Composite material based on Fe3O4 nano-particles as carrier as well as preparation method and application of composite material

Abstract

The invention discloses a composite material based on Fe3O4 nanoparticles as a carrier, and a preparation method and application thereof, and relates to the technical field of functional materials and aging monitoring, the composite material comprises a carrier, a fluorescent probe and a free radical scavenger; the carrier is a Fe3O4 nano particle (PEI coated Fe3O4) modified by polyethyleneimine (PEI); the fluorescent probe is a pH alkali response type LGBDP fluorescent probe; the free radical trapping agent is 4-oxygen-TEMPO (tetramethylpiperidinooxy); the LGBDP fluorescent probe and 4-oxygen-TEMPO are sequentially bonded on the surface of the PEI (at) Fe3O4 through a Schiff base reaction, so that an LGBDP-PEI (at) Fe3O4-TEMPO aging probe is formed; the composite material is a composite system formed by blending the aging probe and a polymer base material. The composite material has the characteristics of real-time property, non-destructive property and high sensitivity, can track the aging process of 0-312 hours, can intuitively reflect the aging stage by the change of fluorescence intensity, is suitable for various high polymer materials such as PLA, and can adapt to different monitoring requirements by adjusting the mass fraction of the probe.

Description

Technical Field

[0001] This invention relates to the field of functional materials and aging monitoring technology, specifically to composite materials based on Fe3O4 nanoparticles as carriers, their preparation methods, and their applications. Background Technology

[0002] Under the influence of environmental factors such as heat, light, oxidation, and radiation, the microstructure of polymer materials gradually deteriorates, leading to performance degradation and shortened service life. Traditional aging monitoring methods struggle to achieve real-time, non-destructive, and highly sensitive comprehensive monitoring, failing to simultaneously acquire key information such as microstructural changes and free radical evolution during the aging process, thus limiting in-depth research into aging mechanisms.

[0003] Functionalized magnetic nanoparticles, due to their unique magnetic and optical properties and tunable surface chemistry, have shown great potential in the field of multimodal monitoring. Fe3O4 nanoparticles, with their high magnetic susceptibility and superparamagnetism, can serve as excellent carriers for magnetic resonance imaging (MRI); fluorescent probes can intuitively reflect changes in the microenvironment through signal variations; and paramagnetic resonance imaging (EPR) can reveal the generation and evolution of free radicals. Integrating the functions of these three technologies to construct multimodal responsive composite materials is an effective way to solve the challenges of monitoring the aging of polymer materials.

[0004] Based on this, the present invention designs a composite material using PEI-modified Fe3O4 nanoparticles as a carrier, which is bonded to a pH-responsive fluorescent probe and a free radical scavenger. Through the synergistic effect of multimodal imaging, it achieves comprehensive monitoring of the aging process of polymer materials. Summary of the Invention

[0005] To address the shortcomings of existing polymer material aging monitoring methods that cannot acquire multi-dimensional aging information in real time, non-destructively, and with high sensitivity, this invention provides a composite material based on Fe3O4 nanoparticles as a carrier, its preparation method, and its application.

[0006] Composite materials based on Fe3O4 nanoparticles as supports include supports, fluorescent probes, and free radical scavengers;

[0007] The carrier is Fe3O4 nanoparticles modified with polyethyleneimine (PEI) (PEI@Fe3O4); the fluorescent probe is a pH-responsive LGBDP fluorescent probe.

[0008] The free radical scavenger is 4-oxy-TEMPO;

[0009] The LGBDP fluorescent probe and 4-oxygen-TEMPO are sequentially bonded to the surface of PEI@Fe3O4 via a Schiff base reaction to form an LGBDP-PEI@Fe3O4-TEMPO aged probe.

[0010] The composite material is a composite system formed by blending the aging probe with a polymer substrate.

[0011] As a further aspect of the present invention, the polymer substrate is polylactic acid (PLA); the mass fraction of the aging probe in the composite material is 0.1% to 10.0%.

[0012] The preparation method of composite materials based on Fe3O4 nanoparticles as carriers includes the following steps:

[0013] Preparation of S1 and LGBDP-PEI@Fe3O4: Weigh 300 mg (1 eq) of LGBDP and 420 mg (2 eq) of PEI@Fe3O4, add them to a 100 mL single-necked round-bottom flask, add 10 mL of tetrahydrofuran as a solvent, add 40 mL of anhydrous methanol as a solvent, and add 5 mL of glacial acetic acid as a catalyst; heat to reflux under N2 protection, react for 24 h, centrifuge, discard the supernatant, wash three times each with tetrahydrofuran and dichloromethane, and dry under vacuum to obtain solid LGBDP-PEI@Fe3O4;

[0014] Preparation of S2 and LGBDP-PEI@Fe3O4-TEMPO aging probe: Weigh 300 mg of dried LGBDP-PEI@Fe3O4 and 132 mg of 4-oxy-TEMPO, dissolve them in 25 mL of anhydrous methanol, add 2 mL of glacial acetic acid as a catalyst; heat to reflux under N2 protection, react for 24 h, centrifuge, discard the supernatant, wash with dichloromethane until the supernatant is colorless, and vacuum dry to obtain LGBDP-PEI@Fe3O4-TEMPO solid powder;

[0015] S3. Preparation of composite material products: Weigh LGBDP-PEI@Fe3O4-TEMPO aging probe and polymer substrate at a mass fraction of 0.1%~10.0%, add an appropriate amount of dichloromethane and shake thoroughly to dissolve and prepare composite material sample solution; use the pressing method to make composite material discs or other molded products.

[0016] As a further aspect of the present invention, the polymer substrate mentioned in step S3 is polylactic acid (PLA), and the mass ratio of the aging probe to PLA is as follows: 8.0 mg: 7992.0 mg, 40.0 mg: 7960.0 mg, 80.0 mg: 7920.0 mg, 400.0 mg: 7600.0 mg, and 800.0 mg: 7200.0 mg, which correspond to mass fractions of 0.1%, 0.5%, 1.0%, 5.0%, and 10.0%, respectively.

[0017] As a further aspect of the present invention, a multimodal real-time monitoring method for the aging process of polymer materials is provided, wherein the multimodal monitoring includes coordinated monitoring by fluorescence imaging (FI), magnetic resonance imaging (MRI), and paramagnetic resonance imaging (EPR).

[0018] As a further aspect of the present invention, the monitoring process includes:

[0019] Using a fluorescence imager with an excitation wavelength of 440 nm and a filter wavelength of 535 nm, the changes in fluorescence intensity during the aging process of composite materials were detected.

[0020] Using a magnetic resonance imaging system, with ExpressHeadNeckArray-CspineArray coils and OSagT2FlexFRFSE-DNE sequence, coronal scanning imaging of composite materials was performed. The scan slice thickness was 0.7 mm, the interslice spacing was 0.0 mm, TR was 2236.0, and TE was 68.0.

[0021] By observing the trend of fluorescence intensity decreasing, increasing, and then decreasing again, along with changes in magnetic resonance imaging signals, and combining this with the evolution of free radicals revealed by paramagnetic resonance imaging, we can achieve real-time tracking and mechanism analysis of the aging process.

[0022] As a further aspect of the present invention, the polymer material is polylactic acid (PLA), and the aging time monitoring range is 0~312h.

[0023] The present invention achieves the following beneficial effects compared to the prior art:

[0024] 1. Achieve multimodal collaborative monitoring: Integrate the advantages of fluorescence imaging, magnetic resonance imaging, and paramagnetic resonance imaging to make up for the shortcomings of single monitoring methods and comprehensively acquire aging information.

[0025] 2. Excellent monitoring performance: It features real-time, non-destructive and high sensitivity, and can track the aging process from 0 to 312 hours. The changes in fluorescence intensity directly reflect the aging stage.

[0026] 3. Mechanism Exploration Value: By correlating free radical capture with signal response, it provides molecular-level evidence for the study of aging mechanisms of polymer materials.

[0027] 4. Wide range of applications: Applicable to various polymer materials such as PLA, and can be adapted to different monitoring needs by adjusting the probe mass fraction. Attached Figure Description

[0028] Figure 1 Schematic diagram of the preparation process of LGBDP-PEI@Fe3O4-TEMPO;

[0029] Figure 2Fluorescence imaging of PLA discs doped with different mass fractions of aging probes as aging time (0~312h).

[0030] Figure 3 : Curves showing the change in fluorescence intensity of PLA discs aged with 0.5% and 1.0% mass fraction probes over aging time;

[0031] Figure 4 Magnetic resonance imaging (MRI) images of PLA discs doped with different mass fractions of aging probes as aging time (0~312h). Detailed Implementation

[0032] 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.

[0033] Example 1: Preparation of LGBDP-PEI@Fe3O4

[0034] Weigh 300 mg (1 eq) of LGBDP and 420 mg (2 eq) of PEI@Fe3O4 into a 100 mL single-necked round-bottom flask. First, add 10 mL of tetrahydrofuran and stir to aid dissolution, then add 40 mL of anhydrous methanol as the reaction solvent, and slowly add 5 mL of glacial acetic acid as the catalyst. Place the reaction system under a N2 protective atmosphere and heat to reflux, maintaining this temperature for 24 h. After the reaction is complete, centrifuge (8000 r / min, 10 min) to discard the supernatant. Wash the sample three times each with tetrahydrofuran and dichloromethane, centrifuging after each wash. Finally, dry the precipitate in a vacuum drying oven (60 °C, 12 h) to obtain LGBDP-PEI@Fe3O4 solid.

[0035] Example 2: Preparation of LGBDP-PEI@Fe3O4-TEMPO aging probe

[0036] Weigh 300 mg of the dried LGBDP-PEI@Fe3O4 prepared in Example 1 and 132 mg of 4-oxy-TEMPO, and add them together to 25 mL of anhydrous methanol. After stirring and dissolving, add 2 mL of glacial acetic acid as a catalyst. Heat the reaction system to reflux under N2 protection and continue the reaction for 24 h. After the reaction is complete, centrifuge (8000 r / min, 10 min) and discard the supernatant. Wash repeatedly with dichloromethane and centrifuge until the supernatant is colorless. Place the obtained solid powder in a vacuum drying oven (60 °C, 12 h) to dry, and obtain the LGBDP-PEI@Fe3O4-TEMPO aged probe.

[0037] Example 3: Preparation of LGBDP-PEI@Fe3O4-TEMPO / PLA composite discs

[0038] Weigh the raw materials according to the following mass ratios:

[0039] 0.1% mass fraction: 8.0 mg aging probe + 7992.0 mg PLA

[0040] 0.5% mass fraction: 40.0 mg aging probe + 7960.0 mg PLA

[0041] 1.0% mass fraction: 80.0 mg aging probe + 7920.0 mg PLA

[0042] 5.0% mass fraction: 400.0 mg aging probe + 7600.0 mg PLA

[0043] 10.0% mass fraction: 800.0 mg aging probe + 7200.0 mg PLA

[0044] Add each set of raw materials to a glass bottle, add an appropriate amount of dichloromethane, and shake thoroughly to completely dissolve the raw materials, thus preparing a homogeneous composite material sample solution. Use a tableting method (pressure 10 MPa, holding pressure for 5 min) to prepare composite material discs for later use.

[0045] Example 4: Multimodal monitoring experiment of composite material aging

[0046] Fluorescence imaging experiment: The FusionFX7Edge chemiluminescence imager from VIBER Bioimaging was used to detect the fluorescence intensity of composite discs with different aging times (0h, 8h, 16h, 24h, 48h, 72h, 120h, 168h, 240h, 312h) using 440nm as the excitation wavelength and 535nm as the filter wavelength, and the changes in fluorescence signal were recorded.

[0047] Magnetic resonance imaging experiment: The Optima MR360 magnetic resonance imaging system from General Electric (GE) was used, equipped with an ExpressHeadNeckArray-CspineArray coil. The OSagT2FlexFRFSE-DNE sequence was used to scan the coronal position of the composite disc. The scanning parameters were set as follows: slice thickness 0.7 mm, slice spacing 0.0 mm, TR 2236.0, TE 68.0. The changes in magnetic resonance imaging signals at different aging stages were recorded.

[0048] Results analysis: As the aging time increases, the fluorescence intensity of the composite material exhibits a characteristic change of "first decreasing, then increasing, and then decreasing again". The magnetic resonance imaging signal gradually changes with the deterioration of the microstructure. Combined with the free radical evolution data obtained by paramagnetic resonance imaging, the aging process can be fully tracked and the aging mechanism can be clarified.

[0049] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A composite material based on Fe3O4 nanoparticles as a carrier, characterized in that, Includes carriers, fluorescent probes, and free radical scavengers; The carrier is Fe3O4 nanoparticles modified with polyethyleneimine (PEI) (PEI@Fe3O4); the fluorescent probe is a pH-responsive LGBDP fluorescent probe. The free radical scavenger is 4-oxy-TEMPO; The LGBDP fluorescent probe and 4-oxygen-TEMPO are sequentially bonded to the surface of PEI@Fe3O4 via a Schiff base reaction to form an LGBDP-PEI@Fe3O4-TEMPO aged probe. The composite material is a composite system formed by blending the aging probe with a polymer substrate.

2. The composite material according to claim 1, characterized in that, The polymer substrate is polylactic acid (PLA); the mass fraction of the aging probe in the composite material is 0.1%~10.0%.

3. A method for preparing the composite material as described in claim 1 or 2, characterized in that, Includes the following steps: Preparation of S1 and LGBDP-PEI@Fe3O4: Weigh 300 mg (1 eq) of LGBDP and 420 mg (2 eq) of PEI@Fe3O4, add them to a 100 mL single-necked round-bottom flask, add 10 mL of tetrahydrofuran as a solvent, add 40 mL of anhydrous methanol as a solvent, and add 5 mL of glacial acetic acid as a catalyst; heat to reflux under N2 protection, react for 24 h, centrifuge, discard the supernatant, wash three times each with tetrahydrofuran and dichloromethane, and dry under vacuum to obtain solid LGBDP-PEI@Fe3O4; Preparation of S2 and LGBDP-PEI@Fe3O4-TEMPO aging probe: Weigh 300 mg of dried LGBDP-PEI@Fe3O4 and 132 mg of 4-oxy-TEMPO, dissolve them in 25 mL of anhydrous methanol, add 2 mL of glacial acetic acid as a catalyst; heat to reflux under N2 protection, react for 24 h, centrifuge, discard the supernatant, wash with dichloromethane until the supernatant is colorless, and vacuum dry to obtain LGBDP-PEI@Fe3O4-TEMPO solid powder; S3. Preparation of composite material products: Weigh LGBDP-PEI@Fe3O4-TEMPO aging probe and polymer substrate at a mass fraction of 0.1%~10.0%, add an appropriate amount of dichloromethane and shake thoroughly to dissolve and prepare composite material sample solution; use the pressing method to make composite material discs or other molded products.

4. The preparation method according to claim 3, characterized in that, The polymer substrate mentioned in step S3 is polylactic acid (PLA), and the mass ratio of aging probe to PLA is as follows: 8.0 mg: 7992.0 mg, 40.0 mg: 7960.0 mg, 80.0 mg: 7920.0 mg, 400.0 mg: 7600.0 mg, and 800.0 mg: 7200.0 mg, which correspond to mass fractions of 0.1%, 0.5%, 1.0%, 5.0%, and 10.0%, respectively.

5. An application of the composite material as described in claim 1 or 2, characterized in that, This is used for multimodal real-time monitoring of the aging process of polymer materials, including the coordinated monitoring of fluorescence imaging (FI), magnetic resonance imaging (MRI), and paramagnetic resonance imaging (EPR).

6. The application according to claim 5, characterized in that, The monitoring process includes: Using a fluorescence imager with an excitation wavelength of 440 nm and a filter wavelength of 535 nm, the changes in fluorescence intensity during the aging process of composite materials were detected. Using a magnetic resonance imaging system, with ExpressHeadNeckArray-CspineArray coils and OSagT2FlexFRFSE-DNE sequence, coronal scanning imaging of composite materials was performed. The scan slice thickness was 0.7 mm, the interslice spacing was 0.0 mm, TR was 2236.0, and TE was 68.

0. By observing the trend of fluorescence intensity decreasing, increasing, and then decreasing again, along with changes in magnetic resonance imaging signals, and combining this with the evolution of free radicals revealed by paramagnetic resonance imaging, we can achieve real-time tracking and mechanism analysis of the aging process.

7. The application according to claim 5 or 6, characterized in that, The polymer material is polylactic acid (PLA), and the aging time monitoring range is 0~312h.

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