GTR film, and preparation method and application thereof
By combining piezoelectric and photothermal effects in GTR membranes, a GTR membrane with rapid sterilization and long-lasting antibacterial effects was prepared, solving the problem of poor antibacterial effect of existing GTR membranes and achieving a highly efficient antibacterial effect in the treatment of periodontitis.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SICHUAN UNIV
- Filing Date
- 2025-05-09
- Publication Date
- 2026-05-26
AI Technical Summary
The existing GTR membrane is not effective enough in the treatment of periodontitis, is susceptible to bacterial infection, which can affect the surgical outcome and even lead to failure.
GTR films were prepared by uniformly dispersing Ag@PDA@BaTiO3 nanoparticles in L-polylactic acid using electrospinning technology. Combining the piezoelectric effect and near-infrared photothermal effect, the piezoelectric material was used to generate an electric field and photothermal effect under mechanical stimulation to kill bacteria.
It achieves rapid sterilization and long-lasting antibacterial effect, avoiding the use of additional antibiotics. The piezoelectric effect continues to play a role in the healing process, significantly improving the antibacterial ability of the membrane and avoiding the problem of bacterial resistance.
Smart Images
Figure CN120324686B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of biomedical materials technology, and more specifically to a GTR membrane, its preparation method, and its application. Background Technology
[0002] Periodontitis causes damage to both soft and hard tissues, and can even lead to tooth loss, impacting patients' quality of life. Guided tissue regeneration (GTR) is a key surgical strategy in periodontal treatment. The GTR membrane, placed between the gum and tooth after flap surgery, acts as a barrier to prevent rapidly growing epithelial cells and soft tissue-derived cells from ingraining towards the root, thus buying time for undifferentiated cells from the periodontal ligament. If these undifferentiated cells can preemptively occupy the blood clot and exposed root surface, they can differentiate into osteoblasts, fibroblasts, and other histiogenic cells, ultimately forming a complete set of periodontal tissues, including bone, periodontal ligament, and cementum.
[0003] During GTR surgery, physical curettage can only remove most of the irritants; many bacteria still colonize areas inaccessible to surgical instruments, often requiring medication to enhance sterilization. During the long healing process, the open environment of the oral cavity attracts various opportunistic pathogens, making the barrier membrane, as an implant material, susceptible to bacterial infection. This not only affects the surgical outcome but can even lead to surgical failure. Currently, commercially available barrier membranes are primarily used as physical barriers and lack adequate antibacterial capabilities.
[0004] Therefore, barrier membranes with long-lasting antibacterial effects urgently need to be developed to overcome the limitations of traditional options. Summary of the Invention
[0005] This invention provides a GTR membrane, its preparation method, and its application, in order to solve the problem that the antibacterial effect of GTR membranes in the prior art is not ideal.
[0006] In a first aspect, the present invention provides a method for preparing a GTR membrane, comprising the following steps: uniformly dispersing BaTiO3 in a Tris buffer solution, dissolving dopamine hydrochloride powder in the reaction system, stirring evenly, centrifuging to collect the precipitate, cleaning and drying to obtain PDA@BaTiO3 nanoparticles; adding the PDA@BaTiO3 nanoparticles to a silver ammonia solution, stirring at room temperature, centrifuging to collect the precipitate, cleaning and drying to obtain Ag@PDA@BaTiO3 particles; uniformly dispersing the Ag@PDA@BaTiO3 particles in a hexafluoroisopropanol solution of L-polylactic acid, electrospinning the reaction system to obtain a fiber membrane, and sequentially performing ventilation, high-temperature annealing, and natural cooling to room temperature to obtain the GTR membrane.
[0007] As one possible implementation, the method for preparing the silver ammonia solution includes the steps of: dissolving AgNO3 in deionized water, adding ammonia water dropwise while shaking, until the initially formed precipitate just dissolves.
[0008] As one possible implementation, the concentration of the Tris buffer solution is 0.01–0.05 mol / L, the pH is 8.5, and the particle size of the dispersed phase is 10 mm; and / or, the concentration of silver ions in the silver ammonia solution is 0.04–0.08 mol / mL; and / or, the mass-volume fraction of the hexafluoroisopropanol solution of L-polylactic acid is 8%–12%.
[0009] As one possible implementation, the ratio of BaTiO3 to the Tris buffer solution is 1:100-120 in g / mL; and / or, the mass ratio of dopamine hydrochloride to BaTiO3 is 1:4-5; and / or, the ratio of PDA@BaTiO3 nanoparticles to silver ammonia solution is 1:40-50 in g / mL.
[0010] As one possible implementation, the cleaning includes the steps of rinsing three times with deionized water; and / or, the drying includes the steps of freeze drying for 24–36 hours.
[0011] As one possible implementation, the electrospinning includes the steps of: placing a syringe containing the reaction system at a distance of 15 cm from the receiver, operating at a flow rate of 1 mL / h, and performing electrospinning at a voltage of 15 kV; and / or, the conditions for electrospinning are: the receiver speed is 1500 r / min, and the total working time is 210 min; and / or, the conditions for high-temperature annealing are: high-temperature annealing at 105 °C for 10 h.
[0012] Secondly, the present invention provides a GTR membrane prepared by the preparation method described in any possible implementation of the first aspect.
[0013] Thirdly, the present invention provides the application of the GTR membrane described in any possible implementation of the second aspect in the preparation of implant materials after periodontal flap surgery.
[0014] The piezoelectric effect refers to the change in the internal charge distribution of certain crystalline or polymeric materials (such as barium titanate, zinc oxide, and polyvinylidene fluoride) when subjected to pressure, vibration, or deformation, thereby creating a potential difference on the material surface. Piezoelectric antibacterial technology is an emerging antibacterial strategy that utilizes the electric field generated by piezoelectric materials under mechanical stress to inhibit or kill bacteria. This electromechanical coupling characteristic provides a unique physical pathway for antibacterial applications: when a piezoelectric material comes into contact with bacteria and is subjected to external mechanical stimulation (such as bodily fluid flow, human movement, or ultrasound), the piezoelectric field generated on its surface can directly disrupt the integrity of the bacterial cell membrane, or catalyze the generation of free radicals such as reactive oxygen species (ROS), interfering with bacterial metabolism and leading to their death.
[0015] The application of near-infrared (NIR) responsive photothermal materials in the field of antibacterial research has attracted much attention in recent years. NIR photothermal materials absorb light energy of specific wavelengths and efficiently convert it into heat energy, generating localized instantaneous high temperatures (above 50–60°C) that directly disrupt bacterial cell membrane structures, denature proteins, and cause DNA damage. Furthermore, these materials (such as noble metal nanostructures, carbon-based materials, and semiconductor polymers) can be further enhanced in antibacterial efficiency and reduced in required light power through surface functionalization or composite design, combining photothermal effects with synergistic chemical / photodynamic antibacterial mechanisms.
[0016] Compared to traditional antibiotics and chemical disinfectants, piezoelectric materials and near-infrared responsive photothermal antibacterial materials offer significant advantages. First, their mechanism of action relies on physical electric fields and free radical reactions or thermal effects, effectively circumventing the problem of pathogen resistance. Second, piezoelectric materials require no external power source, activating solely through mechanical energy in the environment. Furthermore, compared to traditional UV or visible light-excited photosensitizers, near-infrared light possesses deeper tissue penetration (up to the centimeter level) and lower biological tissue absorption and scattering characteristics, offering possibilities for treating deep infections. Therefore, combining piezoelectric and photothermal effects in GTR membranes is a promising strategy, beneficial for achieving highly efficient and long-lasting antibacterial effects.
[0017] This invention provides a GTR membrane with both piezoelectric and photothermal effects, exhibiting rapid sterilization and long-lasting antibacterial properties. Its preparation process is simple: Ag@PDA with photothermal effects is coated onto barium titanate, then mixed with PLLA and spun into a film. This enhances the piezoelectric properties of the membrane material and also achieves excellent photothermal conversion performance. During GTR surgery, near-infrared radiation rapidly kills bacteria, avoiding the need for additional antibiotics. During the subsequent healing process, the piezoelectric effect continues to play a role, maintaining the antibacterial effect. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 An optical photograph of the electrospun film prepared according to an embodiment of the present invention.
[0020] Figure 2 SEM images of the electrospun membrane provided in an embodiment of the present invention.
[0021] Figure 3 The open-circuit voltage measurement results of the GTR membrane provided in the embodiments of the present invention.
[0022] Figure 4 The photothermal performance test results of the GTR film provided in the embodiments of the present invention.
[0023] Figure 5 The antibacterial performance test results of the GTR membrane provided in the embodiments of the present invention.
[0024] Figure 6 The results of the biocompatibility test of the GTR membrane provided in the embodiments of the present invention are shown, wherein Control is the control group. Detailed Implementation
[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0026] To address the issue of insufficient antibacterial effect of GTR membranes in existing technologies, this invention provides an experiment on the preparation and performance testing of a GTR membrane.
[0027] The technical solution of the present invention will be further described below with reference to specific embodiments.
[0028] Example 1
[0029] This embodiment provides an experiment for the preparation of a GTR membrane.
[0030] 302.5 mg of Tris (>99.9% (T), Aladdin, China) was dissolved in 250 mL of deionized water to form a Tris buffer solution (pH 8.5, 10 nm). 2.5 g of BaTiO3 (200 nm) powder was uniformly dispersed in 250 mL of the prepared Tris buffer solution and sonicated for 30 min to ensure uniform dispersion. Subsequently, 0.5 g of dopamine hydrochloride powder was dissolved in the reaction system, stirred at 60 °C for 12 h, centrifuged, and the precipitate was washed three times with deionized water. The precipitate was freeze-dried for 24 h to obtain PDA@BaTiO3 nanoparticles.
[0031] 1 g of the prepared PDA@BaTiO3 nanoparticles were added to 50 mL of 0.4 M silver ammonia solution (340 mg AgNO3 was dissolved in 50 mL of deionized water, and then ammonia was added dropwise while shaking until the initially formed precipitate was just dissolved). The solution was stirred at room temperature for 2 h to allow the Ag in the solution to reach a certain concentration. + Polydopamine was in situ reduced to Ag nanoparticles, which were then loaded onto the surface of PDA@BaTiO3. The precipitate was centrifuged and washed three times with deionized water to remove unreacted AgNO3. Finally, it was freeze-dried for 24 h to obtain Ag@PDA@BaTiO3 particles with a core-shell structure.
[0032] Polylactic acid (PLLA) with a molecular weight of 260,000 (Jinan Daigang Biotechnology Co., Ltd.) was dissolved in hexafluoroisopropanol (Aladdin) to prepare a 10% (w / v) solution. The solution was stirred for 2 hours to ensure complete dissolution of PLLA in the hexafluoroisopropanol. Ag@PDA@BaTiO3 particles were then added and ultrasonically dispersed for 2 hours to ensure uniform dispersion of the nanoparticles. A 10mL syringe with a 19-gauge needle was placed 15cm away from the receiver, and electrospinning was performed at a flow rate of 1mL / h and a voltage of 15kV. The receiver speed was 1500r / min, and the total working time was 210min. The electrospun fiber membrane was placed in a fume hood overnight to allow residual organic solvents to evaporate completely. The membrane was then annealed at 105℃ for 10 hours and then naturally cooled to room temperature to obtain the PLLA+AgPBT, i.e., a GTR membrane.
[0033] Barium titanate (BTO) nanoparticles and the prepared PDA@BaTiO3 nanoparticles were respectively doped into a 10% (w / v) PLLA solution, and PLLA+BTO films and PLLA+PBT films were prepared using the same electrospinning parameters. Pure PLLA films were then prepared using the same electrospinning parameters.
[0034] Optical images of PLLA, PLLA+BTO, PLLA+PBT, and PLLA+AgPBT are shown below. Figure 1As shown. Electron microscopy scans were performed on PLLA, PLLA+BTO (PLLA / BT), PLLA+PBT (PLLA / PBT), and PLLA+AgPBT (PLLA / AgPBT) in this embodiment, yielding the following results: Figure 2 The SEM results are shown. (By...) Figure 1 and Figure 2 It can be seen that the color of the membrane changes from light to dark as different nanoparticles are loaded; the nanoparticles are uniformly dispersed in the PLLA fibers, proving that the GTR membrane was successfully prepared.
[0035] Example 2
[0036] This embodiment provides a performance testing experiment for the GTR membrane.
[0037] The piezoelectric properties of the membrane were verified by testing its electrical output performance under ultrasonic stimulation. The open-circuit voltage of the membrane was measured using an electrochemical workstation. This example verifies the piezoelectric properties of PLLA, PLLA+BTO (PLLA+BT), PLLA+PBT, and PLLA+AgPBT from Example 1, yielding the following results: Figure 3 The results are shown. Figure 3 It can be seen that the piezoelectric output of the composite film with added nanoparticles is enhanced compared to the pure PLLA film. The piezoelectric performance of PLLA is relatively weak. After being combined with the piezoelectric ceramic BTO, the material combines excellent piezoelectric output with the flexibility of organic piezoelectric materials. The reason for the further improvement in the piezoelectric output of PLLA+PBT may be that the polydopamine layer on the surface of barium titanate reduces the difference in interfacial energy between BTO and PLLA. The piezoelectric output of the PLLA+AgPBT group is the largest, possibly because the addition of Ag as a conductive phase is conducive to electron transfer.
[0038] To investigate the in vitro photothermal conversion effect of electrospun membranes, 808nm near-infrared laser irradiation was used. Infrared thermal imager was used to measure the temperature changes of the GTR membrane under different power densities in a PBS humid environment, and the results were obtained as follows: Figure 4 The results are shown. (By...) Figure 4 It was observed that at 1.5, 1.8, and 2.0 W / cm², 2 The temperature changes after irradiation with power densities of 1 / 3 / 5 / 7 / 10 min were measured. The temperature change of the film was positively correlated with the power density of the near-infrared light. In comparison, 2.0 W / cm²... 2 The temperature of the PLLA+AgPBT film was increased from 23℃ to 38.2 / 52.1 / 54.8 / 58.0 / 60.1℃ respectively after 1 / 3 / 5 / 7 / 10 min of near-infrared irradiation. Therefore, the GTR film prepared in Example 1 has good photothermal conversion efficiency, and because of 2.0 W / cm 2The PLLA+AgPBT membrane can heat up to above 50℃ within 5 minutes, which is a suitable temperature for antibacterial activity. Therefore, 2.0 W / cm² was selected for subsequent bacterial experiments. 2 Near-infrared light was used as the experimental parameter.
[0039] Staphylococcus aureus was removed from a -80°C ultra-low temperature freezer and placed in a clean bench for further processing. After thawing, a sterile inoculation loop was used to transfer the frozen bacterial block from the test tube into 20 mL of Luria-Bertani (LB) medium, and incubated overnight at 37°C and 150 rpm. The OD value of the overnight bacterial culture was measured using a microplate reader. 630 Dilute the bacterial culture to 1×10⁻⁶ 6 For later use. Cut the GTR membrane prepared in Example 1 into 1.5cm × 1.5cm pieces, soak in 75% alcohol for 30 minutes, and then sterilize under ultraviolet light in a clean bench for 12 hours. Add the sterilized membrane to a 24-well plate, followed by 500μL of diluted bacterial solution. For the control group, only 500μL of diluted bacterial solution is added. The samples are then subjected to ① sonication for 10 minutes. 6 Treatment consisted of three phases: ① CFU / mL treatment for 5 / 10 / 20 min (US+); ② Near-infrared irradiation for 5 / 10 / 20 min (NIR); ③ Near-infrared treatment for 5 / 10 / 20 min followed by sonication for the same duration (NIR / US+). After treatment, the mixture was plated, with 100 μL of the incubated bacterial suspension (diluted to 10⁻⁶) added to each agar plate. 3 (CFU / mL), then spread it evenly in this area using a disposable spreader. Incubate the spread agar plate overnight at 37°C. After incubation, place the agar plate under a colony counter and take a picture. The colony count is shown below. Figure 5 As shown, from Figure 5 As can be seen, the membrane with piezoelectric and photothermal effects exhibits excellent antibacterial effects after ultrasonic and near-infrared light treatment. According to calculations, after 5 minutes of ultrasonic treatment, the material provided by this invention achieves an antibacterial rate of approximately 18.5% through the piezoelectric effect, while 5 minutes of near-infrared irradiation alone can achieve an antibacterial rate of 98%. When most bacteria are killed under near-infrared irradiation and ultrasonic treatment is continued, the antibacterial efficiency of the membrane is greatly improved, reaching almost 100%.
[0040] Cytotoxicity on PLLA, PLLA+BTO (PLLA+BT), PLLA+PBT, and PLLA+AgPBT membranes was investigated using a CCK-8 assay kit. GTR membranes prepared in Example 1 were cut to 1.5 cm × 1.5 cm pieces, immersed in 75% ethanol, irradiated with UV light for 30 min, and then washed with phosphate-buffered saline (PBS). 500 μL of cell suspension (5 × 10⁻⁶ cells / well) was added to each well of a 24-well plate.5 Cells (cells / mL) were seeded into wells of a plate and incubated overnight at 37°C in a humidified incubator containing 5% CO2. After cell attachment, the cells were washed with PBS, and sterile membrane material was added. 500 μL of DMEM complete medium was added to each well, while cells grown in the medium without material served as a control group. The plates were incubated for 24 hours, then the supernatant was removed, washed with PBS, and cell culture medium containing 10% CCK-8 was added. After a further 2-hour incubation, the absorbance of the medium was measured at 450 nm using an Infinite F50 microplate reader (Tecan, USA). Figure 6 The results are shown. The results indicate that PLLA, PLLA+BT, PLLA+PBT, and PLLA+AgPBT all exhibit good biocompatibility.
[0041] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0042] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A method for preparing a GTR membrane, characterized in that, Includes the following steps: BaTiO3 was uniformly dispersed in Tris buffer solution, and dopamine hydrochloride powder was dissolved in the reaction system. The mixture was stirred until homogeneous, centrifuged to collect the precipitate, cleaned, and dried to obtain PDA@BaTiO3 nanoparticles. The ratio of BaTiO3 to Tris buffer solution was 1:100~120 (g / mL), and the mass ratio of dopamine hydrochloride to BaTiO3 was 1:4~5. The PDA@BaTiO3 nanoparticles were added to a silver ammonia solution, stirred at room temperature, centrifuged to collect the precipitate, cleaned and dried to obtain Ag@PDA@BaTiO3 particles. The ratio of the PDA@BaTiO3 nanoparticles to the silver ammonia solution was 1:40~50, in g / mL. The Ag@PDA@BaTiO3 particles were uniformly dispersed in a hexafluoroisopropanol solution of L-polylactic acid. The reaction system was electrospun to obtain a fiber membrane, which was then subjected to ventilation, high-temperature annealing, and natural cooling to room temperature to obtain the GTR membrane.
2. The preparation method according to claim 1, characterized in that, The preparation method of the silver ammonia solution includes the following steps: Dissolve AgNO3 in deionized water, then add ammonia dropwise while shaking until the initially formed precipitate just dissolves.
3. The preparation method according to claim 1, characterized in that, The concentration of the Tris buffer solution is 0.01~0.05 mol / L, the pH is 8.5, and the particle size of the dispersed phase is 10 mm. And / or, the concentration of silver ions in the silver ammonia solution is 0.04~0.08 mol / mL; And / or, the mass-volume fraction of the polylactic acid in hexafluoroisopropanol solution is 8%~12%.
4. The preparation method according to claim 1, characterized in that, The cleaning process includes the following steps: rinsing with deionized water three times; And / or, the drying includes the step of freeze drying for 24-36 hours.
5. The preparation method according to claim 1, characterized in that, The electrospinning includes the following steps: The syringe containing the reaction system was placed 15 cm away from the receiver and operated at a flow rate of 1 mL / h, with electrospinning performed at a voltage of 15 kV. And / or, the conditions for electrospinning are: the receiver speed is 1500 r / min, and the total working time is 210 min; And / or, the conditions for the high-temperature annealing are: high-temperature annealing at 105°C for 10 hours.
6. A GTR membrane prepared by the method of any one of claims 1 to 5.
7. The application of the GTR membrane according to claim 6 in the preparation of implant materials after periodontal flap surgery.