To prepare copper ion-crosslinked regenerated silk fibroin （Cu-RSF） sutures using a modified wet-spinning process， characterize their physicochemical properties， and evaluate their wound healing-promoting efficacy and biosafety.

Regenerated silk fibroin was used as the raw material to fabricate sutures via wet-spinning technology， followed by Cu²⁺ crosslinking. Scanning electron microscopy （SEM） and Fourier transform infrared spectroscopy （FTIR） were employed to observe the micro-morphology and analyze the chemical structure. Uniaxial tensile testing was conducted to optimize the Cu²⁺ crosslinking concentration， mechanical draw ratio， and self-twisting time. The agar diffusion method， cell counting kit-8 （CCK-8） assay， and L929 fibroblast scratch assay were performed to evaluate antibacterial activity， biocompatibility， and cell migration-promoting capacity in vitro， respectively. A total of 50 SPF-grade male Sprague-Dawley rats aged 6–8 weeks were enrolled to establish a full-thickness dorsal skin incision model and divided into the Cu-RSF group and the 6-0 Mersilk^® group （25 rats per group）， and the skin incisions were closed with interrupted sutures using Cu-RSF and 6-0 Mersilk^® sutures， respectively. Wound healing was observed and skin tissue at the suture site were harvested on postoperative days 3， 5， 7， 10， and 14 for hematoxylin-eosin （HE） and Masson's staining (on postoperative days 7 and 14) to comprehensively assess the pro-healing effects. On postoperative day 14， tissues from the heart, liver, spleen, lung, and kidney were collected from 5 rats each in the Cu-RSF group and the normal control group, and subjected to HE staining for the evaluation of biological safety.

The Cu-RSF sutures prepared with 1.00%（w/v） Cu²⁺ crosslinking， a 1∶1.6 rotational speed ratio mechanical draw， and 6 min self-twisting exhibited a mean diameter of （101.92±1.67） μm， a maximum tensile strength of 674.8 MPa （the breaking load was approximately 6.6 N）， and a β-sheet content of 78.60%±1.15%. In vitro， the Cu-RSF sutures demonstrated significant antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa， favorable biocompatibility， and markedly promoted fibroblast migration. In vivo， compared with 6-0 Mersilk^® sutures， the Cu-RSF sutures facilitated incision closure. On postoperative day 7， the collagen deposition rate in the Cu-RSF group was 68.236%±2.334%， which was significantly higher than that in the 6-0 Mersilk^® group （37.980%±1.466%）， the difference was statistically significant （P<0.001）. Organ toxicity assessment on postoperative day 14 confirmed favorable biosafety of the Cu-RSF sutures.

Cu-RSF sutures exhibit excellent mechanical properties， antibacterial activity， and pro-repair functions， effectively accelerating postoperative incision healing.