Preparation method and application of a carbon-based loaded heterojunction antibacterial photosensitizer with constant light reaction

Abstract

This invention discloses a method for preparing a carbon-based heterojunction antibacterial photosensitizer with normal light reaction. The method includes the following steps: (1) filtering the powdered fruit shell carbon-based material to remove floating powder; (2) washing and drying the fruit shell carbon-based material, then pyrolyzing it at high temperature, and then transferring it to a flask; (3) adding nitric acid, stirring and heating to 80°C, refluxing for 4 hours, cooling, filtering, washing, and then drying for 12 hours to obtain modified fruit shell carbon-based material; (4) taking 10-30 mg of PCE-10 and MEIC and mixing them with 50-200 ml of chloroform respectively to obtain two mixed solutions, then mixing and stirring them at a volume ratio of 1:1 to obtain a blended solution; (5) uniformly coating the blended solution onto the modified fruit shell carbon-based material and drying for 12 hours to obtain the antibacterial photosensitizer of this invention. The antibacterial photosensitizer obtained by the method of this invention can respond under normal light and has excellent bactericidal ability. It is used for the sterilization of suspended methicillin-resistant Staphylococcus aureus or suspended Pseudomonas aeruginosa, and is simple, safe and reliable to use.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic antibacterial technology, specifically a method for preparing a carbon-based supported heterojunction antibacterial photosensitizer that undergoes normal light reaction and its application. Background Technology

[0002] The medical environment is a key site for the aggregation and spread of pathogenic microorganisms, and the effectiveness of antibacterial disinfection is directly related to infection control, medical safety, and public health stability. Existing disinfection methods all have significant limitations. For example, ultraviolet sterilization relies on high-intensity irradiation, which can damage the human body and leaves blind spots, making it unsuitable for use in occupied settings. While high-temperature and high-pressure sterilization is thorough, the process is cumbersome, time-consuming, and can easily damage heat-sensitive precision instruments. Chemical disinfectants are convenient and easy to use, but they have problems such as residues, irritation, and inducing microbial resistance, making it difficult to meet the safe and efficient clinical needs.

[0003] With the widespread use of antibiotics, the proliferation and spread of drug-resistant bacteria has become a major challenge in the medical field, significantly increasing the difficulty of infection treatment, mortality, and medical costs, and seriously threatening the health of high-risk groups. Although photosensitizers are currently used to address nosocomial infections caused by drug-resistant bacteria, most existing photosensitizers only respond to specific strong light, have poor adaptability, and suffer from problems such as high cost and insufficient biosafety.

[0004] Therefore, developing an antibacterial photosensitizer that can respond under normal light, is easy to prepare, safe, efficient, economical, and environmentally friendly is of great practical significance for making up for the shortcomings of traditional disinfection, improving the antibacterial level of the medical environment, and preventing drug-resistant bacterial infections. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a carbon-based supported heterojunction antibacterial photosensitizer that responds to normal light and its application. The antibacterial photosensitizer obtained by the method can respond to normal light, has excellent bactericidal ability, and can be used for sterilization of suspended methicillin-resistant Staphylococcus aureus or suspended Pseudomonas aeruginosa. It is simple to use, safe and reliable.

[0006] The present invention solves the above-mentioned technical problems by means of the following technical solution:

[0007] Invention 1: The present invention discloses a method for preparing a photosensitive carbon-based supported heterojunction antibacterial photosensitizer, comprising the following steps:

[0008] (1) Filter the powdered fruit shell carbon-based material through a 100-mesh standard test sieve to remove floating powder;

[0009] (2) The filtered shell carbon-based material is washed with deionized water, then placed in a 60°C oven to dry completely, then taken out and spread on a porcelain boat and placed in a tube furnace for high-temperature pyrolysis, and then transferred to a flask after cooling.

[0010] (3) Add nitric acid with a mass concentration of 30% to 60% to the flask in step (2). The amount of nitric acid is 5 ml of nitric acid per 1 g of fruit shell carbon-based material. Then stir and heat to 80°C and reflux for 4 h. After cooling, filter and wash with distilled water until the filtrate is neutral. Then place it in a 60°C oven and dry for 12 h to obtain the modified fruit shell carbon-based material.

[0011] (4) Take 10-30 mg of PCE-10 and mix it with 50-200 ml of chloroform to obtain mixture A; take 10-30 mg of MEIC and mix it with 50-200 ml of chloroform to obtain mixture B; then mix mixture A and mixture B at a volume ratio of 1:1, and stir at 800 r / min and 25℃ for 12-36 h to obtain a blended solution;

[0012] (5) The blend solution is uniformly coated onto the modified nutshell carbon-based material in step (3). The weight ratio of the blend solution to the modified nutshell carbon-based material is 1:1000 to 5000. Then, it is dried at 60°C for 12 hours to obtain the carbon-based loaded heterojunction antibacterial photosensitizer that reacts normally with light.

[0013] In step (1), the length of the powdered fruit shell carbon-based material does not exceed 2 mm.

[0014] In step (2), the high-temperature pyrolysis operation is as follows: evacuate the tubular furnace for 5 minutes, then purge with nitrogen at 200 ml / min for 10 minutes, and then raise the temperature to 500℃ at 8℃ / min and hold for 4 hours.

[0015] In step (2), the shell carbon-based material is cooled to room temperature and then transferred to a flask.

[0016] Invention 2: Application of the photosensitive carbon-based supported heterojunction antibacterial photosensitizer of the present invention: The photosensitive carbon-based supported heterojunction antibacterial photosensitizer is used for the sterilization of suspended methicillin-resistant Staphylococcus aureus or suspended Pseudomonas aeruginosa.

[0017] The sterilization procedure is as follows:

[0018] The carbon-based heterojunction antibacterial photosensitizer with normal light reaction was placed in a solution containing methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa. An LED lamp was used as the light source. After the adsorption in the dark reached equilibrium, the light was started. Samples were taken every 10 minutes, and the concentration of surviving bacteria was determined by plate counting method. The kill rate was calculated until sterilization was completed.

[0019] The LED lamp has a power of 30 W and a wavelength range of 400–780 nm; the concentration of the solution containing methicillin-resistant Staphylococcus aureus (MRSA) or the solution containing Pseudomonas aeruginosa is 10⁸ CFU / mL, and the concentration of the carbon-based loaded heterojunction antibacterial photosensitizer in the mixed solution is 0.1–15 μg / mL.

[0020] Compared with the prior art, the carbon-based heterojunction antibacterial photosensitizer obtained by the method of the present invention can generate a large amount of reactive oxygen species in a short time under normal light conditions, and induce rapid death of bacteria by attacking the bacterial cell membrane, oxidizing intracellular enzymes and nucleic acids.

[0021] The method of the present invention has the following beneficial effects:

[0022] (1) The carbon-based heterojunction antibacterial photosensitizer obtained by the present invention can remove more than 99% of methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. The bactericidal effect can still be maintained after multiple cycles of use, and the stability of repeated use is excellent.

[0023] (2) The method of the present invention is based on the photoresponse performance of the photosensitizer itself. When irradiated by normal light, it generates electron-hole pairs, which react with water and oxygen in the environment to generate hydroxyl radicals and superoxide radicals, which penetrate and destroy the cell membrane structure of bacteria, thereby completely killing bacteria. This process can achieve the purpose of highly efficient inactivation of bacteria without the aid of any external chemical substances, and has excellent bactericidal ability, high efficiency and safety.

[0024] (3) The carbon-based heterojunction antibacterial photosensitizer obtained by the method of the present invention has excellent antibacterial properties and a broad antibacterial spectrum. It can be used in hospitals to control drug-resistant bacterial infections, such as in environmental cleaning and medical devices. It is also characterized by simple preparation, easy operation, reusability, no drug resistance, safety, high efficiency and low cost, and has great promotional value.

[0025] (4) The present invention uses natural biomass-derived carbon materials as the substrate, which has the characteristics of large specific surface area, strong hydrophilicity and good biocompatibility. The substrate can be naturally degraded and has high recycling efficiency. It achieves green and environmentally friendly throughout the entire life cycle from preparation to disposal, which meets the needs of sustainable development. Attached Figure Description

[0026] Figure 1 The effect of the carbon-based supported heterojunction antibacterial photosensitizer with normal light reaction obtained in Example 1 of the present invention on methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa under different light exposure times.

[0027] Figure 2The effect of the carbon-based heterojunction antibacterial photosensitizer with normal light reaction obtained in Example 2 of the present invention at different concentrations on methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa.

[0028] Figure 3 This study evaluates the hemolytic activity of the carbon-based supported heterojunction antibacterial photosensitizer with normal light reaction obtained in Example 3 of the present invention. Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments. It should be noted that the embodiments described below are intended to facilitate understanding of the present invention and are not intended to limit it in any way. Various modifications and improvements made to the present invention without departing from its spirit should fall within the scope of protection defined by the claims.

[0030] Example 1:

[0031] The method for preparing the photosensitive carbon-based supported heterojunction antibacterial photosensitizer of the present invention includes the following steps:

[0032] (1) Remove floating powder by filtering the carbon-based material of the fruit shell with a length not exceeding 2 mm using a 100-mesh standard inspection sieve;

[0033] (2) The filtered shell carbon-based material was washed with deionized water and then dried in an oven at 60°C for 12 hours to make it completely dry. It was then spread on a porcelain boat and placed in a tube furnace for high-temperature pyrolysis. After cooling to room temperature, it was transferred to a 250ml round-bottom flask.

[0034] (3) Add 30% nitric acid to the flask. The amount of nitric acid is 5 ml of nitric acid per 1 g of shell carbon-based material. Then stir and heat to 80°C and reflux for 4 h. After cooling, filter and wash with distilled water until the filtrate is neutral. Then dry in an oven at 60°C for 12 h to obtain modified shell carbon-based material.

[0035] (4) Take 10 mg of PCE-10 and 10 mg of MEIC and mix them with 50 ml of chloroform respectively to prepare two solutions. Then mix them at a volume ratio of 1:1 and stir at 800 r / min and 25℃ for 36 h to obtain a blended solution.

[0036] (5) The blended solution was uniformly coated on the modified fruit shell carbon-based material at a weight ratio of 1:2000 and dried at 60°C for 12 hours to obtain a carbon-based loaded heterojunction antibacterial photosensitizer that reacts normally with light.

[0037] In application, the normally photosensitive carbon-based loaded heterojunction antibacterial photosensitizer obtained in this embodiment was placed in solutions containing suspended methicillin-resistant Staphylococcus aureus (MRSA) and suspended Pseudomonas aeruginosa, respectively, and placed in a reaction vessel. The concentration of the normally photosensitive carbon-based loaded heterojunction antibacterial photosensitizer in the mixed solution was 10 μg / mL. A 30W LED lamp was used as the light source. Irradiation was started after dark-state adsorption reached equilibrium, and the illumination period was 0–60 min. Samples were taken every 10 min, and the concentration of surviving bacteria was determined by plate counting to calculate the kill rate.

[0038] The wavelength range of the LED lamp is 400–780 nm, and the concentration of the solution containing methicillin-resistant Staphylococcus aureus and the solution containing Pseudomonas aeruginosa are both 10⁸ CFU / mL.

[0039] The antibacterial effect of this embodiment: From Figure 1 It can be seen that after 50 minutes of light exposure, the carbon-based supported heterojunction antibacterial photosensitizer of the present invention, which is subject to normal light reaction, achieves a 99% kill rate against methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, demonstrating antibacterial effect.

[0040] Example 2:

[0041] The method for preparing the photosensitive carbon-based supported heterojunction antibacterial photosensitizer of the present invention includes the following steps:

[0042] (1) Remove floating powder by filtering the carbon-based material of the fruit shell with a length not exceeding 2 mm using a 100-mesh standard inspection sieve;

[0043] (2) The filtered shell carbon-based material was washed with deionized water and then dried in an oven at 60 ℃ for 12 h until completely dry. It was then spread on a porcelain boat and placed in a tube furnace for high-temperature pyrolysis. After cooling to room temperature, it was transferred to a 250 ml round-bottom flask.

[0044] (3) Add 60% nitric acid to the flask. The amount of nitric acid is 5 ml of nitric acid per 1 g of fruit shell carbon-based material. Stir and heat to 80 °C and reflux for 4 h. After cooling, filter and wash with distilled water until the filtrate is neutral. Then dry in an oven at 60 °C for 12 h to obtain modified fruit shell carbon-based material.

[0045] (4) Take 20 mg of PCE-10 and 20 mg of MEIC and mix them with 100 ml of chloroform respectively to prepare two solutions. Then mix them at a volume ratio of 1:1 and stir at 800 r / min and 25 ℃ for 24 h to obtain a blended solution.

[0046] (5) The blended solution was uniformly coated on the modified fruit shell carbon-based material at a weight ratio of 1:1000, and then dried at 60 °C for 12 h to obtain a carbon-based loaded heterojunction antibacterial photosensitizer that reacts normally with light.

[0047] In application, the normally photosensitive carbon-based loaded heterojunction antibacterial photosensitizer obtained in this embodiment was placed in solutions containing methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, respectively, and placed in a reaction vessel. The concentration of the normally photosensitive carbon-based loaded heterojunction antibacterial photosensitizer in the mixed solution was 0.1–15 μg / mL. A 30W LED lamp was used as the light source. Irradiation was started after dark-state adsorption reached equilibrium and lasted for 60 minutes. Samples were taken at each antibacterial photosensitizer concentration gradient, and the concentration of surviving bacteria was determined by plate counting to calculate the kill rate. The wavelength range of the LED lamp was 400–780 nm; the concentration of the solutions containing MRSA and Pseudomonas aeruginosa was 10⁸ CFU / mL.

[0048] The antibacterial effect of this embodiment: From Figure 2 It can be seen that the concentration of the carbon-based supported heterojunction antibacterial photosensitizer of the present invention, which is subject to photoreaction, is 15 μg / mL, and it achieves a 100% kill rate against methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, thus exhibiting the best antibacterial effect.

[0049] Example 3:

[0050] The method for preparing the photosensitive carbon-based supported heterojunction antibacterial photosensitizer of the present invention includes the following steps:

[0051] (1) Remove floating powder by filtering the carbon-based material of the fruit shell with a length not exceeding 2 mm using a 100-mesh standard inspection sieve;

[0052] (2) The filtered shell carbon-based material was washed with deionized water, then dried in an oven at 60 ℃ for 12 h until completely dry, then spread on a porcelain boat and placed in a tube furnace for high-temperature pyrolysis, and then cooled to room temperature before being transferred to a 250 ml round-bottom flask.

[0053] (3) Add 45% nitric acid to the flask. The amount of nitric acid is 5 ml of nitric acid per 1 g of fruit shell carbon-based material. Stir and heat to 80 °C and reflux for 4 h. After cooling, filter and wash with distilled water until the filtrate is neutral. Then dry in an oven at 60 °C for 12 h to obtain modified fruit shell carbon-based material.

[0054] (4) Take 30 mg of PCE-10 and 30 mg of MEIC and mix them with 200 ml of chloroform respectively to prepare two solutions. Then mix them at a volume ratio of 1:1 and stir at 800 r / min and 25 ℃ for 12 h to obtain a blended solution.

[0055] (5) The blended solution was uniformly coated on the modified fruit shell carbon-based material at a weight ratio of 1:5000, and then dried at 60°C for 12 hours to obtain a carbon-based loaded heterojunction antibacterial photosensitizer that reacts normally with light.

[0056] In application, the carbon-based heterojunction antibacterial photosensitizer obtained in this embodiment was added to a 4% rabbit erythrocyte (RBC) suspension that had been washed multiple times with phosphate-buffered saline (PBS). The suspension was placed in a reaction vessel, and a 30 W LED lamp was used as the light source. After the dark adsorption reached equilibrium, illumination was started. The concentration of the carbon-based heterojunction antibacterial photosensitizer was 5–15 μg / mL, and the illumination time was 60 min. Ultrapure water (UP water) was set as a positive control and physiological saline as a negative control. The reaction sample was incubated at 37 °C for 2 h, and then centrifuged at 1000 rpm for 5 min. The supernatant after centrifugation was taken, and the hemoglobin content was quantitatively detected at a wavelength of 540 nm using a microporous spectrophotometer.

[0057] The hemolytic activity of the carbon-based supported heterojunction antibacterial photosensitizer in this embodiment: From Figure 3 It can be seen that when the concentration of the carbon-based supported heterojunction antibacterial photosensitizer is 5, 10, and 15 μg / mL, less than 4% of RBCs are lysed, and the hemolysis rate is lower than the generally accepted standard of 5%, indicating that the overall hemolytic activity of the carbon-based supported heterojunction antibacterial photosensitizer of the present invention is negligible.

[0058] The carbon-based material made from fruit shells mentioned in the above three embodiments can be selected from pistachio shells, peanut shells, chestnut shells, walnut shells, coconut shells, etc. The high-temperature pyrolysis operation method of the tubular furnace is as follows: evacuate the tubular furnace for 5 minutes, then purge with nitrogen at 200 ml / min for 10 minutes, and then raise the temperature to 500℃ at 8℃ / min and hold for 4 hours.

Claims

1. A method for preparing a photosensitive carbon-based supported heterojunction antibacterial photosensitizer, characterized in that, The preparation method includes the following steps: (1) Filter the powdered fruit shell carbon-based material through a 100-mesh standard test sieve to remove floating powder; (2) The filtered shell carbon-based material is washed with deionized water, then placed in a 60°C oven to dry completely, then taken out and spread on a porcelain boat and placed in a tube furnace for high-temperature pyrolysis, and then transferred to a flask after cooling. (3) Add nitric acid with a mass concentration of 30% to 60% to the flask in step (2). The amount of nitric acid is 5 ml of nitric acid per 1 g of fruit shell carbon-based material. Then stir and heat to 80°C and reflux for 4 h. After cooling, filter and wash with distilled water until the filtrate is neutral. Then place it in a 60°C oven and dry for 12 h to obtain the modified fruit shell carbon-based material. (4) Take 10-30 mg of PCE-10 and mix it with 50-200 ml of chloroform to obtain mixture A. Take 10-30 mg of MEIC and mix it with 50-200 ml of chloroform to obtain mixture B. Then mix mixture A and mixture B at a volume ratio of 1:1 and stir at 800 r / min and 25℃ for 12-36 h to obtain a blended solution. (5) The blend solution is uniformly coated onto the modified nutshell carbon-based material in step (3). The weight ratio of the blend solution to the modified nutshell carbon-based material is 1:1000 to 5000. Then, it is dried at 60°C for 12 hours to obtain the carbon-based loaded heterojunction antibacterial photosensitizer that reacts normally with light.

2. The method for preparing the photosensitive carbon-based supported heterojunction antibacterial photosensitizer according to claim 1, characterized in that, In step (1), the length of the powdered fruit shell carbon-based material does not exceed 2 mm.

3. The method for preparing the photosensitive carbon-based supported heterojunction antibacterial photosensitizer according to claim 1 or 2, characterized in that, In step (2), the high-temperature pyrolysis operation is as follows: evacuate the tubular furnace for 5 minutes, then purge with nitrogen at 200 ml / min for 10 minutes, and then raise the temperature to 500℃ at 8℃ / min and hold for 4 hours.

4. The method for preparing the photosensitive carbon-based supported heterojunction antibacterial photosensitizer according to claim 1 or 2, characterized in that, In step (2), the shell carbon-based material is cooled to room temperature and then transferred to a flask.

5. The application of the photosensitive carbon-based supported heterojunction antibacterial photosensitizer obtained by the preparation method according to claims 1 to 4, characterized in that, The aforementioned photosensitive carbon-based supported heterojunction antibacterial photosensitizer was used for the sterilization of suspended methicillin-resistant Staphylococcus aureus or suspended Pseudomonas aeruginosa.

6. The application of the photosensitive carbon-based supported heterojunction antibacterial photosensitizer according to claim 5, characterized in that, The sterilization procedure is as follows: The carbon-based heterojunction antibacterial photosensitizer with normal light reaction was placed in a solution containing methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa. An LED lamp was used as the light source. After the adsorption in the dark reached equilibrium, the light was introduced. Samples were taken every 10 minutes, and the concentration of surviving bacteria was determined by plate counting method. The kill rate was calculated until sterilization was completed.

7. The application of the photosensitive carbon-based supported heterojunction antibacterial photosensitizer according to claim 6, characterized in that, The LED lamp has a power of 30 W and a wavelength range of 400–780 nm; the concentration of the solution containing methicillin-resistant Staphylococcus aureus (MRSA) or the solution containing Pseudomonas aeruginosa is 10⁸ CFU / mL, and the concentration of the carbon-based loaded heterojunction antibacterial photosensitizer in the mixed solution is 0.1–15 μg / mL.

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