Rare earth photo-thermal biological protein composite fiber and preparation method and heat storage and heat preservation application thereof

Abstract

The invention relates to the technical field of biology, in particular to a rare earth photo-thermal biological protein composite fiber and a preparation method and heat storage and heat preservation application thereof. The invention provides a photo-thermal biological protein fiber, the photo-thermal biological protein fiber is obtained by carrying out wet spinning forming on rare earth nanoparticles, recombinant protein and polysaccharide and then carrying out EDC / NHS treatment and stretching, and a test result shows that the photo-thermal biological protein fiber is high in mechanical property, good in high photo-thermal efficiency and good in application prospect. Compatibility of mechanical properties and photo-thermal efficiency is achieved, and a new strategy is provided for development of novel high-performance photo-thermal fibers.

Description

Technical Field

[0001] The 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 thermal insulation applications. Background Art

[0002] Fiber materials play a vital role in the fields of people's livelihood, optics, electricity and medical technology. Spectral thermal fiber, also known as photothermal fiber, is a fiber in which the mineral elements in nanoparticles processed by nanotechnology are uniformly melted into the fiber. Photothermal fiber can be divided into active and passive thermal management to exert its photothermal performance. Passive thermal regulation refers to the regulation of heat by the human body's own heat dissipation without inputting external heat energy. Active thermal regulation can achieve heating / cooling by actively transferring heat into / out of the human body through external input. However, active and passive thermal management still require electrical energy drive in most cases, which is difficult to apply under extreme conditions.

[0003] Using sunlight to directly achieve efficient photothermal conversion of fiber materials and heat storage in equipment is an important direction to solve this problem. However, the photothermal fibers currently prepared have poor mechanical properties, low mechanical properties, and low photothermal efficiency. Therefore, it is of great significance to develop photothermal biofibers that have both mechanical properties and photothermal conversion efficiency, which can provide new material support for the preparation of heat storage and insulation equipment under 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 bio-protein 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 Z1 or Z2 structural units and ELP structural units;

[0007] The ELP structural unit is elastin-like, and its amino acid composition is VPGXG, wherein 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 Teng's blue or Bruce's blue.

[0012] Further, in the present invention, the core structure of the recombinant protein comprises:

[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 of 1 to 5, b2 is an integer of 5 to 15, b3 is an integer of 1 to 16, b4 is an integer of 1 to 10, b5 is an integer of 20 to 40, b6 is an integer of 5 to 15, and b7 is an integer of 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 biological protein fiber. In a specific embodiment of the present invention, the screening of recombinant proteins is included; in the present invention, the recombinant protein can be K18, K36, K72, K144, SE and / or RE. The test results show that the photothermal biological protein 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, the nanoparticles and the 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 polysaccharides is optimized, and experimental results show that the mass ratio of the recombinant protein RE, Bruce Blue modified photothermal nanoparticles and polysaccharides 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 polysaccharides is 1:1:10 has both 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 Teng's blue or Bruce's blue; Fe 2+ With [Fe(CN)6] 4- Reaction, generating a dark blue precipitate, which is Prussian blue; Fe 2+ With [Fe(CN)6] 3- The two products show similar colors (blue) and contain exactly the same chemical elements and chemical formulas. The properties of the two products are the same or basically the same as those of the two products in the determination of X-ray, magnetic susceptibility, photoelectron spectrum and Mössbauer spectrum. In the present invention, the two products can be replaced with each other. In the actual reaction, potassium ferrocyanide K4Fe(CN)6 contains ferrocyanide complex ions [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, Teng's blue is obtained by using potassium ferrocyanide for the reaction.

[0041] In the present invention, the nanoparticles can be obtained by directly doping the nanoparticles obtained by modifying Teng's blue with recombinant protein and sodium alginate to obtain the photothermal protein fiber of the present invention, or can be unmodified NaNdF4 modified by Teng's blue during the spinning process, which is not limited by the present invention. 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 of the in situ modification method.

[0042] The present invention provides a method for preparing the photothermal protein fiber, which comprises the following steps: collecting fibers after extruding a spinning solution into a coagulation solution, and obtaining the biological protein fiber by cross-linking and stretching the fibers;

[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] Furthermore,

[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 direct doping method. In this case, the preparation method comprises: 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 biological protein 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 of the present invention can also be modified by using NaNdF4 in situ to complete the modification of Teng's blue in the preparation process of the photothermal protein fiber of the present invention; specifically, the steps include: extruding a spinning solution containing NaNdF4, sodium alginate, recombinant protein and K3Fe(CN)6 into a coagulation bath and collecting the fibers, and the fibers are cross-linked and stretched to obtain the biological protein fibers; the coagulation bath is a mixture of calcium chloride and ferrous chloride, wherein the concentration of calcium chloride is preferably 20 mg / mL; the concentration of ferrous chloride 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 generate Teng's blue modified on NaNdF4.

[0051] In the present invention, the cross-linking reagent is a mixed solution 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 solution is extruded into a coagulation solution for spinning, it can also be stretched after secondary cross-linking through a mixed solution of EDC and NHS to obtain the bioprotein fiber of the present invention. The mass ratio of EDC to 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, 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 for a first reaction and then precipitating to obtain NaNdF4;

[0056] Step 2, mixing the NaNdF4 and NOBF4 and centrifuging to collect 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 make the concentration of NH4F 3.3 mmol and the concentration of sodium oleate 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 for 40 min;

[0066] The precipitating 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 NaNdF4 to NOBF4 is (25-30): (3-8). In a specific embodiment of the present invention, 1 mL of N,N-dimethylformamide (DMF) solution containing 40-80 mg / mL NOBF4 is added to 10 mL of n-hexane solution containing 300 mg NaNdF4; further, the molar concentration ratio of 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 N,N-dimethylformamide (DMF) solution containing 60 mg / mL NOBF4 is added to 10 mL of n-hexane solution containing 300 mg NaNdF4.

[0071] The citric acid modification condition is to immerse in a citric acid solution and ultrasonicate 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 the existing technology. While considering the performance, the 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 toughness.

[0079] The recombinant protein described in the present invention is composed of a core protein with a fusion sequence or a HIS tag or other sequence 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, culturing, inducing and lysing to obtain a crude extract containing the recombinant protein, and 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 more than 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 performance and excellent coordination performance of rare earth elements and the special amino acid structure of protein to prepare rare earth high-strength and high-toughness biological 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. Usually, 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, 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 at least one application of the following A) to C) in the field of electrical and / or optical conductors, the field of smart wearables and / or the field of medical bionics:

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

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

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

[0092] The present invention provides a photothermal bioprotein fiber, which is obtained by wet spinning rare earth nanoparticles, recombinant proteins and polysaccharides and then stretching them through EDC / NHS treatment. Experimental results show that the photothermal bioprotein fiber of the present invention has high mechanical properties and good photothermal efficiency, achieves compatibility between mechanical properties and photothermal efficiency, and provides a new strategy for developing new high-performance photothermal fibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Figure 1 The SDS-PAGE image after the ELP protein purification in Example 1 is shown;

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

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

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

[0097] Figure 5 1 is a graph showing the photothermal performance 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 10 shows the light-heat performance curve of the fiber obtained by 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 the light-heat performance curve of the fiber obtained by post-drawing treatment in Example 11 (the temperature drop in the final stage is caused by the removal of the light source);

[0101] Fig. 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, preparation methods and heat storage and heat preservation applications thereof. Those skilled in the art can refer to the contents of this article and appropriately improve the process parameters to achieve the desired results. It should be noted in particular that all similar substitutions and modifications are obvious to those skilled in the art, and they are all deemed 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 of this article 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: 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] Amino acid structural unit of RE8: 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 nano-ion 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 biological protein fiber of the present invention. The photothermal biological protein fiber of the present invention has high mechanical properties and good photothermal efficiency, and achieves 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 in conjunction with the embodiments:

[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 p-value was 0.6-0.8, IPTG was added to a final concentration of 0.1 mM and induced expression overnight at 28.5°C. The cells were collected by centrifugation and stored at -80°C.

[0116] After the cells were resuspended in the lysis buffer, lysozyme, DNA enzyme, and magnesium chloride were added, and the cells were ultrasonically broken. After the supernatant was collected by centrifugation, it was purified by nickel column, anion exchange column, and desalting column in sequence to obtain the target protein. Taking K18, K36, K72, K144, SE36, and RE8 as examples, SDS-PAGE analysis was performed. 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 NdCl3 in 20 mL oleic acid and octadecene, oleic acid / octadecene is 3 / 7 (v / v), add NH4F and sodium oleate under stirring, preferably in amounts of 3.3 mmol and 1.25 mmol, respectively. Vacuum and raise the temperature to 110°C, then heat to 310°C under N2 protection and keep for 40 min, cool to room temperature, add ethanol for precipitation, centrifuge, and wash with ethanol / cyclohexane, the product is dispersed in cyclohexane or n-hexane;

[0119] To 10 mL of n-hexane solution containing 300 mg of NaNdF4, 1 mL of N,N-dimethylformamide (DMF) solution containing NOBF4 was added, and NOBF4 was preferably 60 mg / mL. Centrifugation was performed, and 5 mL of saturated citric acid (CA) solution was added to the precipitate, and ultrasonication was performed for 30 min to obtain NaNdF4@CA nanoparticles;

[0120] Take 1mL of 60mg / L NaNdF4@CA solution and add it to 50mL of water, add 5mL of FeSO4 and CA aqueous solution, and 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 clustered morphology with a size of about 200nm and uniform distribution, as shown in Figure 2. Figure 4 shown.

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

[0122] Prepare aqueous solutions 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 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 bio-fiber 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. Good rare earth photothermal bio-fibers are obtained, wherein the degree of post-stretching 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 aqueous solutions 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 bio-fiber 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. Good rare earth photothermal bio-fibers are obtained, wherein the degree of post-stretching is preferably 100% of the original fiber length.

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

[0126] Prepare aqueous solutions 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 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 bio-fiber 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. Good rare earth photothermal bio-fibers are obtained, wherein the degree of post-stretching is preferably 100% of the original fiber length.

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

[0128] Prepare aqueous solutions 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 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 bio-fiber 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. Good rare earth photothermal bio-fibers are obtained, wherein the degree of post-stretching is preferably 100% of the original fiber length.

[0129] Example 7 Preparation of SE-sodium alginate composite rare earth photothermal biofiber doped with 1% NaNdF4@TB by direct doping

[0130] Prepare aqueous solutions 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 bio-fiber 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. Good rare earth photothermal bio-fibers are obtained, wherein the degree of post-stretching is preferably 100% of the original fiber length.

[0131] Example 8 Direct doping to prepare 1% NaNdF4@TB doped RE-sodium alginate composite rare earth photothermal biofiber

[0132] Prepare aqueous solutions 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 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 bio-fiber 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. Good rare earth photothermal bio-fibers are obtained, wherein the degree of post-stretching 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 aqueous solutions 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 bio-fiber 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. Good rare earth photothermal bio-fibers are obtained, wherein the degree of post-stretching is preferably 100% of the original fiber length.

[0135] Example 10 Direct doping to prepare 5% doped NaNdF4@TB RE-sodium alginate composite rare earth photothermal biofiber

[0136] Prepare aqueous solutions 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 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 bio-fiber 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. Good rare earth photothermal bio-fibers are obtained, wherein the degree of post-stretching 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 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, collect the fibers, and the extrusion speed is preferably 50 μL / min. The coagulation bath is a solution of calcium chloride and ferrous chloride, the calcium chloride concentration is preferably 20 mg / mL, and the ferrous chloride concentration is 0.5 mg / mL. During the spinning process, K3Fe(CN)6 and ferrous chloride react to form Prussian blue. A high-performance rare earth photothermal biofiber is obtained. The collected fibers are soaked in EDC / NHS solution and then post-stretched, and the concentrations of EDC / NHS are preferably 0.3 and 0.1 mg / mL, respectively. Good rare earth photothermal biofibers are obtained, wherein the post-stretching degree is preferably 100% of the original fiber length.

[0139] Example 12 Preparation of rare earth photothermal biofibers 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, and the concentration of neodymium chloride is preferably 40 mg / mL, and the concentration of ferrous chloride is 0.5 mg / mL. A high-performance rare earth photothermal bio-fiber 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. Good rare earth photothermal bio-fibers are obtained, wherein the degree of post-stretching is preferably 100% of the original fiber length.

[0141] Example 13 Testing of fiber mechanical strength and testing of fiber optical and thermal properties

[0142] The specific test method is: take the stretched fiber 8mm, use the single fiber tensile tester, set the test length to 5mm, clamp the fiber, stretch it at a speed of 10mm / min, and obtain the tensile value; the fiber diameter is measured by a microscope, the tensile strength is obtained by the ratio of the tensile force to the fiber cross-sectional area, and the tensile curve is obtained by processing the origin software. It can be seen that the breaking strength of the fibers prepared in Examples 3 to 8 is above 400MPa (Table 1), which can meet the application requirements of clothing fabric preparation. Among them, the fiber prepared in Example 3 is preferably 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 illumination was tested using a FLIR infrared thermal imaging camera, and the temperature change curve over time was recorded, such as Figures 5 to 9 As shown in (Table 2). 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 optimal, which are 311.62±10.52MPa and 153.81±6.21%, respectively (Guo Jianjun. Research on photothermal nanoparticle functionalized silkworm silk protein composites [D]. Jiangsu University of Science and Technology, 2022. DOI: 10.27171 / d.cnki.ghdcc.2022.000448.).

[0150] RSF-PDA composite fiber, strength 246MPa, photothermal efficiency 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 core structure of the recombinant protein is composed of ELP structural units or at least one of Z1 or Z2 structural units and ELP structural units; The amino acid sequence of the ELP structural unit is VPGXG, wherein X is K or V; The amino acid sequence of the Z1 structural unit is PAATAVSHTTHHAP; The amino acid sequence of the Z2 structural unit is VGSGGRPSDSYGAPGGGN; The polysaccharide includes sodium alginate, chitosan or cellulose; The nanoparticles are NaNdF4 modified with Teng's blue or Bruce's blue.

2. The photothermal protein fiber according to claim 1, characterized in that: 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 of 1 to 5, b2 is an integer of 5 to 15, b3 is an integer of 1 to 16, b4 is an integer of 1 to 10, b5 is an integer of 20 to 40, b6 is an integer of 5 to 15, and b7 is an integer of 5 to 15.

3. The photothermal protein fiber according to claim 1 or 2, 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.

4. The photothermal protein fiber according to any one of claims 1 to 3, characterized in that: The mass ratio of the recombinant protein, nanoparticles and polysaccharide is 1:(1-5):

10.

5. The photothermal protein fiber according to any one of claims 1 to 4, characterized in that: The particle size of the nanoparticles is 180nm~220nm.

6. The method for preparing the photothermal protein fiber according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: collecting fibers after extruding the spinning solution into a coagulation solution, and obtaining the biological protein fibers through cross-linking and stretching the 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.

7. The preparation method according to claim 6, 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 NaNdF4, recombinant protein, sodium alginate, and K3Fe(CN)6 is (2~10):2:20:0.

5.

8. A photothermal nanocomposite material, characterized in that: It comprises at least one of the biological protein fibers described in any one of claims 1 to 5 and / or the biological protein fibers prepared by the preparation method described in claim 6 or 7 and a matrix thereof.

9. Application 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: A), the biological protein fiber according to any one of claims 1 to 5; B), biological protein fiber prepared by the preparation method according to claim 6 or 7; C) The photothermal nanocomposite material according to claim 8.

10. 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 biological protein fiber according to any one of claims 1 to 5; b) Bioprotein fiber prepared by the preparation method according to any one of claims 6 or 7; c) The photothermal nanocomposite material according to claim 8.

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