A high-swell release freeze-thaw type bletilla striata polysaccharide bacteriostatic gel mask and a preparation process thereof

Abstract

This invention discloses a high-swelling, slow-release, freeze-thaw type Bletilla striata polysaccharide antibacterial repair gel mask and its preparation process, belonging to the fields of medical aesthetic cold compress dressings and long-lasting skin care gel materials. The raw materials contain only Bletilla striata polysaccharide, PVA1799, and deionized water, without chemical cross-linking agents or preservatives. This invention uses multi-stage low-temperature freeze-thaw physical cross-linking as its core, and optimizes the entire set of freeze-thaw parameters through response surface methodology: BSP to PVA dry basis mass ratio 0.88, 4 freeze-thaw cycles, single freezing for 16 h, and room temperature thawing for 8 h. Industrial production uses -80 ℃, while laboratory testing can use -56 ℃. The finished product exhibits an inhibition zone of 3.23±0.25 mm against Escherichia coli and 3.69±0.37 mm against Staphylococcus aureus; a swelling rate of 553.0%, a porosity of 45.5%, a gel strength of 2421.4 g∙cm, and a water vapor transmission rate of 3483.87 g∙m⁻²∙24h⁻¹. SEM reveals a slow-release porous structure, and IR confirms the formation of numerous hydrogen bonds during freeze-thaw cycles. The mask boasts excellent water-locking ability, long-lasting antibacterial and moisturizing effects, and an elastic fit to the skin. It is suitable for severely dehydrated, acne-prone skin, and post-cosmetic procedures for cold compress repair. Its long-lasting skincare effect surpasses that of regular bath gels.

Description

Technical Field

[0001] This invention belongs to the fields of natural polysaccharide long-lasting skin care gel and Class II medical aesthetic cold compress dressing materials, specifically involving a white ginseng polysaccharide antibacterial facial gel mask that has undergone multiple rounds of low-temperature freeze-thaw cross-linking and ultra-high swelling slow-release. Background Technology

[0002] Existing Bletilla striata polysaccharide gel masks are formed by stirring at room temperature, resulting in weak network cross-linking, limited water absorption and retention capacity, rapid release of active ingredients, and significant loss of effective substances after 10 minutes of application, leading to poor long-term repair effects. Conventional chemically cross-linked masks pose a risk of irritation. Existing freeze-thawed Bletilla striata gels lack systematic quantitative optimization of the interaction between the formulation ratio, number of freeze-thaw cycles, and freeze-thaw temperature. They also lack two sets of low-temperature processes suitable for different laboratories / factories and have not developed a specific facial mask forming solution.

[0003] Freeze-thaw cycles can reconstruct a slow-release porous network through ice crystal reconstruction, significantly enhancing the swelling and water-retaining capacity of materials. However, existing research has not optimized the optimal time ratio of 16 hours of freezing followed by 8 hours of thawing, resulting in a weaker antibacterial effect against Staphylococcus aureus and failing to meet the long-term antibacterial needs of acne-prone skin. This invention optimizes the entire set of freeze-thaw parameters through response surface methodology to obtain a gel substrate with ultra-high swelling and high Staphylococcus aureus inhibition, which can be directly molded into a facial mask, filling the gap in long-lasting, slow-release whitening and skincare gels. Summary of the Invention

[0004] The technical problems this invention aims to solve are: no chemical cross-linking, no preservatives, reducing facial mask irritation; utilizing freeze-thaw cycles to construct a slow-release porous network, significantly improving swelling and water retention capacity, achieving long-lasting polysaccharide release; optimizing two freeze-thaw temperature control processes (-80℃ universal / -56℃ precise) to adapt to different production equipment; optimizing the freeze-thaw time ratio to significantly improve the Staphylococcus aureus inhibition effect, suitable for acne-prone skin; the complete process can directly prepare human-shaped open-pore gel masks, meeting multiple needs such as fit, breathability, and long-lasting repair.

[0005] Complete technical solution: Mask base material formulation: only Bletilla striata polysaccharide, PVA1799, deionized water, BSP: PVA dry basis 0.88, no additional additives; Complete freeze-thaw preparation process: 25 mg / mL BSP, 100 mg / mL PVA mother liquor preparation; mixing and stirring, ultrasonic degassing; injection into a face mold, 4 freeze-thaw cycles, single freezing 16h / thawing 8h; freeze-thaw temperature -80℃ (mass production) or -56℃ (precise temperature control in the laboratory); room temperature stable, aseptic cutting, vacuum packaging.

[0006] Key performance characteristics: The diameter of the inhibition zone against Escherichia coli is 3.23±0.25 mm, and the diameter of the inhibition zone against Staphylococcus aureus is 3.69±0.37 mm, demonstrating outstanding inhibitory effects against acne-causing bacteria; the swelling rate is 553.0%, allowing it to store 5.5 times its own weight in water for long-lasting hydration; the porosity is 45.5%, with slow-release pores that slowly release Bletilla striata polysaccharides; the gel strength is 2421.4 g∙cm, providing a flexible and conformable fit to facial contours without breakage; the water vapor permeability is 3483.87 g∙m⁻²∙24h⁻¹, ensuring the mask does not feel stuffy or leave a white cast; SEM and IR studies confirm that the freeze-thaw cycle forms a uniform hydrogen-bonded porous network, preserving the complete activity of the polysaccharides.

[0007] Beneficial effects: Ultra-high swelling and long-lasting hydration: 553% swelling rate, far exceeding that of ordinary stirred gels, providing continuous hydration throughout the application, suitable for severely dry skin; Powerful acne suppression: Significantly enhanced antibacterial effect against Staphylococcus aureus, improving closed comedones and inflammatory acne; Dual freeze-thaw process options: -80℃ ultra-low temperature freezer is industry-standard equipment with low mass production threshold, while -56℃ solution is suitable for precision laboratory research and development; Slow-release structure: Freeze-thaw cross-linking network delays the release of Bletilla striata polysaccharides, with continuous effect 20-30 minutes after application; Green and safe: No cross-linking agents, no preservatives, can be used as a cold compress on broken skin after medical aesthetic procedures; Predictable process: High response surface model fitting degree, stable batch performance, and suitable for industrial-scale production. Attached Figure Description

[0008] Figure 1 This is a roadmap for freeze-thaw process technology.

[0009] Figure 2 This is a bar chart of the inhibition zone for single-factor freeze-thaw parameters.

[0010] Figure 3 These are actual photos of antibacterial plates under different freeze-thaw conditions.

[0011] Figure 4 This is a 3D surface interaction diagram with contour lines.

[0012] Figure 5 Multi-magnification SEM micrograph of the optimal freeze-thaw mask substrate.

[0013] Figure 6 This is the infrared spectrum of the face mask.

[0014] Figure 7 Plate photos used to verify the antibacterial properties of the optimal process face mask. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0016] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0017] Example 1: -80 ℃ Industrial-grade general-purpose freeze-thaw gel mask: 25 mg / mL Bletilla striata polysaccharide aqueous solution and 100 mg / mL PVA solution stock solution were mixed at a BSP:PVA mass ratio of 0.88, stirred evenly at a constant temperature, and ultrasonically degassed at 150 W for 10 min; the mixture was injected into a 0.3 mm thick face opening mold; frozen at -80 ℃ for 16 h, then thawed at room temperature for 8 h, completing one cycle, and repeated 4 times; after the freeze-thaw cycle, the mixture was allowed to stand at room temperature for 2 h to release internal stress; the eyes, mouth, and nose were cut on a sterile table, and the masks were individually packaged in vacuum aluminum foil to obtain a highly swollen antibacterial gel mask. Performance testing: The diameter of the inhibition zone for Escherichia coli was 3.23±0.25 mm, and the diameter of the inhibition zone for Staphylococcus aureus was 3.69±0.37 mm; the swelling ratio was 553.0%, and the porosity was 45.5%; the gel strength was 2421.4 g∙cm; the water vapor transmission rate was 3483.87 g∙m⁻²∙24h⁻¹; SEM showed a uniform sustained-release porous structure, and IR showed that the characteristic peaks of polysaccharides were intact.

[0018] Example 2: -56 ℃ Precision Temperature Controlled Freeze-Thaw Mask: The premixing, stirring, degassing, freeze-thaw time, and number of cycles were completely consistent with Example 1, except that the freeze-thaw constant temperature was adjusted to -56 ℃. The model predicted an E. coli inhibition zone of 3.20 mm, which is suitable for small-batch preparation in laboratory research.

[0019] Comparative Example 1: With only one freeze-thaw cycle, the cross-linking network was incomplete, and the inhibition zone of E. coli was only 1.47 mm, resulting in a significant decrease in antibacterial performance.

[0020] Comparative Example 2: A single freeze-thaw cycle of 20 hours of freezing + 4 hours of thawing resulted in a Staphylococcus aureus inhibition zone of only 1.39 mm, verifying that 16 hours of freezing + 8 hours of thawing is the optimal freeze-thaw duration of this invention.

[0021] Comparative Example 3: 4 °C refrigeration instead of low-temperature freeze-thaw cycles failed to form an effective cross-linked network, with an inhibition zone of only 0.42 mm, rendering it useless.

[0022] Applications: This freeze-thaw gel mask has strong water absorption and can be used daily as a long-lasting moisturizing mask; for inflammatory acne-prone skin, use 3 times a week to inhibit pathogenic bacteria on the surface and reduce redness and swelling; after laser or microneedling procedures, apply a cold compress for 15 minutes to soothe burning sensations, repair the skin barrier, and without causing irritation or adverse reactions.

Claims

1. A highly swelling, slow-release, freeze-thaw type Bletilla striata polysaccharide antibacterial and repairing gel mask, characterized in that, The raw materials consist only of Bletilla striata polysaccharide (BSP), polyvinyl alcohol (PVA) 1799, and deionized water, and do not contain chemical cross-linking agents or artificial preservatives. The dry basis BSP to PVA mass ratio is 0.

88. The gel is composed of a three-dimensional porous sustained-release network formed by freeze-thaw cycle-induced hydrogen bonds. Performance indicators: inhibition zone diameter for Escherichia coli ≥ 3.20 mm, inhibition zone diameter for Staphylococcus aureus ≥ 3.60 mm, swelling rate 540%~560%, porosity 43%~48%, gel strength 2300~2500 g∙cm; the mask is a human-shaped elastic gel sheet with openings for eyes, nose, and mouth.

2. The gel mask according to claim 1, characterized in that, Infrared characteristic peaks: 3401 cm⁻¹ strong hydroxyl broad peak, 2925 cm⁻¹ C-H peak, 1064 cm⁻¹ characteristic peak of Bletilla striata polysaccharide glycoside, the polysaccharide antibacterial structure is completely preserved during the freeze-thaw process.

3. The preparation process of the freeze-thaw gel mask according to any one of claims 1 to 2, characterized in that, The process comprises two core steps: premixing and homogenization, and low-temperature freeze-thaw crosslinking. S1: Mother liquor preparation: Prepare a 25 mg / mL aqueous solution of Bletilla striata polysaccharide, dissolve PVA1799 in a 95℃ water bath, prepare a 100 mg / mL PVA solution, and cool for later use. S2: Premixing and homogenization: Mix the two mother liquors at a dry basis (BSP:PVA = 0.88), stir at a constant temperature until homogeneous, and remove air bubbles using ultrasonic degassing. S3: Freeze-thaw crosslinking: Inject the mixture into a face-specific mold. A single freeze-thaw cycle consists of 16 hours of low-temperature freezing, followed by 8 hours of thawing at 25℃, for a total of 4 cycles. The freeze-thaw temperature can be either a standard industrial solution of -80℃ or a precise temperature control solution of -56℃. S4: Post-processing: After freeze-thaw completion, allow the mixture to stand at room temperature for 2 hours to release internal stress, aseptically cut and puncture, and vacuum-pack each mask individually to obtain the finished product.

4. The preparation process according to claim 3, characterized in that, Instead of using the 20-hour freezing + 4-hour thawing regimen in a single freeze-thaw cycle, 16 hours of freezing combined with 8 hours of thawing can significantly improve the antibacterial ability against Staphylococcus aureus.

5. The preparation process according to claim 3, characterized in that, The order of influence of various factors on antibacterial performance is: freeze-thaw cross-linking temperature > BSP / PVA mass ratio > number of freeze-thaw cycles.

6. The gel mask according to claim 1, characterized in that, Hyaluronic acid, panthenol and other skincare active ingredients can be added, with a total added mass fraction ≤0.5%.

7. The gel mask according to claim 1, characterized in that, Used for long-lasting moisturizing masks, antibacterial masks for acne-prone skin, and cold compresses after cosmetic procedures.

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