Bilayered vascular grafts based on silk proteins

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Developing small-diameter vascular grafts faces challenges in regeneration, thrombosis, intimal hyperplasia, and mechanical integrity.
• Existing silk-based grafts require improvements in mechanical and hemocompatibility properties.

Purpose of the Study:

• To develop a bilayered silk fibroin (SF) vascular graft with enhanced mechanical properties and hemocompatibility.
• To create a graft that supports blood vessel regeneration while minimizing adverse effects.

Main Methods:

• Fabrication of a bilayered graft with an inner silk fiber-reinforced SF tube containing heparin and a porous outer SF layer.
• Incorporation of heparin for sustained release and lyophilization for creating a nanofibrous outer layer.
• In vitro assessment of mechanical strength, burst pressure, suture retention, mechanical compliance, cytocompatibility, and hemocompatibility.

Main Results:

• The fiber-reinforced SF tube demonstrated comparable or superior mechanical strength, burst pressure, and suture retention compared to saphenous veins.
• Sustained heparin release for over 1 month improved blood compatibility.
• The porous outer layer, resembling extracellular matrix, facilitated cell growth.
• In vitro studies confirmed good cytocompatibility and hemocompatibility.

Conclusions:

• The developed bilayered silk fibroin vascular graft offers promising mechanical and hemocompatibility properties for tissue engineering.
• The combination of fiber reinforcement, heparin incorporation, and a porous outer layer addresses key challenges in vascular graft development.
• This novel graft design shows potential for successful blood vessel regeneration and clinical application.