Application of multifunctional colloidal silver in promoting wound healing and preventing scar formation

Abstract

The invention provides application of multifunctional colloidal silver in promotion of wound healing and prevention of scar formation, the multifunctional colloidal silver is colloidal poly (5-hydroxytryptamine) / silver, the colloidal poly (5-hydroxytryptamine) / silver is formed by coating a silver core with a poly (5-hydroxytryptamine) shell, and an external preparation prepared from the colloidal poly (5-hydroxytryptamine) / silver as a raw material can be used for promotion of healing of skin infected wounds and prevention of skin scar formation. And a wider application choice is provided for silver-containing metal external preparations.

Description

Technical Field

[0001] The present invention relates to the field of medical metal materials, and more particularly to the application of a multifunctional colloidal silver in promoting wound healing and preventing scar formation. Background Art

[0002] In recent years, topical preparations based on metals and metal oxides have been widely used in the adjuvant treatment of clinical infectious wounds. Among them, topical preparations containing silver metals have been used for a long time in the treatment of clinical wound infections due to their broad-spectrum antibacterial activity and low drug resistance. However, during the application of topical preparations containing silver metals, the strong antibacterial effect of silver ions will cause damage to normal cells, resulting in a slow wound healing rate, easy scar hyperplasia, and poor wound recovery effect. Patent application CN117085173A discloses a scar-free wound healing promoting material, which can be prepared from a tissue adhesive, a bioactive polypeptide and conductive material nano silver powder. This material can be used to promote wound healing and prevent scar formation, but this function can only be achieved under the action of electrical stimulation, with a large operation difficulty and high cost. Summary of the Invention

[0003] To solve the problems of the prior art, the purpose of the present invention is to provide the application of a multifunctional colloidal silver in promoting wound healing and preventing scar formation. The multifunctional colloidal silver is colloidal poly-5-hydroxytryptamine / silver, formed by a silver core coated with a poly-5-hydroxytryptamine shell. The topical preparation made from it can be used to promote the healing of skin infected wounds and prevent scar formation, providing a broader application option for topical preparations containing silver metals.

[0004] The technical solution of the present invention is as follows:

[0005] The application of a multifunctional colloidal silver in promoting wound healing and preventing scar formation, wherein the multifunctional colloidal silver is colloidal poly-5-hydroxytryptamine / silver, formed by a silver core coated with a poly-5-hydroxytryptamine shell.

[0006] As a further improvement of the above solution, a topical preparation made from the colloidal poly-5-hydroxytryptamine / silver is used to promote the healing of skin infected wounds.

[0007] As a further improvement of the above solution, a topical preparation made from the colloidal poly-5-hydroxytryptamine / silver is used to prevent scar formation.

[0008] As a further improvement of the above solution, the topical preparation is a gel.

[0009] As a further improvement of the above solution, the colloidal poly-5-hydroxytryptamine / silver is prepared by stirring 5-hydroxytryptamine with silver nitrate in a buffer solution with a pH of 7.5 - 9.5.

[0010] As a further improvement of the above solution, the buffer solution is one of NaHCO3 / Na2CO3 buffer solution, phosphate buffer solution, borate buffer solution, and Tris buffer solution.

[0011] As a further improvement of the above solution, the molar ratio of serotonin to silver nitrate is 20:1 to 1:10.

[0012] As a further improvement of the above solution, the colloidal poly-5-hydroxytryptamine / silver is prepared by the following steps: dispersing serotonin in a NaHCO3 / Na2CO3 buffer solution with a pH of 7.5 to 9.5, adding silver nitrate and mixing evenly, stirring vigorously for reaction, and after the reaction is completed, centrifuging to collect the lower colloidal liquid, namely colloidal poly-5-hydroxytryptamine / silver.

[0013] As a further improvement of the above solution, the stirring reaction time is 1 to 60 min, preferably 20 - 40 min.

[0014] As a further improvement of the above solution, the stirring reaction temperature is 20 to 40 °C, preferably 30 °C.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: applying the colloidal poly-5-hydroxytryptamine / silver formed by a silver core coated with a poly-5-hydroxytryptamine shell to the external preparation, through precise structural design, enabling poly-5-hydroxytryptamine and silver to be combined in a more compact and orderly manner, optimizing the physicochemical properties, making it more conducive to promoting cell proliferation, migration, and differentiation, while enhancing the antibacterial ability, thereby comprehensively accelerating the healing process of infected wounds. Animal experiments have proved that the external preparation prepared with the colloidal poly-5-hydroxytryptamine / silver obtained by the present invention not only has a bactericidal effect but also can significantly promote the healing of infected wounds, while the bactericidal effect of ordinary silver-containing external preparations is worse and the wound healing speed is much slower; in addition, this external preparation can also control the expression of TGF-β protein, promote the expression of α-SMA protein, and promote the formation of type III collagen in the skin during the wound repair process, inhibiting the hyperplasia of scars during the wound healing process through multi-faceted regulation and promoting scarless repair of the wound. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 It is the TEM electron micrograph of colloidal p-5-PST / Ag;

[0018] Figure 2 EDS spectrum of colloidal p-5-PST / Ag and the corresponding semi-quantitative results;

[0019] Figure 3 Fourier transform infrared absorption spectrum of colloidal p-5-PST / Ag;

[0020] Figure 4 XPS spectrum of colloidal p-5-PST / Ag, where Figure 4 A is the full scan spectrum, Figure 4 B is the Ag 3d fine spectrum, Figure 4 C is the O 1s fine spectrum, Figure 4 D is the N 1s fine spectrum;

[0021] Figure 5 TEM micrograph of colloidal p-5-PST / Ag at day 360;

[0022] Figure 6 Wound photos of mice in different treatment groups at different times in Experimental Example 1;

[0023] Figure 7 Relative wound area changes of mice in different treatment groups in Experimental Example 1;

[0024] Figure 8 Expression levels of TGF-β protein in wound skin tissue homogenates of mice in different treatment groups at day 5 in Experimental Example 1;

[0025] Figure 9 Expression levels of TNF-α, IL-6, and IL-10 in wound skin tissue homogenates of mice in different treatment groups at day 8 in Experimental Example 1;

[0026] Figure 10 H&E staining results and Masson staining results of wound skin tissue of mice in different treatment groups at day 12 in Experimental Example 1;

[0027] Figure 11 Wound photos of mice in different treatment groups at different times in Experimental Example 2;

[0028] Figure 12 Relative wound area changes of mice in different treatment groups in Experimental Example 2;

[0029] Figure 13 Expression levels of TNF-α, IL-6, IL-10, and TGF-β in wound skin tissue homogenates of mice in different treatment groups at day 4 in Experimental Example 2;

[0030] Figure 14Results of Masson staining of wound skin tissues of mice in different treatment groups on the 4th and 12th days in Experimental Example 2;

[0031] Figure 15 Photographs of rabbit ear wounds in different treatment groups at different times in Experimental Example 3;

[0032] Figure 16 Results of H&E staining of wound skin tissues of rabbit ears in different treatment groups on the 10th and 31st days in Experimental Example 3;

[0033] Figure 17 Results of Masson staining of wound skin tissues of rabbit ears in different treatment groups on the 10th and 31st days in Experimental Example 3;

[0034] Figure 18 Results of immunohistochemical staining of α-SMA protein in wound tissues of rabbit ears in different treatment groups on the 10th and 31st days in Experimental Example 3;

[0035] Figure 19 Results of immunofluorescence staining of type I collagen and type III collagen in wound tissues of rabbit ears in different treatment groups on the 10th and 31st days in Experimental Example 3. Detailed implementation manners

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] The weights of the relevant components mentioned in the embodiments of the present invention specification not only can refer to the specific contents of each component, but also can represent the proportional relationship of the weights between each component. Therefore, as long as the contents of the relevant components in the embodiments of the present invention specification are enlarged or reduced in proportion, they are within the scope disclosed in the embodiments of the present invention specification. Specifically, the mass described in the embodiments of the present invention specification can be mass units well-known in the chemical industry such as μg, mg, g, kg, etc.

[0038] For the convenience of understanding the present invention, the present invention will be described more comprehensively and meticulously below with reference to the specification drawings and preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0039] Unless otherwise defined, all the technical terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0040] Unless otherwise specified, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchases or can be prepared by existing methods.

[0041] Example 1

[0042] Preparation of Colloidal Poly-5-Hydroxytryptamine / Silver

[0043] Disperse 2 mL of 5-HT-HCl solution with a concentration of 100 mM in 97 mL of NaHCO3 / Na2CO3 buffer solution with a pH value of 8.5 and a concentration of 10 mM. Subsequently, add dropwise 1 mL of AgNO3 solution with a concentration of 100 mM, and stir rapidly and evenly. Then, stir vigorously at 30 °C for 30 min, centrifuge to collect the lower colloidal liquid, and wash it 3 times with ultrapure water to obtain colloidal poly-5-hydroxytryptamine / silver (colloidal p-5-PST / Ag).

[0044] The colloidal p-5-PST / Ag was detected and analyzed. The observation results by transmission electron microscope (TEM) are as Figure 1 shown. The colloidal p-5-PST / Ag is spherical-like with uniform size, and its diameter is mainly distributed in the range of 30 - 40 nm, having an obvious core-shell structure. The measurement result of the lattice spacing shows that the d value is 0.238 nm, which is consistent with the (111) crystal plane of Ag.

[0045] The results of energy-dispersive X-ray spectroscopy (EDS) elemental analysis are as Figure 2 shown. The results show that the colloidal p-5-PST / Ag is mainly composed of elements such as C, N, O, and Ag. Among them, the signals of C and N elements are mainly distributed on the surface, while the Ag signal is concentrated in the core region.

[0046] The Fourier transform infrared spectroscopy (FTIR) analysis results of the colloidal p-5-PST / Ag are as Figure 3 shown. The results show that the O-H and N-H stretching vibration peaks of 5-HT at 3420 cm -1 decrease in intensity and shift to higher wavenumbers after the reaction. An obvious p-5-PST characteristic peak appears at 3460 cm -1 for the colloidal p-5-PST / Ag, but the intensity is lower than that of p-5-PST. In addition, corresponding absorption peaks are observed in the characteristic regions of 3000 - 2750 cm -1 (C-H stretching vibration), 1800 - 1600 cm -1 (C=O stretching vibration and N-H bending vibration), and 1150 - 1000 cm -1 (C-O and C-N stretching vibrations), etc., but the peak intensities decrease.

[0047] The results of X-ray photoelectron spectroscopy (XPS) analysis are as Figure 4as shown, where Figure 4 A is the full-scan spectrum, Figure 4 B is the Ag 3d fine spectrum, Figure 4 C is the O 1s fine spectrum, Figure 4 D is the N 1s fine spectrum. The fitting results of the Ag 3d spectrum show that characteristic peaks appear at 367.28 eV, 367.85 eV, 373.19 eV and 373.82 eV for colloidal p-5-PST / Ag, indicating the simultaneous presence of Ag(0) and Ag(+), with Ag(0) being the main component; the characteristic peaks of the O 1s spectrum at 533.49 eV, 532.44 eV and 530.91 eV correspond to C=O, C-O and O-Ag bonds respectively; the characteristic peaks of the N 1s spectrum at 399.77 eV and 398.44 eV are attributed to C-NH2 and N-Ag bonds respectively.

[0048] The above detection and analysis results fully confirm the successful preparation of colloidal p-5-PST / Ag. 5-HT is oxidized to form p-5-PST while reducing Ag + and the latter binds to the Ag core through the hydroxyl and amino groups in its structure to form colloidal p-5-PST / Ag with an obvious p-5-PST coating layer.

[0049] The content of Ag in colloidal p-5-PST / Ag was determined by inductively coupled plasma optical emission spectrometry (ICP-OES), and the reduction rate of 5-HT to Ag + was calculated to reach 44%. After colloidal p-5-PST / Ag was placed at 4 °C for 360 days, its TEM results were as Figure 5 shown. No obvious aggregation occurred for colloidal p-5-PST / Ag, and the particle size did not increase significantly, indicating its good storage stability.

[0050] Comparative Example 1

[0051] Preparation of conventional colloidal silver

[0052] 30 μL of a 100 mM sodium citrate solution and 10 μL of a 100 mM AgNO3 solution were added to 9860 μL of pre-cooled double-distilled water and stirred well. Then, 100 μL of a 100 mM sodium borohydride solution was added to the reaction system, and the reaction was carried out for 30 min under ice bath conditions. The lower colloidal liquid was collected by centrifugation and washed 3 times with ultrapure water to obtain conventional colloidal silver (colloidal Ag).

[0053] Experimental Example 1

[0054] Colloidal p-5-PST / Ag at 40 μg / mL (calculated as Ag) and colloidal Ag were uniformly mixed with 3% carbomer 941 gel at a ratio of 1:1 (v / v) respectively to obtain PST / Ag gel and Ag gel at 20 μg / mL.

[0055] After the mice were anesthetized, a circular full-thickness wound with a diameter of 1 cm was created on their backs. 100 μL of Staphylococcus aureus suspension (1×10 6 CFU / mL) was uniformly inoculated on the skin around and on the surface of the wound, and the infection was continuous for 24 h to obtain a mouse model of Staphylococcus aureus-infected wound.

[0056] The mice were randomly divided into different groups (n = 6). Among them, the mice in the normal group (Normal group) were not infected, the wounds were normal and no treatment was given; the other groups were pre-infected with bacteria. The infected group (Infected group) did not receive any treatment. The treatment groups applied 100 μL of PST / Ag gel (PST / Ag gel group) and Ag gel (Ag gel group) to the mice on the 1st, 3rd, and 5th days respectively. The body weight of the mice was recorded every two days, and the relative wound area of the mice was calculated using Image J. Mucus and skin around the wounds of the mice were collected to prepare homogenates, and the levels of cytokines (TNF-α, IL-6, IL-10, TGF-β) were detected by ELISA. Skin samples around the wounds of each group of mice were taken for H&E staining and Masson staining to analyze the pathological structure of the skin and collagen deposition.

[0057] Wound photos of mice in different treatment groups at different times are as Figure 6 shown, and the statistical results of the relative wound area are as Figure 7 shown. The results showed that obvious yellow secretions appeared in the bacteria-infected wounds, and the healing rate was significantly slowed down, indicating that the construction of the infectious wound model was successful. PST / Ag gel significantly accelerated the healing process of the infected wounds. The wound healing rate reached 50% on the 3rd day of treatment, while the untreated infected wounds and normal wounds required 7 days and 4 days respectively. By the 12th day, the wounds of the mice treated with PST / Ag gel were completely closed and the scabs fell off, showing no significant difference compared with the normal wounds. In contrast, Ag gel only accelerated the wound healing in the early stage of treatment (0 - 5 days), and then the healing rate was significantly slowed down, showing phenomena similar to those of the infected wounds such as protracted non-healing and incomplete epithelialization.

[0058] The results of plate spreading of the wound tissues mucus of each group of mice showed that compared with the infected wounds, a single administration of PST / Ag gel could significantly reduce the wound bacterial load, and almost no viable bacteria were detected after two consecutive administrations; while Ag gel only slightly inhibited the bacterial growth and failed to completely clear the wound bacteria.

[0059] Transforming growth factor-β (TGF-β) is a pleiotropic cytokine closely related to wound healing, which is involved in processes such as inflammatory response, cell proliferation and differentiation, and scar formation. Studies have shown that appropriate TGF-β can promote fibroblasts to synthesize collagen, elastic fibers, and fibronectin, accelerating wound repair; however, excessive TGF-β can induce fibroblasts to differentiate into myofibroblasts and express α-SMA protein, which is a key link in the formation of pathological scars. On the 5th day, the expression levels of TGF-β protein in the wound skin tissue homogenates of mice in different treatment groups were as Figure 8 shown. The results showed that compared with normal wounds, bacterial infection significantly increased the TGF-β level in the skin around the wounds, and both PST / Ag gel and Ag gel treatments reduced the TGF-β level in infected wounds. The TGF-β level in the wounds of the PST / Ag gel group was comparable to that of the normal group. These results indicate that PST / Ag gel does not over-upregulate the expression of TGF-β protein and can reduce the risk of scar formation.

[0060] On the 8th day, the expression levels of TNF-α, IL-6, and IL-10 in the wound skin tissue homogenates of mice in different treatment groups were as Figure 9 shown. The results showed that after treatment with PST / Ag gel, the levels of pro-inflammatory factors (TNF-α, IL-6) in the mouse skin tissue decreased significantly, while the level of anti-inflammatory factor (IL-10) increased, suggesting the subsidence of the inflammatory response.

[0061] On the 12th day, the results of histopathological analysis of the skin tissues of mice in different treatment groups were as Figure 10 shown. The results showed that the wounds of the mice in the PST / Ag gel group were completely closed, and the deposition of collagen (blue in Masson staining) was orderly; while the wounds of the infection group and the Ag gel group were incompletely epithelialized, obvious scabs were visible, and the collagen was arranged disorderly, containing a large number of muscle fibers (red in Masson staining), indicating that PST / Ag gel has excellent in vivo antibacterial and wound-healing effects.

[0062] Experimental Example 2

[0063] Colloidal p-5-PST / Ag (calculated as Ag), colloidal Ag, 5-HT, and p-5-PST at 40 μg / mL were uniformly mixed with 3% carbomer 941 gel at a ratio of 1:1 (v / v) respectively to obtain 20 μg / mL PST / Ag gel, Ag gel, 5-HT gel, and PST gel.

[0064] PST gel and Ag gel were uniformly mixed at a ratio of 1:1 (v / v) to obtain PST+Ag gel.

[0065] The PBS solution was uniformly mixed with 3% carbomer 941 gel at a ratio of 1:1 (v / v) to obtain PBS gel.

[0066] The mice were randomly divided into 7 groups. Among them, group G1 was the normal control group with non-infected wounds, and the remaining 6 groups were all established with Staphylococcus aureus-infected wound models, and were respectively treated with PBS gel (group G2), PST / Ag gel (group G3), 5-HT gel (group G4), PST gel (group G5), Ag gel (group G6), and PST+Ag gel (group G7).

[0067] The wound photos of mice in different treatment groups are as Figure 11 shown, and the changes in the relative area of the wounds are as Figure 12 shown. The results showed that compared with group G2, the wound healing rates of groups G4, G5, and G6 were all improved to a certain extent, but their curative effects were significantly lower than those of group G3; although the wound healing rate of group G7 was better than that of group G6, it was still significantly lower than that of group G3, indicating that PST / Ag gel has an obvious effect on promoting the healing of infected wounds compared with other gels.

[0068] On the 4th day, histopathological analysis and immune analysis were performed on the wound skin tissues of mice in each group. The histopathological results showed that a large number of inflammatory cell infiltrations appeared around the wounds in group G2. The ELISA test results are as Figure 13 shown, which also confirmed that compared with the wounds in group G1, the levels of pro-inflammatory factors TNF-α and IL-6 in the wound tissues of group G2 were significantly increased, and the expression of the anti-inflammatory factor IL-10 was weakened; the levels of pro-inflammatory factors in group G3 were significantly lower than those in other infected wound groups, while the anti-inflammatory factor IL-10 was significantly higher than those in other groups, indicating that after the infected wounds were treated with PST / Ag gel, the levels of pro-inflammatory factors in the tissues could be significantly reduced and the expression of IL-10 could be promoted, having the effect of promoting the subsidence of inflammation. On the 12th day, the histopathological analysis results of the wounds of each mouse showed that the wounds treated with PST / Ag gel presented the best healing state, including characteristics such as complete re-epithelialization, hair follicle regeneration, and angiogenesis.

[0069] As highly plastic immune cells, macrophages undergo a phenotypic transformation from M1 type (pro-inflammatory) to M2 type (anti-inflammatory) during the wound healing process, and this dynamic change is crucial for wound repair. The healing processes of the wounds of mice in each group were evaluated by multiple immunofluorescence staining. The results showed that on the 12th day, the wound tissues treated with PST / Ag gel were mainly composed of M2-type macrophages, while the wound tissues treated with other gels were still mainly composed of M1 type, especially the wounds treated with PBS gel and Ag gel.

[0070] Evaluation of the cell proliferation activity at the wound edge by Ki67 staining revealed that PST / Ag gel significantly enhanced cell proliferation in infected wound tissues, even superior to that in non-infected wounds; 5-HT gel and PST gel also promoted cell proliferation, but their effects were inferior to those of PST / Ag gel.

[0071] Given the crucial role of fibroblasts in early wound healing, the fibroblast activity and collagen deposition in the wound tissues of mice in each group were evaluated by Masson staining at day 4 and day 12, as Figure 14 shown. The results showed that at day 4, treatment with PST / Ag gel (Group G3) significantly increased the deposition of wound collagen (blue), indicating that it accelerated the process of the proliferation phase. At day 12, the newly formed skin in the wounds of Group G3 was mainly composed of orderly arranged collagen fibers, while in the wounds of Group G2, there were both collagen fibers (blue) and a large amount of muscle fibers (red), and there was more collagen deposition but disordered arrangement in the wounds of Group G6.

[0072] The above results indicate that simple physical mixing cannot fully exert the synergistic effect of p-5-PST and Ag. In contrast, through precise structural design, such as the colloidal p-5-PST / Ag provided by the present invention, p-5-PST and Ag can be combined in a more compact and orderly manner, which can optimize their physicochemical properties such as surface area, charge distribution, release behavior, and reactivity. These characteristics are more conducive to promoting cell proliferation, migration, and differentiation, while enhancing the antibacterial ability, thus comprehensively accelerating the healing process of infected wounds.

[0073] Experimental Example 3

[0074] The colloidal p-5-PST / Ag at 40 μg / mL (calculated as Ag) and colloidal Ag were respectively and uniformly mixed with 3% carbomer 941 gel at a ratio of 1:1 (v / v) to obtain 20 μg / mL PST / Ag gel and Ag gel. A blank gel was prepared with 3% carbomer 941 gel and double-distilled water at a ratio of 1:1 (v / v) as a control.

[0075] New Zealand rabbits were caged in the Department of Animal Science, Xiangya Medical College for 1 week. The experimental rabbits were anesthetized by intravenous injection of 30 mg / kg sodium pentobarbital solution through the ear vein, and the ventral side of the rabbit ear was treated with a razor. Three full-thickness skin excision wounds (deep layer and perichondrial layer) were created on the ventral side of the rabbit ear with a sampling needle with a diameter of 10 mm, located at the root, middle, and tip of the rabbit ear respectively, and arranged evenly along the longitudinal axis of the rabbit ear. After all the wounds were completely hemostatic, an appropriate amount of iodophor was bundled with sterile gauze, and then the rabbits were caged separately. Iodophor was applied every day. On the 7th day after surgery, the scabs were removed and the wounds were completely exposed again (marked as D0) to promote the formation of hypertrophic scars. PST / Ag gel (PST / Aggel group), Ag gel (Ag gel group), and blank gel (Blank gel group) were used for treatment respectively, and were applied to the wound site once every two days for a total of 5 times (100 μL each time). Wound photos were recorded on the 0th, 5th, 10th, 17th, 24th, and 31st days. The experimental rabbits died on the 10th and 31st days respectively. Skin tissues at the rabbit ear wounds were collected and analyzed by H&E staining and Masson staining. The α-SMA protein and collagen I / III in the skin tissues were labeled by immunofluorescence and immunohistochemistry to evaluate the deposition level and classification of collagen in the skin.

[0076] During the experiment, the photos of rabbit ear wounds at different times were as Figure 15 shown. The results showed that the wound healing rate of the PST / Ag gel group was significantly faster than that of the other two groups, and the healed wounds were the flattest and smoothest with the least scar hyperplasia; while the wounds in the Ag gel group not only healed slowly but also had obvious scar hyperplasia, manifested as abnormal elevation on the skin surface, dark red masses, and texture hardening.

[0077] Further analyzing the repair conditions of wounds at different stages, the H&E staining results of rabbit ear wounds in each group on the 10th and 31st days were as Figure 16 shown. The results indicated that on the 10th day, the newly formed skin of the wounds in each group was thickened to varying degrees (white arrows), but the thickening of the wounds in the PST / Ag gel group was the lightest, and the regeneration of hair follicles and regular blood vessels could be observed. By the 31st day, there was almost no difference between the newly formed skin of the PST / Aggel group and normal skin, and the hair follicle structure was obvious.

[0078] The Masson staining results of rabbit ear wounds in each group on the 10th and 31st days were as Figure 17 shown. The results showed that the content of collagen fibers (blue) in the wound tissues of the PST / Ag gel group and the Blank gel group was relatively high and arranged orderly, while the Ag gel group was mainly composed of muscle fibers (red).

[0079] Myofibroblasts, as the main component of wound granulation tissue, possess the characteristics of both fibroblasts and smooth muscle cells. They generate contractile force by forming α-SMA-positive actin stress fibers, promoting wound shrinkage and repair. The immunohistochemical staining results of α-SMA protein in the rabbit ear wounds of each group at day 10 and day 31 are as Figure 18 shown. The results show that α-SMA was expressed in the wounds of each group in the early stage, and the PST / Ag gel group had the strongest expression, indicating a large proliferation and migration of myofibroblasts, providing support for wound repair. However, in the late stage of repair, the α-SMA expression in the wounds of the PST / Ag gel group and the Blank gel group gradually decreased, suggesting that myofibroblasts transformed into a quiescent state or underwent apoptosis, which was beneficial to maintaining tissue homeostasis and reducing scar formation. In contrast, the wounds of the Ag gel group still showed continuous high expression of α-SMA, which was consistent with the obvious scar hyperplasia in this group while almost no scar formation in the PST / Ag gel group.

[0080] Collagen, as the main component of the extracellular matrix, its type and distribution directly affect the function and morphology of the newly formed skin. Type I collagen is mainly distributed in the dermis layer, providing strength and toughness to the skin; type III collagen mainly exists in the superficial layer, endowing the skin with elasticity and softness. During wound healing, the excessive deposition of type I collagen is a key factor in scar formation, while the increase in the content of type III collagen may improve the scar texture. By detecting the expression levels of collagen I / III in the rabbit ear wound tissues of each group at day 10 and day 31 to evaluate skin repair, the results are as Figure 19 shown. In the early stage, more type I collagen (red) was deposited in the skin of the wounds in the Blank gel group and the Ag gel group, while the PST / Ag gel group was mainly composed of type III collagen (green). As time went by, the distribution of type I and type III collagen in the skin of the wounds in the Blank gel group tended to be normal, with a large amount of type III collagen distributed in the surface layer and a small amount of type I collagen present in the dermis layer; the collagen distribution in the Ag gel group was disorderly; but the skin of the wounds in the PST / Ag gel group was still mainly composed of type III collagen, with only a small amount of type I collagen expression, indicating that the newly formed skin in the PST / Ag gel group was softer and more elastic.

[0081] In summary, the treatment of skin wounds with PST / Ag gel does not induce abnormal activation and proliferation of fibroblasts at the wound site, nor does it cause excessive secretion and deposition of type I collagen. On the contrary, PST / Ag gel can promote fibroblasts to secrete more type III collagen, making the newly formed wound show better softness and elasticity. Experiments have shown that compared with blank gel and Ag gel, the use of PST / Ag gel can significantly accelerate wound healing while preventing the formation of hypertrophic scars and promoting scar-free rapid healing of wounds.

[0082] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. Use of a multifunctional colloidal silver in promoting wound healing and preventing scar formation, characterized in that, The multifunctional colloidal silver is colloidal poly-5-hydroxytryptamine / silver, which is formed by a silver core coated with a poly-5-hydroxytryptamine shell.

2. The application according to claim 1, characterized in that An external preparation is prepared from the colloidal poly-5-hydroxytryptamine / silver as a raw material for promoting the healing of skin infected wounds.

3. The application according to claim 1, characterized in that An external preparation is prepared from the colloidal poly-5-hydroxytryptamine / silver as a raw material for preventing scar formation.

4. The application according to any one of claims 1 to 3, characterized in that, The colloidal poly-5-hydroxytryptamine / silver is prepared by stirring 5-hydroxytryptamine and silver nitrate in a buffer solution with a pH of 7.5 to 9.

5.

5. The application according to claim 4, characterized in that, The buffer solution is one of NaHCO3 / Na2CO3 buffer solution, phosphate buffer solution, borate buffer solution, and Tris buffer solution.

6. The application according to claim 4, characterized in that The molar ratio of the 5-hydroxytryptamine to the silver nitrate is 20:1 to 1:

10.

7. The application according to claim 4, wherein The colloidal poly-5-hydroxytryptamine / silver is prepared by the following steps: dispersing 5-hydroxytryptamine in a NaHCO3 / Na2CO3 buffer solution with a pH of 7.5 to 9.5, adding silver nitrate and mixing evenly, stirring vigorously for reaction, and centrifuging to collect the lower-layer colloidal liquid after the reaction is completed, thus obtaining the colloidal poly-5-hydroxytryptamine / silver.

8. The application according to claim 7, wherein The stirring reaction time is 1 to 60 minutes.

9. The application according to claim 7, characterized in that, The stirring reaction temperature is 20 to 40 °C.

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