Hemocompatibility and antimicrobial study using chitosan-coated braided silk fibroin fibers

Silk fibers are biomaterials widely employed in various biomedical applications and products used to treat, repair, and replace damaged tissues, alongside being modified with other biomaterials. This study investigates the hemocompatibility and antimicrobial properties of chitosan-coated braided silk fibroin fibers (SFF), and their potential applications in biomedical implants and as sutures in wound dressings. The SFF was braided using a three-strand hand-braiding method and coated with a chitosan solution. The layer-by-layer dipping-coating method was used for coating. The samples were characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and light microscopy to assess the coating integrity and surface morphology. The SEM revealed swollen, smooth surfaces, which indicated successful chitosan coating, while the XRD patterns confirmed the semi-crystalline nature of the coated fibers with broad peaks typical of biopolymers. Hemocompatibility was assessed using the following coagulation parameters: prothrombin time (PT sec; PT), international normalized ratio (INR), and activated partial thromboplastin time (APTT). The results indicated an improved clotting time compared to the controls, which suggests anticoagulant properties. The antimicrobial activity was evaluated using the agar disc diffusion method against six microorganisms: E. faecalis, B. cereus, S. aureus, E. coli, P. aeruginosa, and C. albicans. The chitosan-coated fibers showed significantly larger inhibition zones than the uncoated controls, thus confirming enhanced antimicrobial efficacy. The study demonstrates that chitosan coating substantially improves the biological property of SFFs, which supports the potential of chitosan-coated SFFs as multifunctional biomaterials suitable for surgical sutures, wound care, and tissue engineering applications.