同轴静电纺壳聚糖/聚氧化乙烯-丝素纤维的制备及其生物活性OA北大核心CSTPCD

At present,bone defects caused by trauma,infection,bone tumors,etc.are very common.Serious bone damage caused by major diseases often exceeds the bone's self-healing ability,but the bone tissue's own repair and regeneration ability is not quite satisfactory.In this case,it is necessary to find a good repair material to treat these bone injury diseases.As natural polymers,chitosan(CS)and silk fibroin(SF)are widely available and easy to obtain,and they will only degrade to water and carbon dioxide when implanted into the human body,so they have good biocompatibility and degradability.In this paper,CSPEO-SF nanofibers were prepared by coaxial electrostatic spinning technology.The shell layer of CS and PEO could ensure the fibers to have good hydrophilic properties,antimicrobial properties,and in vitro bioactivity,and the SF in the core layer served as a core template to ensure the fibers to have certain mechanical strength.Then,glutaraldehyde(GA)was used to transform some of the amino groups in the fibers into aldimine groups to improve the water resistance of the fiber membrane.Tests such as XRD and FTIR were carried out on the fibers before and after cross-linking,and it was found that the aldehyde-imide groups were successfully produced after cross-linking,and it was concluded from the SEM images that the fiber diameters increased after cross-linking,and the fracture strength increased,but the tensile strain decreased.Different nanofibers were prepared by varying the mass ratio of CS,PEO and SF,and it was observed from the SEM images that the fiber diameter increased with the increase in the mass proportion of PEO and SF.Subsequently,the mechanical properties,porosity and swelling properties were tested,and it was found that the increase of both CS and SF ratio decreased the flexibility,swelling properties and porosity of the fibers,but increased the mechanical properties of the fibers.All the fibers were able to reach a porosity of more than 80%,and a swelling rate of up to 675%.Finally,the results of the above tests were compared.The more balanced C7P3S10 samples were selected to compare with the SF fibers for the subsequent antimicrobial performance and in vitro bioactivity tests.Antimicrobial experiments were reflected by the dilution coating plate method.Firstly,the fibers were mixed with the appropriate amount of bacterial solution for 8 h,and then the cultured bacterial solution was coated onto agar medium for 24 h.In the meanwhile,the number of colonies on the medium was observed and recorded,and compared with the blank control group.The rate of bacterial inhibition was calculated,and it was found from the results of the experiment that although the antimicrobial performance of CSPEO-SF fibers after the cross-linking modification treatment was decreased,it was still stronger than that of SF fibers.The in vitro bioactivity experiment was conducted by immersing the fibers in simulated body fluid(SBF)at a ratio of 1.5 mg/mL for a period of time to observe the generation of hydroxyapatite(HA),which revealed that the Ca/P ratio of HA on the surface of CSPEO-SF fibers was closer to that of human bone,and that the in vitro bioactivity of CSPEO-SF fibers was better than that of SF fibers.Through the above experiments,it can be concluded that CSPEO-SF fibers can have promising prospects in biomedical applications.