A method for surface hydrophilic modification of cotton thread, its applications and cotton thread for tear detection

Abstract

The application belongs to the field of biomedical materials, and relates to a surface hydrophilic modification method of cotton thread, application of the surface hydrophilic modification method and cotton thread for tear detection. The surface hydrophilic modification method of the cotton thread comprises the following steps: reacting the cotton thread with a chemical linking agent for a certain time, then adding a hydrophilic modifier containing an end amino group into the system, and continuing to react for a certain time to obtain the cotton thread with a surface hydrophilic. The chemical linking agent is a polyacyl chloride. The hydrophilic modifier containing the end amino group is one of an amino-terminated chitosan, an amino-terminated glucose and an amino-terminated polyethylene glycol. The application realizes the connection of the hydrophilic modifier and the cotton thread by the esterification reaction of the chemical linking agent and the hydroxyl group on the surface of the cotton thread, and then the amidation reaction of the amino in the hydrophilic modifier and the active site of the chemical linking agent. The modified cotton thread has good hydrophilicity, and the tear can be quickly absorbed.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, specifically to a method for surface hydrophilic modification of cotton thread, its application, and cotton thread for tear detection. Background Technology

[0002] Tears are a fluid secreted by the lacrimal glands and have a complex composition. Normal tears have multiple functions, including barrier function, antibacterial activity, bactericidal effect, and immune regulation. They play an important role in protecting the eyeball and maintaining visual function. Therefore, changes in tears can reflect eye diseases. For this reason, accurate detection of changes in tears is crucial for the diagnosis and management of various eye diseases.

[0003] In existing technologies, tear test strips are frequently used to measure a patient's tear production. Furthermore, tear testing is necessary in animal models after medication administration during the development of many dry eye drugs. However, tear test strips are inconvenient to fold during use, and frequent hand contact can easily lead to contamination. In addition, the relatively stiffness of tear test strips can cause strong irritation to the eyes, resulting in extreme discomfort for patients. Therefore, there is a need for a novel tear testing product that is easy to package and use, and does not irritate the eyes.

[0004] Pure cotton thread offers numerous advantages, including excellent biocompatibility, portability, softness, and lightweight properties, making it less likely to irritate the patient's eyes and thus an ideal substrate for preparing tear film testing threads. However, some cotton threads have hydrophobic surfaces. Due to the high surface tension on these surfaces, water absorption is poor, resulting in extremely low tear diffusion efficiency. This makes it difficult to accurately measure tear diffusion speed and also hinders the assessment of the severity of dry eye symptoms and the effectiveness of medications.

[0005] Therefore, it is necessary to improve the diffusion efficiency of the liquid on the surface of the cotton thread so that it can be used as a tear detection thread. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the problem in existing technologies where some cotton threads have poor surface hydrophilicity, resulting in poor tear diffusion efficiency and difficulty in accurately detecting tear diffusion speed, this invention provides a method for surface hydrophilic modification of cotton threads, its application, and cotton threads for tear detection.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0010] In a first aspect, the present invention provides a method for surface hydrophilic modification of cotton thread, comprising the following steps:

[0011] The cotton thread is reacted with a chemical binder for a certain time, and then a hydrophilic modifier containing terminal amino groups is added to the system. After the reaction continues for a certain time, a cotton thread with a hydrophilic surface is obtained.

[0012] The chemical binder is a polyacryl chloride;

[0013] The hydrophilic modifier containing terminal amino groups is one of amino-terminated chitosan, amino-terminated glucose, and amino-terminated polyethylene glycol.

[0014] In the above-described method for surface hydrophilic modification of cotton thread, preferably, the mass ratio of hydrophilic modifier, chemical binder and cotton thread is (10-15):(10-15):(1-5).

[0015] In the above-described method for surface hydrophilic modification of cotton thread, preferably, the polyacrylamide chloride is one of trimellitic anhydride chloride, isophthaloyl chloride, and terephthaloyl chloride; the cotton thread reacts with a chemical binder in a solvent, wherein the solvent is a mixture of tetrahydrofuran and water, and the volume ratio of tetrahydrofuran to water is 1:1.

[0016] In the above-described method for surface hydrophilic modification of cotton thread, preferably, the reaction temperature of the cotton thread with the chemical binder is 25-40℃, and the reaction time is 24-48h.

[0017] After adding a hydrophilic modifier containing terminal amino groups, the reaction temperature is 25-40℃ and the reaction time is 24-48h.

[0018] Secondly, the present invention provides an application of cotton thread prepared by the above-mentioned surface hydrophilic modification method in tear detection.

[0019] Thirdly, the present invention provides a cotton thread for tear detection, which is prepared by immersing the cotton thread prepared by the above-mentioned surface hydrophilic modification method in an alkaline responsive dye solution and then drying it.

[0020] The cotton thread for tear detection as described above, preferably, has an alkaline-responsive dye solution that is an aqueous solution of phenol red.

[0021] The cotton thread used for tear detection as described above preferably contains phenol red in an aqueous solution at a concentration of 0.3-0.5 mg / mL.

[0022] The cotton thread used for tear detection, as described above, is preferably soaked for 1-3 hours.

[0023] The cotton thread used for tear detection, as described above, is preferably dried for 24-48 hours.

[0024] (III) Beneficial Effects

[0025] This invention uses polyacryl chloride as a chemical binder. The chemical binder undergoes an esterification reaction with the hydroxyl groups on the surface of the cotton thread. Then, a hydrophilic modifier containing terminal amino groups is added, such as amino-terminated chitosan, amino-terminated glucose, or amino-terminated polyethylene glycol. The amino groups in these hydrophilic modifiers can undergo an amidation reaction with the residual active sites of the chemical binder, thereby achieving the connection between the hydrophilic modifier and the cotton thread.

[0026] The modified cotton thread surface exhibits excellent hydrophilicity, allowing water to spread rapidly and evenly across the thread surface. This ensures that tears are quickly absorbed by the modified cotton thread and diffuse along its length, enabling it to be used for tear detection and accurately reflect changes in tear levels.

[0027] In addition, the hydrophilic modifiers used in this invention have good biocompatibility and water solubility, which not only ensures the safety of the modified cotton thread, but also avoids potential irritation or damage to the eye tissue. Attached Figure Description

[0028] Figure 1 This is a schematic diagram illustrating the preparation principle of chitosan-modified cotton thread.

[0029] Figure 2 This is a schematic diagram illustrating the preparation principle of polyethylene glycol-modified cotton thread.

[0030] Figure 3 Schematic diagram of the preparation principle of glucose-modified cotton thread;

[0031] Figure 4 This is a schematic diagram of the structure of the phenol red cotton thread prepared in this invention;

[0032] Figure 5 Fourier transform infrared spectra of the cotton yarn surfaces prepared in Examples 1, 2, and 3;

[0033] Figure 6 The ultraviolet absorption spectra of the phenol red cotton threads prepared in Examples 1, 2, and 3 are shown below.

[0034] Figure 7 This is a comparison chart of the tear diffusion test results of the phenol red cotton threads prepared in Examples 1, 2 and 3.

[0035] [Explanation of Labels in the Attached Image]

[0036] 1: Cotton yarn matrix; 2: Phenol red dye. Detailed Implementation

[0037] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to specific embodiments.

[0038] Cotton thread, as a natural cellulose material, is used in tear detection due to its low cost and good biocompatibility. Existing technologies generally consider cotton thread to be hydrophilic, primarily based on the hydroxyl groups contained in its cellulose molecules. However, researchers in this invention have found in practical applications that cotton threads prepared using different manufacturing processes exhibit significant differences in surface wettability, with some threads displaying marked hydrophobicity. This results in extremely poor tear diffusion efficiency and uneven distribution on the cotton thread surface, severely affecting the sensitivity and accuracy of the detection.

[0039] Studies have shown that the surface of such hydrophobic cotton yarns typically possesses dense micro / nano fibers or hierarchical porous micro / nano structures. Although this structure may be formed by specific manufacturing processes, its negative impact on liquid diffusion properties has not been fully considered. Because hydrophobic surfaces are difficult to wet rapidly with tears, unmodified cotton yarns cannot meet the requirements of rapid and uniform absorption in tear detection. Therefore, there is an urgent need to improve the hydrophilicity of such cotton yarns through surface modification techniques to overcome their limitations in bioassay applications.

[0040] In existing technologies, research on the hydrophilic modification of cotton yarn has largely focused on optimizing the performance of conventional hydrophilic cotton yarn, lacking targeted solutions for modifying hydrophobic cotton yarn. This results in some cotton yarns prepared by certain processes being unable to be directly used for tear detection due to their hydrophobicity, thus limiting their application scope.

[0041] To address the above problems, this invention provides a method for surface hydrophilic modification of cotton yarn, comprising the following steps:

[0042] The cotton thread is reacted with a chemical binder for a certain period of time, and then a hydrophilic modifier containing terminal amino groups is added to the system. After the reaction continues for a certain period of time, a cotton thread with a hydrophilic surface is obtained.

[0043] The aforementioned chemical linker can be a polyacrylamide chloride, and the hydrophilic modifier containing terminal amino groups can be amino-terminated chitosan, amino-terminated glucose, or amino-terminated polyethylene glycol.

[0044] The surface of cotton thread has abundant hydroxyl functional groups. In this invention, trimellitic anhydride chloride, isophthaloyl chloride, or terephthaloyl chloride are used as chemical binders. The chemical binders undergo an esterification reaction with the hydroxyl groups on the surface of white pure cotton thread. Then, hydrophilic modifiers containing terminal amino groups are added. The amino groups in these hydrophilic modifiers can undergo an amidation reaction with the active sites remaining in the chemical binders, thereby achieving the connection between the hydrophilic modifiers and the cotton thread.

[0045] In this invention, the modified cotton thread surface exhibits excellent hydrophilicity, allowing water to diffuse rapidly and uniformly across its surface. This ensures that tears are quickly absorbed by the modified thread and diffuse along its length, facilitating tear detection and accurately reflecting changes in tear levels. The cotton thread prepared by this invention is well-suited for diagnosing dry eye patients, demonstrating significant clinical value in this area. Furthermore, the hydrophilic modifiers used in this invention possess excellent biocompatibility and water solubility, guaranteeing the safety of the modified cotton thread and preventing potential irritation or damage to ocular tissues.

[0046] Preferably, the polyacrylamide chloride can be one of trimellitic anhydride chloride, isophthaloyl chloride, and terephthaloyl chloride. In the above reaction, the mass ratio of the hydrophilic modifier, chemical binder, and cotton thread is (10-15):(10-15):(1-5). If the proportions of the hydrophilic modifier and chemical binder are lower than the above range, the hydrophilic modification effect of the cotton thread will be reduced.

[0047] Preferably, the cotton thread reacts with the chemical binder in a solvent, which is a mixture of tetrahydrofuran and water, with a volume ratio of tetrahydrofuran to water of 1:1.

[0048] More preferably, the reaction temperature between the cotton thread and the chemical binder is 25-40℃, and the reaction time is 24-48h. After adding a hydrophilic modifier containing terminal amino groups to the reaction system, the reaction temperature is 25-40℃, and the reaction time is 24-48h. If the above reaction time is less than 24h and the temperature is less than 25℃, the effect of hydrophilic modification of the cotton thread will be reduced.

[0049] If polyethylene glycol and glucose do not contain capped amino groups, the chemical binder will not be able to continue the amidation reaction with the hydrophilic modifier after the esterification reaction with the hydroxyl groups on the cotton thread surface. Therefore, the hydrophilic modifier cannot be attached to the cotton thread surface, and the hydrophilicity of the cotton thread cannot be significantly improved.

[0050] like Figure 1 As shown, if amino-terminated chitosan is used as a hydrophilic modifier and trimellitic anhydride chloride is used as a chemical linker, the reaction principle is as follows:

[0051] The surface of cotton yarn has abundant hydroxyl functional groups, which can undergo esterification reactions with the acyl chloride groups in polyacyl chlorides, thereby introducing a chemical linker onto the cotton yarn surface. After adding amino-terminated chitosan, the anhydride in the trimellitic anhydride acyl chloride can further undergo amidation reactions with the terminal amino groups on the chitosan, modifying the cotton yarn surface with chitosan. If the polyacyl chloride is isophthaloyl chloride or terephthaloyl chloride, its acyl chloride groups can also undergo amidation reactions with the terminal amino groups on the chitosan, modifying the cotton yarn surface with chitosan.

[0052] like Figure 2 As shown, if amino-terminated polyethylene glycol is used as a hydrophilic modifier and trimellitic anhydride chloride is used as a chemical linker, the reaction principle is as follows:

[0053] The surface of cotton yarn has abundant hydroxyl functional groups, which can undergo esterification reactions with the acyl chloride groups in polyacyl chlorides, thereby introducing a chemical binder onto the cotton yarn surface. After adding amino-terminated polyethylene glycol, the anhydride in the trimellitic anhydride acyl chloride can further undergo an amidation reaction with the terminal amino groups on the polyethylene glycol, modifying the polyethylene glycol onto the cotton yarn surface. If the polyacyl chloride is isophthaloyl chloride or terephthaloyl chloride, its acyl chloride groups can also undergo an amidation reaction with the terminal amino groups on the polyethylene glycol, modifying the polyethylene glycol onto the cotton yarn surface.

[0054] Similarly, as Figure 3 As shown, if amino-terminated glucose is used as a hydrophilic modifier and trimellitic anhydride chloride is used as a chemical linker, the reaction principle is as follows:

[0055] The surface of cotton yarn has abundant hydroxyl functional groups, which can undergo esterification reactions with the acyl chloride groups in polyacyl chlorides, thereby introducing a chemical linker onto the cotton yarn surface. After adding amino-terminated glucose, the anhydride in the trimellitic anhydride acyl chloride can further undergo an amidation reaction with the terminal amino groups on the glucose, modifying the glucose onto the cotton yarn surface. If the polyacyl chloride is isophthaloyl chloride or terephthaloyl chloride, its acyl chloride groups can also undergo an amidation reaction with the terminal amino groups on the glucose, modifying the glucose onto the cotton yarn surface.

[0056] The cotton thread prepared by the surface hydrophilic modification method of the present invention can be used in tear detection.

[0057] Furthermore, cotton thread is white, while tears are colorless and transparent liquids, making the diffusion process of tears on the surface of the cotton thread difficult to detect. Therefore, in addition to improving the hydrophilicity of the cotton thread used for tear detection, it is also necessary to solve the problem of visualizing tear diffusion on the surface of the cotton thread.

[0058] To address the aforementioned problems, the present invention also provides a cotton thread for tear detection, which is prepared by immersing the cotton thread prepared by the above-described surface hydrophilic modification method in an alkaline-responsive dye solution and then drying it.

[0059] The preferred alkaline-responsive dye solution is an aqueous solution of phenol red, with a concentration of phenol red dye of 0.3-0.5 mg / mL. The preferred soaking time is 1-3 h, and the preferred drying time is 24-48 h.

[0060] To visualize the diffusion behavior of tears on the surface of cotton thread in real time, this invention adsorbs alkali-responsive phenol red dye onto the surface of cotton thread. Since tears are weakly alkaline, the phenol red dye can change from yellow to red, thereby achieving the goal of visually visualizing the degree of tear diffusion.

[0061] like Figure 4 As shown, the phenol red cotton thread for tear detection prepared by this invention includes a cotton thread matrix 1 (which has undergone surface hydrophilic modification treatment) and phenol red dye 2. The tear detection phenol red cotton thread is generally long and strip-shaped, with a length of up to 7.5 cm. There are creases on the cotton thread, with a crease length of 3-5 mm. The part above the crease is used to adhere to the inside of the eyelid and directly contact the tears.

[0062] To further clarify the present invention and its technological advancements, the following description is provided in conjunction with specific embodiments and technical effects.

[0063] Example 1

[0064] This embodiment provides a method for preparing cotton thread for tear detection, comprising the following steps: adding cotton thread and trimellitic anhydride acyl chloride to a mixed solvent of tetrahydrofuran and water in a volume ratio of 1:1, and reacting at 35°C for 36 hours. Then, chitosan is added to the reaction system, with a mass ratio of chitosan, trimellitic anhydride acyl chloride, and cotton thread of 12:12:3, and the reaction is continued at 35°C for 36 hours to obtain a hydrophilic cotton thread. The hydrophilic cotton thread is then soaked in a 0.5 mg / mL phenol red solution for 2 hours, and then air-dried for 36 hours to obtain a phenol red cotton thread for tear detection.

[0065] Example 2

[0066] This embodiment provides a method for preparing cotton thread for tear detection, comprising the following steps: Cotton thread and trimellitic anhydride chloride are added to a mixed solvent of tetrahydrofuran and water in a volume ratio of 1:1, and reacted at 25°C for 48 hours. Then, amino-terminated polyethylene glycol is added to the reaction system, with the mass ratio of amino-terminated polyethylene glycol, trimellitic anhydride chloride, and cotton thread being 10:10:5, and the reaction continues at 25°C for 48 hours to obtain a hydrophilic cotton thread. The hydrophilic cotton thread is then immersed in a 0.4 mg / mL phenol red solution for 1 hour, and then air-dried for 24 hours to obtain a phenol red cotton thread for tear detection.

[0067] Example 3

[0068] This embodiment provides a method for preparing cotton thread for tear detection, comprising the following steps: Cotton thread and trimellitic anhydride chloride are added to a mixed solvent of tetrahydrofuran and water in a volume ratio of 1:1, and reacted at 40°C for 24 hours. Then, amino-terminated glucose is added to the reaction system, with the mass ratio of amino-terminated glucose, trimellitic anhydride chloride, and cotton thread being 15:15:1, and the reaction continues at 40°C for 24 hours to obtain a hydrophilic cotton thread. The hydrophilic cotton thread is then soaked in a 0.3 mg / mL phenol red solution for 3 hours, and then air-dried for 48 hours to obtain a phenol red cotton thread for tear detection.

[0069] Comparative Example 1

[0070] This comparative example provides a cotton thread for tear detection, which differs from Example 1 in that it has not undergone hydrophilic modification treatment.

[0071] Comparative Example 2

[0072] This comparative example provides a method for preparing cotton thread for tear detection, which differs from Example 2 in that the polyethylene glycol does not contain capped amino groups.

[0073] Comparative Example 3

[0074] This comparative example provides a method for preparing a cotton thread for tear detection, which differs from Example 2 in that the glucose does not contain capped amino groups.

[0075] Test Example 1

[0076] Fourier transform infrared spectra of the phenol red cotton threads for tear detection prepared in Examples 1-3 were obtained respectively. Figure 5 .like Figure 5 As shown, the characteristic peak is at 3402 cm⁻¹. -1 The peak is attributed to the hydroxyl group and has a characteristic peak at 2928 cm⁻¹. -1 These characteristic peaks, belonging to the methylene group, are characteristic peaks of chitosan, polyethylene glycol, and glucose from Examples 1-3, with a characteristic peak of 1633 cm⁻¹. -1 The infrared absorption peaks belonging to the amide functional group indicate that an amidation reaction has occurred. The above characteristic peaks prove that chitosan, polyethylene glycol and glucose were successfully grafted onto the surface of cotton thread in Examples 1-3, respectively.

[0077] Test Example 2

[0078] The ultraviolet absorption spectra of the tear detection phenol red cotton threads prepared in Examples 1-3 and the standard phenol red sample solutions were obtained respectively. Figure 6 This was used to characterize whether phenol red dye was adsorbed onto the surface of the modified cotton thread. Through... Figure 6 It can be seen that, compared with the standard phenol red sample solution, the cotton threads modified with the three different hydrophilic modifiers in Examples 1-3 all showed the same maximum absorption peak (430 cm⁻¹) in aqueous solution as the phenol red solution. -1 This demonstrates that phenol red dye can be effectively adsorbed onto the surface of hydrophilically modified cotton thread and is stably retained in the air.

[0079] Test Example 3

[0080] The phenol red cotton threads for tear detection prepared in Examples 1-3 and Comparative Examples 1-3 were cut into 7.5 cm long strips, and creases of 3-5 mm were made on the threads. Three healthy volunteers, designated as Volunteer A, Volunteer B, and Volunteer C, were selected to test the tear diffusion properties of the hydrophilic modified phenol red cotton threads prepared in Examples 1-3. Specifically, the creases of the phenol red cotton threads were placed on the conjunctiva of the lower eyelid of the volunteers, one-third of the way from the outer corner of the eye. After 20 seconds, the threads were removed, and the tear diffusion length (mm) of the phenol red cotton threads was recorded. Figure 7 .

[0081] pass Figure 7 It can be seen that the tear diffusion lengths of the hydrophilic modified phenol red cotton thread prepared by volunteers A, B, and C in Example 1 were 26 mm, 18 mm, and 15 mm, respectively; the tear diffusion lengths of the hydrophilic modified phenol red cotton thread prepared by volunteers A, B, and C in Example 2 were 38 mm, 26 mm, and 27 mm, respectively; and the tear diffusion lengths of the hydrophilic modified phenol red cotton thread prepared by volunteers A, B, and C in Example 3 were 34 mm, 28 mm, and 32 mm, respectively.

[0082] Similarly, the tear diffusion properties of the phenol red cotton threads prepared in Comparative Examples 1-3 were tested by volunteers A, B, and C respectively, using the same testing methods and times. The average tear diffusion length of the phenol red cotton threads in Comparative Examples 1-3 was approximately 3 mm, indicating that the unmodified cotton threads had poor tear diffusion properties and could not be used for tear measurement. In addition, if the hydrophilic modifier did not contain amino groups, the hydrophilic modification would fail, resulting in poor tear diffusion properties of the cotton threads, which could also not be used for tear measurement.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for surface hydrophilic modification of cotton thread for tear detection, characterized in that, Includes the following steps: Cotton thread with micro-nano structures containing micro-nano fibers or hierarchical pores on its surface is reacted with a chemical binder for a certain period of time. Then, a hydrophilic modifier containing terminal amino groups is added to the system, and the reaction is continued for a certain period of time to obtain a cotton thread with a hydrophilic surface. The cotton thread and the chemical binder are reacted in a solvent, which is a mixture of tetrahydrofuran and water, with a volume ratio of tetrahydrofuran to water of 1:

1. The chemical binder is a polyacryl chloride; the polyacryl chloride is one of trimellitic anhydride chloride, isophthaloyl chloride and terephthaloyl chloride; the mass ratio of hydrophilic modifier, chemical binder and cotton thread is (10-15): (10-15): (1-5); The hydrophilic modifier containing terminal amino groups is one of amino-terminated chitosan, amino-terminated glucose, and amino-terminated polyethylene glycol; the reaction temperature of cotton thread with chemical binder is 25-40 ℃, and the reaction time is 24-48 h; After adding a hydrophilic modifier containing terminal amino groups, the reaction temperature is 25-40 °C and the reaction time is 24-48 h. The cotton thread for tear detection is prepared by immersing the hydrophilic cotton thread in an alkaline-responsive dye solution and then drying it.

2. A cotton thread for tear detection, characterized in that, The cotton thread is prepared by the surface hydrophilic modification method described in claims 1-1.

3. The cotton thread for tear detection according to claim 2, characterized in that, The alkaline-responsive dye solution is an aqueous solution of phenol red.

4. The cotton thread for tear detection according to claim 3, characterized in that, The concentration of phenol red in the aqueous solution is 0.3-0.5 mg / mL.

5. The cotton thread for tear detection according to claim 2, characterized in that, Soaking time is 1-3 hours.

6. The cotton thread for tear detection according to claim 2, characterized in that, The drying time is 24-48 hours.

Images