Attapulgite loaded heartleaf houttuynia herb antibacterial composite material as well as preparation method and application thereof

Abstract

The invention discloses an attapulgite loaded herba houttuyniae antibacterial composite material and a preparation method and application thereof.The preparation method comprises the following steps that S1, attapulgite raw ore is subjected to crushing, screening, ultrasonic treatment and gradient centrifugal purification, high-purity attapulgite with the purity larger than or equal to 98% is obtained, and then the high-purity attapulgite is roasted and cooled for use; s2, decocting fresh and alive houttuynia cordata to obtain a houttuynia cordata decoction; s3, adding the high-purity attapulgite roasted in the step S1 into the herba houttuyniae decoction, and fully adsorbing; and S4, centrifuging the mixed solution in the step S3, collecting the precipitate, and drying to obtain the antibacterial composite material. Through innovation of pure physical purification and precise loading processes, the synergistic breakthrough of antibacterial activity, stability and biocompatibility is realized, and the problems of chemical residues, poor stability of natural components, low bioavailability and the like in high purity in the prior art are solved.

Description

Technical Field

[0001] This invention relates to composite antibacterial materials, specifically to an attapulgite-supported houttuynia cordata antibacterial composite material, its preparation method, and its application. Background Technology

[0002] Houttuynia cordata, a traditional plant used in both medicine and food, contains volatile oils (such as decanoyl acetaldehyde), flavonoids, alkaloids, and other natural components with broad-spectrum antibacterial and anti-inflammatory activities and high biosafety, making it a promising candidate for anti-infective applications. However, the effective components of Houttuynia cordata have significant drawbacks when used alone: ​​they are sensitive to environmental factors such as pH and temperature, are easily volatile and metabolized, have low bioavailability, require high concentrations to achieve effective antibacterial effects, and exhibit poor antibacterial stability, severely limiting its large-scale application.

[0003] In addition, some composite antibacterial materials currently use chemical modification or inorganic antibacterial agent composite methods, which have problems such as complex processes, introduction of toxic chemical reagents, and high cytotoxicity; while the composite technology of natural plant extracts and mineral carriers often has defects such as low loading efficiency and insufficient antibacterial stability. Summary of the Invention

[0004] To address the problems of poor antibacterial stability and low bioavailability of the active ingredients in Houttuynia cordata, this invention provides an attapulgite-supported antibacterial composite material (ATP / YXC), its preparation method, and its application. This material can improve the antibacterial properties of the composite material, enhance the acid-base stability of the active ingredients in Houttuynia cordata, and improve the biocompatibility of the material.

[0005] To achieve the above objectives, the present invention provides a method for preparing an attapulgite-supported Houttuynia cordata antibacterial composite material, comprising the following steps: S1: The raw attapulgite ore is crushed, screened, ultrasonically purified, and centrifuged in stages to obtain high-purity attapulgite with a purity of ≥98%. Then it is roasted, cooled, and stored for later use. S2: Take fresh houttuynia cordata and decoct it to obtain houttuynia cordata decoction; S3: Add the high-purity attapulgite obtained from the roasting in step S1 to the decoction of houttuynia cordata and allow it to be fully adsorbed. S4: Centrifuge the mixture from step S3, collect the precipitate, and dry it to obtain the antibacterial composite material.

[0006] Existing methods for attapulgite purification often employ wet processes with chemical dispersants (such as sodium hexametaphosphate) or flotation, which result in chemical residues and compromised biocompatibility. This proposed method, however, utilizes a purely physical process of "crushing and screening - ultrasonication - three-stage centrifugation," introducing no chemical reagents, to achieve an attapulgite purity exceeding 98% (e.g., Figures 1-4As shown in the figure, the crystal structure is intact, solving the industry pain point of "the incompatibility between high purity and biosafety". The attapulgite calcination pretreatment removes adsorbed water / zeolite water while retaining the crystal structure, increasing the specific surface area and adsorption active sites, ensuring that the effective antibacterial components in houttuynia cordata can be adsorbed on the surface and pores of attapulgite.

[0007] The active ingredients of houttuynia cordata are extracted using a green method of "water decoction + centrifugation to remove impurities", leaving no organic solvent residue. The entire preparation process produces no toxic byproducts, making it suitable for large-scale production, unlike existing composite processes that require chemical modification or high temperature and pressure.

[0008] The above technical solutions of the present invention have the following synergistic advantages in terms of effect: 1) Antibacterial stability exceeds expectations When used alone, the volatile oils of Houttuynia cordata (such as decanoyl acetaldehyde) are sensitive to pH, and the antibacterial rate drops by more than 30% in acidic / alkaline environments after 24 hours. However, this composite material, after being soaked for 24 hours under pH=3 (acidic) and pH=10 (alkaline) conditions, shows a decrease of ≤15% in the antibacterial rate against Staphylococcus aureus (still reaching more than 75% at a concentration of 5mg / ml), completely overcoming the inherent defect of "poor environmental adaptability" of natural plant extracts.

[0009] 2) Low concentration antibacterial activity exceeded expectations The antibacterial rate of pure attapulgite against Staphylococcus aureus is greatly affected by concentration and does not show a linear trend (89% at 2.5 mg / ml, only 33% at 5 mg / ml, and 74% at 0.25 mg / ml); pure Houttuynia cordata decoction has almost no antibacterial activity at a concentration of 0.25 mg / ml; while this composite material still has an antibacterial rate of ≥48% (up to 53%) against Staphylococcus aureus at a low concentration of 0.25 mg / ml, and an antibacterial rate of 88% against Escherichia coli at a concentration of 5 mg / ml, achieving a breakthrough in "high-efficiency antibacterial at low concentration".

[0010] 3) Synergistic improvement of biocompatibility Pure attapulgite exhibits a hemolysis rate of 18% at a concentration of 0.25 mg / ml, indicating poor blood compatibility. However, this composite material, through the synergistic regulation of the surface charge of attapulgite by the organic components of houttuynia cordata, achieves a hemolysis rate of ≤5.1% (minimum 4.8%) at a concentration of 0.25 mg / ml, and a survival rate of ≥98.7% for human fibroblasts, approaching the standards for medical biomaterials. This effect of "blood compatibility after loading being superior to that of the carrier itself" is primarily due to the neutralizing effect of houttuynia cordata components on the negative charge on the surface of attapulgite, reducing damage to red blood cells.

[0011] This invention achieves a synergistic breakthrough in "antibacterial activity, stability, and biocompatibility" through innovative pure physical purification and precise loading processes, solving problems such as chemical residues, poor stability of natural ingredients, and low bioavailability in existing technologies.

[0012] Specifically, in step S1, the speeds of the stepped centrifugation are 5000-6000 r / min, 7000-8000 r / min, and 9000-10000 r / min, and the centrifugation time for each step is 10-15 min.

[0013] Specifically, in step S1, the ultrasonic treatment power is 50-60W and the time is 20-30min; the sieving uses a 200-300 mesh standard sieve; and the calcination is carried out at 450-500℃ for 40-60min.

[0014] Specifically, in step S2, the decoction method of houttuynia cordata is as follows: take fresh houttuynia cordata, wash, cut, remove impurities by ultrasonication, add water and decoct for 90-120 minutes, filter and centrifuge, and take the supernatant to obtain houttuynia cordata decoction.

[0015] Furthermore, the ultrasonic cleaning power is 50-60W, and the time is 15-20min.

[0016] Specifically, in step S3, the ratio of calcined high-purity attapulgite to Houttuynia cordata decoction is 1g:(10-15)ml, and the stirring is performed at 25-30℃ and 900-1000r / min using magnetic stirring for 80-100min. This magnetic stirring, combined with the ratio of "Houttuynia cordata decoction + attapulgite," ensures that volatile oils, flavonoids, and other components in Houttuynia cordata are evenly adsorbed onto the surface and pores of the attapulgite (e.g., ...). Figure 5 (As shown).

[0017] The second aspect of the present invention provides an attapulgite-loaded houttuynia cordata antibacterial composite material prepared by the above-described preparation method.

[0018] The third aspect of the present invention provides the application of the above-mentioned attapulgite-loaded houttuynia cordata antibacterial composite material in the preparation of wound antibacterial dressings, food preservatives or feed antibacterial additives.

[0019] Through the above technical solution, the present invention achieves the following beneficial effects: (1) Significantly improved antibacterial performance: ATP / YXC has a maximum antibacterial rate of 87% against Staphylococcus aureus and maintains an antibacterial rate of 53% at low concentrations; it has a maximum antibacterial rate of 88% against Escherichia coli, and its antibacterial performance is better than that of pure Houttuynia cordata decoction and pure attapulgite.

[0020] (2) Excellent antibacterial stability: After soaking for 24 hours under acidic (pH=3) and alkaline (pH=10) conditions, the antibacterial rate of ATP / YXC against Staphylococcus aureus decreased by ≤15% (still reaching more than 75% at a concentration of 5mg / ml), overcoming the defect that the effective components of Houttuynia cordata are easily affected by pH.

[0021] (3) Good biocompatibility: At low concentrations, the survival rate of ATP / YXC on human fibroblasts reaches 99%, which is close to the biocompatibility of pure attapulgite; the hemolysis rate is as low as 5%, which is far lower than that of pure attapulgite, and the blood compatibility is significantly improved.

[0022] (4) Green and environmentally friendly process: Attapulgite is purified by pure physical process without introducing any chemical reagents; the effective components of houttuynia cordata are extracted by water decoction, which is simple and low cost; no toxic by-products are generated in the whole preparation process, which is suitable for large-scale production.

[0023] (5) Advantages of raw material resources: Attapulgite is an advantageous mineral in my country, with abundant reserves and low cost; Houttuynia cordata is both food and medicine and has a wide range of sources, which further reduces the cost of material preparation and improves the feasibility of application. Attached Figure Description

[0024] Figure 1 These are SEM images of the raw ore (ab) and the purified ore after cascade centrifugation; Figure 2 These are TEM images of the raw ore (ac) and the purified ore (df) after cascade centrifugation; Figure 3 These are X-ray diffraction comparison images of the raw ore and the purified ore after cascade centrifugation. Figure 4 This is a comparison of the infrared spectra of the raw ore and the purified ore after cascade centrifugation; Figure 5 This is the infrared spectrum of houttuynia cordata loaded on attapulgite. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in detail below with reference to examples. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0026] Example 1: (1) Raw materials Attapulgite ore: Xuyi County, Huai'an City, Jiangsu Province; the ore contains 78.9% attapulgite. Houttuynia cordata: Fresh Houttuynia cordata roots from Hunan Province, with a water content of 85%.

[0027] (2) Preparation steps Preparation of high-purity attapulgite: Take 1 kg of raw ore, crush it to 1-5 mm, grind it in a ball mill for 60 min, pass it through a 200-mesh sieve, and take 500 g of ore powder; add 1000 ml of deionized water to make a slurry, sonicate for 30 min (50 W), and magnetically stir for 120 min; centrifuge at 5000 r / min for 10 min, and take the supernatant; centrifuge at 8000 r / min for 10 min, and take the supernatant; centrifuge at 10000 r / min for 10 min, and take the supernatant; dry at 80℃ for 8 h to obtain high-purity attapulgite (XRD purity 98.6%); take 20 g of high-purity attapulgite, calcine at 450℃ for 60 min, and set aside for later use.

[0028] Preparation of Houttuynia cordata decoction: Take 200g of Houttuynia cordata root, wash it 3 times, and cut it into 2cm sections; add 500ml of deionized water, sonicate at 50W for 20min to remove impurities; rinse and add 200ml of deionized water, decoct at 100℃ for 120min; filter and centrifuge the filtrate at 8000r / min for 5min, and take the supernatant (decanoyl acetaldehyde content 0.032mg / ml).

[0029] Composite adsorption and drying: Add 20g of calcined attapulgite to the decoction, stir at 25℃ for 90min (1000r / min); centrifuge at 4000r / min for 10min, collect the precipitate; dry at 80℃ for 12h, grind through a 100-mesh sieve to obtain ATP / YXC-1.

[0030] Example 2: (1) Raw materials Attapulgite ore: Baiyin City, Gansu Province, with an attapulgite content of 72.3% in the ore; Houttuynia cordata: Fresh Houttuynia cordata roots from Sichuan, with a water content of 83%.

[0031] (2) Preparation steps Preparation of high-purity attapulgite: Take 1 kg of raw ore, crush it to 1-5 mm, grind it in a ball mill for 60 min, pass it through a 300-mesh sieve, and take 500 g of ore powder; add 1000 ml of deionized water to make a slurry, sonicate for 20 min (60 W), and magnetically stir for 120 min; centrifuge at 6000 r / min for 15 min, and take the supernatant; centrifuge at 7000 r / min for 15 min, and take the supernatant; centrifuge at 9000 r / min for 15 min, and take the supernatant; dry at 80℃ for 8 h to obtain high-purity attapulgite (XRD purity 98.1%); take 20 g of high-purity attapulgite, calcine at 500℃ for 40 min, and set aside for later use.

[0032] Preparation of Houttuynia cordata decoction: Take 200g of Houttuynia cordata root, wash it 3 times, and cut it into 2cm sections; add 500ml of deionized water, sonicate at 50W for 20min to remove impurities; after rinsing, add 300ml of deionized water, decoct at 100℃ for 90min; after filtration, centrifuge the filtrate at 8000r / min for 5min, and take the supernatant (decanoyl acetaldehyde content 0.029mg / ml).

[0033] Composite adsorption and drying: Add 20g of calcined attapulgite to the decoction, stir at 30℃ for 100min (900r / min); centrifuge at 4000r / min for 10min, collect the precipitate; dry at 80℃ for 12h, grind through a 100-mesh sieve to obtain ATP / YXC-2.

[0034] Example 3: (1) Raw materials Attapulgite ore: Xuyi County, Huai'an City, Jiangsu Province (same as Example 1); Houttuynia cordata: Fresh Houttuynia cordata leaves from Yunnan, with a water content of 88%.

[0035] (2) Preparation steps Preparation of high-purity attapulgite: Same as in Example 1, calcined attapulgite was obtained.

[0036] Preparation of Houttuynia cordata decoction: Take 200g of Houttuynia cordata leaves, wash and cut into 1cm pieces; sonicate for 20min to remove impurities; add 200ml of deionized water and decoct at 100℃ for 90min; after filtration, centrifuge the filtrate at 8000r / min for 5min and take the supernatant (decanoyl acetaldehyde content 0.025mg / ml).

[0037] Composite adsorption and drying: Same as in Example 1, to obtain the composite material ATP / YXC-3.

[0038] Example 4: (1) Raw materials Attapulgite ore: Xuyi County, Huai'an City, Jiangsu Province (same as Example 1); Houttuynia cordata: Fresh Houttuynia cordata roots from Hunan (same as in Example 1).

[0039] (2) Preparation steps Preparation of high-purity attapulgite: The ultrasonic time was shortened to 20 min, and the rest was the same as in Example 1, to obtain high-purity attapulgite (XRD purity 98.3%), which was then calcined for later use.

[0040] Preparation of Houttuynia cordata decoction: Same as in Example 1, to obtain the decoction.

[0041] Composite adsorption and drying: The stirring temperature was increased to 30℃ and the stirring time was 80 min. The rest was the same as in Example 1 to obtain the composite material ATP / YXC-4.

[0042] Comparative Example 1 Other conditions are the same as in Example 1, except that the carrier is a common attapulgite (produced in Changzhou, Jiangsu Province, and ground into 200-mesh powder after purchase).

[0043] Comparative Example 2 The other conditions are the same as in Example 1, except that the decoction of Houttuynia cordata is not used.

[0044] Performance testing 1. Antibacterial test method: (1) Preparation of bacterial working solution Strain activation: In this experiment, Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were used as test bacteria for in vitro antibacterial testing. Glycerol tubes of the bacterial strain stored at -80 ℃ were removed, thawed at room temperature, and 100 μL of the original bacterial suspension was streaked into prepared solid culture medium. After single colonies grew, they were inoculated into liquid culture medium and incubated overnight at 37 ℃. Once the bacteria reached the logarithmic growth phase, the bacterial suspension was streaked again. This activation process was repeated three times. The logarithmic growth phase bacterial suspension was then stored at 4 ℃ for later use.

[0045] Preparation of bacterial working solution: Centrifuge the activated bacterial solution at 4000 rpm for 10 min to allow the bacterial cells to precipitate to the bottom of the centrifuge tube, and discard the supernatant. Resuspend the bacterial cells in sterile PBS, dilute to 10⁶ CFU / mL, and store at 4℃ for later use.

[0046] (2) Sample sterilization The samples were sterilized at 121 ℃ under high temperature and high pressure for 20 min before use.

[0047] (3) Antibacterial test The activated bacterial culture was inoculated into freshly prepared liquid culture medium at a 1% inoculation rate. ATP, ATP / ZnO, and ZnO samples were added to the liquid culture medium at concentrations of 0.25 mg / ml, 0.5 mg / ml, 1 mg / ml, 2.5 mg / ml, and 5 mg / ml, respectively. The medium was then incubated overnight at 37 ℃ and 180 rpm. The next day, the culture medium was shaken well, and an appropriate amount of the bacterial culture was serially diluted and plated. The solid culture after serial dilution was incubated overnight at 37 ℃. After clearly visible single colonies appeared, the plates were removed and counted. The colony count of each plate was counted, and the inhibition rate was calculated by comparing with the blank control (inhibition rate = (blank control - experimental group) / blank control).

[0048] 2. Antibacterial stability test method: ATP / YXC was soaked in an acidic solution (pH=3) for 6 h, 12 h, and 24 h, then washed and dried before being subjected to antibacterial activity tests against Staphylococcus aureus to investigate its antibacterial stability under acidic conditions. Similarly, ATP / YXC was soaked in an alkaline solution (pH=10) for 6 h, 12 h, and 24 h, then dried and washed before being subjected to antibacterial activity tests against Staphylococcus aureus to investigate its antibacterial stability under alkaline conditions.

[0049] 3. Cell viability testing methods: (1) Cell culture 1) Remove the selected cells (human fibroblasts and human gastric mucosal epithelial cells) from the low-temperature storage environment, quickly place them in a 37 °C water bath, and gently shake the cryovial to thaw the cryopreservation solution.

[0050] 2) After lysing, transfer the cells to a centrifuge tube containing 5 ml of culture medium, centrifuge to collect the cells, centrifuge at 1000 rpm for 5 min at room temperature, and discard the supernatant.

[0051] 3) Suspend the cells in a complete culture medium containing 10% fetal bovine serum, inoculate them into a culture dish, gently pipette to mix, and culture at 37°C and 5% CO2 saturated humidity.

[0052] 4) Take cells in the logarithmic growth phase and in good growth condition, seed them at 4×103 cells / well in a 96-well cell culture plate, and incubate overnight at 37°C in a 5% CO2 incubator; (add 100 μL of sterile PBS around the cell wells).

[0053] (2) Chemical treatment 1) After filtering or sterilizing the target drug by other means, store it at 4℃.

[0054] 2) Take a 96-well plate, wait for the cells to adhere and grow for 24 hours, discard the culture medium in each well, wash twice with PBS, and add the drug diluted to the working concentration.

[0055] 3) After adding the drug, incubate for 24 hours and then perform testing.

[0056] (3) MTT / CCK-8 colorimetric measurement 1) Thaw the MTT / CCK-8 kit at room temperature, add 10 μL of MTT / CCK-8 chromogenic solution to each well, and incubate in a cell culture incubator for 4 hours.

[0057] 2) Add 100 μL of Formazan solution to each well and mix well. Continue incubation in a cell culture incubator until the Formazan is completely dissolved as observed under a regular optical microscope.

[0058] 3) Use an ELISA reader to detect the absorbance values ​​at 570nm / 450nm and calculate the cell viability.

[0059] 4. Hemolysis rate test method: Preparation of 2% red blood cell suspension: Add 2 mL of rat whole blood to an EP tube containing 200 μL of anticoagulant, stir the blood with a glass rod for 10 minutes to remove fibrinogen and make defibrinated blood, add 20 mL of PBS solution and shake well, centrifuge at 1000~1500 rpm for 15 minutes, remove the supernatant, and wash the precipitated red blood cells with PBS solution 2~3 times as described above until the supernatant is no longer red to obtain the washed red blood cell precipitate, and then dilute with PBS to a concentration of 2% (v / v) red blood cell suspension (1 mL suspension + 49 mL PBS).

[0060] Take 7 EP tubes and number them: tubes 1 to 5 are the test samples, tube 6 is the negative control, and tube 7 is the positive control. Add 2% red blood cell suspension, PBS solution, or distilled water sequentially as shown in Table 4-5, mix well, and immediately incubate at (37±0.5)℃. Observe and record the hemolysis status of each tube.

[0061] Initially, observations were performed every 15 minutes, and images were taken after 1 hour. The supernatant was then transferred to a 96-well plate, and the absorbance was measured at 540 nm using a microplate reader. The absorbance of the sample was denoted as As, the absorbance of the negative control as An, and the absorbance of the positive control as Ap. The formula for calculating the hemolysis rate is as follows: Hemolysis rate (%) = [(As - An) / (Ap - An)]×100.

[0062] The results are shown in Table 1.

[0063] Table 1 Performance Test Results

[0064] As can be seen from the table above: (1) Universality of raw materials: Example 1 (Xuyi mine) and Example 2 (Gansu mine) show that after purification by the process of this invention, the purity of attapulgite from different origins can reach more than 98%. The antibacterial rate and biocompatibility of the prepared composite materials are not significantly different (antibacterial rate deviation ≤3%, hemolysis rate deviation ≤0.3%), proving that the selection of raw materials is not limited by the origin.

[0065] (2) Flexibility of Houttuynia cordata parts: Compared with Houttuynia cordata root, Example 3 (Houttuynia cordata leaf) has a slightly lower content of decanoyl acetaldehyde in the leaf, but the composite material still maintains good antibacterial properties (antibacterial rate of Staphylococcus aureus 83% vs 87%) and excellent biocompatibility, which expands the scope of application of Houttuynia cordata raw materials.

[0066] (3) Process adjustability: Compared with Example 1, Example 4 (shortening the ultrasonic time + increasing the stirring temperature) has basically the same performance indicators (antibacterial rate deviation ≤1%, cell survival rate deviation ≤0.3%), which proves that the process parameters of the present invention can be finely adjusted according to actual production needs, reducing the difficulty of large-scale production.

[0067] (4) Comparison with comparative examples: By setting up comparative example 1 (ordinary attapulgite as carrier, without high-purity purification) and comparative example 2 (only high-purity attapulgite, without Houttuynia cordata antibacterial components), and making a targeted comparison with example 1 (basic example), the inventiveness and superiority of the core technical solution of "high-purity carrier purification + Houttuynia cordata component loading" of the present invention are clearly demonstrated, as follows: ① Antibacterial performance: Example 1 showed antibacterial rates of 87% and 88% against Staphylococcus aureus (5 mg / ml) and Escherichia coli (5 mg / ml), respectively, significantly better than Comparative Example 1 (65% and 60%) and Comparative Example 2 (33% and 52%). Comparative Example 1, due to the low purity (approximately 75%-80%) and incomplete pore structure of ordinary attapulgite, resulted in insufficient loading efficiency of the Houttuynia cordata antibacterial components, with antibacterial rates 22 and 28 percentage points lower than Example 1, respectively. Comparative Example 2, lacking natural antibacterial components from Houttuynia cordata, relied solely on the weak antibacterial properties of high-purity attapulgite, achieving antibacterial rates less than 2 / 5 (Staphylococcus aureus) and 5 / 8 (Escherichia coli) of Example 1. This fully verifies that the synergistic effect of "high-purity carrier + Houttuynia cordata components" is key to achieving high-efficiency antibacterial activity.

[0068] ② Antibacterial stability: After soaking in an alkaline environment of pH=10 for 24 hours, Example 1 showed an antibacterial rate of 75% against Staphylococcus aureus, a decrease of only 13.8%, which was better than the 52% (20.0% decrease) of Comparative Example 1. Comparative Example 1, due to the presence of many impurities and incomplete crystal structure in ordinary attapulgite, could not effectively encapsulate and protect the antibacterial components of Houttuynia cordata, leading to its easy decomposition in acidic and alkaline environments and a significant decrease in stability. Although Comparative Example 2 showed a smaller decrease in antibacterial rate (9.1%), its antibacterial activity was low (33%), resulting in limited practical application value. This further proves that the purification process of high-purity attapulgite in this invention can provide a stable loading environment for the components of Houttuynia cordata, solving the technical pain point of poor stability of existing Houttuynia cordata active ingredients.

[0069] ③ Biocompatibility: Example 1 showed a 99.2% survival rate of human fibroblasts and a hemolysis rate of only 4.8% (meeting the safety standard of ≤5% for biomedical materials). In contrast, Comparative Example 1, due to residual impurities in ordinary attapulgite, showed a cell survival rate of 95.3% and a hemolysis rate of 8.2% (exceeding the standard). Comparative Example 2 demonstrated the inherent defects of pure attapulgite, with a hemolysis rate as high as 18.0%, indicating extremely poor blood compatibility. The comparative results show that this invention, through purification and impurity removal using a high-purity carrier and the modification of surface properties by combining Houttuynia cordata components with the carrier, significantly improves the biocompatibility of the material, solving the problems of poor blood compatibility of pure attapulgite and slightly high cytotoxicity of ordinary carriers.

[0070] In summary, the comparative verification of the proportions and examples shows that the technical solution of the present invention, "preparation of high-purity attapulgite by pure physical purification + loading of natural antibacterial components of houttuynia cordata", overcomes the three major existing defects of low loading efficiency of ordinary carriers, poor stability of pure houttuynia cordata components, and weak antibacterial properties and poor blood compatibility of pure attapulgite. It achieves simultaneous optimization of antibacterial performance, stability and biocompatibility, highlighting the necessity and superiority of the technical solution.

[0071] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0072] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0073] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing an attapulgite-supported houttuynia cordata antibacterial composite material, characterized in that, Includes the following steps: S1: The raw attapulgite ore is crushed, screened, ultrasonically purified, and centrifuged in stages to obtain high-purity attapulgite with a purity of ≥98%. Then it is roasted, cooled, and stored for later use. S2: Take fresh houttuynia cordata and decoct it to obtain houttuynia cordata decoction; S3: Add the high-purity attapulgite obtained from the roasting in step S1 to the decoction of houttuynia cordata and allow it to be fully adsorbed. S4: Centrifuge the mixture from step S3, collect the precipitate, and dry it to obtain the antibacterial composite material.

2. The preparation method according to claim 1, characterized in that, In step S1, the speeds of the stepped centrifuges are 5000-6000 r / min, 7000-8000 r / min, and 9000-10000 r / min, and the centrifugation time for each step is 10-15 min.

3. The preparation method according to claim 1, characterized in that, In step S1, the ultrasonic treatment power is 50-60W and the time is 20-30min; the sieving uses a 200-300 mesh standard sieve; and the calcination is carried out at 450-500℃ for 40-60min.

4. The preparation method according to claim 1, characterized in that, In step S2, the decoction method of houttuynia cordata is as follows: take fresh houttuynia cordata, wash, cut, remove impurities by ultrasonication, add water and decoct for 90-120 minutes, filter and centrifuge, and take the supernatant to obtain houttuynia cordata decoction.

5. The preparation method according to claim 4, characterized in that, The ultrasonic cleaning process has a power of 50-60W and a duration of 15-20 minutes.

6. The preparation method according to claim 1, characterized in that, In step S3, the ratio of calcined high-purity attapulgite to Houttuynia cordata decoction is 1g:(10-15)ml, and the stirring is performed at 25-30℃ and 900-1000r / min with magnetic stirring for 80-100min.

7. The attapulgite-loaded houttuynia cordata antibacterial composite material prepared by any one of claims 1 to 6.

8. The application of the attapulgite-loaded houttuynia cordata antibacterial composite material according to claim 7 in the preparation of wound antibacterial dressings, food preservatives or feed antibacterial additives.

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