Preparation And Properties Of Antibacterial Silk Fibroin Suture

Antibacterial medical sutures have antibacterial properties,can effectively inhibit pathogens.It can to avoid the occurrence of surgical site infection,relieve the pain to the patient and reduce,recurrence of patients result in postoperative death.However,the existing antibacterial agents such as antibacterial agents induce side effects,resistant bacteria,structural instability and other deficiencies easily.Natural antibacterial agent have good antibacterial properties,environmental protection,human safety,but these application were limited because of their slow release property.In order to improve the drug release time and reduce the side effects at the same time,a silk fibroin(SF)-based braiding suture loaded with a natural antibacterial berberine was developed.The structural features,mechanical properties,drug release properties,degradation properties and antibacterial effects were examined systematically.A silk suture(2 strands 20/22 D + 2 strands 60/65D)with diameter specification of 0.300-0.339 mm was braided using a 16 braiding machine with gear ratio 81/44 and braiding speed 80 rpm.By optimizing the preparation of antibacterial coating materials,the suitable parameters and conditions were obtained.The structure of SF was modified by steam treatment and glycerol modification,to obtain with different structures antibacterial coating material.The results showed that the two treatment methods promoted the formation of β-sheet structure in SF and the antibacterial activity against Staphylococcus aureus and Escherichia coli was improved.Drug release rate within the first 48 hours is faster than 96 hours.The drug release time was up to 7 days or more.The results of antimicrobial coating material degradation showed that SF in its high content of β-sheet is more stable under the folded structure,indicating that by changing the structure of SF composition and can thus control the drug release time.The different coating parameters of the suture were optimized,and the antibacterial and drug-loading properties were used to evaluate the coating parameters.Using multi-layer coating method,different antibacterial medical sutures were obtained.The surface smoothness,knot strength and tensile strength of the coating suture were improved.The results showed that glycerol-modified sutures have better flexibility than steam treatment sutures.The antibacterial test results using Staphylococcus aureus and Escherichia coli showed good antibacterial properties of the drug-loaded suture.The natural antibacterial agent berberine bactericidal or bacteriostatic effect of Staphylococcus aureus is better than E.coli at the same drug concentration conditions.The release rate of berberine under acidic conditions is relatively fast,but it is relatively slow under relatively alkaline conditions.The p H changes have a significant impact on the release rate of berberine.The drug coating layer was found to effectively delay the release of drugs.The release time was up to 7 days.In vitro degradation,the results showed that the drug loading suture possesses a slow degradation rate and stable mechanical properties,the knot strength retention was above 87% and weight loss rate was below 13% within 42 days.In conclusion,this article braided sutures,using silk fibroin as a carrier material carrying natural antibacterial agent drugs,through multi-layer multi-structure coating preparation antibacterial sutures.The findings arising from this project provides a new idea for the application of natural antibacterial agents in the field of antibacterial medical sutures.