Near-infrared chiral magnesium-based superparticle nerve photoconductive tube, preparation method thereof and application of near-infrared chiral magnesium-based superparticle nerve photoconductive tube in peripheral nerve regeneration

Abstract

The invention provides a near-infrared chiral magnesium-based superparticle nerve photoconductive tube, a preparation method thereof and application of the near-infrared chiral magnesium-based superparticle nerve photoconductive tube in peripheral nerve regeneration, and belongs to the field of synthesis and application of medical stent materials. A chiral magnesium-based superparticle is provided; dispersing the chiral magnesium-based superparticles in an organic solvent, and adding polycaprolactone in batches to obtain a high-viscosity spinning solution; carrying out electrostatic spinning on the spinning solution, uniformly covering a roller with non-wrinkle tin foil paper, collecting the tin foil paper covered with spinning, cutting the tin foil paper into small pieces, and soaking the small pieces in absolute ethyl alcohol or a PBS (Phosphate Buffer Solution); the spinning film on the soaked small piece of tin foil paper is rolled into a chiral nerve conduit, after the chiral nerve conduit is rolled, the chiral nerve conduit is strung through a stainless steel rod and dried, plasticization of the conduit is achieved, and the near-infrared chiral magnesium-based superparticle nerve photoelectric conduit is obtained. The near-infrared chiral magnesium-based superparticle nerve photoconductive tube obtained by the invention has important significance on repair after sciatic nerve injury.

Description

Technical Field

[0001] This invention relates to the technical field of medical scaffold material synthesis, and in particular to a near-infrared chiral magnesium-based superparticle nerve photoconductor, its preparation method, and its application in peripheral nerve regeneration. Background Technology

[0002] Peripheral nerve defects are a common clinical injury, affecting millions of people each year. While autologous nerve transplantation yields excellent results, it is limited by drawbacks such as secondary injury, limited supply, and tissue size variations. Neuro-photoconduit can not only provide structural guidance for nerve regeneration but also generate an electrical response through external light stimulation, thereby promoting nerve cell growth and repair of damaged nerve tissue. Neuro-photoconduit has significant scientific importance in the field of nerve regeneration.

[0003] The design of neural photoconductors primarily focuses on optimizing photoelectric materials, particularly improving their photoelectric performance under near-infrared light excitation. However, effectively separating photogenerated electron-hole pairs remains a core challenge in this field. Traditional wide-bandgap semiconductor materials struggle to generate effective photoelectric effects in the near-infrared region, while narrow-bandgap materials cannot effectively utilize near-infrared light due to the rapid recombination of photogenerated electron-hole pairs. To overcome this problem, researchers have explored various methods, such as doping with heteroatoms, constructing P / N heterojunctions, utilizing defect sites, and employing multilayer composite designs, to improve photoelectric conversion efficiency in the near-infrared region.

[0004] Chiral materials can improve photoelectric conversion efficiency in the near-infrared region due to the chiral-induced spin selectivity (CISS) effect. The CISS effect refers to the generation of spin-polarized electron-hole pairs after chiral materials are excited. When a spin-down electron (from the conduction band) is excited, due to the conservation of spin angular momentum, the remaining hole (from the valence band) exhibits a spin-up characteristic and maintains this spin direction. During electron transport, due to spin-orbit coupling, the electron loses its original spin direction and becomes spin-up. However, in a spin-polarized environment, the lack of spin-down holes inhibits recombination. Therefore, photoelectric conversion efficiency can be improved. Furthermore, magnesium is a macroelement with a high safety threshold and good biocompatibility. Magnesium ions have also been shown to promote angiogenesis and improve the microenvironment for nerve regeneration, which is crucial for nerve regeneration and repair. Summary of the Invention

[0005] To address the above technical problems, this invention provides a near-infrared chiral magnesium-based superparticle nerve photoconductor, its preparation method, and its application in peripheral nerve regeneration. This chiral magnesium-based superparticle material exhibits circular dichroism in the near-infrared region, and under near-infrared light irradiation, it can produce excellent photoelectric effects due to chiral-induced spin selectivity. By combining near-infrared chiral magnesium-based superparticles with polymers (such as polycaprolactone), and using electrospinning technology, a chiral magnesium-based superparticle nerve photoconductor (chiral nerve conduit) is prepared. The chiral nerve conduit is implanted into a rat sciatic nerve transection model, and photocurrent generated by irradiating the chiral nerve conduit can stimulate the regeneration and functional recovery of the rat sciatic nerve.

[0006] The first objective of this invention is to provide a method for preparing a near-infrared chiral magnesium-based superparticle nerve photoconductor, comprising the following steps: A chiral magnesium-based superparticle is provided; The chiral magnesium-based superparticles were dispersed in an organic solvent, and a polymer was added to obtain a spinning solution. The spinning solution is electrospun, and the roller is evenly covered with wrinkle-free tin foil. The tin foil covering the spinning is collected, cut into small pieces, and soaked in anhydrous ethanol or PBS buffer solution. The spun membrane on a small piece of soaked tin foil is rolled into a chiral nerve conduit. After the chiral nerve conduit is rolled up, it is strung together with a stainless steel rod and dried to achieve plasticization of the conduit, thus obtaining the near-infrared chiral magnesium-based superparticle nerve photoelectric conduit.

[0007] In some embodiments of the present invention, the chiral magnesium-based superparticles are prepared by the following method: The magnesium source is dispersed and / or dissolved in DMSO solution until uniformly dispersed. Then, a chiral inducing agent solution is added and stirred. Then, n-butyllithium is added and stirred to react. After heating, the reaction is carried out, and the solid phase is separated from the liquid phase. The obtained solid phase is the chiral magnesium-based superparticle.

[0008] In some embodiments of the present invention, the magnesium source is selected from one or more of magnesium acetate, magnesium formate, magnesium chloride, magnesium sulfate, and magnesium nitrate.

[0009] In some embodiments of the present invention, the molar ratio of magnesium source to cysteine ​​is (1:1) to (1:8). The concentration of n-butyllithium is 20-30 wt%. This invention uses n-butyllithium to provide van der Waals interactions to form a chiral helical structure.

[0010] The chiral inducer is selected from cysteine ​​or short peptides containing cysteine.

[0011] In some embodiments of the present invention, the stirring reaction time is 1 to 5 minutes; The heating reaction is carried out at a temperature of 50~90℃ for 2~12 hours.

[0012] In some embodiments of the present invention, the organic solvent is selected from hexafluoroisopropanol; The mass ratio of chiral magnesium-based superparticles to polycaprolactone is (0.1:9.9) to (1:9). The polymer contains one or more of high molecular weight polymers with hydrophilic and hydrophobic groups, preferably one or more of polycaprolactone, collagen, silk fibroin, and polylactic acid; theoretically, any polymer containing both hydrophilic and hydrophobic groups is applicable to this invention. When adding the polymer, it is preferable to add it in batches. Adding it in batches avoids adding too much at once, resulting in a spinning solution with excessive viscosity, which would prevent the magnetic force of the subsequent magnetic stirrer from being sufficient to agitate the rotor.

[0013] In some embodiments of the present invention, the parameters of the electrospinning are: flow rate of 1~3mL / h, spinning voltage of 8-12kV, roller size of r=10cm, h=4cm (any size roller compatible with the instrument is acceptable), and roller speed of 100~1000rpm.

[0014] The present invention uses anhydrous ethanol or PBS buffer solution to soak the film covering the tin foil, making it easy to peel off.

[0015] In some embodiments of the present invention, the near-infrared wavelength range is 700-800 nanometers.

[0016] The second objective of this invention is to provide a near-infrared chiral magnesium-based superparticle nerve photoconductor, which is prepared by the aforementioned method.

[0017] A third objective of this invention is to provide the application of the near-infrared chiral magnesium-based superparticle nerve photoconductor in peripheral nerve regeneration.

[0018] In some embodiments of the present invention, the peripheral nerve includes the sciatic nerve.

[0019] The technical solution of the present invention has the following advantages compared with the prior art: This invention provides a method for preparing a near-infrared chiral magnesium-based superparticle nerve photoconductor and its application in peripheral nerve regeneration. The chiral magnesium-based superparticle is a chiral optically active superparticle material with a distinct chiral helical twist shape in the near-infrared region. After the near-infrared chiral magnesium-based superparticle material is compounded with polycaprolactone, the resulting composite mucus can be electrospun into a film and then formed into a conduit with the aid of a mold. The chiral nerve conduit also possesses near-infrared chiral optical activity, and under near-infrared radiation, due to the chiral-induced spin selectivity effect of the chiral material, it can efficiently generate photocurrent. The chiral photoconductor provided by this invention can be implanted as a biological scaffold material in a rat sciatic nerve transection model. Due to the penetrability of near-infrared light, it can reach the muscle layer, promoting the generation of photocurrent in the nerve conduit, thereby stimulating the regeneration of the surrounding sciatic nerve. Furthermore, the sustained release of magnesium ions in vivo can promote angiogenesis of the severed nerve, thus better promoting nerve regeneration. Finally, the chiral nerve conduit made using magnesium-based superparticle material has high biocompatibility. Attached Figure Description

[0020] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 This is a scanning electron microscope image characterizing a near-infrared chiral magnesium-based superparticle material according to the present invention.

[0021] Figure 2 This is a circular dichroism spectrum characterizing a near-infrared chiral magnesium-based superparticle material according to the present invention.

[0022] Figure 3 This invention characterizes the photocurrent of a near-infrared chiral magnesium-based superparticle material.

[0023] Figure 4 These are microscopic scanning electron microscope images of the two chiral nerve photoconductors characterized by this invention.

[0024] Figure 5 This is a physical image of the second type of chiral nerve photoconductor of the present invention.

[0025] Figure 6 This invention characterizes the circular dichroism spectrum of two chiral nerve photoconductors.

[0026] Figure 7 This invention characterizes the photocurrent of the second type of chiral nerve photoconductor.

[0027] Figure 8 This relates to the biocompatibility of the chiral nerve photoconductor used in the performance testing of this invention.

[0028] Figure 9This is a diagram showing the experimental results of using a chiral nerve photoconductor for sciatic nerve regeneration in rats in Example 1 of this invention. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0030] The technical terms involved in this invention are explained as follows: Near-infrared chiral magnesium-based superparticles: Superparticles that are chiral and optically active in the near-infrared region and are formed by a series of assemblies of magnesium-containing coordination compounds.

[0031] Chiral nerve photoconductor: In this invention, it refers to the process of combining chiral magnesium-based superparticles with polycaprolactone to form a uniform spinning solution, electrospinning the solution, and then rolling it into a conduit shape through a mold.

[0032] This invention provides a method for preparing a near-infrared chiral magnesium-based superparticle nerve photoconductor and its application in peripheral nerve regeneration. First, near-infrared chiral optically active magnesium-based superparticles are synthesized. Then, these superparticles are co-composite with polycaprolactone to form a homogeneous electrospinning solution, which is then electrospun and rolled into a conduit using a mold. The photoelectric effect of the conduit is then studied. Finally, this conduit is implanted as a nerve scaffold material into a rat sciatic nerve transection model, and its repair effect on the rat sciatic nerve is investigated under light irradiation. Example

[0033] This embodiment provides a method for synthesizing near-infrared chiral optically active magnesium-based superparticles, as detailed below: At room temperature, 0.25 mmol of magnesium acetate was first dissolved in 2.5 mL of dimethyl sulfoxide (DMSO) solvent, and then 5 mL of DMSO solution was added. The mixture was stirred for several minutes to ensure complete dispersion. Then, 0.5 mL (1 M) of cysteine ​​solution (prepared fresh) was added and stirred thoroughly to produce a milky white turbid liquid. When the milky white turbid liquid was stable, 1.0 mL of n-butyllithium (25%) was added to the above reaction solution as soon as possible and stirred for 2 minutes. The mixture was then placed in a 50 °C water bath and allowed to stand for 6 hours. After the reaction was completed, the precipitate was collected by centrifugation at 6000 rpm for 10 minutes and then resuspended in water to obtain a chiral magnesium-based superparticle dispersion for later use. Example

[0034] This embodiment provides a method for preparing a chiral nerve conduit, as detailed below: (1) The chiral magnesium-based superparticle dispersion obtained in Example 1 was centrifuged again at 6000 rpm for 10 minutes. The precipitate was collected and dried into powder in a vacuum drying oven at 50°C. 100 mg of the powder was weighed and dispersed in 10 mL of hexafluoroisopropanol solvent. After it was completely dispersed, polycaprolactone (PCL, molecular weight 15W) was added in batches of 200 mg each time. After each addition, the PCL was fully dissolved before adding the next batch. The last addition was 100 mg, and the total amount of PCL added was 900 mg. The final spinning solution was obtained.

[0035] (2) Collect the above spinning solution and put it into a micro-injection pump. Set the flow rate to 1.5 mL / h, the spinning voltage to 10-12 kV, and the roller size to r=10 cm and h=4 cm. Cover the roller evenly with wrinkle-free tin foil and rotate the roller at about 1000 rpm. Perform electrospinning according to the instrument requirements. Collect the tin foil covering the spinning and cut it into rectangular pieces 1.5 cm wide and 4 cm long. Soak the pieces in anhydrous ethanol or 0.01 M PBS buffer solution. Then, use a stainless steel rod with an outer diameter of 2 mm to transfer the spun film from the tin foil to the stainless steel rod. About 8-10 rectangular pieces of tin foil can be rolled into a chiral nerve conduit. After the chiral nerve conduit is rolled, string it together with a stainless steel rod with an outer diameter of 2 mm and place it in a constant temperature drying oven at 50℃. Strictly monitor the state of the conduit in the drying oven to plasticize it and obtain a chiral nerve conduit with good structural strength.

[0036] Characteristic 1 The chiral magnesium-based superparticles obtained in Example 1 were characterized using the following methods: (1) SEM of magnesium-based superparticles: The purified chiral superparticles were diluted to 20 μg / mL, and 15 μL was dropped onto a single-crystal silicon wafer. The wafer was allowed to naturally adsorb and dry, and then imaged using a scanning electron microscope at an accelerating voltage of 10 kV. Figure 1 As shown, the average particle size of the synthesized chiral superparticles is about 1 ± 0.2 μm, exhibiting a chiral helical kink morphology.

[0037] (2) Circular dichroism spectroscopy characterization: The purified chiral magnesium-based superparticles were diluted to 0.5 μg / mL, and air was scanned three times as a blank signal. The scanning range of the chiral superparticles was 200 to 1000 nm, the scanning step size was 0.5 nm, and the scanning speed was 0.1 s / nm; Figure 2 As shown, chiral magnesium-based superparticles exhibit circular dichroism signals across multiple wavelength ranges, with their most typical signal peak located between 700 and 800 nanometers, belonging to the near-infrared region.

[0038] (3) Photocurrent signal testing: Using ITO conductive glass as a substrate, chiral magnesium-based superparticles were uniformly dropped onto the conductive glass substrate, allowed to dry naturally at room temperature, and then cured in a 60℃ oven. The cured ITO conductive glass loaded with chiral superparticles was placed in a two-chamber system filled with 10 mM KCl electrolyte, and ion transport was monitored and current-time curves were recorded using Ag / AgCl electrodes. Figure 3 It can be seen that when near-infrared radiation is introduced at the 30th second, the conductive glass covered with chiral magnesium-based superparticles generates a significant photocurrent signal. When the radiation source is removed at the 60th second, the photocurrent drops to the baseline level.

[0039] Characteristic 2 The chiral nerve photoconductor obtained in Example 2 was characterized using the following methods: Electron microscopy characterization of the spinning solution of chiral nerve photoconductor: A homogeneous spinning solution formed by near-infrared magnesium-based chiral superparticles and polycaprolactone was dropped onto a single-crystal silicon wafer. After natural drying, gold was sputtered onto the wafer for 1 minute, followed by scanning electron microscopy observation. Figure 4 As shown, the spinning solution for synthetic chiral nerve photoconductors exhibits a typical long fibrous structure and displays certain helical twisting characteristics. Furthermore, as... Figure 5 As shown, chiral nerve conduits exhibit a rough surface feature on a macroscopic scale.

[0040] Circular dichroism spectroscopy characterization: The sample obtained from electrospinning was immersed in anhydrous ethanol for 10 minutes. Then, it was carefully separated from the tin foil using fine tweezers and transferred to a quartz plate. Air bubbles were carefully removed, and the sample was cured in a drying oven at 45°C for approximately 10 minutes. Note that the oven temperature and time should be adjusted flexibly to avoid plasticization. This sample was then used for circular dichroism spectroscopy testing. Three scans of air were used as a blank signal. The scanning range of the chiral conduit was 300 to 1000 nm, the scan step size was 0.5 nm, and the scan speed was 0.1 s / nm. Figure 6 As shown, chiral nerve photoconductivity exhibits circular dichroism signals across multiple wavelength ranges, with its most typical signal peak located between 900 and 1000 nanometers.

[0041] (3) Photocurrent signal test: The plasticized chiral nerve conduit was placed in a two-chamber system filled with 10 mM KCl electrolyte. Ion transport was monitored and the current-time curve was recorded using an Ag / AgCl electrode. Figure 7 It can be seen that when near-infrared radiation is introduced at the 30th second, the chiral nerve conduit generates a significant photocurrent signal, which can reach 2.0 mA / cm². 3 When the radiation source was removed at the 60th second, its photocurrent decreased to the baseline level.

[0042] Performance testing Biocompatibility test: 50 μL of the homogeneous spinning solution formed by the composite of near-infrared chiral magnesium-based superparticles and polycaprolactone was pipetted and evenly distributed into the wells of a 96-well plate. The solution was then transferred to a 60°C drying oven to fix the cells in cell culture dishes, followed by a 37°C drying oven for one week to allow complete solvent evaporation. Finally, the solution was completely exposed to UV light for 12 hours for sterilization. Rat Schwann cells were then cultured at a rate of 2 × 10⁻⁶ cells / mL according to the standard cell culture protocol. 4 Cells were seeded per well into treated 96-well plates and cultured at 37°C with 5% CO2 for 72 hours. Cell viability was assessed using a CCK8 assay kit, and OD values ​​were measured using a Bio-Tek microplate reader at 450 nm. A control group was prepared using standard 96-well plates under the same conditions. Figure 8 As shown, the cell activity assay of the chiral nerve photoconductor indicates that the chiral nerve photoconductor has no toxicity to rat Schwann cells.

[0043] Application Example 1 This application example demonstrates the use of a chiral nerve photoconductor in a rat sciatic nerve transection model. A rat sciatic nerve transection model and nerve conduit implantation were performed in a biolicensed and ethically compliant laboratory animal center. Under anesthesia, the hair on the left hind leg of the rat was removed using a shaving tool and depilatory cream. A 1cm incision was made in the ischial region using dissecting scissors. The fascia and muscle were then inertly dissected to locate the sciatic nerve. The sciatic nerve was cut 8mm using microsurgical spring shears, allowing it to retract naturally and form a 1cm transection. Under the procedure of chiral nerve conduit implantation, the conduit was first thoroughly disinfected by soaking in alcohol. Then, both ends of the nerve were sutured into the cavity of the conduit, with two stitches at each end, and aligned. The conduit was then embedded in the muscle tissue, the skin was sutured, and 800,000 units of penicillin were injected intraperitoneally to further combat bacterial infection. Rats were housed in pairs per cage, with frequent bedding changes and chew sticks provided to reduce toe-chewing. Characterization was performed after 3 months of rearing. Figure 9 As shown, the use of chiral nerve photoconductors combined with light irradiation can effectively promote sciatic nerve regeneration in rats.

[0044] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a near-infrared chiral magnesium-based superparticle nerve photoconductor, characterized in that, Includes the following steps: A chiral magnesium-based superparticle is provided; The chiral magnesium-based superparticles were dispersed in an organic solvent, and a polymer was added and stirred to obtain a spinning solution. The spinning solution is electrospun, and the roller is evenly covered with wrinkle-free tin foil. The tin foil covering the spinning is collected, cut into small pieces, and soaked in anhydrous ethanol or PBS buffer solution. The spun membrane on a small piece of soaked tin foil is rolled into a chiral nerve conduit. After the chiral nerve conduit is rolled up, it is strung together with a stainless steel rod and dried to achieve plasticization of the conduit, thus obtaining the near-infrared chiral magnesium-based superparticle nerve photoelectric conduit.

2. The preparation method according to claim 1, characterized in that, The chiral magnesium-based superparticles were prepared by the following method: The magnesium source is dispersed or dissolved in DMSO solution until it is uniformly dispersed. Then, a chiral inducing agent solution is added and stirred. Then, n-butyllithium is added and stirred to react. After heating, the reaction is carried out and the solid phase is separated. The obtained solid phase is the chiral magnesium-based superparticle.

3. The preparation method according to claim 2, characterized in that, The magnesium source is selected from one or more of magnesium acetate, magnesium formate, magnesium chloride, magnesium sulfate, and magnesium nitrate.

4. The preparation method according to claim 2, characterized in that, The molar ratio of magnesium source to cysteine ​​is (1:1) to (1:8). The concentration of n-butyllithium is 20-30 wt%; The chiral inducer is selected from cysteine.

5. The preparation method according to claim 2, characterized in that, The stirring reaction time is 1-5 minutes; The heating reaction is carried out at a temperature of 50~90℃ for 2~12 hours.

6. The preparation method according to claim 1, characterized in that, The organic solvent is selected from hexafluoroisopropanol; The mass ratio of chiral magnesium-based superparticles to polymers is (0.1:9.9) to (1:9); The polymer is one or more of a polymer having hydrophilic and hydrophobic groups.

7. The preparation method according to claim 1, characterized in that, The parameters for electrospinning are: flow rate of 1~3mL / h, spinning voltage of 8-12kV, roller size of r=10cm, h=4cm, and roller speed of 100~1000rpm. The near-infrared wavelength range is 700-800 nanometers.

8. A near-infrared chiral magnesium-based superparticle nerve photoconductor, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the near-infrared chiral magnesium-based superparticle nerve photoconductor of claim 8 in peripheral nerve regeneration.

10. The application according to claim 9, characterized in that, The peripheral nerves include the sciatic nerve.

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