectric unit, the ninth piezoelectric unit, and the tenth piezoelectric unit form a ring structure along the outer contour of the support layer;

[0026] The eleventh piezoelectric unit and the twelfth piezoelectric unit are located inside the annular structure.

[0027] More preferably, the support layer is provided with bio-adhesive or anchoring elements.

[0028] The support layer is mechanically coupled to the middle ear via bio-adhesive or anchoring elements.

[0029] More preferably, the insulating sleeve is a polyimide or fluoropolymer insulating layer.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] This invention overcomes the limitations of existing external cochlear implants in terms of ease of use, long-term stability, and physiological compatibility. This invention achieves a fully internal closed-loop transition from acoustic-mechanical perception to electrophysiological stimulation. Its core innovation lies in its highly integrated micro-sensing structure, passive energy conversion mechanism, and highly biomimetic integration with the human auditory physiological structure. Specifically, this invention includes the following key innovations:

[0032] 1. Fully implantable middle ear cavity structure:

[0033] This invention is implanted entirely into the middle ear cavity, completely eliminating external components. It achieves endogenous energy and signal acquisition through mechanical coupling with the tympanic membrane and ossicular chain, significantly reducing the risk of infection and improving the user's quality of life.

[0034] 2. MEMS-based multi-frequency piezoelectric sensor array:

[0035] Miniature piezoelectric sensing units with N preset resonant frequencies were fabricated using microelectromechanical systems (MEMS) technology or similar high-precision fabrication techniques. Each sensor's size is controlled within 2×2×2 mm³. Precise control of the resonant frequency is achieved by adjusting the thickness of the piezoelectric sensing region (0.001–0.2 mm) and the electrode layer (0.001–10 μm), while the support structure maintains a constant thickness (0.1–0.5 mm). This design achieves discrete coverage of the 20–8000 Hz audible frequency band within a limited space.

[0036] 3. Topological mapping structure of cochlear internal electrodes:

[0037] Each piezoelectric sensor is connected to a platinum-iridium alloy wire electrode, the surface of which is covered with a bio-stable insulating coating, and the end is equipped with a platinum contact electrode. The electrode array is implanted into the scala tympani of the cochlea using microsurgical techniques, and its position is allocated according to the frequency topology distribution of the cochlea to achieve high-fidelity reconstruction of the frequency-spatial correspondence.

[0038] 4. Bionic encapsulation and biocompatibility treatment:

[0039] The piezoelectric array is three-dimensionally integrated according to the curvature of the human eardrum and is encapsulated in a highly biocompatible coating such as parylene-C to ensure that it does not cause rejection or tissue fibrosis during long-term implantation, while maintaining the mechanical sensitivity of the sensing unit.

[0040] 5. Passive operating mechanism and ultra-long lifespan:

[0041] The system requires no external power supply or active circuitry, relying solely on the piezoelectric effect to achieve sound-to-electricity conversion. Its all-solid-state structure, combined with biocompatible materials, theoretically offers a lifespan of over a century, significantly superior to existing battery-dependent implantable devices. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure of the present invention in use;

[0043] Figure 2 This is a schematic diagram of one structure of the present invention;

[0044] Figure 3 This is a schematic diagram of one structure of the present invention;

[0045] Figure 4 This is a schematic diagram of the sensing unit of the present invention;

[0046] Figure 5 This is a cross-sectional view of the piezoelectric unit of the present invention.

[0047] Reference numerals: 2 represents platinum wire, 4 represents the sensing element, 6 represents the insulating jacket, 4a represents the upper electrode layer, 4b represents the piezoelectric sensing layer, 4c represents the lower electrode layer, 41 represents the first piezoelectric unit, 42 represents the second piezoelectric unit, 43 represents the third piezoelectric unit, 44 represents the fourth piezoelectric unit, 45 represents the fifth piezoelectric unit, 46 represents the sixth piezoelectric unit, 47 represents the seventh piezoelectric unit, 48 represents the eighth piezoelectric unit, 49 represents the ninth piezoelectric unit, 410 represents the tenth piezoelectric unit, and 411 represents the eleventh piezoelectric unit. 412 is the twelfth piezoelectric unit, 51 is the first platinum electrode contact, 52 is the second platinum electrode contact, 53 is the third platinum electrode contact, 54 is the fourth platinum electrode contact, 55 is the fifth platinum electrode contact, 56 is the sixth platinum electrode contact, 57 is the seventh platinum electrode contact, 58 is the eighth platinum electrode contact, 59 is the ninth platinum electrode contact, 510 is the tenth platinum electrode contact, 511 is the eleventh platinum electrode contact, and 512 is the twelfth platinum electrode contact. Detailed Implementation

[0048] See Figures 1 to 5 Specific embodiment 1: A cochlear implant for the middle ear includes a sensing unit 4 and a stimulating electrode unit, with the sensing unit 4 directly connected to the stimulating electrode unit. The sensing unit 4 includes a support layer made of silicon or silicon dioxide. The sensing unit 4 also includes piezoelectric units fixed to the support layer. Each piezoelectric unit includes an upper electrode layer 4a, a piezoelectric sensing layer 4b made of piezoelectric material, and a lower electrode layer 4c stacked along the thickness direction. Each piezoelectric unit has a different resonant frequency. The stimulating electrode unit includes platinum electrode contacts corresponding to the piezoelectric units. The platinum electrode contacts are connected to the piezoelectric units via platinum wires 2. The stimulating electrode unit also includes an insulating sleeve 6 connected to the support layer. The platinum electrode contacts protrude from the insulating sleeve 6, and the platinum wires 2 connected to the platinum electrode contacts are separated from each other by the insulating sleeve 6. The platinum electrode contacts are arranged sequentially along the length of the insulating sleeve 6, and the resonant frequency of the piezoelectric units connected to the platinum electrode contacts decreases sequentially from the vicinity of the support layer to the distance from the support layer along the length of the insulating sleeve 6. This invention achieves a direct connection between the sensing unit 4 and the stimulation electrode unit, omitting the signal processing circuit between the conventional sensing unit 4 and the stimulation electrode unit. At the same time, it eliminates the need for external power supply and active circuitry, relying purely on the piezoelectric effect to achieve sound-to-electric conversion.

[0049] The upper electrode layer 4a is a platinum or gold layer. The lower electrode layer 4c is a platinum or gold layer. The piezoelectric induction layer 4b is aluminum nitride or lead zirconate titanate. The platinum wire 2 is welded to the lower electrode layer.

[0050] The thickness of the upper electrode layer 4a is 0.001–10 μm; the thickness of the lower electrode layer 4c is 0.001–10 μm; the thickness of the piezoelectric sensing layer 4b is 0.001–0.2 mm; the thickness of the support layer is 0.1–0.5 mm; and the diameter of the platinum wire 2 is 50 μm.

[0051] During the assembly of the sensor unit 4, the piezoelectric unit is pressed into the support layer to form a human ear tympanic membrane structure. The outer surface of the human ear tympanic membrane structure is covered with a 3–5 μm thick parylene-C coating by chemical vapor deposition.

[0052] The resonant frequency of the piezoelectric element is an integer multiple of 100 Hz; among all the piezoelectric elements, the smallest resonant frequency is 200 Hz and the largest resonant frequency is 8000 Hz.

[0053] All piezoelectric units include a first piezoelectric unit 41 with a resonant frequency of 200Hz, a second piezoelectric unit 42 with a resonant frequency of 300Hz, a third piezoelectric unit 43 with a resonant frequency of 400Hz, a fourth piezoelectric unit 44 with a resonant frequency of 500Hz, a fifth piezoelectric unit 45 with a resonant frequency of 600Hz, a sixth piezoelectric unit 46 with a resonant frequency of 800Hz, a seventh piezoelectric unit 47 with a resonant frequency of 1000Hz, an eighth piezoelectric unit 48 with a resonant frequency of 2000Hz, a ninth piezoelectric unit 49 with a resonant frequency of 3000Hz, and a piezoelectric unit 400Hz with a resonant frequency of 400Hz. The tenth piezoelectric unit 410 with a 0Hz frequency, the eleventh piezoelectric unit 411 with a resonant frequency of 5000Hz, and the twelfth piezoelectric unit 412 with a resonant frequency of 6000Hz; the first piezoelectric unit 41, the second piezoelectric unit 42, the third piezoelectric unit 43, the fourth piezoelectric unit 44, the fifth piezoelectric unit 45, the sixth piezoelectric unit 46, the seventh piezoelectric unit 47, the eighth piezoelectric unit 48, the ninth piezoelectric unit 49, and the tenth piezoelectric unit 410 form a ring structure along the outer contour of the support layer; the eleventh piezoelectric unit 411 and the twelfth piezoelectric unit 412 are located inside the ring structure.

[0054] The insulating sleeve 6 has, along its length, sequentially connected to the following platinum electrode contacts from the adjacent support layer to the distance away from the support layer: first platinum electrode contact 51, second platinum electrode contact 52, third platinum electrode contact 53, fourth platinum electrode contact 54, fifth platinum electrode contact 55, sixth platinum electrode contact 56, seventh platinum electrode contact 57, eighth platinum electrode contact 58, ninth platinum electrode contact 59, tenth platinum electrode contact 510, eleventh platinum electrode contact 511, and twelfth platinum electrode contact 512. The nth platinum electrode contact is connected to the nth piezoelectric unit, where n is an integer.

[0055] The platinum electrode contact (first platinum electrode contact 51) connected to the first piezoelectric unit 41 is used to contact and activate the top turn region of the cochlea, and the platinum electrode contact (twelfth platinum electrode contact 512) connected to the twelfth piezoelectric unit 412 is used to contact and activate the bottom turn region.

[0056] A bio-adhesive or anchoring element is provided on the support layer. The support layer achieves mechanical coupling in the middle ear through the bio-adhesive or anchoring element. The insulating sleeve 6 is a polyimide or fluoropolymer insulating layer.

[0057] This invention is based on a three-tiered biomimetic mechanism of structural acoustics—piezoelectric conversion—neuroelectric stimulation:

[0058] External sound waves travel through the external auditory canal to the tympanic membrane, causing it to vibrate mechanically. This vibration is then conducted through the ossicles to the piezoelectric sensor array. Since each sensor has a preset resonant frequency (e.g., ƒ1=200 Hz, ƒ2=400 Hz, …, ƒ_N=8000 Hz), when a certain frequency component matches the sensor's resonant point, that unit generates maximum charge output due to the piezoelectric effect; the output of non-resonant units is negligible, thus achieving spatial selectivity of frequency-sensor characteristics.

[0059] The generated microcurrent is transmitted directly to a pre-placed electrode inside the cochlea via a wire, stimulating the spiral ganglion cells in that region. For example, a 200 Hz signal activates the apical rotation region of the cochlea, while an 8000 Hz signal activates the basal rotation region, strictly following the tonotopy of the cochlea. Through this mechatronic-electroneuronic interface, the system achieves frequency analysis-electrical stimulation conversion without external power supply, reconstructing the frequency resolution function of the damaged cochlea.

[0060] The system is essentially a passive mechanical filter bank. Its core is to replace the digital signal processing (DSP) module in traditional cochlear implants with a physical resonant structure. It utilizes the intrinsic frequency selectivity of piezoelectric materials to achieve acoustic-electric conversion, thereby achieving reliable hearing reconstruction under extreme size and power consumption constraints.

[0061] The middle ear cavity is accessed via mastoidectomy or a retro-auricular approach. The sensor is attached to the inner surface of the tympanic membrane or the long crus of the incus, and mechanical coupling is achieved using bio-adhesive or micro-anchors. With the assistance of a surgical navigation system, the stimulating electrode is implanted into the scala tympani through a round window or fenestration and positioned along the basilar membrane to ensure anatomical matching between each platinum electrode contact and the frequency response area of ​​the cochlea. Finally, the surgical cavity is closed to complete the full implantation.

[0062] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A cochlear implant for the middle ear, comprising a sensing portion and a stimulating electrode portion, characterized in that, The sensing unit is directly connected to the stimulation electrode unit; The sensing unit includes a support layer, and the support layer is made of silicon or silicon dioxide. The sensing unit also includes piezoelectric units fixed to the support layer. Each piezoelectric unit includes an upper electrode layer, a piezoelectric sensing layer made of piezoelectric material, and a lower electrode layer stacked along the thickness direction. Each piezoelectric element has a different resonant frequency; The stimulation electrode section includes platinum electrode contacts that correspond one-to-one with the piezoelectric units, and the platinum electrode contacts are connected to the piezoelectric units via platinum wires; The stimulation electrode section also includes an insulating sleeve connected to the support layer, the platinum electrode contacts protruding from the insulating sleeve, and the platinum wires connected to the platinum electrode contacts one by one being separated from each other by the insulating sleeve. The platinum electrode contacts are arranged sequentially along the length of the insulating sleeve, and the resonant frequency of the piezoelectric unit connected to the platinum electrode contacts decreases sequentially from the vicinity of the support layer to the distance from the support layer along the length of the insulating sleeve.

2. The cochlear implant for middle ear implantation according to claim 1, characterized in that: The upper electrode layer is a platinum layer or a gold layer.

3. The cochlear implant for middle ear implantation according to claim 1, characterized in that: The lower electrode layer is a platinum layer or a gold layer.

4. The cochlear implant for middle ear implantation according to claim 1, characterized in that: The piezoelectric sensing layer is aluminum nitride or lead zirconate titanate.

5. The cochlear implant for middle ear implantation according to claim 1, characterized in that: The thickness of the upper electrode layer is 0.001–10 μm; The thickness of the lower electrode layer is 0.001–10 μm; The thickness of the piezoelectric sensing layer is 0.001–0.2 mm; The thickness of the support layer is 0.1–0.5 mm; The platinum wire has a diameter of 50 μm.

6. The cochlear implant for middle ear implantation according to claim 1, characterized in that: During the assembly of the sensing unit, the piezoelectric unit is pressed into the support layer to form a human ear tympanic membrane structure. The outer surface of the human ear tympanic membrane structure is covered with a 3–5 μm thick parylene-C coating by chemical vapor deposition.

7. The cochlear implant for middle ear implantation according to claim 1, characterized in that: The resonant frequency of the piezoelectric unit is an integer multiple of 100 Hz; Of all the piezoelectric units, the smallest resonant frequency is 200Hz and the largest resonant frequency is 8000Hz.

8. The cochlear implant for middle ear implantation according to claim 1, characterized in that: All piezoelectric units include a first piezoelectric unit with a resonant frequency of 200Hz, a second piezoelectric unit with a resonant frequency of 300Hz, a third piezoelectric unit with a resonant frequency of 400Hz, a fourth piezoelectric unit with a resonant frequency of 500Hz, a fifth piezoelectric unit with a resonant frequency of 600Hz, a sixth piezoelectric unit with a resonant frequency of 800Hz, a seventh piezoelectric unit with a resonant frequency of 1000Hz, an eighth piezoelectric unit with a resonant frequency of 2000Hz, a ninth piezoelectric unit with a resonant frequency of 3000Hz, a tenth piezoelectric unit with a resonant frequency of 4000Hz, an eleventh piezoelectric unit with a resonant frequency of 5000Hz, and a twelfth piezoelectric unit with a resonant frequency of 6000Hz. The first piezoelectric unit, the second piezoelectric unit, the third piezoelectric unit, the fourth piezoelectric unit, the fifth piezoelectric unit, the sixth piezoelectric unit, the seventh piezoelectric unit, the eighth piezoelectric unit, the ninth piezoelectric unit, and the tenth piezoelectric unit form a ring structure along the outer contour of the support layer; The eleventh piezoelectric unit and the twelfth piezoelectric unit are located inside the annular structure.

9. A cochlear implant for the middle ear according to claim 1, characterized in that: The support layer is provided with bio-adhesive or anchoring components. The support layer is mechanically coupled to the middle ear via bio-adhesive or anchoring elements.

10. A cochlear implant for the middle ear according to claim 1, characterized in that: The insulating sleeve is a polyimide or fluoropolymer insulating layer.

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