As the deacetylation product of natural polysaccharide chitin, chitosan has many excellent physical and chemical properties, such as biocompatibility, biodegradability, non-toxic, multi reactivity, low irritation, broad-spectrum antibacterial, etc. Chitosan has been found for more than one hundred years. Now, chitosan has been widely used in textile, paper making, food, medicine and chemical industry.
1、 Biomedical applications:
1. Burn dressing and wound healing agent: Chitosan has good biocompatibility and is widely used in biomedical and pharmaceutical fields. It can be used as burn dressing and wound healing agent. Chitosan can be used to treat wounds before bandage gauze, which can greatly improve the speed of wound healing.
2. Absorbable surgical suture: the absorbable surgical suture made of chitosan has high mechanical strength, can be stored for a long time, can be disinfected by conventional methods, can be dyed, can be mixed with drugs, can be degraded and absorbed by tissues, and can avoid the pain of patients' suture removal.
3. Reduce blood lipid, blood pressure and cholesterol: It is also found that chitosan can reduce blood lipid, blood pressure and cholesterol, and prevent cardiovascular and cerebrovascular diseases.
Animal experiments show that chitosan has pharmacological effects such as inhibiting gastric acid, resisting gastric ulcer, and diminishing inflammation, and can be used as a drug to treat peptic ulcer and hyperacidity. Chitosan has been widely used as an additive of anti-tumor health food.
A large number of literatures have reported that chitosan has broad-spectrum antibacterial properties, and has a good inhibitory effect on a variety of bacteria, fungi, and even some viruses.
The antibacterial property of chitosan is closely related to its deacetylation degree, molecular weight, solvent and pH of the system. However, the application of chitosan is greatly limited because it is difficult to dissolve in water and most solvents. At the same time, the antibacterial ability of chitosan itself is relatively mild, and it is difficult to achieve the ideal antibacterial effect.
1. Antimicrobial effect of chitosan
Chitosan has abundant amino groups on its surface, which is the key to its antibacterial properties. Gold chitosan high-density chitosan indicates that a large number of scholars have studied the factors affecting the antibacterial activity of chitosan at present. Research shows that the source, degree of deacetylation, molecular weight and concentration of chitosan have a great impact on the antibacterial effect. At the same time, external factors such as pH, water content and solvent of the environment also have a significant impact on the antibacterial activity of chitosan.
2. Chitosan derivative
The surface of chitosan is rich in hydroxyl and amino groups, and these active groups can be chemically modified to prepare various chitosan derivatives. The modified derivatives not only retain the original advantages of chitosan, but also give them some new properties, such as the improvement of water solubility, the enhancement of antibacterial properties, etc.
3. Antibacterial properties of antibacterial factor composite chitosan
Although chitosan has a certain antibacterial ability, its antibacterial ability is relatively mild, and its antibacterial ability can be fully reflected only under a certain pH condition, which greatly limits the antibacterial ability of chitosan. It is an effective method to add some antibacterial factors to chitosan to improve its antibacterial property. This composite chitosan combines many advantages of antibacterial agent and chitosan, and is a potential antibacterial material. At present, the external antibacterial factors studied mainly include nano silver particles, metal oxides, antibiotics, antibacterial peptides and organic antibacterial agents.
To sum up, the research, improvement, mechanism discussion and application of chitosan antibacterial properties are mainly focused on chitosan, chitosan derivatives and chitosan composites. The surface of chitosan is rich in amino and carboxyl groups, which provides a rich site for the chemical modification of chitosan expressed by gold chitosan high-density chitosan. The main factors affecting the antibacterial properties of chitosan and its derivatives or compounds can be summarized as follows:
1) The influence of chitosan properties, such as degree of deacetylation, molecular weight, etc;
2) Interaction of amino group and other derived groups;
3) Influence of the action environment, such as pH, solvent, concentration, etc;
4) In general, nano scale chitosan has better antibacterial effect.