Reduced graphene oxide fiber confined fe3o4 nanoparticle composite and preparation method thereof

Abstract

The application relates to a reduced graphene oxide fiber confined Fe3O4 nanoparticle composite material and a preparation method thereof. The composite material is composed of reduced graphene oxide fiber (rGOF) with a directional micro-nanobelt structure (a large number of long strip / belt structures with a width in the micron to nanometer scale are arranged in parallel along the same direction on the surface or inside the material) and Fe3O4 nanoparticles confined on the reduced graphene oxide fiber; the Fe3O4 nanoparticles are distributed in an ordered chain shape along the axial direction of the reduced graphene oxide fiber; the Fe3O4 nanoparticles and the reduced graphene oxide fiber are stably combined through Fe-O-C covalent bonds, and the application has the advantages that one-dimensional confined structure-induced ordered arrangement is realized, the synthesis process is optimized, the stable Fe-O-C covalent bond between Fe3O4 and the rGO skeleton is formed, the interface structure stability and the magnetic coupling efficiency are ensured, and the application has wide application prospects in the biomedical field.

Description

Technical Field

[0001] This invention relates to the field of nanocomposite materials technology, specifically to a reduced graphene oxide fiber-confined Fe3O4 nanoparticle composite material and its preparation method, as well as the application of this material in the biomedical field. Background Technology

[0002] Iron oxide (Fe3O4) nanoparticles, with their excellent superparamagnetism, good biocompatibility, and low toxicity, have broad application prospects in biomedical fields such as MRI contrast agents, magnetic targeted drug delivery, and magnetothermal therapy. However, single magnetic nanoparticles face two major bottlenecks in practical applications: first, the particles tend to aggregate, leading to a decrease in magnetic properties; second, they lack multifunctional integration capabilities, making it difficult to meet the needs of modern integrated diagnosis and treatment.

[0003] Graphene and its derivatives, such as graphene oxide and reduced graphene oxide, possess extremely high specific surface areas, excellent mechanical properties, and rich surface chemical properties, making them ideal carriers for loading Fe3O4 nanoparticles. In existing technologies, graphene / Fe3O4 composites primarily exhibit a two-dimensional sheet structure with magnetic particles randomly distributed on the sheet surface. Although fibrous graphene composites have been reported (e.g., CN106158426A), their applications are concentrated in energy storage, and the Fe3O4 nanoparticles are "randomly distributed on the reduced graphene oxide sheets," failing to achieve ordered arrangement and confined control.

[0004] Therefore, developing a novel composite material that can precisely control the aggregation state of Fe3O4 nanoparticles to form stable interfacial bonds and possess multifunctional integration capabilities has significant technological value and clinical application prospects. Summary of the Invention

[0005] This invention aims to solve the technical problems of random distribution of Fe3O4 nanoparticles in graphene matrix, difficulty in precise control of aggregation state, and unstable interfacial bonding in the prior art. It provides a Fe3O4 nanoparticle composite material confined in reduced graphene oxide fibers and its preparation method, which realizes the ordered arrangement of Fe3O4 nanoparticles along the fiber axis and stable interfacial chemical bonding.

[0006] This invention provides a reduced graphene oxide fiber-confined Fe3O4 nanoparticle composite material, which consists of reduced graphene oxide fibers (rGOF) with oriented micro-nano strip structures (forming a large number of long strip / band structures with widths ranging from micrometers to nanometers, arranged parallel in the same direction on the surface or inside the material) and Fe3O4 nanoparticles confined on the reduced graphene oxide fibers; the Fe3O4 nanoparticles are distributed in an ordered chain-like manner along the axial direction of the reduced graphene oxide fibers; and the Fe3O4 nanoparticles and the reduced graphene oxide fibers form a stable interfacial bond through Fe-OC covalent bonds.

[0007] As a preferred embodiment of the present invention, the particle size of the Fe3O4 nanoparticles is no greater than 50 nm.

[0008] As a preferred embodiment of the present invention, the mass fraction of Fe3O4 nanoparticles relative to reduced graphene oxide fibers in the composite material is controlled to be 25% or less.

[0009] As a preferred embodiment of the present invention, the diameter of the reduced graphene oxide fiber is 55-90 μm.

[0010] Another objective of this invention is to provide a method for preparing a composite material of reduced graphene oxide fibers confined with Fe3O4 nanoparticles, comprising the following steps: Step 1: Prepare graphene oxide colloids (GO colloids) using the modified Hummers method; Step 2: Prepare a composite material of reduced graphene oxide fibers and Fe3O4 nanoparticles using an in-situ confined hydrothermal method; Step 3: The reduced graphene oxide fiber and Fe3O4 nanoparticle composite material assembled by in-situ confined hydrothermal method is taken out after natural cooling, thus obtaining the reduced graphene oxide fiber confined Fe3O4 nanoparticle composite material with a one-dimensional visco-nano oriented structure.

[0011] As a preferred embodiment of the present invention, the concentration of graphene oxide colloid in step 1 is 4-10 mg / mL.

[0012] As a preferred embodiment of the present invention, in step 2, the magnetic stirring parameters for the mixture of graphene oxide colloid and Fe3O4 nanoparticles in the in-situ confined hydrothermal method are: a stirring speed of 200-500 rpm / min and a stirring time of 20-60 min; and an ultrasonic power of 200 W and a stirring time of 45 min.

[0013] As a preferred embodiment of the present invention, in the in-situ confined hydrothermal method used in step 2, the hydrothermal reaction temperature is 120-200℃, the reaction time is 2-8h, and the reactor inner diameter is 0.5-1.0.

[0014] This invention provides an application of the reduced graphene oxide fiber confined Fe3O4 nanoparticle composite material prepared by the above method in the preparation of magnetic resonance imaging contrast agents, magnetic targeted drug delivery carriers, photothermal therapy agents, magnetothermal therapy agents, tissue engineering scaffold materials, electromagnetic wave absorbing materials, electromagnetic shielding materials, or radar stealth materials.

[0015] The beneficial effects of this invention are as follows: By optimizing the synthesis process, a composite material of Fe3O4 nanoparticles confined to reduced graphene oxide fibers was prepared, achieving strong covalent bonding between Fe3O4 and rGOF. The Fe3O4 nanoparticles are more firmly anchored on the carbon matrix, making them less prone to detachment. Furthermore, the composite material exhibits better structural stability and is more resistant to degradation in biological fluids, providing structural assurance for the stable and effective transmission of magnetic coupling effects. Based on the ordered chain structure of Fe3O4, Fe-OC interfacial bonding, and excellent magnetic anisotropy of the composite material of this invention, this material holds promise as a T2-weighted contrast agent for magnetic resonance imaging. In addition, the fiber structure of the rGOF-confined Fe3O4 nanoparticle composite material prepared by this invention facilitates the formation of a three-dimensional conductive network, combining the dielectric loss characteristics of rGOF carbon materials with the magnetic loss mechanism of magnetic nanoparticles, thus showing broad application prospects in the field of electromagnetic wave absorption. Attached Figure Description

[0016] Figure 1 This is a low-magnification scanning electron microscope (SEM) image (10 mg / 20 nm) of the rGOF-confined Fe3O4 nanoparticle composite material in Example 2.

[0017] Figure 2 This is a high-magnification scanning electron microscope (SEM) image (25 mg / 20 nm) of the rGOF-confined Fe3O4 nanoparticle composite material in Example 2.

[0018] Figure 3 The Fourier transform infrared (FTIR) spectrum (50 mg / 20 nm) of the rGOF-confined Fe3O4 nanoparticle composite material in Example 2 is shown.

[0019] Figure 4 The image shows the X-ray photoelectron spectroscopy (XPS) C1s spectrum (50 mg / 20 nm) of the rGOF-confined Fe3O4 nanoparticle composite material in Example 2.

[0020] Figure 5 The image shows the X-ray photoelectron spectroscopy (XPS) O1s spectrum (50 mg / 20 nm) of the rGOF-confined Fe3O4 nanoparticle composite material in Example 2.

[0021] Figure 6The image shows the X-ray photoelectron spectroscopy (XPS) Fe2p spectrum (50 mg / 20 nm) of the rGOF-confined Fe3O4 nanoparticle composite material in Example 2.

[0022] Figure 7 It is the superconducting quantum interference (SQUID) hysteresis loop (25mg / 20nm) of the rGOF-confined Fe3O4 nanoparticle composite material in Example 2.

[0023] Figure 8 This is a low-magnification scanning electron microscope (SEM) image (50 mg / 50 nm) of the rGOF-confined Fe3O4 nanoparticle composite material in Comparative Example 1.

[0024] Figure 9 This is a high-magnification scanning electron microscope (SEM) image (50 mg / 50 nm) of the rGOF-confined Fe3O4 nanoparticle composite material in Comparative Example 1.

[0025] Figure 10 The Fourier transform infrared (FTIR) spectrum (50 mg / 50 nm) of the rGOF-confined Fe3O4 nanoparticle composite material in Comparative Example 1 is shown.

[0026] Figure 11 Comparative Example 1 Superconducting quantum interference (SQUID) hysteresis loop (50 mg / 50 nm) of rGOF-confined Fe3O4 nanoparticle composite material. Detailed Implementation

[0027] Example 1

[0028] This embodiment provides a reduced graphene oxide fiber-confined Fe3O4 nanoparticle composite material. The composite material consists of reduced graphene oxide fibers (rGOF) with oriented micro-nano strip structures (forming a large number of long strip / ribbon structures with widths ranging from micrometers to nanometers, arranged parallel in the same direction on the material surface or inside the material) and Fe3O4 nanoparticles confined on the reduced graphene oxide fibers. The Fe3O4 nanoparticles are distributed in an ordered chain-like manner along the axial direction of the reduced graphene oxide fibers. The Fe3O4 nanoparticles and the reduced graphene oxide fibers form a stable interfacial bond through Fe-OC covalent bonds. The particle size of the Fe3O4 nanoparticles is no greater than 50 nm. The mass fraction of Fe3O4 nanoparticles relative to the reduced graphene oxide fibers is controlled at 25% or less. The diameter of the reduced graphene oxide fibers is 55-90 μm.

[0029] Example 2

[0030] See Figure 1-7As shown, this embodiment provides a method for preparing a composite material of reduced graphene oxide fibers confined to Fe3O4 nanoparticles, including the following steps: Step 1: Prepare graphene oxide colloids (GO colloids) using the modified Hummers method; Weigh out 28g of natural graphite powder, 1.5g of sodium nitrate, and 9g of potassium permanganate. Measure 69mL of concentrated sulfuric acid. Add the graphite powder and sodium nitrate sequentially, and stir magnetically in an ice-water bath until completely dissolved. While continuously stirring, slowly add potassium permanganate powder to the mixture. Seal the container and react for 90 minutes. Remove the ice-water bath, then raise the temperature of the reaction system to 45℃ and stir at this temperature for 2 hours. After the temperature maintenance is complete, allow the solution to cool to room temperature, then slowly add 300mL of ice water, followed by dropwise addition of 30% hydrogen peroxide until... Bubbles cease to form in the solution, and the color turns bright yellow. After the reaction solution stands for 12 hours, it is washed three times with 10% hydrochloric acid solution, then washed with deionized water until neutral. After centrifugation at 200 rpm / min for 5 minutes, the graphene oxide is ultrasonically treated (120 W, 30 minutes) to form a graphene oxide suspension. Finally, it is centrifuged at 5000 rpm / min and 10000 rpm / min for 5 minutes, and then ultrasonically dispersed for 1 hour to obtain a uniform and stable GO colloidal dispersion.

[0031] Step 2: Prepare a composite material of reduced graphene oxide fibers and Fe3O4 nanoparticles using an in-situ confined hydrothermal method; 10 mg, 25 mg, and 50 mg of Fe3O4 nanoparticles with a particle size of 20 nm (mass fractions of 5%, 12.5%, and 25%, respectively) were slowly added to a GO colloidal dispersion with a concentration of 6 mg / mL. The mixture was magnetically stirred at 300 rpm for 30 min, followed by ultrasonic treatment at a power of 200 W for 45 min. The solutions were then injected into capillaries with an inner diameter of 1.0 mm using a 1 mL syringe. The ends of the capillaries were then rapidly melted and sealed using an alcohol torch to form a closed, confined reaction space. The sealed capillaries were then placed in a drying oven for hydrothermal reaction at 160 °C for 6 h.

[0032] Step 3: The reduced graphene oxide fiber and Fe3O4 nanoparticle composite material assembled by in-situ confined hydrothermal method is taken out after natural cooling, thus obtaining the reduced graphene oxide fiber confined Fe3O4 nanoparticle composite material with a one-dimensional visco-nano oriented structure.

[0033] Comparative Example 1 See Figure 8-11 As shown, this embodiment provides a method for preparing rGOF-confined Fe3O4 nanoparticle composite materials, including the following steps: Step 1: Weigh out 28g of natural graphite powder, 1.5g of sodium nitrate, and 9g of potassium permanganate. Measure 69mL of concentrated sulfuric acid. Add the graphite powder and sodium nitrate sequentially, and magnetically stir in an ice-water bath until completely dissolved. While continuously stirring, slowly add potassium permanganate powder to the mixture. Seal the container and react for 90 minutes. Remove the ice-water bath, then raise the temperature of the reaction system to 45℃ and stir at this temperature for 2 hours. After the temperature maintenance is complete, allow the solution to cool to room temperature, slowly add 300mL of ice water, and then add 30% hydrogen peroxide dropwise. When water is added to the solution, bubbles stop being produced and the color turns bright yellow. After the reaction solution stands for 12 hours, it is washed three times with 10% hydrochloric acid solution, and then washed with deionized water until neutral. After centrifugation at 200 rpm / min for 5 minutes, the graphene oxide is ultrasonically treated (120W, 30 minutes) to form a graphene oxide suspension. Finally, it is centrifuged at 5000 rpm / min and 10000 rpm / min for 5 minutes respectively, and then ultrasonically dispersed for 1 hour to obtain a uniform and stable GO colloidal dispersion.

[0034] Step 2: Take 50 mg (mass fraction 25%) of Fe3O4 nanoparticles with a particle size of 50 nm and slowly add them to a GO colloidal dispersion with a concentration of 6 mg / mL. Stir magnetically at 300 rpm / min for 30 min, and then sonicate at a power of 200 W for 45 min. Inject the above solution into a capillary tube with an inner diameter of 1.0 mm using a 1 mL syringe. Then, use an alcohol torch to quickly melt and seal both ends of the capillary tube to form a closed, confined reaction space. Place the sealed capillary tube in a drying oven for hydrothermal reaction at a temperature of 160 °C for 6 h.

[0035] Step 3: After natural cooling, the material is removed to obtain rGOF-confined Fe3O4 nanoparticle composite material.

[0036] The experimental comparison data of Examples 2 and 3 are described in detail below: 1) The morphology, structure, and properties of the reduced graphene oxide fiber-confined Fe3O4 nanoparticle composite material from Example 2 were characterized. The results showed that the rGOF fibers exhibited a oriented strip structure, such as... Figure 1 As shown, within its confinement, Fe3O4 nanoparticles were successfully distributed along its axial direction, as... Figure 2 As shown in the black box; Figure 3FTIR characterization showed that the Fe-O characteristic peak (570 cm⁻¹) blue-shifted to 590.1 cm⁻¹, a blue shift exceeding 10 cm⁻¹, indicating a strong covalent bond between Fe and O. XPS characterization showed that the peak position ratio of the C1s spectrum at 285.6 eV increased from 9.81% for rGOF alone to 11.17%, the COC corresponding to O1s increased from 12.22% to 14.79%, and the Fe 2p spectrum showed obvious satellite peaks, such as... Figure 4 , 5 As shown in Figure 6, this further corroborates the Fe-OC covalent bond between Fe3O4 nanoparticles and rGOF. The SQUID test results show that the saturation magnetization of the sample is 19.4 emu / g and the coercivity is 10.9 Oe, indicating that the rGOF-confined Fe3O4 nanoparticle composite material in Example 2 has ferrimagnetism. Under the one-dimensional confinement of rGOF, Fe3O4 nanoparticles form ordered chain-like aggregates, which produce a significant magnetic dipole coupling effect and enhance the magnetic anisotropy of the system.

[0037] 2) The morphology, structure, and properties of the reduced graphene oxide fiber-confined Fe3O4 nanoparticle composite material in Comparative Example 1 were characterized. The results showed that the rGOF nanosheets did not form a oriented fiber nanoribbon structure during hydrothermal synthesis, possibly due to steric hindrance from the Fe3O4 nanoparticles, which limited the ordered and oriented distribution of the GO nanosheets. Figure 8 , 9 As shown, due to the lack of the confinement-inducing effect of the rGOF orientation structure, the distribution of Fe3O4 nanoparticles is random and there is no obvious chain structure. Figure 10 FTIR characterization revealed a Fe-OC characteristic peak at 585.4 eV; XPS characterization showed that the C1s spectrum peak ratio at 285.6 eV increased from 9.81% in the single rGOF to 10.72%, the COC corresponding to O1s increased from 12.22% to 15.05%, and a more obvious satellite peak appeared in the Fe2p spectrum; SQUID test results showed that the saturation magnetization of the sample was 28.8 emu / g and the coercivity was 39 Oe, indicating that the rGOF-confined Fe3O4 nanoparticle composite material in Comparative Example 1 has subferromagnetism, and the ferromagnetic characteristics of the sample are stronger with the increase of Fe3O4 loading.

[0038] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A composite material of reduced graphene oxide fibers confined to Fe3O4 nanoparticles, characterized in that, The composite material consists of reduced graphene oxide fibers with oriented micro-nano strip structures and Fe3O4 nanoparticles confined on the reduced graphene oxide fibers; the Fe3O4 nanoparticles are distributed in an ordered chain-like manner along the axial direction of the reduced graphene oxide fibers; the Fe3O4 nanoparticles and the reduced graphene oxide fibers form a stable interfacial bond through Fe-OC covalent bonds.

2. The reduced graphene oxide fiber-confined Fe3O4 nanoparticle composite material according to claim 1, characterized in that, The Fe3O4 nanoparticles have a particle size of no more than 50 nm.

3. The reduced graphene oxide fiber-confined Fe3O4 nanoparticle composite material according to claim 1, characterized in that, The mass fraction of Fe3O4 nanoparticles relative to reduced graphene oxide fibers in the composite material is controlled at 25% or less.

4. The reduced graphene oxide fiber-confined Fe3O4 nanoparticle composite material according to claim 1, characterized in that, The diameter of the reduced graphene oxide fibers is 55-90 μm.

5. The method for preparing a reduced graphene oxide fiber-confined Fe3O4 nanoparticle composite material according to claim 1, characterized in that, Includes the following steps: Step 1: Prepare graphene oxide colloids using the modified Hummers method; Step 2: Prepare a composite material of reduced graphene oxide fibers and Fe3O4 nanoparticles using an in-situ confined hydrothermal method; Step 3: The reduced graphene oxide fiber and Fe3O4 nanoparticle composite material assembled by in-situ confined hydrothermal method is taken out after natural cooling, thus obtaining the reduced graphene oxide fiber confined Fe3O4 nanoparticle composite material with a one-dimensional visco-nano oriented structure.

6. The method for preparing a reduced graphene oxide fiber-confined Fe3O4 nanoparticle composite material according to claim 5, characterized in that, The concentration of graphene oxide colloid in step 1 is 4-10 mg / mL.

7. The method for preparing a reduced graphene oxide fiber-confined Fe3O4 nanoparticle composite material according to claim 5, characterized in that, In step 2, the in-situ confined hydrothermal method used a magnetic stirring parameter of 200-500 rpm / min for a mixture of graphene oxide colloid and Fe3O4 nanoparticles, and a time of 20-60 min; the ultrasonic power was 200 W for a time of 45 min.

8. The method for preparing a reduced graphene oxide fiber-confined Fe3O4 nanoparticle composite material according to claim 5, characterized in that, In step 2, the in-situ confined hydrothermal method uses a hydrothermal reaction temperature of 120-200℃, a reaction time of 2-8h, and a reactor inner diameter of 0.5-1.

0.

9. The application of the reduced graphene oxide fiber confined Fe3O4 nanoparticle composite material prepared by any one of claims 6 to 8 in the preparation of magnetic resonance imaging contrast agents, magnetically targeted drug delivery carriers, photothermal therapy agents, magnetothermal therapy agents, tissue engineering scaffold materials, electromagnetic wave absorbing materials, electromagnetic shielding materials, or radar stealth materials.

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