Self-assembly ferritin light nano reactor and preparation method thereof

Abstract

The invention is applicable to the technical field of nano materials, and provides a self-assembled ferritin optical nano reactor and a preparation method thereof. According to the invention, ferritin is used as a construction element, eosin Y (EY) is modified on the surface of ferritin through covalent interaction, then two cationic carbon quantum dots (CD1 and CD2) are introduced by utilizing electrostatic interaction, a cascade fluorescence resonance energy transfer (FRET) system is constructed, and capture and directional transfer of ultraviolet-visible wide-spectrum light energy are realized. On the basis of the system, a self-assembled ferritin light nano-reactor (CDs-EY at Fn) is designed and constructed, light energy is collected by integrating an artificial light capture system (CD1 / CD2), a photocatalytic reaction model is introduced, and efficient conversion from light energy to chemical energy is realized. The device has the characteristics of bionic controllability, efficient conversion and environment friendliness, and provides a new strategy and a new thought for light-driven energy conversion (such as hydrogen evolution reaction), environmental governance and artificial photosynthetic system design.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterials, and in particular relates to a self-assembled ferritin photonanoreactor and a preparation method thereof. Background Art

[0002] Energy is the cornerstone of human development. Its sustainable transformation not only profoundly impacts ecological balance but also the survival of human civilization and the realization of an environmentally friendly future. With the rapid development of industrialization, the energy crisis has become increasingly severe. Due to its clean and renewable properties, the utilization and conversion of solar energy has attracted widespread attention from scientists. Photonanoreactors offer promising research prospects by combining the photosensitivity of nanomaterials with the efficient mass transfer characteristics of microreactors to drive light energy conversion and material transformation. Guided by the global energy transition and carbon neutrality goals, photonanoreactors have demonstrated unique advantages in synthetic chemistry, CO2 reduction, and pollutant degradation. However, in practical applications, photonanoreactors face multiple challenges, including low light absorption efficiency (e.g., conventional catalysts such as TiO2 can only utilize ultraviolet light), high charge recombination rates leading to energy loss, poor material stability (e.g., degradation or corrosion), environmental toxicity (e.g., heavy metals or non-degradable materials), high cost (e.g., reliance on precious metals), and limited interfacial mass transfer.

[0003] The natural photosynthetic system is a sophisticated energy conversion network. Plants, algae, and other organisms efficiently convert solar energy into chemical energy through the electron transport chain of Photosystem II / I and the enzyme-confined catalysis of the Calvin cycle. This mechanism offers advantages such as broad spectral absorption, targeted energy transfer, and micro-regional control of reactions. This system is a core driver of the global carbon-oxygen cycle and a cornerstone of ecological balance. Inspired by this, substantial progress has been made in efficiently converting solar energy through approaches such as biomimetic structures and the design of broad-spectrum absorber materials.

[0004] In view of the above-mentioned problems existing in existing photo-nanoreactors, in order to break through the technical bottleneck, the present invention proposes a self-assembled ferritin photo-nanoreactor and a preparation method thereof. Summary of the Invention

[0005] The purpose of the present invention is to provide a self-assembled ferritin photo-nanoreactor and a preparation method thereof, aiming to solve the problems raised in the above background technology.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A self-assembled ferritin photo-nanoreactor, comprising:

[0008] Ferritin serves as an assembly template;

[0009] Eosin Y is covalently anchored to the surface of ferritin to form an EY@Fn complex;

[0010] Cationic carbon quantum dots CD1 and CD2 self-assemble with EY@Fn through electrostatic interactions to construct a cascade fluorescence resonance energy transfer system, denoted as CDs-EY@Fn, to achieve the directional transfer of light energy from CD1→CD2→eosin Y.

[0011] Furthermore, the ferritin is wild-type human heavy chain ferritin.

[0012] Furthermore, the Eosin Y is modified on the surface of ferritin through amino-directed covalent coupling.

[0013] Furthermore, the cationic carbon quantum dots CD1 and CD2 correspond to blue-violet and blue luminescence characteristics, respectively.

[0014] Furthermore, the assembly ratio of the photo-nanoreactor is Fn:CD1:CD2=1:10:3, and the total concentration C (Fn / CDs) =0.1 mg / mL, self-assembled by electrostatic complementation at pH 6.0.

[0015] A method for preparing the self-assembled ferritin photo-nanoreactor according to the above-mentioned method comprises the following steps:

[0016] A ferritin solution with a final concentration of 1 mg / mL was dialyzed against 10 μL of a 1 mg / mL eosin Y solution in Tris-HCl buffer at pH 6.0 to form an EY@Fn complex via amino-directed covalent coupling, preserving the cage-like structure;

[0017] Cationic carbon quantum dots CD1 and CD2 were synthesized by hydrothermal method;

[0018] At pH 6.0, CD1, CD2 and EY@Fn were mixed in the ratio of Fn:CD1:CD2=1:10:3, and self-assembled to form CDs-EY@Fn through electrostatic complementarity.

[0019] An application of the self-assembled ferritin photonanoreactor described above in a photocatalytic reaction, wherein the self-assembled ferritin photonanoreactor is used as a catalyst and placed in an aqueous reaction system containing benzothiazole and diphenylphosphine oxide. Under ultraviolet-visible light excitation, light energy is enriched to the EY active center through cascade fluorescence resonance energy transfer, driving a cross-coupling reaction accompanied by hydrogen evolution.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention uses ferritin as a building block, modifying its surface with eosin Y (EY) through covalent interactions. Electrostatic interactions are then used to introduce two cationic carbon quantum dots (CD1 and CD2, blue and blue, respectively), creating a cascade fluorescence resonance energy transfer (FRET) system that captures and directionally transfers UV-visible broad-spectrum light energy (with an energy transfer efficiency of 61%). Based on this system, a self-assembled ferritin photonanoreactor (CDs-EY@Fn) was designed and constructed. This system collects light energy through an integrated artificial light-harvesting system (CD1 / CD2) and introduces a photocatalytic reaction model (e.g., an aqueous system containing benzothiazole and diphenylphosphine oxide). This enriches light energy to the EY active center via a cascade FRET (CD1→CD2→EY) reaction, driving a cross-coupling reaction accompanied by hydrogen evolution. This results in a highly efficient conversion of light energy to chemical energy, with a photocatalytic yield of 74.68%. The present invention utilizes the natural cage structure of ferritin as an assembly template, and completes the cascade energy transfer design and photocatalytic function integration through covalent modification (EY) and electrostatic self-assembly (CD1 / CD2) technology. It has the characteristics of bionic controllability, efficient conversion and environmental friendliness, and provides new strategies and new ideas for light-driven energy conversion (such as hydrogen evolution reaction), environmental governance and artificial photosynthetic system design. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The morphology of CDs-EY@Fn is characterized; (a) is the transmission electron microscope image of CDs-EY@Fn; (b) is the particle size distribution diagram of CDs-EY@Fn; (c) is the elemental analysis diagram of CDs-EY@Fn.

[0023] Figure 2 Schematic diagram of CDs-EY@Fn and its catalytic reaction.

[0024] Figure 3 Figure 3 is the performance of the one-step energy transfer artificial light harvesting system; (a) is the FRET fluorescence spectrum between CD1 and CD2 in CDs-Fn; (b) is the fluorescence lifetime decay curve of the donor CD1 in CDs-Fn; (c) is the energy transfer efficiency under different CD2 ratios; (d) is the antenna effect value of CDs-Fn under different CD2 ratios.

[0025] Figure 4 Figure 2 shows the performance of the two-step energy transfer artificial light harvesting system; (a) is the FRET fluorescence spectrum between CD1, CD2, and EY in CDs-EY@Fn; (b) is the fluorescence lifetime decay curve of the donor CD1 in CDs-EY@Fn; (c) is the energy transfer efficiency of CDs-EY@Fn at different EY ratios; (d) is the antenna effect value of CDs-EY@Fn at different EY ratios.

[0026] Figure 5The potential diagram and particle size distribution diagram of the EY@Fn complex; (a) is the potential diagram of the EY@Fn complex; (b) is the particle size distribution diagram of the EY@Fn complex.

[0027] Figure 6 Transmission electron microscope image and potential diagram of cationic carbon quantum dot CD1; (a) is the transmission electron microscope image of CD1; (b) is the potential diagram of CD1.

[0028] Figure 7 Transmission electron microscope image and potential diagram of cationic carbon quantum dots CD2; (a) is the transmission electron microscope image of CD2; (b) is the potential diagram of CD2.

[0029] Figure 8 Mechanism diagram of photocatalytic hydrogen production reaction. DETAILED DESCRIPTION

[0030] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0031] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0032] Figure 2 The overall design concept of the present invention is demonstrated.

[0033] Example 1: Preparation of self-assembled ferritin photonanoreactor CD1-CD2-EY@Fn (abbreviated as CDs-EY@Fn, where CDs represents CD1 and CD2);

[0034] Step 1: Preparation of EY@Fn complex;

[0035] Using wild-type human heavy chain ferritin (Fn) as a template, eosin Y (EY) was modified on the ferritin surface by amino-directed covalent coupling to form EY@Fn complex, which retained its cage-like structure (particle size of 12.54 nm, Zeta potential of -15.8 mV, as shown in Figure 5). Figure 5 The specific operation is as follows: prepare a Fn solution with a final concentration of 1 mg / mL, add 10 μL of 1 mg / mL Eosin Y solution, and dialyze in Tris-HCl buffer at pH 6.0 to prepare EY@Fn.

[0036] Step 2: Synthesis of cationic carbon quantum dots (CD1 and CD2);

[0037] Two cationic carbon quantum dots (CD1 and CD2, with particle sizes of 2.1 nm and 2.5 nm, and Zeta potentials of +10.3 mV and +15.0 mV, respectively, are synthesized by hydrothermal method. They are blue-purple and blue carbon dots, respectively. Figure 6 and Figure 7 shown).

[0038] Synthesis of CD1: 600 mg of AM, 30 mg of MBA, and 60 mg of KPS were added to 20 mL of deionized water, mixed thoroughly, and dissolved. The resulting solution was transferred to a polytetrafluoroethylene-lined container, then transferred to a reactor, tightened, and placed in a 200°C oven for 8 h. After the reaction was complete, the oven was closed and the reaction mixture was allowed to cool naturally to room temperature. The synthesized carbon dots were transparent and light brown in solution. The solution was then filtered through a 0.22 μm syringe filter, and the filtrate was dialyzed (with deionized water, the dialysate was changed every 6 h, and the molecular weight of the dialysis bag was 3500 Da). After 48 h, the dialyzed liquid was collected and lyophilized in a lyophilization vial. The lyophilized carbon dots were white solids and stored in a refrigerator at 4°C until use.

[0039] Synthesis of CD2: 1 mL of PEI (20 mmol / L) was dissolved in 19 mL of deionized water and mixed thoroughly. The mixture was then transferred to a matching high-pressure reactor lined with polytetrafluoroethylene. The reactor was placed in an oven at 160°C and heated for 10 h. The reactor was then cooled to room temperature. The synthesized carbon dot solution was dialyzed using deionized water as the dialysate and a dialysis bag with a molecular cutoff of 10,000 Da. The dialysate was replaced every 8 h. After 48 h, the carbon dot solution (light yellow) was collected and freeze-dried. The freeze-dried carbon dots were sealed and stored in a refrigerator at 4°C.

[0040] Step 3: three-component self-assembly;

[0041] CD1, CD2 and EY@Fn were self-assembled in proportion at pH 6.0 by electrostatic complementation to complete the preparation of CDs-EY@Fn. The assembly ratio was selected as Fn:CD1:CD2=1:10:3, C (Fn / CDs) =0.1 mg / mL (In this case, only Fn concentration was considered in the assembly, so only Fn was used to represent it).

[0042] Example 2: Characterization of the structure and energy transfer performance of CDs-EY@Fn;

[0043] 2.1 Structural characterization;

[0044] TEM results show that ( Figure 1 In (a), CDs-EY@Fn exhibits a highly monodisperse spherical morphology with an average diameter of 650.00 nm, and distinct units with different contrasts can be clearly observed, confirming a multi-level self-assembly process driven by electrostatic interactions. The particle size of CDs-EY@Fn measured by DLS is 649.10 nm, which is consistent with the TEM results ( Figure 1In order to verify the multi-component integration characteristics of CDs-EY@Fn, elemental analysis was performed and the results showed that ( Figure 1 In (c), C, O, N, and S elements are evenly distributed in CDs-EY@Fn. This is because the three primitives that constitute CDs-EY@Fn all contain rich C, O, and N elements, while S element only exists in Fn and its content is relatively low. Therefore, sulfur element is not obvious compared with the other three elements. This fully proves that CDs-EY@Fn is indeed composed of three primitives.

[0045] 2.2 Characterization of energy transfer performance;

[0046] To verify the efficiency of cascade energy transfer, fluorescence spectroscopy and lifetime decay experiments were carried out:

[0047] (1) Construct a one-step energy transfer light harvesting system, where energy is transferred from CD1 to CD2. In the fluorescence spectrum ( Figure 3 In (a), as the CD2 concentration increases (the CD1 / CD2 ratio changes), it can be observed that the fluorescence intensity of the CD1 emission peak at 380nm has a significant downward trend, while the CD2 emission peak at 460nm begins to appear and the fluorescence intensity continues to increase. Fluorescence lifetime decay experiment ( Figure 3 Figure (b) shows that the average lifetime of CD1 bound to Fn alone is 5.23ns. After the addition of CD2 (CDs-Fn, CD1:CD2=100:30), the average lifetime of CD1 decays to 3.27ns. ET ) and antenna effect value (AE) to evaluate the performance of the light harvesting system, such as Figure 3 As shown in (c), when CD1:CD2=100:30, the energy transfer efficiency reaches the maximum value of 40%. Figure 3 As shown in (d), when CD1:CD2=100:5, the antenna effect value is 10.3, which is the maximum value in the process.

[0048] (2) Construct a two-step energy transfer artificial light harvesting system, where energy is transferred from CD1 to CD2 and finally to EY. Figure 4 In (a), as the ratio of CD1 / CD2 / EY changes, the fluorescence intensity of CD1 at 380nm decreases, and the fluorescence intensity of CD2 at 460nm also decreases. At the same time, the characteristic peak of EY at 545nm appears and the fluorescence intensity gradually increases. Fluorescence lifetime decay experiment ( Figure 4Figure (b) shows that when EY is added, the average lifetime of CD1 in CDs-EY@Fn is significantly attenuated. When CD1:CD2:EY=100:30:5, it is reduced to 2.53ns. When EY is continuously added to CD1:CD2:EY=100:30:20, the lifetime is further reduced to 1.12ns. In addition, the energy transfer efficiency (Φ ET ) and antenna effect value (AE) to evaluate the performance of the light harvesting system, such as Figure 4 As shown in (c), when CD1:CD2:EY=100:30:20, the Φ of the system ET The highest value can reach 61%; Figure 4 As shown in (d), the maximum AE value of 18.3 was obtained when CD1:CD2:EY=100:30:15.

[0049] Example 2: Photocatalytic application of CDs-EY@Fn;

[0050] In the photocatalytic hydrogen production reaction, CDs-EY@Fn was used as a catalyst and placed in an aqueous reaction system containing benzothiazole and diphenylphosphine oxide. The photocatalytic hydrogen production reaction was carried out by a xenon lamp light source (simulating sunlight with an irradiation intensity of 100 mW / cm 2 ) stimulates its broad spectrum light harvesting capability (UV-visible region); light energy is enriched to the EY active center via cascade fluorescence resonance energy transfer (CD1→CD2→EY), driving the cross-coupling reaction accompanied by hydrogen evolution (reaction mechanism as shown in Figure 8 As shown), after 16 hours of reaction, the nuclear magnetic hydrogen spectrum ( 1 H NMR was used to quantitatively analyze the product yield. Simultaneously, EY monomer photocatalysis, a multi-stage biomimetic light harvesting system, and a series of control experiments were set up. The specific conditions and results are as follows:

[0051] Table 1 Photocatalytic activity of CDs-EY@Fn and other control groups

[0052]

[0053]

[0054] Experimental data showed that after 16 hours of photoreaction kinetics tracking, the CDs-EY@Fn biomimetic catalytic system achieved a product yield of 74.68%, which was about 4 times higher than the EY single component system (18.70%), fully verifying the superiority of the two-step energy transfer network.

[0055] in conclusion:

[0056] The present invention is based on the design concept of biomimetic photosynthetic system, and uses the natural cage structure (24-mer, negative surface charge) of ferritin (Fn) as an assembly template. The photosensitive catalyst Eosin Y (EY) is anchored to the Fn surface by covalent modification to construct a reaction center, and two cationic carbon quantum dots (CD1 and CD2) are introduced as light-harvesting antennas. The electrostatic complementarity is used to drive the three components (CD1, CD2, EY@Fn) to self-assemble under pH 6.0, adjust the ratio of fluorescent chromophores, and realize ultraviolet-visible broadband absorption (CD1→CD2→EY) and directional energy transfer (efficiency 61%) through fluorescence resonance energy transfer (FRET), and finally the enriched light energy is used to catalyze cross-coupling hydrogen evolution and other reactions. The present invention combines dynamic light scattering (DLS), transmission electron microscopy (TEM) and fluorescence lifetime decay experiments to verify the assembly structure and energy transfer path, and uses nuclear magnetic hydrogen spectrum ( 1 H NMR) confirmed that its catalytic yield (74.68%) was significantly better than that of the traditional system. It has the characteristics of bionic controllability, efficient conversion and environmental friendliness, and is suitable for the fields of light-driven energy conversion and environmental governance.

[0057] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the concept of the present invention. These should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A self-assembled ferritin photo-nanoreactor, characterized in that: include: Ferritin serves as an assembly template; Eosin Y is covalently anchored to the surface of ferritin to form an EY@Fn complex; Cationic carbon quantum dots CD1 and CD2 self-assemble with EY@Fn through electrostatic interactions to construct a cascade fluorescence resonance energy transfer system, denoted as CDs-EY@Fn, to achieve the directional transfer of light energy from CD1→CD2→eosin Y.

2. The self-assembled ferritin photo-nanoreactor according to claim 1, characterized in that The ferritin is wild-type human heavy chain ferritin.

3. The self-assembled ferritin photo-nanoreactor according to claim 1, characterized in that The Eosin Y is modified on the surface of ferritin through amino-directed covalent coupling.

4. The self-assembled ferritin photo-nanoreactor according to claim 1, characterized in that The cationic carbon quantum dots CD1 and CD2 correspond to blue-violet and blue luminescence characteristics, respectively.

5. The self-assembled ferritin photo-nanoreactor according to claim 1, characterized in that The assembly ratio of the photo-nanoreactor is Fn:CD1:CD2=1:10:3, and the total concentration C (Fn / CDs) =0.1 mg / mL, self-assembled by electrostatic complementation at pH 6.

0.

6. A method for preparing the self-assembled ferritin photo-nanoreactor according to any one of claims 1 to 5, characterized in that: The following steps are involved: A ferritin solution with a final concentration of 1 mg / mL was dialyzed against 10 μL of a 1 mg / mL eosin Y solution in Tris-HCl buffer at pH 6.0 to form an EY@Fn complex via amino-directed covalent coupling, preserving the cage-like structure; Cationic carbon quantum dots CD1 and CD2 were synthesized by hydrothermal method; At pH 6.0, CD1, CD2 and EY@Fn were mixed in the ratio of Fn:CD1:CD2=1:10:3, and self-assembled to form CDs-EY@Fn through electrostatic complementarity.

7. Use of the self-assembled ferritin photo-nanoreactor according to any one of claims 1 to 5 in a photocatalytic reaction, characterized in that: The self-assembled ferritin photonanoreactor was used as a catalyst and placed in an aqueous reaction system containing benzothiazole and diphenylphosphine oxide. Under ultraviolet-visible light excitation, light energy was enriched to the EY active center through cascade fluorescence resonance energy transfer, driving the cross-coupling reaction accompanied by hydrogen evolution.

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