Silk fibroin-gelatine haemostatic sponge loaded with thrombin for wound haemostasis and tissue regeneration

Wound haemostasis is an important part of clinical treatments, especially treatments for patients with avulsion injury, destructive injury and large-scale soft tissue injury. Therefore, developing fast and effective haemostatic materials is critical. This study aimed to design a novel and efficient silk fibroin-gelatine composite haemostatic sponge loaded with thrombin (SFG@TB) to assist in wound haemostasis.

The SFG@TB composite haemostatic sponge was formed with gelatine, silk fibroin and thrombin through a freeze-drying technique. First, the material characteristics of SFG@TB were measured, including the elastic modulus, swelling rate and porosity. Second, in vitro cell coculture experiments, in vivo embedding experiments and haemolytic analyses were performed to evaluate the biocompatibility of SFG@TB. Then, coagulation experiments and femoral artery and liver bleeding models were used to evaluate the haemostatic performance of SFG@TB. Finally, the ability of SFG@TB to promote tissue healing was evaluated through experiments with Sprague-Dawley rat models of injury.

Compared with gelatine sponges, SFG@TB exhibited outstanding mechanical properties and water absorption properties. In addition, the excellent biosafety of the composite haemostatic sponge was confirmed by cell experiments, subcutaneous embedding experiments and haemolytic analysis. Based on the in vitro coagulation test results, SFG@TB exhibited greater adhesion of red blood cells and platelets and a shorter dynamic coagulation time. Compared to the use of silk fibroin-gelatine composite haemostatic sponges or gelatine sponges, the introduction of thrombin resulted in a shorter haemostasis time and a smaller bleeding volume, as revealed by in vivo coagulation tests. The experiments with Sprague-Dawley rat models of injury indicated that SFG@TB accelerated the wound healing process and reduced scar width, which was accompanied by thicker granulation tissue.

Overall, the SFG@TB composite haemostatic sponge, which exhibits outstanding mechanical properties, good haemostatic performance and high biosafety, promoted wound haemostasis and tissue repair. Therefore, the SFG@TB composite haemostatic sponge could be a promising material for wound haemostasis.