Rare earth photothermal bioprotein composite fiber, preparation method thereof and heat storage and heat preservation application

Abstract

The present invention relates to the field of biotechnology, and in particular to rare earth photothermal bioprotein composite fibers, their preparation methods, and their applications in heat storage and insulation. The present invention provides photothermal bioprotein fibers, which are formed by wet spinning rare earth nanoparticles, recombinant proteins, and polysaccharides, followed by EDC / NHS treatment and stretching. Test results demonstrate that the photothermal bioprotein fibers exhibit high mechanical properties and high photothermal efficiency, achieving compatibility between mechanical properties and photothermal efficiency, providing a new strategy for the development of novel, high-performance photothermal fibers.

Description

Technical Field

[0001] The present invention relates to the field of biotechnology, and in particular to rare earth photothermal bioprotein composite fibers, a preparation method thereof, and heat storage and heat preservation applications. Background Art

[0002] Fiber materials play a vital role in the fields of public health, optics, electronics, and medical technology. Spectral thermal fiber, also known as photothermal fiber, is a fiber made by uniformly incorporating mineral elements from nanoparticles processed using nanotechnology. Photothermal fiber can be categorized into active and passive thermal management methods to achieve thermal performance. Passive thermal regulation relies on the body's own internal heat dissipation and heat dissipation without external heat input. Active thermal regulation achieves heating and cooling by actively transferring heat into and out of the body through external input. However, both active and passive thermal management methods still require electrical power in most cases, making them difficult to apply under extreme conditions.

[0003] Harnessing sunlight to directly achieve efficient photothermal conversion in fiber materials and heat storage in equipment is an important approach to addressing this challenge. However, currently produced photothermal fibers have poor mechanical properties and low photothermal efficiency. Therefore, developing photothermal biofibers that combine both mechanical properties and photothermal conversion efficiency is of great significance and could provide new material support for the preparation of heat storage and insulation equipment for extreme conditions. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide rare earth photothermal bioprotein composite fibers, a preparation method thereof, and heat storage and heat preservation applications.

[0005] The present invention provides a photothermal biological protein fiber, the raw materials of which include recombinant protein, nanoparticles and polysaccharide;

[0006] The core structure of the recombinant protein is composed of ELP structural units or at least one of the Z1 or Z2 structural units and ELP structural units;

[0007] The ELP structural unit is elastin-like, and its amino acid composition is VPGXG, where X is K or V;

[0008] The amino acid sequence of the Z1 structural unit is PAATAVSHTTHHAP;

[0009] The amino acid sequence of the Z2 structural unit is VGSGGRPSDSYGAPGGGN;

[0010] The polysaccharide includes sodium alginate, chitosan or cellulose;

[0011] The nanoparticles are NaNdF4 modified with Tengger's blue or Bruce's blue.

[0012] Furthermore, in the present invention, the core structure of the recombinant protein includes:

[0013] [(VPGVG) b1 (VPGKG) b2 ] b3 and / or

[0014] [PAATAVSHTTHHAP(VPGKG) b4 ] b5 and / or

[0015] [VGSGRPSDSYGAPGGGNP(VPGKG) b6 VPG] b7 ;

[0016] Among them, b1 is an integer from 1 to 5, b2 is an integer from 5 to 15; b3 is an integer from 1 to 16; b4 is an integer from 1 to 10, b5 is an integer from 20 to 40, b6 is an integer from 5 to 15, and b7 is an integer from 5 to 15.

[0017] Specifically, in a specific embodiment of the present invention, the core sequence of the recombinant protein includes:

[0018] K18 core sequence: [(VPGVG)(VPGKG)9]2

[0019] K36 core sequence: [(VPGVG)(VPGKG)9]4

[0020] K72 core sequence: [(VPGVG)(VPGKG)9]8

[0021] K144 core sequence: [(VPGVG)(VPGKG)9] 16

[0022] SE (core sequence): [PAATAVSHTTHHAP(VPGKG)5] 36

[0023] RE (core sequence): [VGSGGRPSDSYGAPGGGN(VPGKG)5VPG]8

[0024] In the specific implementation of the present invention, adding necessary fusion sequences or protein tags to the above core sequences to form new recombinant proteins is also protected by the present invention, and the present invention does not limit this.

[0025] In a specific embodiment of the present invention, the recombinant protein has at least one of the amino acid sequences shown in SEQ ID NO: 4 to SEQ ID NO: 9.

[0026] In the present invention, when b1 is 1, b2 is 9, and b3 is 2, the recombinant protein is K18, and its amino acid sequence is shown in SEQ ID NO: 4;

[0027] In the present invention, when b1 is 1, b2 is 9, and b3 is 4, the recombinant protein is K36, and its amino acid sequence is shown in SEQ ID NO: 5;

[0028] In the present invention, when b1 is 1, b2 is 9, and b3 is 8, the recombinant protein is K72, and its amino acid sequence is shown in SEQ ID NO: 6;

[0029] In the present invention, when b1 is 1, b2 is 9, and b3 is 16, the recombinant protein is K144, and its amino acid sequence is shown in SEQ ID NO: 7;

[0030] In the present invention, when b4 is 5 and b5 is 36, the recombinant protein is SE36 (also referred to as SE in the present invention), and its amino acid sequence is shown in SEQ ID NO: 8;

[0031] In the present invention, when b6 is 5 and b7 is 8, the recombinant protein is RE (also referred to as RE8 in the present invention), and its amino acid sequence is shown in SEQ ID NO: 9;

[0032] The present invention screens the raw materials of the photothermal bioprotein fiber. In a specific embodiment of the present invention, the screening includes recombinant protein screening. In the present invention, the recombinant protein can be K18, K36, K72, K144, SE and / or RE. The test results show that the photothermal bioprotein fiber prepared with RE recombinant protein, polysaccharide and nanoparticles has high mechanical strength and good photothermal efficiency.

[0033] In the present invention,

[0034] The mass ratio of the recombinant protein, nanoparticles and polysaccharide is 1:(1-5):10;

[0035] Furthermore, in the present invention,

[0036] The polysaccharide is sodium alginate;

[0037] The nanoparticles are NaNdF4 modified with Teng's blue;

[0038] In some embodiments of the present invention, the ratio of the recombinant protein, nanoparticles and polysaccharide is optimized, and experimental results show that the mass ratio of the recombinant protein RE, Bruce blue modified photothermal nanoparticles and polysaccharide can be 1:1:10; it can also be 1:2.5:10; it can also be 1:5:10; the experimental results show that the photothermal bioprotein fiber prepared when the mass concentration ratio of the recombinant protein, nanoparticles and polysaccharide is 1:1:10 has high mechanical strength and good photothermal efficiency.

[0039] The particle size of the nanoparticles is 180nm to 220nm.

[0040] In the present invention, the nanoparticles are NaNdF4 modified with Tengger's blue or Bruce's blue; Fe 2+ With [Fe(CN)6] 4- Reaction, forming a dark blue precipitate, which is Prussian blue; Fe 2+ With [Fe(CN)6] 3- The reaction produces a dark blue color called Teng's blue; the two products exhibit similar colors (blue) and contain exactly the same chemical elements and chemical formulas. In addition, the properties of the two products are the same or substantially the same as those determined by X-ray, magnetic susceptibility, photoelectron spectroscopy, and Mössbauer spectroscopy. In the present invention, the two products can be used interchangeably. In the actual reaction, potassium ferrocyanide K4Fe(CN)6 contains a ferrocyanide complex ion [Fe(CN)6] 4- , and Fe 2+ The blue product obtained by the reaction is Prussian blue; potassium ferrocyanide K3Fe(CN)6 contains ferrocyanide complex ion [Fe(CN)6] 3- , and Fe 2+ The blue product obtained by the reaction is Teng's blue. In a specific embodiment of the present invention, potassium ferrocyanide is used to carry out the reaction to obtain Teng's blue.

[0041] In the present invention, the photothermal protein fibers described herein can be prepared by direct doping of nanoparticles obtained by direct Tengger's Blue modification with recombinant protein and sodium alginate, or by Tengger's Blue modification of unmodified NaNdF4 during the spinning process. Experimental results indicate that the performance of photothermal protein fibers prepared using the direct doping method is slightly superior to that obtained using the in situ modification method.

[0042] The present invention provides a method for preparing the photothermal protein fiber, which comprises the following steps: extruding a spinning solution into a coagulation solution and then collecting the fibers, crosslinking and stretching the fibers to obtain the bioprotein fiber;

[0043] The spinning solution is selected from at least one of the following:

[0044] I), a mixture of nanoparticles, recombinant protein and sodium alginate;

[0045] II), a mixture of NaNdF4, sodium alginate, recombinant protein and K3Fe(CN)6.

[0046] Further,

[0047] The spinning solution is a mixture of nanoparticles, recombinant protein and sodium alginate, and the coagulation solution is a calcium chloride solution with a concentration of 20-40 mg / mL; the mass ratio of the nanoparticles, recombinant protein and sodium alginate is 1:(1-5):10;

[0048] The spinning solution is a mixture of NaNdF4, sodium alginate, recombinant protein and K3Fe(CN)6, and the coagulation solution is a mixture of calcium chloride and ferrous chloride, wherein the concentration of calcium chloride is 20 mg / mL and the concentration of ferrous chloride is 0.5-1 mg / mL; the mass ratio of NaNdF4, recombinant protein, sodium alginate, and K3Fe(CN)6 is (2-10):2:20:0.5.

[0049] In the present invention, the nanoparticles can be modified with Teng's blue and then prepared into the photothermal protein fiber of the present invention by a direct doping method. In this case, the preparation method includes: extruding a spinning solution containing the nanoparticles, recombinant protein and sodium alginate into a coagulation bath calcium chloride solution and then collecting the fibers, and crosslinking and stretching the fibers to obtain the bioprotein fiber; wherein the concentration of calcium chloride in the calcium chloride solution is 20 to 40 mg / mL; preferably 20 mg / mL.

[0050] The nanoparticles described in the present invention can also be modified with Teng's blue using an in-situ modification method using NaNdF4 during the preparation of the photothermal protein fiber described in the present invention; specifically, the method comprises the following steps: extruding a spinning solution containing NaNdF4, sodium alginate, recombinant protein, and K3Fe(CN)6 into a coagulation bath, collecting the fibers, and crosslinking and stretching the fibers to obtain the bioprotein fibers; the coagulation bath is a mixture of calcium chloride and ferrous chloride, wherein the calcium chloride concentration is preferably 20 mg / mL; the ferrous chloride concentration is 0.5-1 mg / mL, preferably 0.5 mg / mL. At this time, during the spinning process, K3Fe(CN)6 reacts with ferrous ions to form Teng's blue, which is modified on the NaNdF4.

[0051] In the present invention, the cross-linking reagent is a mixture of EDC and NHS, wherein the mass concentration ratio of EDC to NHS is (1-4): (1-2).

[0052] In the present invention, after the mixed liquid is extruded into a coagulation liquid for spinning, it can also be stretched after secondary cross-linking with a mixed liquid of EDC and NHS to obtain the bioprotein fiber of the present invention. The mass ratio of EDC and NHS is (1-4): (1-2). In a specific embodiment of the present invention, the concentrations of EDC and NHS are 0.2-0.4 mg / mL and 0.1-0.2 mg / mL, respectively. Specifically, the concentrations of EDC and NHS are preferably 0.3 and 0.1 mg / mL, respectively.

[0053] The test results of the present invention show that the performance of the photothermal protein fiber prepared by the direct doping method is slightly better than that prepared by the in situ modification method.

[0054] In the present invention, in the direct doping method, the nanoparticles are prepared by the following steps:

[0055] Step 1: mixing neodymium salt in a mixed solvent of oleic acid and octadecene, and then reacting with a sodium source and a fluorine source to obtain NaNdF4;

[0056] Step 2: mixing the NaNdF4 and NOBF4, centrifuging, collecting the precipitate, and modifying the precipitate with citric acid to obtain NaNdF4@CA;

[0057] Step 3, the NaNdF4@CA and FeSO4 react with cyanide in the presence of citric acid to obtain the nanoparticles;

[0058] Furthermore, in the preparation method of the present invention,

[0059] In step 1,

[0060] The neodymium salt includes at least one of NdCl3, Nd(NO3)3, Nd(CH3CO2)3, Nd(TFA)3 or Nd(ACAC)3;

[0061] The sodium source comprises at least one of sodium oleate, NaF, NaTFA or NaOA;

[0062] The fluorine source includes any one of NH4F or NaF;

[0063] In the mixed solvent of oleic acid and octadecene, the volume ratio of oleic acid to octadecene is 3:7;

[0064] The molar ratio of the neodymium salt, the sodium source and the fluorine source is (0.5-1.5):(3-4):(1-1.5), specifically 1:3.3:1.25; in the present invention, NdCl3 is dissolved in oleic acid and octadecene to a final concentration of 1 mmol, and then NH4F and sodium oleate are added to achieve a NH4F concentration of 3.3 mmol and a sodium oleate concentration of 1.25 mmol after addition.

[0065] The conditions of the first reaction are: heating to 110°C in vacuum and then heating to 310°C under N2 protection and maintaining for 40 min;

[0066] The precipitation reagent is anhydrous ethanol;

[0067] The precipitation further includes a first washing step;

[0068] The first washing reagent includes ethanol and / or cyclohexane, and specifically, washing is performed using ethanol and cyclohexane in sequence.

[0069] In step 2,

[0070] The mass concentration ratio of the NaNdF4 to NOBF4 is (25-30): (3-8). In a specific embodiment of the present invention, 1 mL of an N,N-dimethylformamide (DMF) solution containing 40-80 mg / mL NOBF4 is added to 10 mL of a n-hexane solution containing 300 mg of NaNdF4. Further, the molar concentration ratio of the NaNdF4 to NOBF4 is (27-28): (5-6), more specifically 27.273:5.455. In a more specific embodiment of the present invention, 1 mL of an N,N-dimethylformamide (DMF) solution containing 60 mg / mL NOBF4 is added to 10 mL of a n-hexane solution containing 300 mg of NaNdF4.

[0071] The conditions for the citric acid modification are immersing in a citric acid solution and ultrasonicating for 30 minutes;

[0072] The concentration of the citric acid solution is 50-64.3%. In a specific embodiment of the present invention, it is a saturated citric acid solution with a specific concentration of 64.3%.

[0073] In step 3,

[0074] The mass concentration ratio of the NaNdF4@CA, FeSO4, citric acid and cyanide is (0.01-0.1): (3-4): (4-5.5): (7.5-9); specifically 0.06: 3.8: 4.803: 8.225.

[0075] The cyanide is potassium ferrocyanide;

[0076] After the reaction with cyanide and centrifugation, a washing step is also included, wherein the washing solution is a mixture of water and acetone, wherein the content of acetone is 30vt% to 70vt%, specifically, the content of acetone is 50vt%;

[0077] The cyanide is potassium ferrocyanide and / or potassium ferrocyanide; if the cyanide is potassium ferrocyanide, the rare earth nanoparticles are NaNdF4 modified with Teng's blue; if the cyanide is potassium ferrocyanide, the rare earth nanoparticles are NaNdF4 modified with Bruce's blue; in a specific embodiment of the present invention, the cyanide is potassium ferrocyanide.

[0078] The selection of raw materials in the preparation process of the biological protein fiber of the present invention is also crucial to the performance of the biological protein fiber obtained. Sodium alginate is converted into alginic acid after reaction, and alginic acid is a water-soluble molecule. The selection of protein molecules in the present invention has also changed on the basis of existing technology. While considering performance, compatibility is also considered. In the interaction between protein and alginate, the mechanical properties of the composite fiber are further enhanced to achieve high strength and high toughness.

[0079] The recombinant protein described in the present invention is composed of a core protein with a fusion sequence or a HIS tag added thereto. In a specific embodiment of the present invention, the recombinant protein is obtained by transforming a recombinant plasmid containing a nucleotide sequence encoding the recombinant protein into competent Escherichia coli cells, followed by culture, induction and lysis to obtain a crude extract containing the recombinant protein. The crude extract is further purified by a nickel column, an ion exchange column and a desalting column to obtain the recombinant protein. The purity of the recombinant protein can reach over 90%.

[0080] In the present invention, the skeleton of the recombinant plasmid is a commonly used expression plasmid of Escherichia coli, and the expression plasmid includes but is not limited to pET-25b, pET-28a and the like.

[0081] The present invention makes use of the special light response properties and excellent coordination properties of rare earth elements, as well as the special amino acid structure of proteins, to prepare rare earth high-strength and high-toughness bio-protein composite fibers with both photothermal functions and mechanical properties. The fibers can achieve efficient photothermal conversion under sunlight and can be used for heat storage and insulation of special equipment.

[0082] The present invention mainly utilizes recombinant protein structure assembly for fiber molding. Generally, the introduction of inorganic nanoparticles will affect the protein structure assembly, resulting in reduced performance, especially in the in situ synthesis process. The present invention achieves the synergy of mechanical and photothermal properties by regulating the process. In the specific embodiment of the present invention, the preparation method of the biological protein fiber is adjusted, and the preparation method of the corresponding nanoparticles is also adaptively changed (direct doping, in situ spinning and neodymium ion cross-linking). In addition, the present invention also adjusts the doping concentration of nanoparticles, recombinant proteins and sodium alginate, the protein polymerization degree, etc., to obtain the biological protein fiber of the present invention with both photothermal and mechanical properties.

[0083] The present invention provides applications of at least one of the following A) to C) in the field of electrical and / or optical conductors, smart wearables, and / or medical bionics:

[0084] A), the biological protein fiber of the present invention;

[0085] B) biological protein fiber prepared by the preparation method of the present invention;

[0086] C) The photothermal nanocomposite material of the present invention.

[0087] The present invention uses rare earth nanoparticles and silk fibroin as raw materials and utilizes a direct doping method to synthesize the bioprotein fiber described in the present invention. Experimental results show that the bioprotein fiber described in the present invention has both high photothermal efficiency and mechanical properties, providing a new strategy for the development of new high-performance photothermal fibers, and can be widely used in the preparation of special outdoor thermal insulation equipment for extreme environments.

[0088] The method for heat preservation and / or heat conduction is to use at least one of the following a) to c) for heat preservation and / or heat conduction:

[0089] a) The biological protein fiber of the present invention;

[0090] b) Bioprotein fiber prepared by the preparation method of the present invention;

[0091] c) The photothermal nanocomposite material of the present invention.

[0092] The present invention provides photothermal bioprotein fibers, which are formed by wet spinning of rare earth nanoparticles, recombinant proteins and polysaccharides and then stretched by EDC / NHS treatment. Test results show that the photothermal bioprotein fibers of the present invention have high mechanical properties and good photothermal efficiency, achieving compatibility between mechanical properties and photothermal efficiency, and providing a new strategy for the development of new high-performance photothermal fibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Figure 1 Figure 2 shows the SDS-PAGE image of the purified ELP protein in Example 1;

[0094] Figure 2 1 is an SDS-PAGE image of the purified SE protein with a degree of polymerization of 36 in Example 1;

[0095] Figure 3 1 is an SDS-PAGE image of the purified RE protein with a degree of polymerization of 8 in Example 1;

[0096] Figure 4 TEM image of the rare earth photothermal nanoparticles obtained in Example 2, scale: 50 nm;

[0097] Figure 5 1 shows the photothermal performance curve of the fiber obtained after post-drawing treatment in Example 8 (the temperature drop in the final stage is caused by the removal of the light source);

[0098] Figure 6 The photothermal performance curve of the fiber obtained after post-drawing treatment in Example 9 is shown (the temperature drop in the final stage is caused by the removal of the light source);

[0099] Figure 7 1 shows a photothermal performance curve of the fiber obtained after post-drawing treatment in Example 10 (the temperature drop in the final stage is caused by the removal of the light source);

[0100] Figure 8 1 shows a photothermal performance curve of the fiber obtained after post-drawing treatment in Example 11 (the temperature drop in the final stage is caused by the removal of the light source);

[0101] Figure 9 14 shows the photothermal performance curve of the fiber obtained after post-drawing treatment in Example 12 (the temperature drop in the final stage is caused by the removal of the light source). DETAILED DESCRIPTION

[0102] The present invention provides rare earth photothermal bioprotein composite fibers, their preparation methods, and heat storage and heat preservation applications. Those skilled in the art can refer to the contents of this article and appropriately improve the process parameters to achieve them. It should be noted in particular that all similar replacements and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications herein without departing from the content, spirit, and scope of the present invention to implement and apply the technology of the present invention.

[0103] Z1 structural unit (SRT): PAATAVSHTTHHAP, (SEQ ID NO: 1);

[0104] Z2 structural unit (Resilin): VGSGGRPSDSYGAPGGGN, (SEQ ID NO: 2);

[0105] The amino acid structural unit of elastin ELP is: VPGXG (SEQ ID NO: 3), wherein X is K or V;

[0106] The amino acid sequence of K18: MGAGP[(VPGVG)(VPGKG)9]2GWPH6, (SEQ ID NO: 4);

[0107] The amino acid sequence of K36: MGAGP[(VPGVG)(VPGKG)9]4GWPH6, (SEQ ID NO: 5);

[0108] The amino acid sequence of K72: MGAGP[(VPGVG)(VPGKG)9]8GWPH6, (SEQ ID NO: 6);

[0109] Amino acid sequence of K144: MGAGP[(VPGVG)(VPGKG)9] 16 GWPH6, (SEQ ID NO: 7);

[0110] Amino acid structural unit of SE36: [PAATAVSHTTHHAP(VPGKG)5] 36 PAATAVSDIWPH6C, (SEQ IDNO:8);

[0111] The amino acid structural unit of RE8 is: MGQG[VGSGRPSDSYGAPGGGNP(VPGKG)5VPG]8WH6, (SEQ ID NO: 9);

[0112] In the present invention, the photothermal protein fiber can be prepared by using NaNdF4 nanoparticles as a substrate, undergoing surface modification, and in situ growing Putten's blue (TB) on its surface to obtain Putten's blue-modified photothermal nanoparticles NaNdF4@TB. NaNdF4@TB is mixed with a spinning solution containing recombinant protein and polysaccharide, wet-spun into shape, and further stretched after secondary cross-linking with EDC / NHS to obtain the photothermal bioprotein fiber of the present invention. The photothermal bioprotein fiber of the present invention has high mechanical properties and good photothermal efficiency, achieving compatibility between mechanical properties and photothermal efficiency, providing a new strategy for the development of new high-performance photothermal fibers, and has good application prospects.

[0113] The test materials used in the present invention are all common commercial products and can be purchased on the market. The present invention is further described below with reference to the following examples:

[0114] Example 1 Expression and purification of chimeric protein

[0115] The chimeric protein expression vector was transformed into E. coli BLR (DE3) competent cells, and positive monoclonal colonies were picked in LB solid medium and grown in LB medium to OD 600 When the OD is 3-4, transfer to TB medium. 600 When the mRNA expression level was between 0.6 and 0.8, IPTG was added to a final concentration of 0.1 mM and expression was induced overnight at 28.5°C. The cells were collected by centrifugation and stored at -80°C.

[0116] After resuspending the cells in lysis buffer, add lysozyme, DNA enzyme, and magnesium chloride, disrupt by ultrasound, collect the supernatant by centrifugation, and purify it in sequence through nickel column, anion exchange column, and desalting column to obtain the target protein. Taking K18, K36, K72, K144, SE36, and RE8 as examples, perform SDS-PAGE analysis. Figures 1 to 3 Finally, the target protein was lyophilized and stored in a -80℃ refrigerator.

[0117] Example 2 Preparation of rare earth photothermal nanoparticles

[0118] Dissolve 1 mmol of NdCl₃ in 20 mL of oleic acid and octadecene at a ratio of oleic acid / octadecene of 3 / 7 (v / v). Add NH₄F and sodium oleate while stirring, preferably in amounts of 3.3 mmol and 1.25 mmol, respectively. Evacuate the mixture and raise the temperature to 110°C. Then, heat to 310°C under nitrogen for 40 minutes. Cool to room temperature, add ethanol for precipitation, centrifuge, and wash with ethanol / cyclohexane. The product is then dispersed in cyclohexane or n-hexane.

[0119] To a 10 mL hexane solution containing 300 mg of NaNdF4, add 1 mL of a N,N-dimethylformamide (DMF) solution containing NOBF4, preferably 60 mg / mL. Centrifuge and add 5 mL of a saturated citric acid (CA) solution to the precipitate. Ultrasonicate for 30 minutes to obtain NaNdF4@CA nanoparticles.

[0120] Take 1mL of 60mg / L NaNdF4@CA solution and add it to 50mL of water. Then add 5mL of FeSO4 and CA aqueous solution. Then add 5mL of K3Fe(CN)6 aqueous solution with the same concentration as FeSO4. The concentration of FeSO4 and CA is preferably 5mM FeSO4 and 0.09MCA. Centrifuge, wash with water / acetone, and disperse the product in water. The nanoparticles were analyzed by transmission electron microscopy and showed a cluster morphology, about 200nm in size, and uniform distribution. Figure 4 shown.

[0121] Example 3 Direct doping preparation of 1% doped NaNdF4@TB K18-sodium alginate composite rare earth photothermal biofiber

[0122] Prepare an aqueous solution of sodium alginate, K18, and NaNdF4@TB. The sodium alginate concentration is preferably 20 mg / mL, the protein concentration is preferably 2 mg / mL, and the NaNdF4@TB concentration is 2 mg / mL. Extrude the protein solution into a coagulation bath for wet spinning, and collect fibers. The extrusion speed is preferably 50 μL / min. The coagulation bath is a calcium chloride solution, and the concentration is preferably 20 mg / mL. A high-performance rare earth photothermal biofiber is obtained. The collected fibers are soaked in EDC / NHS solution and then post-stretched. The concentrations of EDC / NHS are preferably 0.3 and 0.1 mg / mL, respectively. A good rare earth photothermal biofiber is obtained, wherein the post-stretching degree is preferably 100% of the original fiber length.

[0123] Example 4 Preparation of 1% NaNdF4@TB-doped K36-sodium alginate composite rare earth photothermal biofiber by direct doping

[0124] Prepare an aqueous solution of sodium alginate, K36, and NaNdF4@TB. The sodium alginate concentration is preferably 20 mg / mL, the protein concentration is preferably 2 mg / mL, and the NaNdF4@TB concentration is 2 mg / mL. Extrude the protein solution into a coagulation bath for wet spinning, and collect the fibers. The extrusion speed is preferably 50 μL / min. The coagulation bath is a calcium chloride solution, and the concentration is preferably 20 mg / mL. A high-performance rare earth photothermal biofiber is obtained. The collected fibers are soaked in EDC / NHS solution and then post-stretched. The concentrations of EDC / NHS are preferably 0.3 and 0.1 mg / mL, respectively. A good rare earth photothermal biofiber is obtained, wherein the post-stretching degree is preferably 100% of the original fiber length.

[0125] Example 5 Direct doping preparation of 1% NaNdF4@TB doped K72-sodium alginate composite rare earth photothermal biofiber

[0126] Prepare an aqueous solution of sodium alginate, K72, and NaNdF4@TB. The sodium alginate concentration is preferably 20 mg / mL, the protein concentration is preferably 2 mg / mL, and the NaNdF4@TB concentration is 2 mg / mL. Extrude the protein solution into a coagulation bath for wet spinning, and collect fibers. The extrusion speed is preferably 50 μL / min. The coagulation bath is a calcium chloride solution, and the concentration is preferably 20 mg / mL. A high-performance rare earth photothermal biofiber is obtained. The collected fibers are soaked in EDC / NHS solution and then post-stretched. The concentrations of EDC / NHS are preferably 0.3 and 0.1 mg / mL, respectively. A good rare earth photothermal biofiber is obtained, wherein the post-stretching degree is preferably 100% of the original fiber length.

[0127] Example 6 Direct doping preparation of 1% NaNdF4@TB doped K144-sodium alginate composite rare earth photothermal biofiber

[0128] Prepare an aqueous solution of sodium alginate, K144, and NaNdF4@TB. The sodium alginate concentration is preferably 20 mg / mL, the protein concentration is preferably 2 mg / mL, and the NaNdF4@TB concentration is 2 mg / mL. Extrude the protein solution into a coagulation bath for wet spinning, and collect fibers. The extrusion speed is preferably 50 μL / min. The coagulation bath is a calcium chloride solution, and the concentration is preferably 20 mg / mL. A high-performance rare earth photothermal biofiber is obtained. The collected fibers are soaked in EDC / NHS solution and then post-stretched. The concentrations of EDC / NHS are preferably 0.3 and 0.1 mg / mL, respectively. A good rare earth photothermal biofiber is obtained, wherein the post-stretching degree is preferably 100% of the original fiber length.

[0129] Example 7 Direct doping preparation of 1% doped NaNdF4@TB SE-sodium alginate composite rare earth photothermal biofiber

[0130] Prepare an aqueous solution of sodium alginate, SE, and NaNdF4@TB. The sodium alginate concentration is preferably 20 mg / mL, the protein concentration is preferably 2 mg / mL, and the NaNdF4@TB concentration is 2 mg / mL. Extrude the protein solution into a coagulation bath for wet spinning, and collect the fibers. The extrusion speed is preferably 50 μL / min. The coagulation bath is a calcium chloride solution, and the concentration is preferably 20 mg / mL. A high-performance rare earth photothermal biofiber is obtained. The collected fibers are soaked in EDC / NHS solution and then post-stretched. The concentrations of EDC / NHS are preferably 0.3 and 0.1 mg / mL, respectively. A good rare earth photothermal biofiber is obtained, wherein the post-stretching degree is preferably 100% of the original fiber length.

[0131] Example 8 Preparation of 1% NaNdF4@TB-doped RE-sodium alginate composite rare earth photothermal biofiber by direct doping

[0132] Prepare an aqueous solution of sodium alginate, RE, and NaNdF4@TB. The sodium alginate concentration is preferably 20 mg / mL, the protein concentration is preferably 2 mg / mL, and the NaNdF4@TB concentration is 2 mg / mL. Extrude the protein solution into a coagulation bath for wet spinning, and collect fibers. The extrusion speed is preferably 50 μL / min. The coagulation bath is a calcium chloride solution, and the concentration is preferably 20 mg / mL. A high-performance rare earth photothermal biofiber is obtained. The collected fibers are soaked in EDC / NHS solution and then post-stretched. The concentrations of EDC / NHS are preferably 0.3 and 0.1 mg / mL, respectively. A good rare earth photothermal biofiber is obtained, wherein the post-stretching degree is preferably 100% of the original fiber length.

[0133] Example 9: Direct doping to prepare 2.5% doped NaNdF4@TB RE-sodium alginate composite rare earth photothermal biofiber

[0134] Prepare an aqueous solution of sodium alginate, RE, and NaNdF4@TB. The sodium alginate concentration is preferably 20 mg / mL, the protein concentration is preferably 2 mg / mL, and the NaNdF4@TB concentration is 5 mg / mL. Extrude the protein solution into a coagulation bath for wet spinning, and collect the fibers. The extrusion speed is preferably 50 μL / min. The coagulation bath is a calcium chloride solution, and the concentration is preferably 20 mg / mL. A high-performance rare earth photothermal biofiber is obtained. The collected fibers are soaked in EDC / NHS solution and then post-stretched. The concentrations of EDC / NHS are preferably 0.3 and 0.1 mg / mL, respectively. A good rare earth photothermal biofiber is obtained, wherein the post-stretching degree is preferably 100% of the original fiber length.

[0135] Example 10 Preparation of 5% doped NaNdF4@TB RE-sodium alginate composite rare earth photothermal biofiber by direct doping

[0136] Prepare an aqueous solution of sodium alginate, RE, and NaNdF4@TB. The sodium alginate concentration is preferably 20 mg / mL, the protein concentration is preferably 2 mg / mL, and the NaNdF4@TB concentration is 10 mg / mL. Extrude the protein solution into a coagulation bath for wet spinning, and collect fibers. The extrusion speed is preferably 50 μL / min. The coagulation bath is a calcium chloride solution, and the concentration is preferably 20 mg / mL. A high-performance rare earth photothermal biofiber is obtained. The collected fibers are soaked in EDC / NHS solution and then post-stretched. The concentrations of EDC / NHS are preferably 0.3 and 0.1 mg / mL, respectively. A good rare earth photothermal biofiber is obtained, wherein the post-stretching degree is preferably 100% of the original fiber length.

[0137] Example 11 Preparation of rare earth photothermal biofibers by in-situ modification during spinning

[0138] Prepare an aqueous solution of sodium alginate, RE, and NaNdF4. The sodium alginate concentration is preferably 20 mg / mL, the protein concentration is preferably 2 mg / mL, and the NaNdF4 concentration is preferably 10 mg / mL. Add a K3Fe(CN)6 solution to the spinning solution. Preferably, the K3Fe(CN)6 concentration is 0.5 mg / mL. Extrude the protein solution into a coagulation bath for wet spinning, and collect the fibers. The extrusion rate is preferably 50 μL / min. The coagulation bath is a solution of calcium chloride and ferrous chloride, preferably with a calcium chloride concentration of 20 mg / mL and a ferrous chloride concentration of 0.5 mg / mL. During the spinning process, the K3Fe(CN)6 and ferrous chloride react to form Prussian blue. A high-performance rare earth photothermal biofiber is obtained. The collected fibers are then soaked in an EDC / NHS solution and post-stretched. The EDC / NHS concentrations are preferably 0.3 and 0.1 mg / mL, respectively. A high-quality rare earth photothermal biofiber is obtained, wherein the post-stretching degree is preferably 100% of the original fiber length.

[0139] Example 12 Preparation of rare earth photothermal biofiber by neodymium ion crosslinking

[0140] Prepare an aqueous solution of sodium alginate, RE, and K3Fe(CN)6. The sodium alginate concentration is preferably 20 mg / mL, the protein concentration is preferably 2 mg / mL, and the K3Fe(CN)6 concentration is preferably 0.5 mg / mL. The protein solution is extruded into a coagulation bath for wet spinning, and the fibers are collected. The extrusion speed is preferably 50 μL / min. The coagulation bath is a solution of neodymium chloride and ferrous chloride, the neodymium chloride concentration is preferably 40 mg / mL, and the ferrous chloride concentration is 0.5 mg / mL. A high-performance rare earth photothermal biofiber is obtained. The collected fibers are soaked in EDC / NHS solution and then post-stretched. The concentrations of EDC / NHS are preferably 0.3 and 0.1 mg / mL, respectively. A good rare earth photothermal biofiber is obtained, wherein the post-stretching degree is preferably 100% of the original fiber length.

[0141] Example 13 Testing of Fiber Mechanical Strength and Fiber Photothermal Properties

[0142] The specific testing method is as follows: 8mm of fiber was stretched, and a single fiber tensile tester was used with a test length of 5mm. After clamping the fiber, it was stretched at a speed of 10mm / min to obtain the tensile force value. The fiber diameter was measured using a microscope, and the tensile strength was obtained by calculating the ratio of tensile force to fiber cross-sectional area. The tensile curve was obtained using Origin software. It can be seen that the breaking strength of the fibers prepared in Examples 3 to 8 was above 400MPa (Table 1), which can meet the application requirements of clothing fabric preparation. Among them, the fiber prepared in Example 3 was significantly better than the solutions in Examples 4 and 5.

[0143] Ten single fibers prepared in Examples 8 to 12 were twisted into bundles and subjected to a photothermal performance test under the light of a xenon lamp equipped with a solar spectrum filter. The light intensity used was measured by an optical power meter to be 0.1 W / cm 2 The temperature change of the fiber under light is tested using a FLIR infrared thermal imaging camera, and the temperature change curve over time is recorded, such as Figures 5 to 9 The results show that the photothermal efficiency of the five tested fibers is greater than 60%, which can meet the needs of outdoor active heating and equipment insulation.

[0144] Table 1. Test results of fiber mechanical strength

[0145] Examples and protein types Strength (Mpa) <![CDATA[Toughness (MJ / m 3 )]]> Modulus (GPa) Elongation at break (%) 3 (K18, direct doping) 518±50 36.1±5.0 14.2±1.5 9.9±0.8 4 (K36, direct doping) 419±25 44.1±10.8 9.9±0.3 14.9±2.9 5 (K72, direct doping) 412±36 36.1±5.0 13.3±1.2 14.2±1.4 6 (K144, direct doping) 403±25 29.1±4.6 10.9±0.3 10.8±1.2 7 (SE 1%, direct doping) 607±74 69.0±12.7 13.3±1.2 16.0±1.9 8 (RE 1%, direct doping) 768±56 52.3±3.3 24.0±4.7 9.9±1.0 9 (RE 2.5%, direct doping) 327±22 41.7±6.4 12.1±0.9 15.5±2.4 10 (RE 5%, direct doping) 224±53 27.8±11.6 6.7±2.2 17.5±5.5 11RE (in-situ spinning) 324±50 32.8±12.2 11.1±1.5 13.8±3.5 12RE (neodymium ion cross-linking) 264±38 26.0±12.1 9.6±2.9 14.0±6.4

[0146] Table 2. Test results of fiber optical and thermal properties

[0147] Example Photothermal efficiency 8 62％ 9 71％ 10 74％ 11 72％ 12 64％

[0148] Comparative Example 1 compared with other fibers

[0149] The breaking strength and breaking elongation of RSF / MoO2NPs hybrid fibers with a content of 0.04wt% are the best, which are 311.62±10.52MPa and 153.81±6.21%, respectively (Guo Jianjun. Research on photothermal nanoparticle functionalized silk fibroin composites [D]. Jiangsu University of Science and Technology, 2022. DOI: 10.27171 / d.cnki.ghdcc.2022.000448.).

[0150] RSF-PDA composite fiber has a strength of 246 MPa and a photothermal efficiency of 33% (Chen, Wei., et al. "Polydopamine-Induced Multilevel Engineering of Regenerated Silk Fibroin Fiberfor Photothermal Conversion." Small (Weinheim an der Bergstrasse, Germany) 18.11(2022):e2107196).

[0151] The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Photothermal protein fiber, characterized in that: Raw materials include recombinant proteins, nanoparticles, and polysaccharides; The preparation method of the nanoparticles comprises the following steps: Step 1: mixing neodymium salt in a mixed solvent of oleic acid and octadecene, and then reacting with a sodium source and a fluorine source for a first reaction and then precipitating to obtain NaNdF4; Step 2: The NaNdF4 and NOBF4 are mixed and centrifuged to collect the precipitate, and the precipitate is modified with citric acid to obtain NaNdF4@CA; Step 3: The NaNdF4@CA and FeSO4 react with cyanide in the presence of citric acid to obtain the nanoparticles; The cyanide is potassium ferrocyanide and / or potassium ferrocyanide; if the cyanide is potassium ferrocyanide, the nanoparticles are NaNdF4 modified with Teng's blue; if the cyanide is potassium ferrocyanide, the nanoparticles are NaNdF4 modified with Bruce's blue; The core structure of the recombinant protein comprises: [(VPGVG) b1 (VPGKG) b2 ] b3 and / or [PAATAVSHTTHHAP(VPGKG) b4 ] b5 ; and / or [VGSGRPSDSYGAPGGGNP(VPGKG) b6 LPG] b7 ; Among them, b1 is an integer from 1 to 5, b2 is an integer from 5 to 15, b3 is an integer from 1 to 16, b4 is an integer from 1 to 10, b5 is an integer from 20 to 40, b6 is an integer from 5 to 15, and b7 is an integer from 5 to 15.

2. The photothermal protein fiber according to claim 1, characterized in that The recombinant protein has at least one of the amino acid sequences shown in SEQ ID NO: 4 to SEQ ID NO:

9.

3. The photothermal protein fiber according to claim 1 or 2, characterized in that: The mass ratio of the recombinant protein, nanoparticles and polysaccharide is 1: (1-5):

10.

4. The photothermal protein fiber according to claim 3, characterized in that The particle size of the nanoparticles is 180nm~220nm.

5. The method for preparing the photothermal protein fiber according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: extruding a spinning solution into a coagulation solution and then collecting fibers, and cross-linking and stretching the fibers to obtain the photothermal protein fibers; The spinning solution is selected from at least one of the following: I), a mixture of nanoparticles, recombinant protein and sodium alginate; II), a mixture of NaNdF4, sodium alginate, recombinant protein and K3Fe(CN)6.

6. The preparation method according to claim 5, characterized in that The spinning solution is a mixture of nanoparticles, recombinant protein and sodium alginate, and the coagulation solution is a calcium chloride solution with a concentration of 20-40 mg / mL; the mass ratio of the nanoparticles, recombinant protein and sodium alginate is 1: (1-5): 10; The spinning solution is a mixture of NaNdF4, sodium alginate, recombinant protein and K3Fe(CN)6, and the coagulation solution is a mixture of calcium chloride and ferrous chloride, wherein the concentration of calcium chloride is 20 mg / mL and the concentration of ferrous chloride is 0.5~1 mg / mL; the mass ratio of the NaNdF4, recombinant protein, sodium alginate, and K3Fe(CN)6 is (2~10):2:20:0.

5.

7. Photothermal nanocomposite material, characterized in that: The invention comprises at least one of the photothermal protein fiber according to any one of claims 1 to 4 and / or the photothermal protein fiber prepared by the preparation method according to claim 5 or 6, and a matrix thereof.

8. Application of at least one of the following items A) to C) in the fields of electrical and / or optical conductors, smart wearables, and / or medical bionics: A), the photothermal protein fiber according to any one of claims 1 to 4; B) Photothermal protein fiber prepared by the preparation method according to claim 5 or 6; C) The photothermal nanocomposite material according to claim 7.

9. A method for heat preservation and / or heat conduction, characterized in that: Use at least one of the following a) to c) for heat preservation and / or heat conduction: a), the photothermal protein fiber according to any one of claims 1 to 4; b) Photothermal protein fiber prepared by the preparation method according to claim 5 or 6; c) The photothermal nanocomposite material according to claim 7.

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