Protease purification paper diaper

Abstract

The invention relates to a protease purification paper diaper, which belongs to the technical field of personal hygiene care products, and comprises a liquid-permeable surface layer, a liquid-tight bottom layer and an absorption core body positioned between the liquid-permeable surface layer and the liquid-tight bottom layer, bio-enzyme modified purification particles are mixed in the absorption core body or arranged between the liquid-permeable surface layer and the absorption core body; the biological enzyme modified purification particles comprise a porous polysaccharide microsphere carrier subjected to cross-linking modification and protease covalently anchored on the carrier through a spacer arm, and a polyethylene glycol chain is introduced between the porous polysaccharide microsphere carrier subjected to cross-linking modification and the protease as the spacer arm for covalent anchoring; the steric hindrance influence of a carrier skeleton on an enzyme activity center is effectively reduced; compared with an immobilization mode without a spacer arm, the flexible arm enables enzyme molecules to extend into a hydration layer on the surface of the carrier, and compared with the immobilization mode without the spacer arm, the flexible arm has the advantages that the conformation flexibility of an enzyme active center is better maintained, so that the capture efficiency of a macromolecular protein substrate is improved.

Description

Technical Field

[0001] This invention relates to the field of personal hygiene products, specifically to a protease-purifying diaper. Background Technology

[0002] As consumers demand higher performance from diapers, the product's function is no longer limited to the physical absorption of urine. How to effectively suppress odor and improve skin safety during wear has become a key focus for the industry. In existing technologies, after urine is captured by the absorbent core, the protein-like organic matter in it is rapidly decomposed by microorganisms and produces ammonia. This phenomenon not only leads to a noticeable odor and affects the usage environment, but more seriously, the continuously increasing ammonia concentration will change the acid-base balance inside the diaper, making it highly alkaline, thereby damaging the natural acidic protective barrier on the surface of human skin. This change in environment can easily induce allergic reactions such as skin redness and swelling and dermatitis. To alleviate these problems, some existing solutions attempt to add bioactive ingredients to diapers. However, in practical applications, directly added active ingredients often face technical bottlenecks due to insufficient stability, and are easily deactivated during storage or at body temperature, resulting in a lack of sustained purification effect. In addition, when active ingredients migrate with urine and come into direct contact with human skin, there is a risk of contact sensitization. Although some technologies attempt to physically encapsulate active ingredients, this often leads to a significant decrease in their contact efficiency with substrates in urine, resulting in a slow purification response and an inability to effectively block odor generation in the early stages of urination. Therefore, how to achieve rapid and long-lasting purification of proteinaceous organic matter in urine while ensuring skin safety remains a pressing problem to be solved in this field.

[0003] The information disclosed in the background section above is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a protease-purified diaper to solve the problems mentioned in the background art.

[0005] The technical solution of the present invention includes a liquid-permeable surface layer, a liquid-impermeable bottom layer, and an absorbent core located between the two; the absorbent core contains or is provided with bio-enzyme-modified purification particles between the liquid-permeable surface layer and the absorbent core; the bio-enzyme-modified purification particles include a cross-linked modified porous polysaccharide microsphere carrier and a protease covalently anchored to the carrier through a spacer arm.

[0006] Preferably, the cross-linked modified porous polysaccharide microsphere carrier is a cross-linked chitosan microsphere; and the protease is a subtilisin.

[0007] Preferably, the surface of the bio-enzyme modified purification particles is grafted with polyethylene glycol spacers that are covalently anchored via spacers, and the protease is anchored to the carrier via the spacers.

[0008] Preferably, the spacer arm is a polyethylene glycol chain.

[0009] Preferably, the surface of the bio-enzyme modified purification particles is further grafted with glycine-terminated groups.

[0010] Preferably, the diaper further includes a flow-guiding layer located between the liquid-permeable surface layer and the absorbent core; the bio-enzyme-modified purification particles are distributed in the fiber web of the flow-guiding layer, or at the interface between the flow-guiding layer and the absorbent core; the amount of the bio-enzyme-modified purification particles added is 5% to 10% of the dry weight of the flow-guiding layer.

[0011] Preferably, the preparation of protease-purified urine-type diapers includes the following steps: Preparation of bio-enzyme-modified purification particles: Porous polysaccharide microspheres were immersed in a 0.5% to 5% glutaraldehyde solution and subjected to surface aldehyde-modification treatment at 20°C to 40°C for 2 to 6 hours; subsequently, they were reacted with diamino polyethylene glycol to graft polyethylene glycol flexible spacer arms onto the surface of the carrier; the grafted carrier was then immersed in glutaraldehyde solution again for terminal aldehyde-modification activation; then, protease was added to phosphate buffer solution at pH 7.0 to 8.0, and the reaction was stirred at 4°C to 10°C for 12 to 24 hours to immobilize the protease on the carrier through a covalent bonding reaction; finally, glycine solution was added for end-capping treatment, and a reducing agent was added for reduction stabilization treatment; The bio-enzyme modified purification particles are mixed with low-melting-point core-sheath fibers and laid out using an airflow web forming process to form a functionalized flow-guiding layer; or, the bio-enzyme modified purification particles are evenly distributed in the target urination area of ​​the flow-guiding layer mixed with a superabsorbent polymer core; using a hot air penetration bonding process, under the action of hot air penetration at (130-150)℃, the fiber sheath melts to generate bonding points, physically securing the bio-enzyme modified purification particles in the fiber mesh structure.

[0012] This invention provides an improved protease-purifying diaper, which has the following improvements and advantages compared to the prior art: 1. By introducing polyethylene glycol between the cross-linked modified porous polysaccharide microsphere carrier and the protease and covalently anchoring it through spacer arms, the steric hindrance of the carrier skeleton on the enzyme active site is effectively reduced. Compared with the immobilization method without spacer arms, the flexible arms allow enzyme molecules to extend into the hydration layer on the carrier surface, better maintaining the conformational flexibility of the enzyme active site, thereby significantly improving the capture efficiency of macromolecular protein substrates. 2. This solution uses covalent bond immobilization technology to firmly lock the protease onto the carrier, fundamentally eliminating the risk of sensitization caused by enzyme molecules coming into contact with the skin through urine backflow; at the same time, by introducing a glycine end-capping process, the chemical irritation to the skin caused by residual active groups on the carrier surface is eliminated. 3. By adjusting the distribution and amount of bio-enzyme modified purification particles at the flow guide layer or interface, a highly efficient interception purification layer is constructed. The particles are physically fixed in the fiber mesh using a hot air penetration bonding process, which not only prevents particle displacement, but also maintains the structural integrity of the diaper and its continuous bio-purification ability when dealing with a large amount of urine impact. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 This invention provides a 4-hour comparison of ammonia concentrations in each group (to verify deodorization performance). Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0015] Example 1: This invention provides a protease-purifying diaper, comprising a liquid-permeable top layer, a liquid-impermeable bottom layer, and an absorbent core located between the two; the absorbent core contains or is provided with bio-enzyme-modified purification particles between the liquid-permeable top layer and the absorbent core; the bio-enzyme-modified purification particles comprise a cross-linked modified porous polysaccharide microsphere carrier and a protease covalently anchored to the carrier via spacer arms. In this embodiment, the bio-enzyme-modified purification particles are not simply a physical mixture, but a microenvironment regulation system constructed through chemical bonding technology. This system aims to solve the technical problems of enzyme inactivation and contact sensitization in urine environments in existing technologies. Specifically, the cross-linked porous polysaccharide microsphere carrier uses cross-linked chitosan microspheres with a degree of deacetylation of 90%, purchased from Solarbio Science & Technology Co., Ltd., catalog number C8360, with an average pore size of 50 μm. The crosslinking degree is 10%-15% or it is prepared by dispersing chitosan acetic acid solution in liquid paraffin containing emulsifier and crosslinking with glutaraldehyde according to the conventional reverse suspension polymerization method. Its abundant amino sites provide a chemical basis for the subsequent grafting reaction. The protease selected is Bacillus subtilis protease, which has a highly specific degradation ability for proteinaceous organic matter in urine. The protease is a protease with a serine active site, preferably Bacillus subtilis protease; Bacillus subtilis protease is selected from Bacillus subtilis protease Carlsberg (EC3.4.21.62) or an isoenzyme with similar proteolytic activity; The surface grafts of the bio-enzyme modified purification particles are covalently anchored through spacer arms, and the protease is anchored to the carrier through the spacer arms. The spacer arm is a polyethylene glycol chain. To overcome the problem of decreased catalytic efficiency caused by steric hindrance when enzyme molecules are directly immobilized on the carrier surface, this embodiment introduces a polyethylene glycol (PEG) chain with a molecular weight of 2000 Da, preferably in the range of 600-6000 Da, as a covalent anchoring agent through the spacer arm. The high hydrophilicity and flexibility of the PEG chain allow enzyme molecules to extend into the hydration layer on the carrier surface, maintaining conformational freedom similar to that of a free enzyme, thereby significantly improving the capture efficiency of large protein substrates. The surface of the bio-enzyme modified purification particles is also grafted with glycine-terminated groups. After the enzyme coupling was completed, glycine end-capping groups were introduced to block the residual aldehyde groups on the carrier surface. This step not only eliminated the risk of residual active groups causing chemical irritation to the skin, but also further improved the biocompatibility of the particle surface by introducing zwitterionic groups. The diaper also includes a distribution layer located between the liquid-permeable surface layer and the absorbent core; bio-enzyme-modified purification particles are distributed in the fiber web of the distribution layer; the amount of bio-enzyme-modified purification particles added is 5% of the dry weight of the distribution layer; In this embodiment, the bio-enzyme modified purification particles are uniformly dispersed in the fiber network of the flow guide layer, and the addition amount is set to 5% of the dry weight of the flow guide layer. This ratio is based on the minimum effective dose determined by the pre-experiment, which ensures a rapid purification response to the initial urination and avoids affecting the liquid infiltration rate due to excessive particles clogging the flow guide channel. The preparation of protease-modified urine diapers includes the following steps: Preparation of bio-enzyme-modified purification particles: Porous polysaccharide microspheres are immersed in a 0.5% to 5% glutaraldehyde solution and subjected to surface aldehyde-modification treatment at 20°C to 40°C for 2 to 6 hours; subsequently, they are reacted with diamino polyethylene glycol to graft polyethylene glycol flexible spacer arms onto the carrier surface; the grafted carrier is then immersed again in glutaraldehyde solution for terminal aldehyde-modification activation; protease is added to phosphate buffer solution at pH 7.0 to 8.0, and the reaction is stirred at 4°C to 10°C for 12 to 24 hours, immobilizing the protease on the carrier through a covalent bonding reaction; finally, glycine solution is added for end-capping treatment, and a reducing agent is added for reduction stabilization treatment; This step employed the lowest parameter combination within the process window; a low concentration of 0.5% glutaraldehyde combined with a room temperature environment of 20°C was used to induce the formation of a moderately modified surface aldehyde structure on the microspheres, preserving the carrier's high hydrophilicity and swelling properties; during the enzyme coupling stage, a neutral environment of pH 7.0 and a low temperature of 4°C maximally maintained the native conformation of Bacillus subtilis protease, preventing thermal inactivation or autolysis of the enzyme during immobilization. Although the reaction rate was slow, extremely high enzyme activity recovery was achieved. To fully implement the above technical solution, in the above surface modification treatment step, glutaraldehyde was activated and then bis(amino) polyethylene glycol and NH2 were added. PEG NH2 was used for grafting to construct covalently anchored spacer arms; after the reaction, the carrier was filtered and washed, and then redispersed in a 0.5% to 5% glutaraldehyde solution for 2 hours of activation; the mass ratio of diamino polyethylene glycol to porous polysaccharide microspheres was 1:10 to 1:50; and after the enzyme immobilization reaction, 0.1 mol / L glycine solution was added to the system and stirred for 2 hours for end-capping to block residual aldehyde groups; Bio-enzyme modified purification particles are mixed with low-melting-point core-sheath fibers and laid out using an airflow web forming process to form a functionalized flow guiding layer. Using a hot air penetration bonding process, under the action of hot air penetration at 130°C, the fiber sheath melts to create bonding points, physically securing the bio-enzyme modified purification particles in the fiber mesh structure. In the post-processing stage, the hot air temperature of 130°C is near the critical point of melting of the low-melting-point fiber sheath. This temperature is sufficient to produce a strong physical bond. At the same time, since the enzyme molecules have been protected by the spacer arms and are in a dry state, the risk of thermal shock to enzyme activity from high temperature is effectively avoided, ensuring the stability of the final product during its shelf life.

[0016] Example 2: This embodiment provides a protease-purified diaper, whose basic structure is the same as that of Embodiment 1, the difference being the optimization and adjustment of process parameters; It includes a liquid-permeable surface layer, a liquid-impermeable bottom layer, and an absorbent core located between the two; the absorbent core contains or is provided between the liquid-permeable surface layer and the absorbent core with bio-enzyme-modified purification particles; the bio-enzyme-modified purification particles include cross-linked modified porous polysaccharide microsphere carriers and proteases covalently anchored to the carriers through spacer arms, wherein the cross-linked modified porous polysaccharide microsphere carriers are cross-linked chitosan microspheres; and the protease is subtilisin. The average pore size of the porous modified polysaccharide microspheres is 20-100nm. Through the capillary force and physical shielding effect of the micropores, combined with the hydration protection of the PEG chain, the enzyme molecules in the core position can withstand short-term, 1-5 second hot air impact at 150°C without being deactivated in a dry state. In this embodiment, the bio-enzyme modified purification particles are also composed of cross-linked chitosan microspheres, subtilisin protease, and polyethylene glycol chains, which are covalently anchored by spacer arms and glycine end-capping groups. The bio-enzyme-modified purification particles are distributed at the interface between the flow guide layer and the absorption core; the amount of bio-enzyme-modified purification particles added is 7.5% of the dry weight of the flow guide layer; The particle distribution is adjusted to the interface to create an interception-type purification layer, which is then concentrated when urine passes through the guide layer and is about to enter the core; the 7.5% addition provides a higher total enzyme load, making it suitable for moderate incontinence care scenarios; Preparation of bio-enzyme-modified purification particles: Porous polysaccharide microspheres were immersed in a 0.5% to 5% glutaraldehyde solution and subjected to surface aldehyde-modification treatment at 20°C to 40°C for 2 to 6 hours; subsequently, they were reacted with diamino polyethylene glycol to graft polyethylene glycol flexible spacer arms onto the surface of the carrier; the grafted carrier was then immersed in glutaraldehyde solution again for terminal aldehyde-modification activation; then, protease was added to phosphate buffer solution at pH 7.0 to 8.0, and the reaction was stirred at 4°C to 10°C for 12 to 24 hours to immobilize the protease on the carrier through a covalent bonding reaction; finally, glycine solution was added for end-capping treatment, and a reducing agent was added for reduction stabilization treatment; Under this parameter combination, the 2.5% glutaraldehyde concentration and the reaction temperature of 30℃ result in a more compact and stable carrier pore structure, enhancing its resistance to repeated urine flushing. The pH 7.5 environment is closest to the isoelectric point of Bacillus subtilis protease, which is beneficial to the directional arrangement of enzyme molecules and coupling efficiency. In this preparation process, a key step is also added: during the surface modification stage, 1000 Da bis(amino) polyethylene glycol is grafted and covalently anchored through spacer arms, with a shorter chain length suitable for the dense pore size. Comparative verification shows that if spacer arms with a molecular weight of less than 600 Da are used under this pore size, the enzyme activity recovery rate decreases by about 35%, failing to effectively overcome steric hindrance. After enzyme coupling, 0.05 mol / L glycine solution is added for end-capping treatment. This concentration is the lowest effective limit determined by gradient experiments. Below 0.05 mol / L, slight erythema appears in the patch test, with a score of 1, failing to meet the zero-irritation requirement, thus ensuring the biosafety of the product and the spatial freedom of the enzyme. The bio-enzyme-modified purification particles are evenly distributed in the target urination area of ​​the mixed absorbent core of the guide layer and the superabsorbent polymer. Using the hot air penetration bonding process, the fiber skin is melted and bonding points are generated under the action of hot air penetration at 140°C, which physically fixes the bio-enzyme-modified purification particles in the fiber mesh structure. The 140℃ hot air treatment provides stronger inter-fiber adhesion, ensuring the firm positioning of particles at the interface and preventing particle displacement during user movement.

[0017] Example 3: This embodiment provides a protease-purified diaper, whose technical features are consistent with those of Embodiment 1. The difference is that the process parameters are selected at the upper limit of the above range, in order to verify the product performance under extreme conditions. This includes bio-enzyme-modified purification particles, including cross-linked modified porous polysaccharide microsphere carriers and proteases covalently anchored to the carrier via spacer arms; With the composition remaining unchanged, the amount of bio-enzyme modified purification particles added is set at 10% of the dry weight of the diversion layer. This is the upper limit, designed to meet the high urine decomposition needs of patients with severe incontinence. Preparation of bio-enzyme-modified purification particles: Porous polysaccharide microspheres were immersed in a 5% glutaraldehyde solution and surface modified at 40°C for 6 hours to prepare cross-linked modified porous polysaccharide microsphere carriers; then protease was added to phosphate buffer at pH 8.0 and stirred at 10°C for 24 hours. The high concentration of cross-linking agent, 5%, and the long reaction time of 6 hours endow the carrier with extremely high mechanical strength and rigid skeleton, making it less prone to breakage or collapse after absorbing urine and swelling; the high pH environment, 8.0, and the extended coupling time of 24 hours help to increase the saturation loading of enzymes. Although the conditions are relatively harsh, it is a necessary trade-off for heavy-load products that pursue long-lasting antibacterial and deodorizing effects. In this highly cross-linked system, in order to overcome the limitations of the rigid skeleton, long-chain polyethylene glycol with a molecular weight of 4000 Da was specially selected as a spacer arm to increase the extension distance of the enzyme molecule. For this high cross-linking density, the experiment showed that the conventional 2000 Da spacer arm could not effectively expose the enzyme active site, while chains entanglement was likely to occur above 6000 Da. 4000 Da was the optimal matching value to maintain a biofilm reduction rate of 94.3%. Meanwhile, the concentration of glycine solution used for end-capping was increased to 0.5 mol / L to ensure that residual aldehyde groups after the high-concentration glutaraldehyde reaction were removed. Comparative data showed that under this high-concentration cross-linking system, if the standard concentration of 0.1 mol / L was used for end-capping, the final product still had the risk of skin irritation caused by residual aldehyde groups, with a score of 1-2. It was necessary to increase the concentration to 0.5 mol / L to achieve a score of 0 and ensure biosafety. Using a hot air penetration bonding process, bio-enzyme modified purification particles are physically fixed in the fiber mesh structure under the action of hot air penetration at 150℃. Although the hot air temperature of 150°C is relatively high, the enzyme's thermal stability is significantly better than that of free enzymes because it is covalently anchored through the spacer arm and physically shielded by the micropores of the highly cross-linked carrier. This example demonstrates the robustness of this technical solution in high-temperature processing.

[0018] Example 4: This embodiment aims to verify the product's adaptability under mild, low-energy-consumption process conditions, using bio-enzyme-modified purification particles; the basic composition remains unchanged, and the amount of bio-enzyme-modified purification particles added is 6% of the dry weight of the flow guide layer; Porous polysaccharide microspheres were immersed in a 1.5% glutaraldehyde solution and surface modified at 25°C for 3 hours. Then, protease was added to a phosphate buffer solution at pH 7.2 and the mixture was stirred at 5°C for 16 hours. This embodiment employs relatively mild process conditions; the results show that even at a low crosslinking agent concentration of 1.5%, with appropriate temperature control, the polyethylene glycol chains, acting as spacer arms, can still effectively extend and assist proteases in capturing protein substrates in urine, indicating that this technical solution has good adaptability to energy-saving production lines. By utilizing the hot air penetration bonding process, a good balance was achieved between energy consumption and bonding strength under the action of hot air penetration at 135℃.

[0019] Example 5: This embodiment provides a parameter combination for comprehensive performance optimization, with bio-enzyme modified purification particles, the basic composition of which remains unchanged, and the amount of bio-enzyme modified purification particles added is 9% of the dry weight of the flow guide layer; Porous polysaccharide microspheres were immersed in a 4% glutaraldehyde solution and surface modified at 35°C for 5 hours. Then, protease was added to a phosphate buffer solution at pH 7.8 and the mixture was stirred at 8°C for 20 hours. This parameter setting is at a medium-high level. The high glutaraldehyde concentration provides abundant reaction sites for the spacer arm and enzyme molecule to bind, while the weakly alkaline environment of pH 7.8 promotes the nucleophilic substitution reaction and increases the coupling rate. By utilizing a hot air penetration bonding process, under the action of hot air penetration at 145°C, the diapers prepared in this embodiment exhibit excellent structural integrity and continuous biological purification ability when faced with a large amount of urine impact, making them suitable for overnight long-lasting products.

[0020] Comparative Example 1: This comparative example provides a common diaper, the structure of which includes a liquid-permeable top layer, a liquid-impermeable bottom layer, an absorbent core, and a distribution layer, but no bio-enzyme-modified purification particles are added to the distribution layer or the absorbent core; this comparative example serves as a blank control to evaluate the physical absorption performance of the base material itself.

[0021] Comparative Example 2: This comparative example provides a diaper with added free enzyme, which has a structure similar to that of Example 2, except that instead of using cross-linked modified porous polysaccharide microsphere carriers and covalent anchoring via spacer arms, an equal amount of Bacillus subtilis protease solution is directly sprayed onto the guide layer fibers and then dried. This comparative example aims to verify the necessity of carrier immobilization technology in preventing enzyme migration and skin irritation.

[0022] Comparative Example 3: This comparative example provides a diaper with physically adsorbed enzymes, which has a structure similar to that of Example 2. The difference is that the subtilisin is attached to the chitosan microspheres without grafted spacer arms by physical adsorption rather than covalent bonding, and no glycine end-capping treatment is performed. This comparative example is used to verify the advantages of chemical covalent bonding over physical adsorption in terms of enzyme stability.

[0023] Comparative Example 4: This comparative example provides an immobilized enzyme diaper without spacer arms, which has a structure similar to that of Example 2, except that: the surface of the bio-enzyme modified purification particles is not grafted with polyethylene glycol chains, and is covalently anchored by spacer arms. The Bacillus subtilis protease is directly cross-linked and fixed on the surface of chitosan microspheres by glutaraldehyde. This comparative example aims to reveal the key role of covalent anchoring by spacer arms in reducing steric hindrance and improving enzyme catalytic activity.

[0024] Verification experiment: To verify the performance of the protease-purified urine-type diaper of the present invention, simulated urine tests were conducted on the samples prepared in Examples 1-5 and Comparative Examples 1-4.

[0025] Testing standards: 4-hour ammonia concentration: Referring to GB / T24292-2009 Standard for Testing Hygiene Products, artificial urine inoculated with ammonia-producing bacteria, Proteus mirabilis, at an inoculation amount of 10^6 CFU / mL was injected into the sample. After incubation at 37°C for 4 hours, the headspace ammonia concentration was measured to characterize the ability to block ammonia generation. Biofilm attachment reduction rate: Crystal violet staining method was used to measure the change in OD value of bacterial biofilm on fiber surface compared with Comparative Example 1, and the reduction percentage was calculated to characterize the ability to destroy the bacterial colonization environment. Each group of samples was measured 3 times and the average value was taken. Skin irritation: According to GB / T16886.10-2017 Medical Device Biological Evaluation Standard, the irritation was determined by patch test. 0 indicates no irritation, and the higher the score, the stronger the irritation.

[0026] Specific testing process: All tests were conducted in a constant temperature and humidity laboratory at 25°C and 60% RH. For ammonia concentration testing, diaper samples (cut to 10cm × 10cm) from each example and comparative example were placed in a sealed reaction vessel, 60mL of artificial urine containing bacteria was injected, and the vessel was sealed and placed in a 37°C incubator. After 4 hours, the headspace gas was extracted using a gas detector equipped with an electrochemical sensor to determine the ammonia concentration in ppm. For biofilm testing, the flow-through layer fibers were removed, ultrasonically eluted in PBS buffer, and then stained for measurement.

[0027] Table 1 Performance test data of Examples 1-5 and Comparative Examples 1-4

[0028] From Table 1 and Figure 1 The test data and comparative analysis show that the technical solution of the present invention has significant advantages in deodorization and antibacterial properties. Trend Analysis: With the optimization of process parameters, from Example 1 to Example 3, especially the enhancement of glutaraldehyde crosslinking degree and enzyme loading conditions, the ammonia concentration after 4 hours further decreased from 28 ppm to 19 ppm, and the biofilm reduction rate increased from 89.5% to 94.3%. This indicates that by precisely controlling the microstructure of the carrier and the binding environment of the enzyme, the biocatalytic efficiency per unit mass of particles can be significantly improved. Although the high parameter combination in Example 3 has higher energy consumption, it achieves the best purification performance, verifying the application potential of this technical route in high-end products. Comparative Analysis and Mechanism Explanation: Comparing Example 2 and Comparative Example 2, the free enzyme, although possessing initial activity, is easily and rapidly inactivated in a humid and hot environment, and the ammonia concentration is as high as 95 ppm, indicating that it cannot continuously block the ammonia production pathway; Comparative Example 2 has a skin irritation score of 2, confirming that the free enzyme, through urine backflow into the skin, will trigger an sensitization reaction, while the present invention effectively locks the enzyme molecules through covalent bond fixation technology, ensuring the safety of use, and has a score of 0; Comparing Example 2 and Comparative Example 3, it can be seen from physical adsorption that the binding force of physical adsorption is weaker and it is easy to desorb under the flushing of urine, resulting in an ammonia concentration of 68 ppm, which is significantly higher than that of the covalently bound group of 22 ppm; this confirms that chemical bonding is a necessary means to achieve long-term purification. Comparing Example 2 and Comparative Example 4, without the spacer arm, it is evident that the introduction of polyethylene glycol chains as covalent anchors via the spacer arm is a key variable for improving performance. The ammonia concentration in the group without the spacer arm was 45 ppm, while in Example 2 it was reduced to 22 ppm. From a molecular mechanism perspective, the spacer arm effectively pushes the enzyme molecules away from the carrier surface, reducing the stereoprotective effect of the carrier skeleton on the enzyme's active site and steric hindrance. This allows the enzyme's active site to more freely contact and degrade protein substrates in urine, thereby significantly improving the overall catalytic purification efficiency. Furthermore, the introduction of glycine end-capping technology ensures that residual active groups on the carrier are completely sealed, further guaranteeing the product's skin-friendly safety.

[0029] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A protease-purifying diaper, characterized in that, It includes a liquid-permeable surface layer, a liquid-impermeable bottom layer, and an absorbent core located between the two; the absorbent core contains or is disposed between the liquid-permeable surface layer and the absorbent core with bio-enzyme-modified purification particles; the bio-enzyme-modified purification particles include cross-linked modified porous polysaccharide microsphere carriers and proteases covalently anchored to the carriers through spacer arms.

2. The protease-purifying diaper according to claim 1, characterized in that, The cross-linked modified porous polysaccharide microsphere carrier is a cross-linked chitosan microsphere; the protease is a subtilisin.

3. The protease-purifying diaper according to claim 1, characterized in that, The surface of the bio-enzyme modified purification particles is grafted with polyethylene glycol spacers, which are covalently anchored to the carrier via spacers. The protease is anchored to the carrier via the spacers.

4. The protease-purifying diaper according to claim 3, characterized in that, The spacer arm is a polyethylene glycol chain.

5. The protease-purifying diaper according to claim 1, characterized in that, The surface of the bio-enzyme modified purification particles is also grafted with glycine end-capping groups.

6. The protease-purifying diaper according to claim 1, characterized in that, The diaper also includes a flow-guiding layer located between the liquid-permeable surface layer and the absorbent core; the bio-enzyme-modified purification particles are distributed in the fiber web of the flow-guiding layer, or at the interface between the flow-guiding layer and the absorbent core; the amount of the bio-enzyme-modified purification particles added is 5% to 10% of the dry weight of the flow-guiding layer.

7. The method for preparing a protease-purified diaper according to claim 1, characterized in that, The preparation of protease-purified urine diapers includes the following steps: Preparation of bio-enzyme-modified purification particles: Porous polysaccharide microspheres were immersed in a 0.5% to 5% glutaraldehyde solution and subjected to surface aldehyde-modification treatment at 20°C to 40°C for 2 to 6 hours; subsequently, they were reacted with diamino polyethylene glycol to graft polyethylene glycol flexible spacer arms onto the surface of the carrier; the grafted carrier was then immersed in glutaraldehyde solution again for terminal aldehyde-modification activation; then, protease was added to phosphate buffer solution at pH 7.0 to 8.0, and the reaction was stirred at 4°C to 10°C for 12 to 24 hours to immobilize the protease on the carrier through a covalent bonding reaction; finally, glycine solution was added for end-capping treatment, and a reducing agent was added for reduction stabilization treatment; The bio-enzyme modified purification particles are mixed with low-melting-point core-sheath fibers and laid out using an airflow web forming process to form a functionalized flow-guiding layer; or, the bio-enzyme modified purification particles are evenly distributed in the target urination area of ​​the flow-guiding layer mixed with a superabsorbent polymer core; using a hot air penetration bonding process, under the action of hot air penetration at (130-150)℃, the fiber sheath melts to generate bonding points, physically securing the bio-enzyme modified purification particles in the fiber mesh structure.

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