All-organic degradable piezoelectric power sensor and preparation method thereof

Abstract

A fully organic degradable piezoelectric force sensor and a method for preparing the same are disclosed. Amino acid (polypeptide) wafer, preferably isoleucine wafer, under stress-induced alignment, the crystal shows very ordered structure and smooth surface on the mesoscale, which significantly enhances the piezoelectric response. In addition, the force sensor is suitable for long-term detection of physiological movements, including breathing and muscle contraction. More importantly, due to all organic and biological components, the force sensor is biocompatible and completely biodegradable. The compatibility and degradability of the force sensor in the physiological environment make it possible for the development of tissue engineering and implanted biomedical devices.

Description

Technical Field

[0001] This invention relates to a fully organic biodegradable pressure sensor and its preparation method. Background Technology

[0002] Biomedical force sensors can detect biophysiological stress and subtle movements, showing potential applications in the early assessment and diagnosis of chronic and acute diseases in vivo, as well as in health monitoring and long-term rehabilitation tracking. For in vivo use, sensors must be implantable, flexible, biocompatible, and especially biodegradable to avoid tissue damage, immune inflammation, and invasive removal procedures. Among various force sensors, piezoelectric sensors have attracted considerable attention due to their high sensitivity, ease of fabrication, and, particularly, lack of battery power requirements. However, most piezoelectric sensors designed for biomedical engineering contain inorganic piezoelectric materials, such as lead zirconate titanate (PZT)-based nanostructures or non-degradable synthetic polymers, such as polyvinylidene fluoride (PVDF), which significantly limits their true clinical application. In recent years, biodegradable force sensors based on biodegradable and biocompatible piezoelectric PLLA have been reported, but these still contain inorganic elements such as metallic conductive layers, which may affect kidney function. Designing fully organic and fully degradable piezoelectric sensors for in vivo biomedical applications remains challenging.

[0003] Piezoelectric biomaterials have been widely used in the field of bio-force sensors in recent years due to their good biocompatibility and degradability. Amino acid crystals, as a type of bio-piezoelectric material, have attracted widespread attention due to their well-developed crystal structure, simple preparation methods, and high self-assembly efficiency. However, due to the disordered arrangement at the mesoscale, even though some amino acids possess piezoelectric coefficients exceeding 10 pC / N, it is difficult to develop sensitive and reliable force sensors based on amino acid crystals. Because of the different polarity directions of the crystals, the domains in bulk materials lack ordered arrangement and uniform polarization, resulting in weak piezoelectric performance at the macroscale. Furthermore, effective methods for tuning large-scale (typically larger than millimeters) amino acid crystals remain to be developed, as crystals are generally rigid and brittle with high mechanical strength. Simultaneously, the irregular surface of amino crystal-based materials makes it difficult to achieve complete adhesion with electrodes, severely affecting sensor performance. Summary of the Invention

[0004] The problem to be solved by this invention is to propose an innovative solution to address the shortcomings of the prior art, mainly involving a fully organic biodegradable piezoelectric sensor with good biocompatibility, its preparation method and application.

[0005] To address the aforementioned issues, the present invention employs the following solution: a fully organic biodegradable piezoelectric sensor, based on isoleucine amino acid crystals, which exhibits excellent compatibility and degradability in physiological environments and can be used in biomedicine and clinical settings.

[0006] A fully organic biodegradable voltage sensor is provided, comprising two polylactic acid-polyaniline electrodes sandwiching an amino acid (peptide) wafer and encapsulating it with polylactic acid adhesive. The amino acid (peptide) wafer is a variety of natural amino acid crystals or peptide crystals.

[0007] Furthermore, in the fully organic biodegradable voltage sensor, the amino acid (peptide) wafer is filled in a hollow polylactic acid membrane, and then sandwiched between two polylactic acid-polyaniline electrodes.

[0008] Furthermore, in the fully organic biodegradable piezoelectric sensor, the amino acid (peptide) wafer is a stress-induced ordered arrangement of amino acid (peptide) wafers.

[0009] A method for fabricating a fully organic biodegradable piezoresistive sensor includes the following steps:

[0010] Preparation of polylactic acid adhesive: Dissolve polylactic acid to a concentration of 50 mg / mL. -1 Polylactic acid adhesive was prepared in dichloromethane for use in the fabrication of force sensors;

[0011] Preparation of amino acid (peptide) wafers: Dissolve amino acids or peptides in deionized water to a concentration of 30 mg / mL. -1 The solution is heated to 65°C and then transferred to an ice-water bath to stand for 6 hours until crystal nuclei grow. Then, the solution is evaporated and crystallized in an oven at 60°C until the liquid volume is reduced to 20% of the original volume. Finally, the amino acid or polypeptide crystals are collected and dried to make wafers.

[0012] To prepare a polylactic acid-polyaniline electrode, the polylactic acid-polyaniline electrode is cut into a thin film with an area larger than that of an amino acid (peptide) wafer;

[0013] Piezoelectric sensor assembly: An amino acid (peptide) wafer is sandwiched between two polylactic acid-polyaniline electrodes, and all edges and surfaces of the device are sealed with polylactic acid glue. After standing and air drying, a fully degradable organic piezoelectric sensor is obtained.

[0014] Furthermore, the method for preparing the all-organic biodegradable pressure sensor involves compressing dried amino acid or polypeptide crystals into a tablet mold under a pressure of 250 bar to obtain a stress-induced ordered arrangement of amino acid (polypeptide) wafers.

[0015] Furthermore, in the preparation method of the all-organic biodegradable voltage sensor, a polylactic acid film is prepared and a hole is made in the middle of it, and the amino acid (peptide) wafer obtained in step (2) is filled into the hole.

[0016] Furthermore, the preparation method of the all-organic biodegradable pressure sensor involves the following preparation of the polylactic acid-polyaniline electrode: polylactic acid particles are pre-dried in a vacuum oven at 60°C, then polylactic acid is dissolved in dichloromethane to a polylactic acid solution concentration of 50 mg mL⁻¹, and then placed in a circular glass dish and evaporated at 25°C for 12 hours to obtain a polylactic acid film with a thickness of 140 μm; one side of the polylactic acid film is immersed in a mixed solution of sulfuric acid (1 M) and aniline (0.3 M), and the entire system is cooled in an ice bath for 2 hours. Then, the polylactic acid-polyaniline electrode is removed, washed with deionized water, and air-dried at room temperature for 12 hours.

[0017] Furthermore, in the preparation method of the all-organic biodegradable piezoresistive sensor, the amino acid wafer is an isoleucine wafer, prepared by the following method:

[0018] (1) Dissolve isoleucine in deionized water to a concentration of 30 mg / mL. -1 Heat to 65°C, then transfer to an ice-water bath and let stand for 6 hours until crystal nuclei grow.

[0019] (2) The solution is evaporated and crystallized in an oven at 60°C until the liquid volume is reduced to 20% of its original volume;

[0020] (3) Collect isoleucine crystals and dry them;

[0021] (4) The dried crystals are compressed into a tablet mold under a pressure of 250 bar to obtain stress-induced ordered isoleucine wafers.

[0022] An application of a fully organic biodegradable piezoelectric sensor in various types of in vivo and / or external force sensing, wherein the fully organic biodegradable piezoelectric sensor is applied to various types of in vivo and / or external force sensing.

[0023] An application of a fully organic biodegradable piezometric sensor in medical devices and / or biomedicine, wherein the fully organic biodegradable piezometric sensor is applied in medical devices and / or biomedicine.

[0024] Based on stress-induced ordered alignment of amino acid or polypeptide crystals, stress-induced alignment results in highly ordered structures and smooth surfaces at the mesoscale, significantly enhancing piezoelectric response. Furthermore, the force sensor has been shown to be implantable in vivo, suitable for long-term detection of physiological movements, including respiration and muscle contraction. More importantly, because all components are organic and biomaterials, the force sensor is biocompatible and fully biodegradable. Stress-induced crystal alignment provides an alternative method for modulating the internal orientation of biomolecular crystal materials. The biocompatibility and degradability of the force sensor in physiological environments open up possibilities for the development of tissue engineering and implantable biomedical devices.

[0025] This fully organic, biodegradable pressure-electric sensor is suitable for various external or internal force signal sensing applications. It can be implanted long-term and is completely biodegradable within the body, enabling long-term detection and output of physiological motion signals both internally and subcutaneously. It is suitable for various medical device and clinical signal detection applications.

[0026] The technical effects of this invention are as follows: 1. Compared with traditional piezoelectric sensors, the sensing material with ordered arrangement of stress-induced amino acid (peptide) crystals in this invention can provide extremely high signal testing sensitivity.

[0027] 2. Compared with traditional piezoelectric sensors, the all-organic degradable piezoelectric sensor of this invention has ultra-high mechanical strength and stability. The polylactic acid-polyaniline electrode and isoleucine crystal both have extremely high mechanical properties. Furthermore, through stress induction, the amino acid crystal rearranges, thereby achieving ultra-high mechanical strength and toughness of the piezoelectric sensor as a whole.

[0028] 3. Compared to traditional piezoelectric sensors, this all-organic degradable piezoelectric sensor primarily utilizes stress-induced alignment, resulting in a highly ordered structure and smooth surface at the mesoscale, significantly enhancing the piezoelectric response. Furthermore, stress-induced crystal alignment provides an alternative method for regulating the internal orientation of biomolecular crystal materials. Considering the low breakdown voltage of amino acid crystals, stress-induced alignment may be the most suitable and gentlest method for regulating the internal polarity orientation of such bulk materials.

[0029] 4. Compared with traditional force sensors, the all-organic degradable pressure-electric sensor in this invention has the characteristics of high-frequency signal response and long-term stable signal output. It can output a stable signal under high-frequency external force stimulation, and the long-term signal output after subcutaneous implantation does not show significant attenuation for up to four weeks.

[0030] 5. This fully organic degradable voltage sensor uses degradable polymers and essential amino acids or peptides, which have good biocompatibility and degradability.

[0031] 6. The mechanical strength of this all-organic degradable pressure-electric sensor can be controlled by adjusting the proportion of polymer in the material.

[0032] 7. Biodegradable in vivo or in vitro: The all-organic biodegradable piezoelectric sensor of this invention is biodegradable in both in vivo and in vitro environments. Attached Figure Description

[0033] Figure 1 Fabrication of a fully degradable piezoelectric sensor based on stress-induced amino acid crystal alignment.

[0034] Figure 2 Characterization of isoleucine single crystals in an all-organic degradable piezoresistive sensor and stress-induced alignment of isoleucine crystals.

[0035] Figure 3 Stress sensing based on a fully degradable piezoelectric sensor with stress-induced amino acid crystal alignment.

[0036] Figure 4 In vivo and in vitro motion sensing based on a fully degradable piezoelectric sensor with stress-induced amino acid crystal alignment.

[0037] Figure 5 Biocompatibility testing of fully degradable piezoelectric sensors based on stress-induced amino acid crystal alignment.

[0038] Figure 6 The biodegradability and long-term sensing stability of fully degradable piezoelectric sensors based on stress-induced amino acid crystal alignment in vitro and in vivo. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings.

[0040] A method for preparing a fully organic biodegradable voltage sensor involves dissolving polylactic acid to a concentration of 50 mg / mL. -1 Polylactic acid (PLA) adhesive was prepared in dichloromethane for the fabrication of a force sensor. A square PLA film mold (10 mm × 10 mm) with a thickness of 0.3 mm was prepared, with a central hole (8 mm in diameter) to form a wafer with a diameter of ~8 mm and a thickness of ~0.35 mm, which was then filled into the hole. PLA-polyaniline electrodes were cut into 10 mm × 10 mm square films. A square PLA film with stress-induced crystals was sandwiched between two PLA-polyaniline electrodes. All edges and surfaces of the device were then sealed with PLA adhesive, dried, and the device encapsulation was completed. Figure 1a) For sensors used in vivo, the device size is 8 mm × 8 mm, and the wafer diameter is 6.5 mm. To improve the biodegradability of the crystal, the crystal wafer is directly sandwiched between two polylactic acid-polyaniline electrodes without using a polylactic acid mold, sealed with polylactic acid glue, and allowed to air dry to obtain a fully degradable organic piezoelectric sensor.

[0041] A method for preparing a fully organic biodegradable piezoresistive sensor, wherein a polylactic acid-polyaniline electrode is prepared by the following method: To prepare a polylactic acid film, polylactic acid is dissolved to a concentration of 50 mg / mL. -1 The polylactic acid (PLA) film was then cast in a glass dish and evaporated at 25°C for 12 hours to obtain a 140 μm thick PLA film. PLA particles were dried overnight at 60°C in a vacuum oven and then dissolved in dichloromethane. To prepare the PLA-polyaniline electrode, one side of the PLA film was immersed in a mixed solution of sulfuric acid (1 M) and aniline (0.3 M), and the entire system was soaked in ice water for 2 hours. The PLA-polyaniline electrode was then removed, washed with deionized water, and air-dried at room temperature for 12 hours.

[0042] A method for fabricating a fully organic biodegradable piezoresistive sensor, based on stress-induced alignment of isoleucine crystals, is prepared by dissolving isoleucine in deionized water to a concentration of 30 mg / mL. -1 The solution was heated to 65°C and then transferred to an ice-water bath to stand for 6 hours until crystal nuclei grew. The solution was then evaporated and crystallized in a 60°C oven until the liquid volume decreased to 20% of its original volume. Finally, the isoleucine crystals were collected and dried. To achieve stress-induced alignment, the prepared crystals were compressed in a tablet mold (forming circular tablets with a diameter of 8 mm and a thickness of 1.5 mm) under a pressure of 250 bar, resulting in disc-shaped crystals. Figure 1 b). Histidine crystals with stress-induced alignment were prepared using the method described above.

[0043] The following are examples of performance tests for various aspects of the present invention.

[0044] Example 1: Characterization of isoleucine single crystals and stress-induced alignment of isoleucine crystals in this invention.

[0045] In this invention, the morphology of isoleucine single crystals was first studied using scanning electron microscopy (SEM) and optical microscopy. Figure 2 a) Isoleucine amino acids form elongated crystals with high light transmittance. The mechanical strength of the crystals was also studied using atomic force microscopy (AFM) nanoindentation. The Young's modulus and stiffness of this crystal reached 3.6 GPa and 68.2 Nm, respectively. -1It is comparable to high-stress pyrolytic graphite (HOPG). Figure 2 b). Furthermore, the thermal stability of isoleucine crystals was evaluated by thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses. Figure 2 c). Thermogravimetric analysis and differential scanning calorimetry both showed that isoleucine crystals remained stable at 283℃. To investigate the atomic-level molecular packing pattern within the crystal, the single-crystal structure was solved and analyzed in detail. The crystal arrangement of the isoleucine single crystal is as follows: Figure 2 As shown in d, the monoclinic angle (β) is ~96°. Isoleucine crystallizes with two independent nonplanar isoleucine molecules in an asymmetric unit. Typically, an isoleucine molecule forms 7 hydrogen bonds with its neighboring molecules, indicating that hydrogel bonds are the main driving force for isoleucine stacking.

[0046] This application example also demonstrates stress-induced amino acid crystal arrangement. For example... Figure 2 As shown in the figure, stress-induced isoleucine crystals were prepared using a pelleting method under 250 bar pressure, and the microstructure of the isoleucine crystals before (-stress) and after (+stress) pressure was studied using scanning electron microscopy (SEM). The stress-induced oriented crystals exhibit a layered structure at the mesoscale, similar to a shell-like layered structure. All these results indicate that stress-induced amino acid crystal arrangement exhibits ordered alignment characteristics. Considering the low breakdown voltage of amino acid crystals, stress-induced alignment may be the most suitable and gentlest method for regulating the internal polarity orientation of such bulk materials.

[0047] Example 2: This invention is tested in terms of force-electric sensing signals.

[0048] In this invention, a force sensor based on stress-induced amino acid crystal alignment was directly force-sensing tested and verified. The force-sensing performance was evaluated for the first time by monitoring the open-circuit voltage output after applying a 1 Hz impact force to the force sensor. Sensors fabricated using isoleucine crystals without stress-induced alignment (-stress) and sensors fabricated without crystals (control) were also tested. Figure 3 The input force causes the force sensor to output a peak-to-peak voltage, which has the same frequency as the input signal. Generally, the voltage output increases with increasing force. Figure 3 a). The voltage output of the force sensor fabricated using stress-induced aligned isoleucine crystals is approximately three times higher than that of the force sensor fabricated using un-stress-induced aligned isoleucine crystals. Furthermore, the sensor's voltage output remains clear even under external forces as low as 0.1 N (1 kPa), indicating a wide force sensing range and high sensitivity. Figure 3b). Note that the voltage output of the crystalless sensor is almost negligible, indicating that the piezoelectric response is primarily attributed to the isoleucine crystal. Furthermore, the voltage output of the force sensor remains consistent after undergoing over 5000 impacts, demonstrating long-term stability of the cyclic sensing. Figure 3 c).

[0049] Example 3: In vitro and external motion sensing tests of the present invention.

[0050] To demonstrate the application of the all-organic biodegradable force sensor in motion sensing, in vitro human motion detection and in vivo physiological motion detection in mice were performed. Figure 4 First, the force sensor is fixed to the index finger with elastic tape to monitor finger movement. Figure 4 a). Clearly, this sensor can accurately respond to varying degrees of bending and provide reliable measurements over multiple cycles. As the finger bending angle increases, the output voltage increases from 25 mV to 100 mV. Simultaneously, the force sensor's flexibility and high sensitivity enable it to detect small changes in wrist flexion and gentle swallowing movements (a). Figure 4 bc). Furthermore, the polylactic acid encapsulation of the sensor allows the device to operate well in aquatic environments. The force sensor's open-circuit voltage underwater is essentially the same as its open-circuit voltage in air, and it exhibits good sealing performance in aquatic environments. Figure 4 de).

[0051] To demonstrate the potential applications of this sensor in biological systems, the present invention evaluated the in vivo sensing performance of the sensor in adult SD rats. Figure 4 f). Force sensors are implanted under the skin in the chest and leg areas. Two insulated wires are connected to the polyaniline layer of the device to monitor the output signal, avoiding interference from bioelectrical signals. Even under anesthesia, the device implanted in the chest can detect the voltage signal caused by the deformation induced by respiration. Figure 4 g). Furthermore, when the rat's leg was gently stretched and cyclically released, the implanted force sensor generated a voltage output of ~30 mV ( Figure 4 h). All these results demonstrate that force sensors based on stress-induced amino acid crystal alignment can reliably perform motion sensing both in vivo and in vitro.

[0052] Example 4: Biocompatibility of the present invention demonstrated in cell and animal experiments.

[0053] This embodiment demonstrates the biocompatibility of the force sensor based on stress-induced amino acid crystal alignment in this invention. In in vitro biocompatibility assays, human breast cancer cells (MDA-MB-231) and human adipose-derived stem cells (ADMSCs) were co-cultured with the force sensor. Cell morphology and viability were then determined using fluorescence staining. Figure 5 ac). For example Figure 5 As shown in Figure a, the cytoskeleton and nuclei of MDA-MB-231 and ADMSCs cultured for 24 h in the presence of force sensors were similar to those of the control group, indicating that cell morphology, distribution, and density were unaffected. In the presence of force sensors in both cell types, almost no cell death was observed, and the survival rate was higher than 99%. Figure 5 c).

[0054] The in vivo biocompatibility of the sensor was evaluated based on dorsal subcutaneous implantation in a rat model. Figure 5 df). The sham surgery group served as a control. Histological evaluation (hematoxylin and erosion (H&E) staining) results showed that one day after subcutaneous implantation, the force sensor did not cause any significant damage to the surrounding dermis and muscle layer. Figure 5 d). Both groups showed mild inflammation with no significant lymphocyte or eosinophil response. Immunofluorescence staining showed that the expression levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) around the sensor were similar to those in the sham surgery group. Figure 5 e) further indicates a mild inflammatory response. In addition, hematological examinations (white blood cell (WBC) count, red blood cell (RBC) count, hemoglobin (HGB) and platelet (PLT) count) and blood biochemistry examinations (alanine transferase (ALT), aspartate transferase (AST), urea (urea), creatinine (CREA), creatine kinase (CK), lactate dehydrogenase (LDH), Ca2+) further confirmed the presence of inflammatory markers. 2+ and Mg 2+ The study investigated the acute systemic toxicity of the sensor. These indicators were similar to those in the sham-operated group and the control group, indicating that sensor implantation did not cause systemic inflammation or affect the function of major organs. Figure 5 f). A slight decrease in platelets may be related to postoperative coagulation. All these in vitro and in vivo experimental results demonstrate that the force sensor based on stress-induced amino acid crystal alignment has good biocompatibility, indicating its great potential as an implantable monitoring device.

[0055] Example 5: Long-term stability and biodegradability of the present invention.

[0056] Because all components used in this force sensor are organic and biodegradable, it is expected to exhibit good biodegradability. The in vitro degradation of the force sensor was investigated for the first time by incubation at 37°C for 6 weeks in simulated body fluid (SBF) buffer. From the fourth week onwards, the weight of the sensor decreased sharply. Figure 6 a) This may be due to leakage of amino acid crystals caused by damage to the polylactic acid-polyaniline layer. The sensor lost over 60% of its original weight within 6 weeks. The microstructure of the device degradation in the SBF also resembles... Figure 6As shown in b, a noticeable porous structure appeared starting in week 2, and the sensor completely broke after 6 weeks. We anticipate that the degradation of the sensor is primarily due to the breakdown of the polymer network caused by the hydrolysis of polylactic acid. The force sensing capability of the device after incubation in SBF for different times was also evaluated. Figure 6 c). The open-circuit voltage amplitude remained essentially constant for the first three weeks, then decreased significantly starting in the fourth week, consistent with the change in body weight. Considering sensor degradation, the sharp decline starting in the fourth week also indicates that the device's force-sensing capability will remain consistent until the polylactic acid encapsulation is severely damaged.

[0057] This invention also evaluated the in vivo biodegradability and long-term sensing stability of the force sensor in a rat model. Figure 6 (dg). Histological evaluation (H&E staining) of the sensor and surrounding tissue was performed at different implantation times. Resin embedding was used to prevent sensor detachment. During H&E staining preparation, the amino acid crystals within the polymer layer were completely dissolved in the organic solvent. For example... Figure 6 As shown in the diagram, the force sensor gradually degrades in vivo. Cracks in the polylactic acid-polyaniline layer increase over time. After 6 weeks, the polylactic acid-polyaniline layer is significantly thinner and penetrated by granulation tissue, indicating sensor rupture and healing of the damaged tissue. The in vivo degradation rate is lower than the in vitro degradation rate, possibly due to limited contact between the sensor and tissue fluid. Finally, its long-term force sensing capability in vivo was also evaluated. Figure 6 (hi). The output electrical signals of respiration and leg extension in rats remained consistent for four weeks post-implantation, then decreased at week 5, consistent with the degradation of the force sensor in vivo. All these results demonstrate that the all-organic force sensor based on stress-induced amino acid crystal alignment exhibits good biodegradability and long-term sensing stability both in vivo and in vitro.

Claims

1. A method for preparing a fully organic biodegradable piezoresistive sensor, characterized in that, The fully organic biodegradable voltage sensor consists of two polylactic acid-polyaniline electrodes sandwiching an amino acid or peptide wafer, and encapsulated with polylactic acid adhesive. The amino acid or peptide wafer is various natural amino acid crystals or short peptide crystals. The fabrication method of the fully organic biodegradable voltage sensor includes the following steps: Step (1): Preparation of polylactic acid glue: Polylactic acid is dissolved in dichloromethane with a concentration of 50 mg mL-1 to prepare polylactic acid glue, which is used to make force sensors; Step (2): Preparation of amino acid or polypeptide wafers: Dissolve amino acids or polypeptides in deionized water at a concentration of 30 mg / mL, heat to 65°C, then transfer to an ice-water bath and let stand for 6 h until crystal nuclei grow. Then, evaporate and crystallize the solution in an oven at 60°C until the liquid volume is reduced to 20% of the original volume. Finally, collect the amino acid or polypeptide crystals and dry them to make wafers. Step (3): Prepare polylactic acid-polyaniline electrode by cutting the polylactic acid-polyaniline electrode into a thin film with an area larger than that of amino acid or polypeptide wafers; Step (4): Assembly of piezoelectric sensor device: sandwich an amino acid or polypeptide wafer between two polylactic acid-polyaniline electrodes, seal all edges and surfaces of the device with polylactic acid glue, and let it stand to air dry to obtain a fully degraded organic piezoelectric sensor.

2. The method for preparing the all-organic biodegradable piezoresistive sensor according to claim 1, characterized in that, The amino acid or polypeptide wafers are filled in a hollow polylactic acid membrane and then sandwiched between two polylactic acid-polyaniline electrodes.

3. The method for preparing the all-organic biodegradable piezoresistive sensor according to claim 1, characterized in that, The amino acid or polypeptide wafer is a stress-induced ordered arrangement of amino acids or polypeptides.

4. The method for preparing the all-organic biodegradable piezoresistive sensor according to claim 1, characterized in that, The dried amino acid or polypeptide crystals are compressed into a tablet mold under a pressure of 250 bar to obtain stress-induced ordered amino acid or polypeptide wafers.

5. The method for preparing the all-organic biodegradable piezoresistive sensor according to claim 1, characterized in that, Prepare a polylactic acid film and make a hole in the middle of it, and fill the hole with the amino acid or polypeptide wafer obtained in step (2).

6. The method for preparing the all-organic biodegradable piezoresistive sensor according to claim 1, characterized in that, The polylactic acid-polyaniline electrode was prepared by the following method: polylactic acid particles were pre-dried in a vacuum oven at 60°C, and then the polylactic acid was dissolved in dichloromethane to a polylactic acid solution concentration of 50 mg / mL. -1 The polylactic acid (PLA) film was then placed in a circular glass dish and evaporated at 25°C for 12 hours to obtain a 140 μm thick PLA film. One side of the PLA film was immersed in a mixed solution of sulfuric acid and aniline, where the molar concentration of sulfuric acid was 1 mol / L and the molar concentration of aniline was 0.3 mol / L. The entire system was cooled in an ice bath for 2 hours. The PLA-PLA electrode was then removed, washed with deionized water, and air-dried at room temperature for 12 hours.

7. The method for preparing the all-organic biodegradable piezoresistive sensor according to claim 1, characterized in that, The amino acid wafer is an isoleucine wafer, prepared by the following method: (1) Dissolve isoleucine in deionized water to a concentration of 30 mg / mL. -1 Heat to 65°C, then transfer to an ice-water bath and let stand for 6 hours until crystal nuclei grow. (2) The solution is evaporated and crystallized in an oven at 60°C until the liquid volume is reduced to 20% of its original volume; (3) Collect isoleucine crystals and dry them; (4) The dried crystals are compressed into a tablet mold under a pressure of 250 bar to obtain stress-induced ordered isoleucine wafers.

8. The application of the all-organic biodegradable piezoelectric sensor prepared by the method of claim 1 in various in vivo and / or external force sensing applications, characterized in that, The all-organic biodegradable pressure-electric sensor prepared by the method described in claim 1 is applied to various types of in vivo and / or external force sensing.

9. The application of a fully organic biodegradable piezometric sensor prepared by the method described in claim 1 in medical devices and / or biomedicine, characterized in that, The all-organic biodegradable piezoresistive sensor prepared by the method of claim 1 can be applied to medical devices and / or biomedicine.

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