| The vast clinical application of antibiotics has resulted in serious bacterial resistant.The emergence of bacterial resistance problems and the frequent infection of drug-resistant bacteria have brought great technical challenges to the current clinical anti-infection treatment and seriously threatened the health of all human.We urgently need to use an effective and less resistant method to replace or directly assist the use of traditional antibiotic treatment,photodynamic antibacterial chemotherapy is expected to develop into a new type of drug therapy to solve bacterial resistance.Researchers have found that wounds are extremely susceptible to various bacterial infections.At present,various detection tools for clinical diagnosis of wound bacteria in real time have many problems such as long working cycle,high cost,and cumbersome operation.Therefore,the development of rapid and efficient bacterial detection methods has important practical significance for the prevention and control of various pathogenic microorganisms.In this thesis,Pseudomonas aeruginosa,Staphylococcus aureus and Escherichia coli are used as models to prepare a new type of intelligent wound antibacterial dressing.The wound dressing can sense the presence of pathogenic microorganisms in real time to control the release of photosensitizers automatically provide colorimetric response when an infection occurs,so that the purpose of simultaneous visual detection of pathogenic bacteria and photosensitive intelligent antibacterial can be achieved.The main research contents of the paper are as follows:(1)An antibacterial agent with photosensitizing activity extracted from Eclipta prostrata: 2,2':5',2''-trithiophene-5-carbaldehyde(3T-CHO),modified3T-CHO with tryptophan.The MIC of the modified photosensitizer(3TT)reached 3.12 ?g/m L;Xenon as the light source,the photodynamic sterilization effect of 3T-CHO and 3TT reaches 100%.Incandescent lamps and visible light as light sources,only 3TT has a good photodynamic sterilization effect.The spot diameter was fixed D = 2 cm,the bacteriostatic rate of 3TT reaches 100%.In the singlet oxygen yield test,3TT is significantly better than 3T-CHO.The cytotoxicity was tested by MTT method.When the concentration of 3TT was increased from 0.625 ?M to 10?M,the survival rate of fibroblasts reached more than 80%.(2)3TT is filled into the vesicles,the obtained vesicles are loaded on the hydrogel dressing with detection function,and an antibacterial dressing with real-time detection and photosensitive intelligent antibacterial preparation is prepared.The ratio of hydrogel to vesicle is 5:1,it has good swelling performance and degradation performance,and the photodynamic sterilization effect on P.aeruginosa and S.aureus can reach 100%;According to the detection of pathogenic bacteria,the antibacterial dressing can visually detect S.aureus and P.aeruginosa.(3)To study the effect of photodynamic antimicrobial of wound infection in rats.Experiment in vivo was conducted with the wound rats infected with Pathogenic bacteria as model,the dimensions of wounds were measured by vernier caliper,based on which the wounds area and wound healing rate were calculated.Inflammatory cytokines TNF-?,IL-8,MMP-9,MMP-3,IL-2 and MMP-8 in the tissue were measured by Elisa assay.The results showed that the 3TT irradiated group showed reduced inflammatory cells and increased fibroblasts to accelerate wound healing.The result reveals that 3TT has no toxic effect on wounds.The singlet oxygen produced by the photosensitive antibacterial agents under light irradiation inactivated the pathogen and accelerated wound healing,the wound healing rate is over 90%. |
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