Bacteriostatic hand sanitizer and preparation method thereof

Abstract

The invention discloses a bacteriostatic hand sanitizer and a preparation method thereof, and belongs to the technical field of hand sanitizers. The bacteriostatic hand sanitizer is prepared from the following raw materials in parts by weight: 100 to 150 parts of hand sanitizer matrix, 0.5 to 8 parts of tea tree essential oil, 0.5 to 1.5 parts of green tea carbon dots and 0.01 to 0.1 part of nisin. According to a triple antibacterial scheme, bacterial cell membranes become unstable and permeability is increased due to attack of tea carbon dots, and the tea tree essential oil deeply destroys the cell membrane structure by utilizing initial damage caused by the carbon dots, so that structural collapse of bacteria is caused; the nisin can be highly specifically combined with a key precursor synthesized by a bacterial cell wall, so that the formation of a peptidoglycan network is prevented, and the nisin and the peptidoglycan damage a bacterial membrane at present and can enter bacteria more smoothly; even if bacteria survive in early attack, the bacteria can be cracked and die due to the fact that new cell walls cannot be synthesized; and the cleaning agent has good dirt-removing power, and is safe and non-irritant.

Description

Technical Field

[0001] This invention belongs to the field of hand sanitizer technology, specifically relating to an antibacterial hand sanitizer and its preparation method. Background Technology

[0002] Hand hygiene is one of the most direct and effective ways to prevent the spread of disease. In daily life, people wash their hands to remove dirt and kill or inhibit pathogenic microorganisms carried on their hands, such as Escherichia coli and Staphylococcus aureus, thereby blocking the chain of contact transmission. As the mainstream hand hygiene product, hand sanitizer has evolved from basic cleaning and dirt removal to having multiple functions such as antibacterial and skin care.

[0003] Currently, commercially available antibacterial hand sanitizers are mainly classified into the following categories based on their active ingredients: Chemically synthesized antibacterial agents: These hand sanitizers typically use chemically synthesized antibacterial agents such as triclosan, chloroxylenol, and benzalkonium chloride as their core ingredients. While they possess broad-spectrum and highly effective antibacterial capabilities, long-term use has raised considerable concerns. Potential health risks: For example, triclosan has been shown to have endocrine-disrupting effects, and long-term use may lead to bacterial resistance. The U.S. Food and Drug Administration has banned its addition to some personal care products.

[0004] Skin irritation: High concentrations of chemical antibacterial agents can easily damage the skin's natural barrier, leading to dryness, tightness, allergies, or even dermatitis, affecting the user experience and skin health.

[0005] Environmental impact: These chemicals are not easily completely degraded after being released, and may have potential impacts on aquatic ecosystems.

[0006] Natural plant extract type: To address the problems associated with chemically synthesized antibacterial agents, hand sanitizers marketed with natural ingredients such as tea tree oil, mugwort extract, and aloe vera have emerged. These products are generally gentler and safer. However, they also have significant limitations: Limited antibacterial efficacy: The antibacterial spectrum of single plant extracts is relatively narrow, and the antibacterial strength is often not as good as that of synthetic antibacterial agents, making it difficult to meet the high standards of hygiene protection.

[0007] Unstable ingredients: Many natural active ingredients are easily deactivated by factors such as light, heat, and pH, resulting in a decrease in product efficacy during its shelf life.

[0008] Single mechanism of action: Its antibacterial effect depends on a specific pathway, and bacteria can easily develop tolerance through adaptive mutation.

[0009] Furthermore, most existing hand sanitizers, whether chemical or natural, rely on a single antibacterial mechanism, which tends to reach a plateau in effectiveness when faced with complex and diverse microbial environments. Therefore, the market urgently needs a new type of hand sanitizer that combines highly effective antibacterial action, long-lasting effects, high safety, and a pleasant user experience.

[0010] In recent years, the application of nanomaterials in the biomedical field has provided new ideas for antibacterial technology. Among them, carbon dots, as a novel carbon-based nanomaterial, have attracted widespread attention due to their advantages such as small size, good water solubility, high biocompatibility, and ease of functionalization. Studies have shown that some carbon dots not only possess photoinduced antibacterial activity but can also directly disrupt bacterial cell membrane structures through electrostatic adsorption. However, how to cleverly combine carbon dots with traditional natural antibacterial ingredients to construct a multi-target, synergistic antibacterial system and successfully apply it to daily chemical products such as hand sanitizers remains an area that needs further development. Summary of the Invention

[0011] In view of this, the purpose of this invention is to provide an antibacterial hand sanitizer and its preparation method. The hand sanitizer prepared by this invention is sterilized through multiple pathways, has excellent sterilization ability, good decontamination ability, and is safe and non-irritating.

[0012] To achieve the above objectives, the present invention provides the following technical solution: This invention provides an antibacterial hand sanitizer, comprising the following raw materials in parts by weight: 100-150 parts hand sanitizer base, 0.5-8 parts tea tree essential oil, 0.5-1.5 parts green tea carbon dots, and 0.01-0.1 parts nisin.

[0013] Preferably, the hand sanitizer base comprises 80-100 parts deionized water, 8-12 parts surfactant, 1-5 parts foaming agent, 1-3 parts humectant, 0.1-0.8 parts thickener, 0.1-3 parts pH adjuster, and 0.1-0.5 parts preservative.

[0014] Preferably, the surfactant is one of alkyl glycoside, disodium lauroyl amphoteric acid, and sodium cocoyl aminopropionate.

[0015] Preferably, the foaming agent is one of cocamidopropyl betaine and lauramidopropylamine oxide.

[0016] Preferably, the thickener is one of sodium chloride, lauramide propylamine oxide, and cocamidomethyl MEA.

[0017] Preferably, the tea tree oil is extracted from the tender branches or leaves of the tea tree.

[0018] Tea tree oil's main component, terpenes, are strongly hydrophobic small molecules that can effectively penetrate and "dissolve" the phospholipid bilayer of bacterial cell membranes, disrupting their integrity. This creates pores in the membrane, leading to the leakage of crucial substances such as intracellular ions and ATP, causing the bacteria to die as they are unable to maintain normal physiological functions.

[0019] Preferably, the method for preparing the green tea carbon dots is as follows: Green tea powder and water were mixed and reacted at 180°C for 8 hours. The reaction solution was then centrifuged to obtain the supernatant. The supernatant was filtered to obtain a clear carbon dot stock solution; The filtrate was placed in a dialysis bag and dialyzed in ultrapure water for 24 hours to remove small molecule salts and impurities; the dialyzed liquid was then freeze-dried to obtain solid carbon dot powder.

[0020] The chemical bonds of organic molecules (catechins, proteins, sugars) in tea leaves break and decompose into smaller fragments. Instead, under high temperature and pressure, they are reassembled into carbon nuclei with nanocrystalline structures through a series of chemical reactions such as dehydrogenation, polymerization, and aromatization. The carbon dots are rich in protonated amino groups with strong positive charges, which strongly electrostatically adsorb to the negatively charged bacterial cell membranes, directly destroying the membrane potential and local structure.

[0021] Preferably, the pore size of the filter membrane is 0.22 μm.

[0022] Preferably, the dialysis molecular weight cutoff is 1000 Da.

[0023] The present invention provides a method for preparing the above-mentioned antibacterial hand sanitizer, comprising the following steps: mixing deionized water, surfactant, foaming agent, humectant and thickener evenly, then adding tea tree oil, green tea carbon dots and nisin and mixing evenly again, then adding pH adjuster and preservative and mixing evenly to obtain antibacterial hand sanitizer.

[0024] It contains at least the following beneficial technical effects: This invention employs a triple antibacterial strategy: the carbon dots in tea leaves disrupt bacterial cell membranes, increasing permeability; tea tree oil utilizes the initial damage caused by the carbon dots to deeply destroy the cell membrane structure, leading to structural collapse of the bacteria; and nisin binds highly specifically to key precursors in bacterial cell wall synthesis, thereby preventing the formation of peptidoglycan networks. With both components now disrupting the bacterial membrane, bacteria can enter more easily. Even if bacteria survive the initial attack, they will lyse and die due to their inability to synthesize new cell walls. Attached Figure Description

[0025] Figure 1 This is a bar chart showing the diameter of the inhibition zone in Experiment Example 2. Detailed Implementation

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0028] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0029] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0030] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0031] Unless otherwise specified, "room temperature" and "normal temperature" in this invention refer to 25±2℃.

[0032] Unless otherwise specified, all raw materials or instruments used in the following embodiments of the present invention are commercially available.

[0033] The preparation method of green tea carbon dots is as follows: Green tea powder and water were mixed and reacted at 180°C for 8 hours. The reaction solution was then centrifuged to obtain the supernatant. The supernatant was filtered through a 0.22 μm filter membrane to obtain a clear carbon dot stock solution; The filtrate was placed in a dialysis bag and dialyzed in ultrapure water through a dialysis membrane with a molecular weight cutoff of 1000 Da for 24 hours to remove small molecule salts and impurities; the dialyzed liquid was then freeze-dried to obtain solid carbon dot powder.

[0034] Example 1: 90 parts deionized water, 10 parts sodium cocoyl aminopropionate, 3 parts laurylamidopropylamine oxide, 2 parts glycerin, and 0.5 parts sodium chloride were mixed evenly. Then, 3 parts tea tree oil, 1 part green tea carbon, and 0.05 parts nisin were added and mixed evenly again. Finally, 2 parts citric acid and 0.3 parts pentylene glycol were added and mixed evenly to obtain an antibacterial hand sanitizer.

[0035] Example 2: 80 parts of deionized water, 8 parts of alkyl glycoside, 1 part of cocamidopropyl betaine, 1 part of glycerin, and 0.1 parts of laurylamidopropylamine oxide were mixed evenly. Then, 0.5 parts of tea tree oil, 0.5 parts of green tea carbon dots, and 0.01 parts of nisin were added and mixed evenly again. Finally, 0.1 parts of citric acid and 0.1 parts of pentylene glycol were added and mixed evenly to obtain an antibacterial hand sanitizer.

[0036] Example 3: 100 parts of deionized water, 12 parts of disodium lauroamphodiacetate, 5 parts of cocamidopropyl betaine, 3 parts of glycerin, and 0.8 parts of cocamidopropyl MEA were mixed evenly. Then, 8 parts of tea tree oil, 1.5 parts of green tea carbon, and 0.1 parts of nisin were added and mixed evenly again. Finally, 3 parts of citric acid and 0.5 parts of pentylene glycol were added and mixed evenly to obtain an antibacterial hand sanitizer.

[0037] Comparative Example 1, This comparative example, compared to Example 1, does not contain green tea carbon dots.

[0038] Comparative Example 2, This comparative example does not contain tea tree oil, unlike Example 1.

[0039] Comparative Example 3, This comparative example does not contain nisin, compared to Example 1.

[0040] Comparative Example 4, Compared with Example 1, this comparative example does not contain green tea carbon dots or tea tree oil.

[0041] Comparative Example 5, Compared with Example 1, this comparative example does not contain green tea carbon dots or nisin.

[0042] Comparative Example 6, Compared with Example 1, this comparative example does not contain tea tree oil or nisin.

[0043] Experimental Example 1, Physicochemical morphology test Experimental methods: Appearance and color: Visually inspect the color, transparency, and uniformity of the hand sanitizer.

[0044] Odor: Sensory evaluation of odor characteristics.

[0045] pH value: The pH value of the hand sanitizer was measured using a precision pH meter, and the temperature was controlled at 25±2℃.

[0046] Viscosity: Viscosity was measured using a rotational viscometer.

[0047] Table 1

[0048] All embodiments have a pH value within the skin-friendly range (5.5-7.0), moderate viscosity, and are easy to apply.

[0049] Experimental Example 2, Sterilization ability test Experimental methods: Inhibition zone test: Agar diffusion method was used.

[0050] Test strains: Escherichia coli (ATCC 25922, Gram-negative) and Staphylococcus aureus (ATCC 6538, Gram-positive).

[0051] Sample preparation: The hand sanitizer stock solution of Examples 1-3 and Comparative Examples 1-6 was soaked in filter paper with a diameter of 6 mm. The negative control was deionized water.

[0052] The bacterial suspension (1×10^6 CFU / mL) was spread on MH agar plates, paper discs were placed on them, and the diameter of the inhibition zone was measured after incubation at 37°C for 24 hours.

[0053] Minimum inhibitory concentration (MIC) test: using the micro-broth dilution method.

[0054] Dilute the hand sanitizer series (from undiluted to 1 / 128), mix with bacterial culture medium, incubate at 37°C for 24 hours, and observe the lowest inhibitory concentration.

[0055] Table 2

[0056] Table 3 MIC values ​​(dilution factor, original solution is 1)

[0057] Examples 1-3 showed significant antibacterial effects, with large inhibition zone diameters and low MIC values. The effects decreased in the comparative examples when any one of the antibacterial components was missing, confirming the synergistic effect of green tea carbon dots, tea tree oil, and nisin.

[0058] Experiment Example 3, Stain removal ability test Experimental methods: Foam performance testing: using a Roche foam tester.

[0059] 50 mL of hand sanitizer concentrate was kept at a constant temperature of 40°C and passed through a foam meter at a fixed flow rate. The initial foam volume and the foam volume after 5 minutes were measured.

[0060] Detergency test: Refer to GB / T 13173-2008 "Determination of detergency of surfactants".

[0061] Artificial dirt preparation: A mixture of carbon black, olive oil, and lecithin is applied to a glass slide.

[0062] Soak the soiled glass slide in a hand sanitizer solution (1% w / w), stir mechanically for 10 minutes, and measure the change in reflectance to calculate the decontamination rate.

[0063] Surface tension: The surface tension of the hand sanitizer concentrate was measured using a surface tension meter (such as Krüss K100).

[0064] Table 4 Decontamination Capacity

[0065] All samples exhibited good foaming properties and detergency, with a detergency rate exceeding 85%. Low surface tension indicates that the hand sanitizer effectively moisturizes skin and removes dirt. The addition of antibacterial ingredients had no negative impact on detergency.

[0066] Experiment Example 4, Safety Stimulation Test Experimental methods: Skin irritation test: Rabbit skin irritation test was used.

[0067] Apply 0.5 mL of undiluted hand sanitizer to the skin on the back of the rabbit and leave it on for 24 hours. After removing the sanitizer, observe the erythema and edema at 1, 24, and 48 hours and score them (0-4 points).

[0068] Human patch trial: Recruit 30 healthy volunteers to conduct a closed patch trial.

[0069] Apply 0.02 mL of undiluted hand sanitizer to the inside of the arm and leave it on for 24 hours. After removing the sanitizer, observe the skin reaction (erythema, edema, itching) at 24 and 48 hours.

[0070] Cytotoxicity assay: MTT assay was performed using human keratinocytes (HaCaT).

[0071] Cells were cultured with serially diluted hand sanitizer for 24 hours, then MTT reagent was added, OD570 nm was measured, and cell viability IC50 was calculated.

[0072] Table 5 Skin Irritation Scores

[0073] Table 6 Results of Human Patch Test

[0074] Table 7 Cytotoxicity test (IC50 value)

[0075] Rabbit skin irritation tests and human patch tests showed no significant irritation in any of the tested samples. The high IC50 values ​​for cytotoxicity indicate that the hand sanitizer is safe for skin cells at normal usage concentrations.

[0076] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An antibacterial hand sanitizer, characterized in that, The ingredients include the following parts by weight: 100-150 parts hand sanitizer base, 0.5-8 parts tea tree oil, 0.5-1.5 parts green tea carbon dots, and 0.01-0.1 parts nisin.

2. The antibacterial hand sanitizer according to claim 1, characterized in that, The hand sanitizer base comprises 80-100 parts deionized water, 8-12 parts surfactant, 1-5 parts foaming agent, 1-3 parts moisturizer, 0.1-0.8 parts thickener, 0.1-3 parts pH adjuster, and 0.1-0.5 parts preservative.

3. The antibacterial hand sanitizer according to claim 2, characterized in that, The surfactant is one of alkyl glycoside, disodium lauroyl amphoteric acid, and sodium cocoaminopropionate.

4. The antibacterial hand sanitizer according to claim 2, characterized in that, The foaming agent is one of cocamidopropyl betaine and lauramidopropylamine oxide.

5. The antibacterial hand sanitizer according to claim 2, characterized in that, The thickener is one of sodium chloride, laurylamidopropylamine oxide, and cocamidomethyl MEA.

6. The antibacterial hand sanitizer according to claim 1, characterized in that, The tea tree oil is extracted from the tender branches or leaves of the tea tree.

7. The antibacterial hand sanitizer according to claim 2, characterized in that, The method for preparing the green tea carbon dots is as follows: Green tea powder and water were mixed and reacted at 180°C for 8 hours. The reaction solution was then centrifuged to obtain the supernatant. The supernatant was filtered to obtain a clear carbon dot stock solution; The filtrate was placed in a dialysis bag and dialyzed in ultrapure water for 24 hours to remove small molecule salts and impurities; the dialyzed liquid was then freeze-dried to obtain solid carbon dot powder.

8. The antibacterial hand sanitizer according to claim 7, characterized in that, The filter membrane has a pore size of 0.22 μm.

9. The antibacterial hand sanitizer according to claim 7, characterized in that, The molecular weight cutoff for dialysis is 1000 Da.

10. The method for preparing the antibacterial hand sanitizer according to claim 6, characterized in that, The process includes the following steps: mixing deionized water, surfactant, foaming agent, humectant, and thickener evenly, then adding tea tree oil, green tea carbon dots, and nisin, mixing evenly again, and finally adding pH adjuster and preservative and mixing evenly to obtain antibacterial hand sanitizer.

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