A method for preparing a pH-responsive swab for wound infection monitoring

Abstract

A preparation method of a pH response cotton swab for wound infection monitoring, first, natural cotton fibers are soaked in a bromocresol green solution for dyeing, and the color of the bromocresol green solution is blue during the dyeing process; the soaked natural cotton fibers are rinsed with a buffer solution; then, the excess buffer solution is squeezed out, the natural cotton fibers are dried, and orange-yellow natural cotton fibers are obtained; finally, the dried natural cotton fibers are fixed on the top end of a thin rod, and the pH response cotton swab is obtained. The color change of the pH response cotton swab after wiping the wound is used to quickly judge the type of wound infection of the patient, the pH value of 4.0-6.0 corresponds to acute wounds, the pH value of 7.0-10.0 corresponds to chronic wounds, corresponding treatment strategies are adopted based on the type of wound, which helps to improve the work efficiency of medical staff; at the same time, compared with the traditional form of dressing, the cotton swab avoids the secondary infection risk caused by multiple times of uncovering the dressing.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, specifically relating to a method for preparing a pH-responsive swab for wound infection monitoring. Background Technology

[0002] Wound microbial infection is a serious problem that can hinder the healing of chronic wounds. Accurate, timely, and early detection of infection, along with real-time monitoring of various infection-related wound healing biomarkers, is crucial for the treatment and care of chronic wounds. However, a clinical approach to regular wound assessment and care requires in-person visits to wound care clinics or hospitals, and dedicated healthcare professionals who regularly spend time assessing wound infection status. Rapid detection of infection, especially in chronic wounds, is a vital step in improving wound management and reducing antibiotic treatment. Healthcare professionals can quickly provide diagnostic results and take appropriate action to treat infected wounds promptly, which is essential for wound healing.

[0003] The pH value of wound exudate is a key parameter for assessing wound infection. Many physiological processes, such as inflammation, collagen formation, and angiogenesis, affect changes in the pH value of wound exudate. Therefore, monitoring wound pH value helps determine the infection status of the wound. Currently, most products on the market for monitoring wound infection are dressings and hydrogels. CN202210263468.4 discloses a dressing for assessing wound infection. This dressing uses bacterial cellulose gel produced by Acetobacter xylinum fermentation as a matrix. It loads a fluorescent substrate, 4-methylumbelliferyl-β-D-glucuronide, which reacts with β-glucuronyl glycoside secreted by bacteria to generate a fluorescent substance, allowing for rapid in-situ detection of bacterial infection. The infection status of the wound can be directly determined by observing the fluorescence. Similarly, CN201910621326.9 discloses a method for preparing a pH-responsive photonic crystal gel base for skin wound treatment. This method prepares a CS / PAA / nano-Cu2WSe4 composite hydrogel and loads it with a pH-responsive photonic crystal base. Because the wound infection site is weakly acidic, the pH-responsive photonic crystal base can exhibit a color reaction under Bragg diffraction, allowing for visual observation of color changes to determine whether the wound is infected. However, the above techniques suffer from complex preparation processes, high costs, and inconvenient use. Therefore, developing a low-cost, easy-to-use pH-responsive swab for detecting wound infection is a pressing issue that needs to be addressed. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the prior art by providing a simple and low-cost method for preparing pH-responsive swabs for wound infection monitoring.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A method for preparing a pH-responsive swab for wound infection monitoring, the method comprising:

[0007] Natural cotton fibers are dyed by soaking them in a bromocresol green solution, during which the bromocresol green solution turns blue.

[0008] Soak the natural cotton fibers in a buffer solution and rinse them.

[0009] After squeezing out excess buffer solution, dry the natural cotton fibers.

[0010] By fixing dried natural cotton fibers to the tip of a thin rod, a pH-responsive swab can be obtained.

[0011] The staining was performed at 60-90℃ for 20-30 minutes.

[0012] The bromocresol green solution is obtained by dissolving bromocresol green powder in an aqueous ethanol solution.

[0013] The mass ratio of bromocresol green powder to natural cotton fiber is 0.5-5:100.

[0014] The mass-to-volume ratio of the natural cotton fiber to the bromocresol green solution is 1 g: 50 mL.

[0015] The volume ratio of ethanol to deionized water in the ethanol-water solution is 1:1 to 9:1.

[0016] The buffer solution is either phosphate buffer or acetate buffer.

[0017] The pH value of the buffer solution is 1.0-3.0.

[0018] The pH value of the buffer solution is 4.0-5.0.

[0019] The drying temperature is 40-60℃.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] This invention discloses a method for preparing pH-responsive swabs for wound infection monitoring. First, natural cotton fibers are soaked in a bromocresol green solution for staining; during the staining process, the bromocresol green solution turns blue. The soaked natural cotton fibers are then rinsed with a buffer solution. Excess buffer solution is squeezed out, and the fibers are dried. Finally, the dried natural cotton fibers are fixed to the tip of a thin rod to obtain the pH-responsive swab. This invention utilizes the color change of the prepared pH-responsive swab after wiping a wound to quickly determine the pH value of the patient's wound. Based on the pH value, the type of wound infection can be determined: a pH value of 4.0-6.0 corresponds to an acute wound; a pH value of 7.0-10.0 corresponds to a chronic wound. Adopting corresponding treatment strategies based on the wound type helps improve the work efficiency of medical staff. Simultaneously, compared to traditional dressings, swabs avoid the risk of secondary infection from repeatedly removing dressings. Furthermore, the preparation method is simple, low-cost, and can be widely applied. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of bromocresol green at different pH values.

[0023] Figure 2 The color change of the pH-responsive cotton swab in Example 1 when it was soaked in an acid-base solution with a pH gradient of 6.0-12.0 is shown.

[0024] Figure 3 The color change of the pH-responsive cotton swab in Example 9 when it was soaked in an acid-base solution with a pH gradient of 6.0-12.0.

[0025] Figure 4 The K / S value curves of pH-responsive swabs prepared in Examples 1-4 are shown.

[0026] Figure 5 The K / S value curves of pH-responsive swabs prepared in Examples 1 and 5-7 are shown.

[0027] Figure 6 The K / S value curves of pH-responsive swabs prepared in Example 7 and Comparative Example 2 are shown. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0029] A method for preparing a pH-responsive swab for wound infection monitoring, the method comprising:

[0030] Natural cotton fibers are dyed by soaking them in a bromocresol green solution, during which the bromocresol green solution turns blue.

[0031] Soak the natural cotton fibers in a buffer solution and rinse them.

[0032] After squeezing out excess buffer solution, dry the natural cotton fibers.

[0033] By fixing dried natural cotton fibers to the tip of a thin rod, a pH-responsive swab can be obtained.

[0034] The staining was performed at 60-90℃ for 20-30 minutes.

[0035] The bromocresol green solution is obtained by dissolving bromocresol green powder in an aqueous ethanol solution.

[0036] The mass ratio of bromocresol green powder to natural cotton fiber is 0.5-5:100.

[0037] The mass-to-volume ratio of the natural cotton fiber to the bromocresol green solution is 1 g: 50 mL.

[0038] The volume ratio of ethanol to deionized water in the ethanol-water solution is 10:0-5:5.

[0039] The buffer solution is either phosphate buffer or acetate buffer.

[0040] The pH value of the buffer solution is 1.0-3.0.

[0041] The pH value of the buffer solution is 4.0-5.0.

[0042] The drying temperature is 40-60℃.

[0043] The principle of this invention is explained as follows:

[0044] Bromocresol green is an extremely sensitive pH indicator; it possesses properties such as... Figure 1 The three forms shown are A, B, and C. Form A exists under extremely acidic conditions (pH less than 3) or in powder form and is orange-yellow. Form B is a monoanion form under acidic conditions (pH=3-4). Form C is a dianion form under pH>5 and is blue.

[0045] The preparation method described in this invention first involves soaking natural cotton fibers in a bromocresol green solution and then heating it to 60-90°C for dyeing. Because natural cotton fibers contain protein, the amino groups (-NH2) in the protein are converted to NH2 during the high-temperature dyeing process. 3+ Meanwhile, since the pH of the dye solution system is neutral, the color of bromocresol green is blue, indicating that bromocresol green has been converted to a dianionic form. The dianionic form of bromocresol green can both electrostatically bind to natural cotton fibers and bind to the NH4+ in natural cotton fibers. 3+The groups bind through electrostatic attraction, thus loading bromocresol green onto the surface of natural cotton fibers. The fibers are then rinsed with phosphate buffer or acetate buffer, excess buffer is squeezed out, and the fibers are dried at 40-60°C to obtain dyed natural cotton fibers. pH-responsive swabs are then prepared using these dyed natural cotton fibers. When the buffer pH is 1.0-3.0, the dyed natural cotton fibers are orange-yellow; when the buffer pH is 4.0-5.0, the dyed natural cotton fibers are light yellow-green.

[0046] Due to the influence of active neutrophils, acute wounds are more acidic, with a pH value between 4.0 and 6.0, while chronic wounds are often weakly alkaline, with a pH value between 7.0 and 10.0, which is more conducive to bacterial growth and reproduction, making the wound more susceptible to bacterial invasion and infection. The pH-responsive swabs prepared in this invention exhibit a significant color change as the ambient pH value increases within the pH range of 4.0 to 12.0. This allows medical personnel to determine whether a wound is acute or chronic based on the color change of the pH-responsive swab after wiping the wound, and thus select the appropriate treatment strategy.

[0047] If the natural cotton fibers are dried directly without rinsing with a buffer solution, the dried fibers will appear light blue, making it impossible to observe any color change in the cotton swab when the wound pH is around 9.0 during actual testing. To improve the pH response, the fibers are rinsed with a phosphate buffer or acetate buffer with a lower pH (1.0-3.0) to remove the bromocresol green solution floating on the surface of the natural cotton fibers and to convert the bromocresol green loaded on the fibers to its A form, giving the fibers an orange-yellow color. After rinsing with the buffer solution, the orange-yellow natural cotton fibers can better distinguish the color changes that occur between pH values ​​of 4.0 and 12.0 with the human eye.

[0048] This invention utilizes an aqueous ethanol solution to dissolve bromocresol green to obtain a bromocresol green solution. This is because the hydrophobic substances pectin and wax on the surface of natural cotton fibers are easily soluble in ethanol during the high-temperature dyeing process, giving the dyed natural cotton fibers better hydrophilicity than ordinary natural cotton fibers. The small amount of bodily fluid exuded from the wound can meet the detection requirements of pH-responsive swabs for wound infection.

[0049] Example 1:

[0050] A method for preparing a pH-responsive swab for wound infection monitoring, comprising the following steps:

[0051] S1. Soak 2g of natural cotton fiber in an Erlenmeyer flask containing 100mL of bromocresol green solution. Place the Erlenmeyer flask in a 40℃ water bath and heat to 90℃ for 25 minutes. During heating, the color of bromocresol green turns blue. After heating, remove the Erlenmeyer flask from the water bath, let it stand, and cool to room temperature. The bromocresol green solution is obtained by dissolving 0.01g of bromocresol green powder in 100mL of an ethanol-water solution, with a volume ratio of anhydrous ethanol to deionized water of 9:1. The natural cotton fiber is Xinjiang cotton.

[0052] S2. Rinse the natural cotton fibers with a phosphate buffer solution, wherein the pH value of the phosphate buffer solution is 2.0;

[0053] S3. Squeeze out the excess buffer solution and place the natural cotton fiber in an oven at 50 ℃ for 6 hours. The dried natural cotton fiber will be orange-yellow.

[0054] S4. Take 0.05g of dried natural cotton fiber and fix it to the top of the thin rod to obtain a pH-responsive cotton swab.

[0055] Example 2:

[0056] The difference from Example 1 is as follows:

[0057] The volume ratio of anhydrous ethanol to deionized water in an aqueous ethanol solution is 8:2.

[0058] Example 3:

[0059] The difference from Example 1 is as follows:

[0060] The volume ratio of anhydrous ethanol to deionized water in an aqueous ethanol solution is 7:3.

[0061] Example 4:

[0062] The difference from Example 1 is as follows:

[0063] The volume ratio of anhydrous ethanol to deionized water in an aqueous ethanol solution is 1:1.

[0064] Example 5:

[0065] The difference from Example 1 is as follows:

[0066] The amount of bromocresol green powder used is 0.02g (1% owf).

[0067] Example 6:

[0068] The difference from Example 1 is as follows:

[0069] The amount of bromocresol green powder used is 0.06g (3% owf).

[0070] Example 7:

[0071] The difference from Example 1 is as follows:

[0072] The amount of bromocresol green powder used is 0.1g (5% owf).

[0073] Example 8:

[0074] The difference from Example 1 is as follows:

[0075] Replace the phosphate buffer with the acetate buffer.

[0076] Example 9:

[0077] The difference from Example 1 is as follows:

[0078] The pH value of the phosphate buffer solution is 4.0; the dried natural cotton fibers are pale yellow-green.

[0079] Comparative Example 1:

[0080] The difference from Example 1 is as follows:

[0081] The phosphate buffer solution has a pH of 7.0, and the dried natural cotton fibers are light blue.

[0082] Comparative Example 2:

[0083] The difference from Example 1 is as follows:

[0084] Replace natural cotton fibers with degreased cotton.

[0085] Performance testing:

[0086] 1. The pH-responsive cotton swabs from Examples 1 and 9 were immersed in 0.1 mL of an acid-base solution with a pH gradient of 6.0-12.0. The color change of the cotton swabs with the pH of the acid-base solution was observed. The observation results of Examples 1 and 9 are as follows: Figure 2 , Figure 3 As shown; by Figure 2 , Figure 3 It can be seen that the pH-responsive swab described in this invention can visually display color changes within a pH range of 6.0-12.0, and only 0.1 mL of acid or alkali solution is needed to make the pH-responsive swab change color, indicating that a very small amount of solution is sufficient to meet the detection requirements.

[0087] 2. Plot the K / S value curves of the pH response swabs in Examples 1-4, as follows: Figure 3 As shown; from Figure 3It can be seen that rinsing with phosphate buffer can preserve bromocresol green on natural cotton fibers; the K / S value of the maximum absorption peak is used to represent the dyeing performance, and the larger the K / S value of the maximum absorption peak, the better the dyeing performance. The K / S value of the maximum absorption peak in Example 1 is the largest among Examples 1-4, reaching 0.258, indicating that the dyeing effect is better when the volume ratio of anhydrous ethanol to deionized water is 9:1.

[0088] 3. Plot the K / S value curves of pH-responsive swabs for Examples 1, 5-7, as follows: Figure 5 As shown; from Figure 5 It can be seen that within the dye concentration range of 0.1-5% owf, the dyeing effect is better as the dye concentration increases.

[0089] 4. Plot the K / S value curves of the pH response swabs for Example 7 and Comparative Example 2, as shown. Figure 6 As shown; from Figure 6 It can be seen that the K / S value of degreased cotton is much lower than that of natural cotton fiber. This is because degreased cotton removes the protein-like substances that bind with bromocresol green, making it difficult for degreased cotton to form a stable bond with bromocresol green.

Claims

1. A method for preparing a pH-responsive swab for wound infection monitoring, characterized in that: The preparation method includes: Natural cotton fibers are dyed by soaking them in a bromocresol green solution, during which the bromocresol green solution turns blue. The soaked natural cotton fibers are rinsed with a buffer solution, which is either a phosphate buffer or an acetate buffer, and the pH value of the buffer solution is 1.0-3.

0. After squeezing out the excess buffer solution, the natural cotton fibers are dried. The dried natural cotton fibers are orange-yellow. By fixing dried natural cotton fibers to the tip of a thin rod, a pH-responsive swab can be obtained.

2. The method for preparing a pH-responsive swab for wound infection monitoring according to claim 1, characterized in that: The staining was performed at 60-90℃ for 20-30 minutes.

3. A method for preparing a pH-responsive swab for wound infection monitoring according to claim 1 or 2, characterized in that: The bromocresol green solution is obtained by dissolving bromocresol green powder in an aqueous ethanol solution.

4. The method for preparing a pH-responsive swab for wound infection monitoring according to claim 3, characterized in that: The mass ratio of bromocresol green powder to natural cotton fiber is 0.5-5:

10.

5. The method for preparing a pH-responsive swab for wound infection monitoring according to claim 4, characterized in that: The mass-to-volume ratio of the natural cotton fiber to the bromocresol green solution is 1 g: 50 mL.

6. The method for preparing a pH-responsive swab for wound infection monitoring according to claim 5, characterized in that: The volume ratio of ethanol to deionized water in the ethanol-water solution is 1:1 to 9:

1.

7. A method for preparing a pH-responsive swab for wound infection monitoring according to claim 1 or 2, characterized in that: The drying temperature is 40-60℃.

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