Protein phosphorescent material as well as preparation method and application thereof

Abstract

The invention provides a protein phosphorescent material as well as a preparation method and application thereof. The preparation method comprises the following steps: dissolving arylboronic acid molecules in water, mixing with a protein solution and an alkaline substance to obtain a mixed solution, carrying out dehydration condensation reaction on the mixed solution to obtain phosphorescent ink, and preparing the phosphorescent ink into the protein phosphorescent material. The preparation conditions are mild, the reaction is rapid, the protein provides a rigid environment to limit molecular thermal power such as vibration and rotation of luminescent molecules so as to inhibit non-radiative transition, and long-life organic room-temperature phosphorescence is realized. Based on the excellent processability and degradability of the fibrous protein, the prepared phosphorescent material can be processed into various material forms and is environment-friendly. In addition, phosphorescence emission is adjusted through stimulation of external conditions such as water, methanol, UV and temperature, and display and hiding of phosphorescence patterns are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic photoelectric materials, and relates to a protein phosphorescent material, a preparation method and application thereof, and specifically to a protein phosphorescent material with multiple material forms and multiple stimulus responses, a preparation method and application thereof. Background Art

[0002] Long-life organic room-temperature phosphorescent (RTP) materials have been applied in a variety of fields, including information encryption, anti-counterfeiting, organic light-emitting diodes (OLEDs), sensing, and bioimaging, due to their advantages, such as low toxicity, long emission lifetime at room temperature, high signal-to-noise ratio, and large Stokes shift. However, the phosphorescence efficiency at room temperature decreases significantly due to the weak spin-orbit coupling (SOC) of triplet excitons and the inevitable rapid nonradiative decay of triplet excitons caused by molecular motion and ambient oxygen and moisture. To achieve long-life organic RTP materials, methods such as crystal engineering, self-assembly, encapsulation, polymerization, or host-guest doping are used to restrict nonradiative transitions (collision, vibration, or rotation) in a rigid environment within polymer and non-polymer systems. This approach controls the motion of molecules / groups and isolates oxygen, thereby suppressing the nonradiative transition of excitons from the excited triplet state to the ground state. The polymer matrix, with its large molecular weight and long molecular chains, provides a sufficiently rigid environment to suppress the thermal motion of molecules and reduce the quenching effect of oxygen and moisture in the ambient atmosphere.

[0003] Currently, through the screening and clever design of polymer-based materials, stimulus-responsive or multi-material phosphorescent materials can be developed for applications in fields such as information encryption, anti-counterfeiting, and sensing. Professor Li Zhen's team prepared humidity-responsive room-temperature phosphorescent materials using PVA as a substrate, achieving information anti-counterfeiting (Completely aqueous processable stimulus responsive organic room temperature phosphorescence materials with tunable afterglow color. Nat. Commun. 2022, 13, 347). Professor Zhang Jun's team prepared antibacterial, waterproof, and environmentally friendly phosphorescent films, coatings, and fibers using cellulose as a substrate (Ultralong phosphorescence cellulose with excellent anti-bacterial, water-resistant, and ease-to-process performance. Nat. Commun. 2022, 13, 1117).

[0004] CN117964838A discloses an intelligent responsive organic room-temperature phosphorescent material, its preparation method, and its application. This method utilizes thermally initiated polymerization of a bipyridine phosphor, a monomer, and a crosslinker to produce an intelligent responsive organic phosphorescent material. The material responds to touch and has broad application prospects in afterglow imaging, information encryption and anti-counterfeiting, warning systems, and sensing.

[0005] Although the existing technology has reported a lot on stimulus-responsive or multi-material organic room-temperature phosphorescent materials, due to the simple chemical structure of synthetic polymers represented by PVA and natural polymers represented by cellulose, it is difficult to achieve complex functionalization, resulting in problems such as limited material form, single stimulus responsiveness, and limited functional applications.

[0006] Therefore, how to develop a new organic phosphorescent material with good processability, environmental friendliness, multi-material form, multi-stimulus responsiveness and multiple functions remains a huge challenge. Summary of the Invention

[0007] In response to the deficiencies in the prior art, the present invention aims to provide a protein phosphorescent material, a preparation method thereof, and an application thereof, and more specifically, to provide a protein phosphorescent material with multiple material forms and multiple stimulus responses, a preparation method thereof, and an application thereof. The present invention selects a protein solution rich in various amino acids as the matrix material. Due to its rich surface chemistry, amino acids with specific functional side chain groups (-OH, -COOH, -NH2) can rapidly undergo dehydration condensation reactions with the B-OH in the arylboronic acid molecules under the action of alkaline substances (such as ammonium hydroxide). Through the structural constraints of the BO covalent bond and the hydrogen bonds in the protein, the radiation process of the triple exciton can be reasonably tamed or protected, thereby improving the stability and weather resistance of the phosphorescent material. In addition, due to the unique comprehensive characteristics of proteins, such as excellent physical and chemical properties, good biocompatibility and adaptability, they can be processed from aqueous solutions or organic solvents into a variety of material forms (films, gels, fibers, nanofibers, freeze-dried scaffolds, microspheres, etc.), and have specific stimulus responsiveness to temperature, humidity and light. Therefore, proteins can provide a platform for the development of multi-material forms (phosphorescent films, phosphorescent nanofibers, phosphorescent freeze-dried scaffolds, phosphorescent microspheres and phosphorescent inks, etc.) and multi-stimulus responsive phosphorescent materials, enabling them to be more widely used in advanced fields.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing a protein phosphorescent material, the method comprising the following steps:

[0010] Arylboronic acid molecules are dissolved in water, and then mixed with a protein solution and an alkaline substance to obtain a mixed solution. The mixed solution undergoes a dehydration condensation reaction to obtain a phosphorescent ink, and the phosphorescent ink is prepared into the protein phosphorescent material.

[0011] The preparation method provided by this invention offers mild preparation conditions and a rapid reaction. Proteins provide a rigid environment that restricts the vibrational and rotational thermal motion of the luminescent molecules, inhibiting non-radiative transitions and achieving long-lived organic room-temperature phosphorescence. Due to the excellent processability and degradability of fibrous proteins, the prepared protein phosphorescent material can be processed into a variety of forms and is environmentally friendly. Furthermore, the invention utilizes external stimuli such as water, methanol, UV light, or temperature to modulate phosphorescent emission, enabling the display and concealment of phosphorescent patterns.

[0012] Preferably, the aromatic boronic acid molecule includes any one or a combination of at least two of 3-biphenylboronic acid, 4-biphenylboronic acid, 1-naphthaleneboronic acid, 1-pyrenylboronic acid, 9-phenanthreneboronic acid, 2-naphthaleneboronic acid, 4-(2-naphthyl)phenylboronic acid, dibenzo[b,d]thiophen-3-ylboronic acid, 1,1':3',1"-terphenyl-5'-boronic acid, and 1,3,5-tris(4-phenylboronic acid)benzene.

[0013] Preferably, the protein solution comprises any one of a silk fibroin solution, a wool keratin solution, a soy protein solution, or a collagen solution, or a combination of at least two thereof. It should be noted that the present invention does not specifically limit the solvent of the protein solution, and for example, it may be water or other solvents that can dissolve the protein into chain proteins.

[0014] Preferably, the alkaline substance comprises ammonium hydroxide.

[0015] Preferably, the concentration of the arylboronic acid molecules in the mixed solution is 0.01%-1%, for example, 0.01%, 0.02%, 0.03%, 0.05%, 0.08%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.

[0016] Preferably, the concentration of the protein solution in the mixed solution is 1%-20%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc.

[0017] Preferably, the concentration of the alkaline substance in the mixed solution is 0.5%-10%, for example, 0.5%, 0.6%, 0.8%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0018] Preferably, the temperature of the dehydration condensation reaction is 20-100°C, for example, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, etc., and the time of the dehydration condensation reaction is 1-60min, for example, 1min, 3min, 5min, 8min, 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min, etc.

[0019] Preferably, the protein phosphorescent material is in the form of any one of phosphorescent film, phosphorescent coating, phosphorescent scaffold, phosphorescent microsphere, phosphorescent nanofiber, or a combination of at least two thereof.

[0020] Preferably, preparing the phosphorescent ink into the protein phosphorescent material specifically includes: preparing the phosphorescent ink into a protein phosphorescent material with room temperature phosphorescence in the form of a film, coating, scaffold, microsphere or nanofiber by drying, freeze drying, spray drying or electrospinning.

[0021] Preferably, the stimulus response means of the protein phosphorescent material includes any one of humidity, temperature, pH, methanol vapor, and deep ultraviolet light, or a combination of at least two thereof.

[0022] Preferably, the excitation light source of the protein phosphorescent material is ultraviolet light with a wavelength range of 254-365 nm, such as 254 nm, 312 nm, 365 nm, etc.

[0023] Preferably, the phosphorescent ink is processed by any one of inkjet printing, screen printing, stamping, and spraying, or a combination of at least two of them.

[0024] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0025] Aryl boronic acid molecules are dissolved in water and then mixed with a protein solution and an alkaline substance to obtain a mixed solution. The mixed solution is subjected to a dehydration condensation reaction at 20-100°C for 1-60 minutes to obtain a phosphorescent ink. The phosphorescent ink is then prepared into a protein phosphorescent material with room temperature phosphorescence in the form of a film, coating, scaffold, microsphere or nanofiber by drying, freeze drying, spray drying or electrospinning.

[0026] In a second aspect, the present invention provides a protein phosphorescent material, which is prepared using the preparation method described in the first aspect.

[0027] Preferably, the protein phosphorescent material has any one of recyclability, adhesion, weldability, and ductility, or a combination of at least two thereof.

[0028] The phosphorescent material prepared by the present invention has good processability, environmental friendliness, multi-material form, multi-stimulus responsiveness and multiple functions. Specifically, the mixed solution is dried, freeze-dried, spray-dried or electrospinning to obtain a film, coating, scaffold, microsphere or nanofiber with room temperature phosphorescence. The matrix material used is protein, and the prepared phosphorescent material is environmentally friendly and biocompatible, and has good recyclability, weldability, 3D ductility and adhesion. Water / methanol molecules penetrate into the protein matrix, which affects the hydrogen bonds between protein molecular chains, thereby causing molecular rearrangement and destroying the rigidity of the molecular chains; 254nm ultraviolet irradiation causes photodegradation of the protein matrix; increasing the temperature causes thermal inactivation of aromatic boronic acid, causing the afterglow to terminate rapidly at high temperature. Therefore, the resulting phosphorescent properties can be adjusted by the stimulation of external conditions such as water, methanol, UV or temperature.

[0029] In a third aspect, the present invention provides a use of the protein phosphorescent material as described in the second aspect in afterglow imaging, information encryption, information anti-counterfeiting, warning or sensing.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The protein phosphorescent materials prepared by the present invention can be applied to more fields due to their excellent processability and functionality, such as complex anti-counterfeiting, information encryption and storage, smart labels, packaging, and detection sensors. In particular, the inherent environmental friendliness, biocompatibility, and biodegradability of proteins make protein-based phosphorescent materials non-polluting to the environment and can establish a good interface with the human body. The preparation strategy of protein-based phosphorescent materials proposed in the present invention is superior to other room temperature phosphorescent materials in terms of comprehensive factors such as processability, stimulus responsiveness, multifunctionality, environmental friendliness, and potential for wide application.

[0032] (2) Since deep ultraviolet light (254 nm) can induce peptide chain breakage and protein photodegradation, water or methanol molecules can destroy hydrogen bonds in protein molecular chains, and elevated temperatures can cause thermal inactivation of arylboronic acid. Therefore, by utilizing the stimulation of external conditions such as water, methanol, UV or temperature to regulate the phosphorescence emission of protein / arylboronic acid materials, the display and hiding of phosphorescent patterns under different stimuli can be achieved. The protein phosphorescent material prepared by the present invention not only provides a good idea for the phosphorescent patterning of current organic room temperature phosphorescent materials, but also further enhances the information encryption and sensing capabilities of protein / arylboronic acid materials.

[0033] (3) The two-dimensional planar structure of the phosphorescent film prepared by the present invention can be combined with complex origami or paper-cutting techniques to create a variety of complex three-dimensional phosphorescent materials. These three-dimensional multifunctional platforms with afterglow have optical and structural stability under ambient conditions and are therefore suitable for the display and encryption of three-dimensional phosphorescent information.

[0034] (4) The phosphorescent ink prepared by the present invention can be processed into different coatings and attached to the surfaces of various substrates. For example, by spraying with a spray gun, a two-dimensional or three-dimensional phosphorescent coating can be easily formed on various substrates, including ceramics, leaves, paper, plastics, specimens, etc. Because proteins have good biocompatibility and water solubility, the phosphorescent coating prepared by the present invention can be fully applied to food anti-counterfeiting and medical anti-counterfeiting. In addition, combined with fluorescent ink, multiple anti-counterfeiting can be achieved, thereby protecting and anti-counterfeiting assets such as banknotes or calligraphy and paintings that require high security. As a new type of ink, the phosphorescent coating prepared by the present invention shows good practical application value, provides a new paradigm for anti-counterfeiting printing, and greatly broadens the application scope of phosphorescent materials in various fields.

[0035] (5) The organic room temperature phosphorescent material of the present invention can be used in optical displays of electronic devices that integrate display, anti-counterfeiting and sensing functions, as well as in new masks that integrate anti-counterfeiting and antibacterial functions.

[0036] (6) The protein and arylboronic acid molecules required for the present invention are cheap and readily available, the preparation method is simple, the reaction conditions are mild, and the invention has excellent economic and environmental properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 These are optical photographs of phosphorescent inks prepared using different arylboronic acid molecules in Examples 2-4 under white light.

[0038] Figure 2 These are afterglow images of the silk fibroin / 4-biphenylboronic acid, silk fibroin / 1-naphthaleneboronic acid, and silk fibroin / 1-pyreneboronic acid phosphorescent films prepared in Example 5.

[0039] Figure 3 These are optical photographs of the phosphorescence decay over time of the silk fibroin / 4-biphenylboronic acid, silk fibroin / 1-naphthaleneboronic acid, and silk fibroin / 1-pyreneboronic acid phosphorescent films prepared in Example 5 after the UV light is turned off.

[0040] Figure 4 These are the fluorescence emission spectra and phosphorescence emission spectra of the silk fibroin / 4-biphenylboronic acid, silk fibroin / 1-naphthaleneboronic acid, and silk fibroin / 1-pyreneboronic acid phosphorescent films prepared in Example 5.

[0041] Figure 5 These are the time-resolved emission decay curves of the silk fibroin / 4-biphenylboronic acid, silk fibroin / 1-naphthaleneboronic acid, and silk fibroin / 1-pyreneboronic acid phosphorescent films prepared in Example 5.

[0042] Figure 6This is an optical photograph of the silk fibroin-based phosphorescent scaffold with different phosphorescent colors prepared by freeze-drying in Example 6 after the ultraviolet light is turned off.

[0043] Figure 7 This is a scanning electron microscope image of the silk fibroin / 4-biphenylboronic acid phosphorescent scaffold prepared by freeze-drying in Example 6.

[0044] Figure 8 This is an optical photograph of the silk fibroin-based phosphorescent microspheres with different phosphorescent colors prepared by spray drying in Example 7 after the ultraviolet light is turned off.

[0045] Figure 9 This is a scanning electron microscope image of the silk fibroin / 4-biphenylboronic acid phosphorescent microspheres prepared by spray drying in Example 7.

[0046] Figure 10 This is an optical photograph of the silk fibroin / 4-biphenylboronic acid phosphorescent nanofibers in Example 8.

[0047] Figure 11 This is a scanning electron microscope image of the silk fibroin / 4-biphenylboronic acid phosphorescent nanofibers in Example 8.

[0048] Figure 12 This is an optical photograph of a phosphorescent coating formed on A4 paper by an inkjet printer using phosphorescent inks prepared with different arylboronic acid molecules in Example 9 after the ultraviolet light is turned off.

[0049] Figure 13 These are optical photographs of the phosphorescent inks prepared using different arylboronic acid molecules in Example 9 after spraying on different substrates.

[0050] Figure 14 This is an optical photograph of the phosphorescent ink prepared using different arylboronic acid molecules in Example 9 printed on a blank cloth bag by screen printing.

[0051] Figure 15 This is an optical photograph of a phosphorescent coating formed on an arm using a stamp using silk fibroin / 4-biphenylboronic acid phosphorescent ink in Example 9.

[0052] Figure 16 1 is a curve showing the change of normalized phosphorescence intensity over time of the phosphorescent film prepared in Example 5 after exposure to ultraviolet light of different wavelengths.

[0053] Figure 17 This is a photo of the afterglow of the silk fibroin-based phosphorescent film after “light writing” in Example 10.

[0054] Figure 18 2 is the phosphorescence intensity change curve of the silk fibroin / 4-biphenylboronic acid film prepared in Example 5 in water or methanol vapor environment.

[0055] Figure 19 This is the phosphorescence pattern of the silk fibroin / 4-biphenylboronic acid film with patterned PMMA coating prepared in Example 11 stimulated by reversible water vapor.

[0056] Figure 20 The functional relationship between the normalized phosphorescence intensity of the glycerol-doped silk fibroin / 4-biphenylboronic acid film prepared in Example 12 and the glycerol doping concentration at different humidity levels.

[0057] Figure 21 The afterglow photographs of the reversible humidity response of the glycerol-doped silk fibroin / 4-biphenylboronic acid film prepared for Examples 10 and 12 were obtained.

[0058] Figure 22 The normalized phosphorescence intensity of the silk fibroin / 4-biphenylboronic acid film prepared in Example 5 is a function of temperature.

[0059] Figure 23 This is an afterglow photograph of the reversible heat capacity achieved by the silk fibroin-based phosphorescent film after light printing in Example 13.

[0060] Figure 24 These are afterglow photos of the silk fibroin / 4-biphenylboronic acid phosphorescent film in Example 15 at different temperatures.

[0061] Figure 25 These are afterglow photos of the polyvinyl alcohol / 4-biphenylboric acid phosphorescent film in Comparative Example 1 at different temperatures. DETAILED DESCRIPTION

[0062] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0063] Example 1: Preparation of silk fibroin solution

[0064] Step 1, Silk Degumming: Weigh 25g of silk cocoons and 21.2g of anhydrous sodium carbonate. Pour 10L of deionized water into a stainless steel bucket and heat using an induction cooker. When the deionized water is about to boil, add the weighed anhydrous sodium carbonate. Continue heating and stirring until boiling to fully dissolve the anhydrous sodium carbonate. Add the weighed silk cocoons and continue boiling for 30 minutes, stirring every 5 minutes to dissolve the sericin on the surface of the raw silk. Rub the degummed silk with deionized water four times to fully remove the sericin from the surface. Finally, wring the degummed silk thoroughly and place it in a fume hood to dry overnight.

[0065] Step 2, silk dissolution: Weigh 80.75g of lithium bromide (99.9%) into a 500mL beaker, dilute to 9.3M in a 100mL volumetric flask, weigh 5g of the degummed silk in step 1 into a 50mL beaker, pour in 20mL of lithium bromide solution, place in a 60℃ oven, shake the beaker every 1 hour, and take out after 4 hours.

[0066] Step 3, Dialysis of the Silk Fibroin Solution: Cut a section of dialysis bag with a molecular weight cut-off of 3500 kDa. Soak the bag in pure water for approximately 5 minutes. Pour the silk solution into the other end of the bag. Once the solution is filled, clamp the other end with a dialysis clamp. Place the bag in a beaker containing 5 L of pure water and begin dialysis. Change the water every 6 hours for a total of 10 times.

[0067] Step 4, centrifugation method of silk fibroin solution: take out the silk fibroin solution in the dialysis bag and pour it into a centrifuge tube, centrifuge it in a high-speed centrifuge, the centrifuge parameters are: 11000r / min, each centrifugation is 20min, and centrifugation is performed twice in total.

[0068] Step 5, storage: put the prepared silk fibroin solution into a centrifuge tube and store it in a 4°C refrigerator for 7 to 10 days.

[0069] Example 2: Preparation of silk fibroin / 4-biphenylboronic acid phosphorescent ink

[0070] Step 1: Dissolve 5 mg of 4-biphenylboronic acid powder in 4 mL of pure water.

[0071] Step 2: Add 1 mL of 25% concentrated ammonia to the 4-biphenylboronic acid aqueous solution and stir at room temperature for 30 minutes until the 4-biphenylboronic acid is fully dissolved to obtain an alkaline 4-biphenylboronic acid aqueous solution;

[0072] Step 3, adding 3 mL of a 12% silk fibroin aqueous solution to an alkaline 4-biphenylboronic acid aqueous solution, reacting at 80° C. for 20 minutes, and cooling to room temperature to obtain a silk fibroin / 4-biphenylboronic acid phosphorescent ink;

[0073] Step 4: Place the prepared silk fibroin / 4-biphenylboronic acid phosphorescent ink into a centrifuge tube and store it in a refrigerator at 4° C. away from light for 10 to 15 days.

[0074] Example 3: Preparation of silk fibroin / 1-naphthaleneboronic acid phosphorescent ink

[0075] Step 1: Dissolve 5 mg of 1-naphthaleneboronic acid powder in 4 mL of pure water.

[0076] Step 2: Add 1 mL of 25% concentrated ammonia to the 1-naphthaleneboric acid aqueous solution and stir at room temperature for 30 minutes until the 1-naphthaleneboric acid is fully dissolved to obtain an alkaline 1-naphthaleneboric acid aqueous solution;

[0077] Step 3, adding 3 mL of a 12% silk fibroin aqueous solution to an alkaline 1-naphthaleneboric acid aqueous solution, reacting at 80° C. for 20 minutes, and cooling to room temperature to obtain a silk fibroin / 1-naphthaleneboric acid phosphorescent ink;

[0078] Step 4: Place the prepared silk fibroin 1-naphthalene boric acid phosphorescent ink into a centrifuge tube and store it in a refrigerator at 4° C. away from light for 10 to 15 days.

[0079] Example 4: Preparation of silk fibroin / 1-pyrenylboronic acid phosphorescent ink

[0080] Step 1: Dissolve 10 mg of 1-pyrenylboronic acid powder in 4 mL of pure water.

[0081] Step 2: Add 1 mL of 25% concentrated aqueous ammonia to the 1-pyrenylboronic acid aqueous solution and stir at room temperature for 30 minutes until the 1-pyrenylboronic acid is fully dissolved to obtain an alkaline 1-pyrenylboronic acid aqueous solution;

[0082] Step 3, adding 3 mL of a 12% silk fibroin aqueous solution to an alkaline 1-pyrenylboronic acid aqueous solution, reacting at 80° C. for 20 minutes, and cooling to room temperature to obtain a silk fibroin / 1-pyrenylboronic acid phosphorescent ink;

[0083] Step 4: Place the prepared silk fibroin / 1-pyrenylboronic acid phosphorescent ink into a centrifuge tube and store it in a refrigerator at 4° C. away from light for 10 to 15 days.

[0084] Figure 1 These are optical photographs of the phosphorescent inks prepared using different arylboronic acid molecules in Examples 2-4 under visible light. It can be seen that the prepared silk fibroin-based phosphorescent inks are transparent solutions with excellent optical properties.

[0085] Example 5: Preparation of silk fibroin-based phosphorescent film

[0086] Step 1: Take 100 μL of 1H,1H,2H,2H-perfluorooctyltriethoxysilane solution in a 1 mL centrifuge tube and place it in a vacuum drying oven with the cap of the centrifuge tube open;

[0087] Step 2: Place a 10 cm diameter silicon wafer in a vacuum drying oven, exposing the side to be treated to air.

[0088] Step 3: Run a vacuum drying oven to perform hydrophobic treatment on the surface of the silicon wafer. The vacuuming time is 20 minutes and the temperature is set to 25°C.

[0089] Step 4: Take out the silicon wafer and place it on a balance table. Take 10 mL of the phosphorescent ink prepared in Examples 2-4 and spread it on the silicon wafer. Control the humidity at 45% RT and the temperature at 25°C for 24 hours.

[0090] Step 5: Remove the dried silk fibroin-based phosphorescent film (~50 μm) from the silicon wafer and store it at room temperature under 30% RT humidity.

[0091] The silk fibroin / 4-biphenylboronic acid phosphorescent film prepared in Example 5 was irradiated with ultraviolet light having an excitation wavelength of 254 nm, the silk fibroin / 1-naphthaleneboronic acid phosphorescent film prepared in Example 5 was irradiated with ultraviolet light having an excitation wavelength of 312 nm, and the silk fibroin / 1-pyrenylboronic acid phosphorescent film prepared in Example 5 was irradiated with ultraviolet light having an excitation wavelength of 365 nm. The afterglow picture and the optical photograph of the phosphorescence decay over time after the ultraviolet lamp was turned off are shown as follows. Figure 2 and Figure 3 shown.

[0092] Figure 2 This is the afterglow picture of the silk fibroin / 4-biphenylboronic acid, silk fibroin / 1-naphthaleneboronic acid, and silk fibroin / 1-pyrenylboronic acid phosphorescent films prepared in Example 5. Figure 2 a is an optical photograph of the silk fibroin / 4-biphenylboronic acid phosphorescent film after the UV light is turned off. Figure 2 b is an optical photograph of the silk fibroin / 1-naphthaleneboronic acid phosphorescent film after the UV light is turned off. Figure 2 c is an optical photograph of the silk fibroin / 1-pyrene boric acid phosphorescent film after the UV light is turned off.

[0093] Figure 3 These are optical photographs of the phosphorescence decay over time of the silk fibroin / 4-biphenylboronic acid, silk fibroin / 1-naphthaleneboronic acid, and silk fibroin / 1-pyreneboronic acid phosphorescent films prepared in Example 5 after the UV light is turned off.

[0094] It can be seen that when the excitation light wavelengths are 254, 312 and 365 nm, all the silk fibroin / boric acid films emit purple or blue fluorescence under ultraviolet light (such as Figure 3 As shown in Figure 2 ), since the aromatic boronic acid extends the π conjugation, after turning off the UV light, the afterglow colors of the three polymer films change from blue to green and red (as shown in Figure 2 ) from the silk fibroin / 4-biphenylboronic acid, silk fibroin / 1-naphthaleneboronic acid, and silk fibroin / 1-pyreneboronic acid phosphorescent films. Figure 2 To the naked eye, the blue afterglow can last for 9 seconds, the yellow-green afterglow can last for 3 seconds, and the red afterglow can last for 0.6 seconds.

[0095] Figure 4The fluorescence emission spectra and phosphorescence emission spectra of the silk fibroin / 4-biphenylboronic acid, silk fibroin / 1-naphthaleneboronic acid, and silk fibroin / 1-pyrenylboronic acid phosphorescent films prepared in Example 5 are shown on the left side of the figure for the fluorescence emission spectrum, and on the right side for the phosphorescence emission spectrum. For the silk fibroin / 4-biphenylboronic acid film, when the excitation wavelength (λex) is 254 nm, the steady-state emission and delayed emission (td=1 ms) show maximum peaks at 323 and 475 nm, respectively. For the silk fibroin / 1-naphthaleneboronic acid film, when the excitation wavelength (λex) is 312 nm, the steady-state emission and delayed emission (td=1 ms) show maximum peaks at 338 and 525 nm, respectively. For the silk fibroin / 1-pyrenylboronic acid phosphorescent film, when the excitation wavelength (λex) is 365 nm, the steady-state emission and delayed emission (td=1 ms) show maximum peaks at 389 and 612 nm, respectively.

[0096] Figure 5 The time-resolved emission decay curves for the silk fibroin / 4-biphenylboronic acid, silk fibroin / 1-naphthaleneboronic acid, and silk fibroin / 1-pyrenylboronic acid phosphorescent films prepared in Example 5 show that the silk fibroin-based phosphorescent films exhibit long-lasting, stable super-afterglow emission. The silk fibroin / 4-biphenylboronic acid film has the longest RTP lifetime, reaching 233 ms, with a corresponding RTP quantum yield of 2.56%. The lifetimes and corresponding phosphorescence quantum yields of the silk fibroin / 1-naphthaleneboronic acid and silk fibroin / 1-pyrenylboronic acid phosphorescent films are 164 ms and 4.5%, and 44 ms and 12.32%, respectively.

[0097] Example 6: Preparation of silk fibroin-based phosphorescent scaffold

[0098] Step 1: Take 40 mL of the phosphorescent ink prepared in Examples 2-4 and pour it into acrylic molds with a side length of 5×5 cm;

[0099] Step 2: Place the acrylic mold containing the phosphorescent ink in a -80°C freezer overnight.

[0100] Step 3: Place the frozen phosphorescent ink into a freeze dryer for 48 hours to obtain a silk fibroin-based phosphorescent scaffold, which is then stored at room temperature with a humidity of 30% RT.

[0101] Figure 6 This is an optical photograph of the silk fibroin-based phosphorescent scaffold with different phosphorescent colors prepared by freeze drying in Example 6 after the ultraviolet light is turned off. Figure 6 a is an optical photograph of the silk fibroin / 4-biphenylboronic acid phosphorescent scaffold after turning off the UV lamp (the excitation wavelength of the UV lamp is 254 nm). Figure 6b is an optical photograph of the silk fibroin 1-naphthalene boric acid phosphorescent scaffold after turning off the UV lamp (the excitation wavelength of the UV lamp is 312 nm). Figure 6 c is an optical photograph of the silk fibroin / 1-pyrenylboronic acid phosphorescent scaffold after turning off the UV lamp (the excitation wavelength of the UV lamp is 365 nm). It can be seen that the silk fibroin-based phosphorescent scaffold prepared by freeze-drying has a complete structure and emits a variety of phosphorescent colors.

[0102] Figure 7 This is a scanning electron microscope image of the silk fibroin / 4-biphenylboronic acid phosphorescent scaffold prepared by freeze-drying in Example 6.

[0103] Example 7: Preparation of silk fibroin-based phosphorescent microspheres

[0104] Step 1: Turn on the spray dryer and the vacuum pump;

[0105] Step 2, set the inlet temperature to 150°C and turn on the heater;

[0106] Step 3: When the inlet temperature reaches 150°C, turn on the compressed air and set the compressed air flow rate to 600 L / h through the needle valve on the flow controller;

[0107] Step 4: Place the feed tube in pure water and turn on the peristaltic pump. Set the peristaltic pump to 30% and the pure water cleaning time to 30 minutes.

[0108] Step 5: Take the feed tube out of the pure water and place it in the phosphorescent ink prepared in Examples 2-4, respectively, and start spray drying;

[0109] Step 6: After spray drying, clean the passages with pure water for 15 minutes and then turn off the instrument.

[0110] Step 7: Collect the phosphorescent microspheres and store them at room temperature with 30% RT humidity.

[0111] Figure 8 This is an optical photograph of silk fibroin-based phosphorescent microspheres with different phosphorescent colors prepared by spray drying in Example 7 after the UV light is turned off. Figure 8 a is an optical photograph of silk fibroin / 4-biphenylboronic acid phosphorescent microspheres after turning off the UV lamp (the excitation wavelength of the UV lamp is 254 nm). Figure 8 b is an optical photograph of silk fibroin / 1-naphthaleneboronic acid phosphorescent microspheres after turning off the UV lamp (the excitation wavelength of the UV lamp is 312 nm). Figure 8 c is an optical photograph of silk fibroin / 1-pyrene boric acid phosphorescent microspheres after turning off the UV lamp (the excitation light wavelength of the UV lamp is 365 nm).

[0112] Figure 9This is a scanning electron microscope image of the silk fibroin / 4-biphenylboronic acid phosphorescent microspheres prepared by spray drying in Example 7.

[0113] Example 8: Preparation of silk fibroin-based phosphorescent nanofibers

[0114] Step 1, concentrating the silk fibroin / 4-biphenylboronic acid phosphorescent ink prepared in Example 2 to 12% wt;

[0115] Step 2: Add the concentrated silk fibroin / 4-biphenylboronic acid phosphorescent ink into a 5 mL syringe, place it on the launch stand of the electrospinning machine, and connect a 19G launch needle;

[0116] Step 3: Set the distance between the receiving board and the transmitter to 10 cm, the voltage to 20 kV, and the injection pump speed to 1 mm / min.

[0117] Step 4: start electrospinning, stop after 3 hours, collect the prepared silk fibroin-based phosphorescent nanofibers, and store them at room temperature under 30% RT humidity.

[0118] Figure 10 This is an optical photograph of the silk fibroin / 4-biphenylboronic acid phosphorescent nanofiber in Example 8. Figure 10 a is an optical photograph of silk fibroin / 4-biphenylboronic acid phosphorescent nanofibers under visible light. Figure 10 b is an optical photograph of silk fibroin / 4-biphenylboronic acid phosphorescent nanofibers after the ultraviolet lamp is turned off (the excitation light wavelength of the ultraviolet lamp is 254 nm).

[0119] Figure 11 This is a scanning electron microscope image of the silk fibroin / 4-biphenylboronic acid phosphorescent nanofibers in Example 8. It can be seen that the prepared silk fibroin-based phosphorescent nanofibers are uniform in size.

[0120] Example 9: Preparation of silk fibroin-based phosphorescent coating

[0121] Step 1: Place the prepared phosphorescent ink in an inkjet printer / spray gun / screen / sponge respectively;

[0122] Step 2: Print the phosphorescent ink on A4 paper using an inkjet printer to form a phosphorescent coating; spray the phosphorescent ink on various substrates using a spray gun to form a phosphorescent coating; print the phosphorescent ink on a flat object using screen printing to form a phosphorescent coating; and print the phosphorescent ink on a substrate using a stamp to form a phosphorescent coating.

[0123] Figure 12Optical photographs of phosphorescent coatings formed on A4 paper using the phosphorescent inks prepared using different arylboronic acid molecules in Example 9 (specifically, those prepared in Examples 2-4) using an inkjet printer, after the UV light was turned off. This demonstrates that silk fibroin-based phosphorescent inks, when used with commercial inkjet printers, can achieve high-resolution, multi-color, large-area anti-counterfeiting printing of phosphorescent patterns.

[0124] Figure 13 These are optical photographs of phosphorescent inks prepared using different arylboronic acid molecules in Example 9 (specifically, those prepared in Examples 2 and 3) after spraying onto different substrates. The upper portion of the figure shows optical photographs of the phosphorescent inks sprayed onto different substrates under visible light, while the lower portion shows optical photographs of the phosphorescent inks sprayed onto different substrates with the UV light turned off. As can be seen, the phosphorescent inks can form two-dimensional or three-dimensional phosphorescent coatings on a variety of substrate surfaces.

[0125] Figure 14 This is an optical photograph of the phosphorescent ink prepared using different arylboronic acid molecules in Example 9 (specifically prepared in Example 2 and Example 3) printed on a blank cloth bag by screen printing. Figure 14 a is an optical photograph of the cloth bag under visible light after screen printing. Figure 14 b is an optical photograph of one side of the cloth bag after screen printing with the UV light turned off. Figure 14 c is an optical photograph of the other side of the cloth bag after screen printing with the UV light turned off.

[0126] Figure 15 This is an optical photograph of a phosphorescent coating formed on an arm using a stamp using silk fibroin / 4-biphenylboronic acid phosphorescent ink in Example 9.

[0127] Example 10: Preparation of “Light Writing” Patterned Silk Fibroin-Based Phosphorescent Film

[0128] Step 1: Take a piece of the phosphorescent film prepared in Example 5 and place a photomask with a pattern on the film;

[0129] Step 2: Place the phosphorescent film with the photomask under a 254nm UV lamp with a power of 40W and a distance of 3cm from the UV lamp.

[0130] Step 3: After 2 hours of UV exposure, turn off the UV lamp, remove the mask on the phosphorescent film, and store the sample at room temperature under 30% RT humidity.

[0131] Figure 16The normalized phosphorescence intensity of the phosphorescent film prepared in Example 5 after exposure to ultraviolet light of different wavelengths changes with time. It can be seen that under the irradiation of ultraviolet light of different wavelengths, the phosphorescence intensity of the three films all shows a trend of gradual decline. Among them, the 254nm ultraviolet light has the greatest effect on the phosphorescence intensity of the three films, and the phosphorescence intensity of the silk fibroin / 4-biphenylboronic acid film decreases the fastest. This shows that the breakage of the silk fibroin molecular chain caused by the 254nm ultraviolet irradiation destroys the rigid environment required for RTP emission and the ultraviolet light causes a certain degree of quenching of the chromophore.

[0132] Figure 17 This is a photograph of the afterglow of the silk fibroin-based phosphorescent film after light writing in Example 10. Figure 17 a is the afterglow photo of one side of the light writing film, Figure 17 b shows the afterglow patterning of two sides of the same film using light. It can be seen that afterglow patterning of silk fibroin-based phosphorescent films can be easily achieved using deep ultraviolet stimulation.

[0133] Example 11: Study on the Stimulus Response of Water / Methanol Vapor to Phosphorescent Films

[0134] Step 1: Place 100 μl of 1H,1H,2H,2H-perfluorooctyltriethoxysilane solution in a 1 mL centrifuge tube and place it in a vacuum drying oven with the tube lid open.

[0135] Step 2: Place a 10 cm diameter silicon wafer in a vacuum drying oven, exposing the side to be treated to air.

[0136] Step 3: Run a vacuum drying oven to perform hydrophobic treatment on the surface of the silicon wafer. The vacuuming time is 20 minutes and the temperature is set to 25°C.

[0137] Step 4: Take out the silicon wafer and place it on a spin coater. Apply 1 mL of the dissolved polymethyl methacrylate (PMMA) solution on the silicon wafer. Set the speed 1 to 500 rpm for 20 s and the speed 2 to 2000 rpm for 60 s.

[0138] Step 5: After the spin coating is completed, the silicon wafer is taken out, a mask is placed on the PMMA coating, and the wafer is placed in a plasma cleaning machine for etching for 30 minutes;

[0139] Step 6: After etching, place the silicon wafer on a balance table, take 10 mL of the prepared phosphorescent ink, spread it on the silicon wafer, control the humidity at 45% RT, the temperature at 25°C, and dry it for 24 hours;

[0140] Step 7: Remove the dried silk fibroin-based phosphorescent film (~50 μm) from the silicon wafer and store it at room temperature under 30% RT humidity.

[0141] Figure 18 2 is the phosphorescence intensity change curve of the silk fibroin / 4-biphenylboronic acid film prepared in Example 5 in water or methanol vapor environment. Figure 18 a is the normalized phosphorescence intensity of the silk fibroin / 4-biphenylboronic acid film prepared in Example 5 that changes with time in a water or methanol vapor environment. Figure 18 b shows the optical photograph and normalized phosphorescence intensity of the silk fibroin / 4-biphenylboronic acid film prepared in Example 5 in response to five repeated cycles of water / methanol vapor stimulation. It can be seen that the phosphorescence intensity of the silk fibroin / 4-biphenylboronic acid film gradually decreases with the extension of the fumigation time. Water vapor quenches RTP more efficiently, essentially completing quenching in 35 minutes. This is because water molecules are smaller and more polar than methanol molecules, making them more likely to disrupt interchain hydrogen bonds. After the film is removed from the water / methanol vapor and dried at room temperature, phosphorescence is restored due to the reorganization of interchain hydrogen bonds. When the film is fumigated with water / methanol vapor again, the phosphorescence intensity decreases again. Therefore, the phosphorescence properties of the film can be controlled by alternating water / methanol vapor fumigation and drying, and remain reversible for at least five cycles without noticeable fatigue. Therefore, the stimuli-responsiveness of silk fibroin / arylboronic acid materials to water / methanol vapor can be exploited to impart information encryption functionality to phosphorescent films.

[0142] Figure 19 This is the phosphorescence pattern of the silk fibroin / 4-biphenylboronic acid film with a patterned PMMA coating prepared in Example 11, which was reversibly stimulated by water vapor. It can be seen that by spin coating, etching and transfer, we composited a transparent polymethyl methacrylate (PMMA) coating with a "dragon" pattern on the surface of the silk fibroin / 4-biphenylboronic acid film. Then, the RTP was quenched by fumigation with water / methanol vapor. Due to the hydrophobicity of PMMA, water / methanol vapor will preferentially penetrate from areas not covered by PMMA. As the fumigation time increases, the "dragon" pattern appears in the form of RTP. When the water / methanol vapor completely penetrates the film, the phosphorescence pattern completely disappears, and the entire film has no phosphorescence emission. After the film is taken out and dried, because the water / methanol vapor will preferentially seep from the areas without PMMA, the RTP in the areas not covered by PMMA will recover first. As the drying time increases, the areas outside the "dragon" pattern appear in the form of RTP, and eventually, the RTP of the entire film is restored. Similarly, the code strip with phosphorescent information showed no information when there was no stimulation, under natural light, or when the UV light was turned off.

[0143] Example 12: Preparation of glycerol-doped silk fibroin-based phosphorescent film

[0144] Step 1: Take 10 mL of the prepared phosphorescent ink into a centrifuge tube, add 180 μl of glycerol, and mix well;

[0145] Step 2: Place 100 μl of 1H,1H,2H,2H-perfluorooctyltriethoxysilane solution in a 1 mL centrifuge tube and place it in a vacuum drying oven with the tube lid open.

[0146] Step 3: Place a 10 cm diameter silicon wafer in a vacuum drying oven, exposing the side to be treated to air.

[0147] Step 4: Run a vacuum drying oven to perform hydrophobic treatment on the surface of the silicon wafer. The vacuuming time is 20 minutes and the temperature is set to 25°C.

[0148] Step 5: Take out the silicon wafer and place it on a balance table. Take 10 mL of phosphorescent ink mixed with glycerol and spread it on the silicon wafer. Control the humidity at 45% RT and the temperature at 25°C and dry it for 24 hours.

[0149] Step 6: Remove the dried silk fibroin-based phosphorescent film (~50 μm) from the silicon wafer and store it at room temperature under 30% RT humidity.

[0150] Figure 20 The normalized phosphorescence intensity of the glycerol-doped silk fibroin / 4-biphenylboronic acid film prepared in Example 12 at various humidity levels is plotted as a function of glycerol doping concentration. It can be seen that glycerol molecules quench phosphorescence by capturing water molecules from the air, disrupting hydrogen bonds within the film. With increasing glycerol content or humidity, the film's phosphorescence intensity gradually decreases. At 30% RH, a glycerol content of 50% is required to completely quench phosphorescence. At 50% RH, a glycerol content of 20% completely quenches RTP.

[0151] Figure 21 Afterglow photographs of the reversible humidity response of glycerol-doped silk fibroin / 4-biphenylboronic acid films prepared for Examples 10 and 12 were also obtained. As can be seen, a "rabbit" RTP pattern was printed on the silk fibroin / 4-biphenylboronic acid film mixed with 30% (w / w) glycerol using a 254nm UV lamp. At an ambient humidity of 50% RH, the silk fibroin / 4-biphenylboronic acid film showed no RTP information. After drying the film, the "rabbit" RTP pattern was revealed. Controlling the display and concealment of the phosphorescent pattern using glycerol further enhances the information encryption capabilities of the silk fibroin / arylboronic acid material.

[0152] Example 13: Study on the Temperature Stimulus Response of Phosphorescent Films

[0153] The “light writing” patterned silk fibroin-based phosphorescent film prepared in Example 10 was placed on a hot plate for heating.

[0154] Figure 22 The normalized phosphorescence intensity of the silk fibroin / 4-biphenylboronic acid film prepared in Example 5 is a function of temperature. Figure 22 a is the normalized phosphorescence intensity of the silk fibroin / 4-biphenylboronic acid film prepared in Example 5 as a function of temperature. Figure 22 b shows the optical image and normalized phosphorescence intensity of the silk fibroin / 4-biphenylboronic acid film prepared in Example 5 after 10 repeated cycles of switching between room temperature and 130°C. As can be seen, due to the high glass transition temperature of silk fibroin, it can maintain a rigid environment at high temperatures, resulting in the silk fibroin-based phosphorescent film maintaining phosphorescence emission at high temperatures and exhibiting reversible temperature responsiveness.

[0155] Figure 23 This is a photograph showing the afterglow of the silk fibroin-based phosphorescent film in Example 13, which achieves reversible heat capacity after light printing. As can be seen, the "light" phosphorescent pattern disappears upon heating to 130°C and recovers upon cooling to room temperature. The silk fibroin / arylboronic acid material exhibits a stable temperature response at high temperatures, endowing it with a certain degree of temperature sensing capability.

[0156] Example 14: Preparation of a Phosphorescent Film with Information Encryption Effect

[0157] Step 1, firmly attaching the glycerol-doped silk fibroin-based phosphorescent film prepared in Example 12 to a clean PDMS substrate;

[0158] Step 2: Set a closed constant temperature water bath to 45°C. After the water vapor in the water bath reaches equilibrium, place the phosphorescent film attached to the PDMS into the constant temperature water bath and fumigate with water vapor for 30 seconds.

[0159] Step 3: Remove the phosphorescent film attached to the PDMS from the water bath, place a grating element with a certain period on the surface of the wet film, and apply constant pressure;

[0160] Step 4: After drying and removing the grating element, a phosphorescent film with a grating structure on the surface is obtained;

[0161] Step 5: attaching the patterned mask to the phosphorescent film with the grating structure imprinted thereon, and exposing the film to water vapor at 45°C for 20 seconds to obtain a phosphorescent film with a grating pattern on the surface;

[0162] Step 6: Use the method of preparing a patterned phosphorescent film by "light writing" in Example 10 to write phosphorescent information on the surface of the film to obtain a phosphorescent film with information encryption effect.

[0163] Example 15: Study on the thermal stability of silk fibroin-based phosphorescent films

[0164] Step 1: Place the 50 μm thick silk fibroin / 4-biphenylboronic acid phosphorescent film prepared in Example 5 on a hot plate.

[0165] Step 2: gradually increase the temperature of the hot stage to 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, and 130°C, and take pictures.

[0166] Figure 24 The afterglow photographs of the silk fibroin / 4-biphenylboronic acid phosphorescent film at different temperatures in Example 15 are shown. It can be seen that at 120°C, the silk fibroin / 4-biphenylboronic acid phosphorescent film still has phosphorescent properties, which is mainly attributed to the glass transition temperature of silk fibroin being 200°C to 220°C.

[0167] Comparative Example 1: Study on the thermal stability of polyvinyl alcohol / 4-biphenylboric acid phosphorescent film

[0168] Step 1: Dissolve 5 mg of 4-biphenylboronic acid powder in 4 mL of pure water.

[0169] Step 2: Add 1 mL of 25% concentrated ammonia to the 4-biphenylboronic acid aqueous solution and stir at room temperature for 30 minutes until the 4-biphenylboronic acid is fully dissolved to obtain an alkaline 4-biphenylboronic acid aqueous solution;

[0170] Step 3: Dissolve 500 mg of polyvinyl alcohol powder in 3 mL of pure water;

[0171] Step 4: Evenly mix the prepared alkaline 4-biphenylboric acid aqueous solution and the polyvinyl alcohol aqueous solution, react at 80° C. for 20 minutes, and cool to room temperature to obtain a polyvinyl alcohol / 4-biphenylboric acid phosphorescent solution;

[0172] Step 5: Take 100 μL of 1H,1H,2H,2H-perfluorooctyltriethoxysilane solution and place it in a 1 mL centrifuge tube. Place the tube in a vacuum drying oven with the lid of the centrifuge tube open.

[0173] Step 6: Place a 10 cm diameter silicon wafer in a vacuum drying oven, exposing the side to be treated to air.

[0174] Step 7: Run a vacuum drying oven to perform hydrophobic treatment on the surface of the silicon wafer. The vacuuming time is 20 minutes and the temperature is set to 25°C.

[0175] Step 8: Take out the silicon wafer and place it on a balance table. Take 10 mL of polyvinyl alcohol / 4-biphenylboronic acid phosphorescent solution and spread it on the silicon wafer. Control the humidity at 45% RT and the temperature at 25°C for 24 hours.

[0176] Step 9, remove the dried polyvinyl alcohol / 4-biphenylboronic acid phosphorescent film (~50 μm) from the silicon wafer and place it on a hot stage;

[0177] In step 10, the temperature of the hot stage is gradually increased to 30° C., 40° C., 50° C., 60° C., 70° C., 80° C., 90° C., 100° C., 110° C., 120° C., and 130° C., and photos are taken.

[0178] Figure 25 The following are photos of the afterglow of the polyvinyl alcohol / 4-biphenylboronic acid phosphorescent film in Comparative Example 1 at different temperatures. It can be seen that the polyvinyl alcohol / 4-biphenylboronic acid phosphorescent film does not exhibit phosphorescent properties at temperatures above 100°C. Compared with the silk fibroin / 4-biphenylboronic acid film with the same chromophore, the polyvinyl alcohol / 4-biphenylboronic acid phosphorescent film has a faster thermal quenching rate. This difference is mainly attributed to the glass transition temperature of silk fibroin (200°C to 220°C) being higher than that of polyvinyl alcohol (approximately 85°C). In the case of polyvinyl alcohol, increasing the temperature not only inactivates the chromophore but also destroys the rigid environment supporting the chromophore due to the induced glass transition, resulting in a sharp drop in the RTP intensity.

[0179] The applicant states that while the above-described embodiments illustrate the protein phosphorescent material, its preparation method, and its application, the present invention is not limited to these embodiments, nor does it necessarily rely on these embodiments for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a protein phosphorescent material, characterized in that: The preparation method comprises the following steps: Arylboronic acid molecules are dissolved in water, and then mixed with a protein solution and an alkaline substance to obtain a mixed solution. The mixed solution undergoes a dehydration condensation reaction to obtain a phosphorescent ink, and the phosphorescent ink is prepared into the protein phosphorescent material.

2. The preparation method according to claim 1, characterized in that The aromatic boronic acid molecules include any one or a combination of at least two of 3-biphenylboronic acid, 4-biphenylboronic acid, 1-naphthaleneboronic acid, 1-pyrenylboronic acid, 9-phenanthreneboronic acid, 2-naphthaleneboronic acid, 4-(2-naphthyl)phenylboronic acid, dibenzo[b,d]thiophen-3-ylboronic acid, 1,1':3',1"-terphenyl-5'-boronic acid, and 1,3,5-tris(4-phenylboronic acid)benzene.

3. The preparation method according to claim 1 or 2, characterized in that The protein solution includes any one of a silk fibroin solution, a wool keratin solution, a soybean protein solution or a collagen solution, or a combination of at least two of them.

4. The preparation method according to any one of claims 1 to 3, characterized in that The alkaline substance includes ammonium hydroxide.

5. The preparation method according to any one of claims 1 to 4, characterized in that In the mixed solution, the concentration of arylboronic acid molecules is 0.01%-1%; Preferably, the concentration of the protein solution in the mixed solution is 1%-20%; Preferably, the concentration of the alkaline substance in the mixed solution is 0.5%-10%.

6. The preparation method according to any one of claims 1 to 5, characterized in that The temperature of the dehydration condensation reaction is 20-100° C., and the time of the dehydration condensation reaction is 1-60 minutes.

7. The preparation method according to any one of claims 1 to 6, characterized in that The protein phosphorescent material is in the form of any one of phosphorescent film, phosphorescent coating, phosphorescent scaffold, phosphorescent microsphere, phosphorescent nanofiber, or a combination of at least two thereof; Preferably, preparing the phosphorescent ink into the protein phosphorescent material specifically comprises: preparing the phosphorescent ink into a protein phosphorescent material having room temperature phosphorescence in the form of a film, coating, scaffold, microsphere or nanofiber by drying, freeze drying, spray drying or electrospinning; Preferably, the stimulus response means of the protein phosphorescent material includes any one of humidity, temperature, pH, methanol vapor, and deep ultraviolet light, or a combination of at least two thereof; Preferably, the excitation light source of the protein phosphorescent material is ultraviolet light with a wavelength range of 254-365 nm; Preferably, the phosphorescent ink is processed by any one of inkjet printing, screen printing, stamping, and spraying, or a combination of at least two of them.

8. A preparation method according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: Aryl boronic acid molecules are dissolved in water and then mixed with a protein solution and an alkaline substance to obtain a mixed solution. The mixed solution is subjected to a dehydration condensation reaction at 20-100°C for 1-60 minutes to obtain a phosphorescent ink. The phosphorescent ink is then prepared into a protein phosphorescent material with room temperature phosphorescence in the form of a film, coating, scaffold, microsphere or nanofiber by drying, freeze drying, spray drying or electrospinning.

9. A protein phosphorescent material, characterized in that: The protein phosphorescent material is prepared by the preparation method according to any one of claims 1 to 8; Preferably, the protein phosphorescent material has any one of recyclability, adhesion, weldability, and ductility, or a combination of at least two thereof.

10. Use of the protein phosphorescent material according to claim 9 in afterglow imaging, information encryption, information anti-counterfeiting, warning or sensing.

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