Research On Preparation And Application Of Alginate Composite Fiber Medical Dressing

Wound healing has a specific biological response and is a dynamic and complex process.Unreasonable and untimely treatment will not only lead to bacterial infection,but also turn into chronic wound.Medical dressing can act as a barrier instead of skin in the process of wound repair and provide a good environment for wound healing.Traditional gauze dressings have limited ability to absorb exudate and stop bleeding,and may adhere to the wound surface and cause secondary damage.For clinical use,the ideal medical dressing should first be biocompatible and hygroscopic,second should have appropriate mechanical properties to ensure its integrity,have appropriate porosity to achieve oxygen permeability,be easy to remove to avoid secondary wounds,and be loaded with drugs to achieve antibacterial and hemostatic properties and promote the growth of new tissue.Therefore,alginate fiber medical dressings with high hygroscopic property,high breathability and biocompatibility have attracted wide attention and become one of the most competitive candidate materials in the field of wound dressings.In this paper,calcium alginate fibers with adjustable size and controllable structure were prepared based on microfluidic spinning technology,and a macro self-assembly strategy was proposed to develop a new medical dressing which can effectively promote wound healing and skin tissue regeneration.The main contents are as follows:Firstly,in order to improve the mechanical and medical properties of alginate fiber,the structure of microfluidic chip was designed and the functional materials were selected.A method of preparing high performance alginate fiber based on microfluidic spinning technology was proposed.The size of linear calcium alginate fiber was precisely regulated by adjusting the flow velocity of internal and external phase during the reaction.Orthogonal test was designed to verify the influence of each component of spinning solution on the mechanical properties of fibers,and the optimal ratio scheme of tensile strength was obtained according to the range analysis results.On this basis,the change process of weight loss rate and mechanical properties of fiber under different air-drying time was studied,and the degradation process of fiber was verified.The change trend of fiber morphology under different drug concentration was studied,and the reason of antibacterial property of fiber was confirmed by infrared spectrum analysis of drug composition.Then,in order to meet the needs of special wounds such as joints and improve the elongation at break of fibers,a new microfluidic chip is designed to prepare fibers with special spiral structure by using microfluidic technology,which can accurately control the characteristics of fiber structure.Based on the improved microfluidic spinning device,the process parameters of forming stable spiral fibers were obtained by utilizing the folding effect of inner phase fluid caused by fluid solidification and channel change,which ensured the stability of spinning process and realized the free transformation of calcium alginate fibers from linear to spiral type in a larger flow range.By studying the relationship between the flow rate and viscosity of spinning fluid and the spiral shape parameters(diameter,pitch and amplitude)of fiber,and analyzing the mechanical properties of fiber,the effective control of process parameters on fiber structure was realized.Finally,in order to solve the problems of insufficient air permeability and poor environmental adaptability of the existing calcium alginate hydrogel dressing,we developed a macro self-assembly strategy,which takes the prepared high-performance one-dimensional linear or spiral fibers as the construction basis,and weaves and fold the fiber dressing into a three-dimensional mesh porous structure through the flat weaving process,which can meet the needs of wounds in different positions of the body.The physical and chemical properties such as swelling,porosity and permeability,as well as the medical properties such as antibacterial and hemostatic properties and cytotoxicity were characterized by experiments,which proved that the dressing has excellent moisture absorption and permeability,good drug slow release properties and biocompatibility,and has a good application prospect in the field of wound dressing.