An improvement of silk-based scaffold properties using collagen type I for skin tissue engineering applications

Silk has been intensively studied for tissue engineering applications owning to its advantages of biodegradability, tunable mechanical properties, versatile processing, and biocompatibility. Silk, however, has few cell signaling domains, so silk alone might not be sufficient to use as the scaffolds for tissue engineering. Here, we demonstrated the improvement of silk scaffold properties by the incorporation of type I collagen [Col; 0, 3.61, 7.69, 14.89, and 50% (w/w)] into silk-based scaffolds. The morphology and properties, including biocompatibility, of the scaffolds were then investigated. Notably, moderate amounts of Col (7.69 and 14.89%) improved fibroblast attachment and supported proliferation on the scaffolds compared to those of silk alone. Both 7.69 and 14.89% Col scaffolds exhibited more organized and smaller pore sizes (144.09 ± 25.97 and 140.67 ± 38.28 μm in diameter, respectively) with thinner walls compared to higher silk content (0 and 3.61% Col) scaffolds. The 7.69 and 14.89% Col also improved the scaffold stability over 21 days, whereas silk alone scaffolds dramatically lost their weight by day 21. The incorporation of collagen also increased water adsorption ability of the scaffolds. Therefore, this study demonstrated the effects of type I collagen toward improving the properties of silk-based scaffolds.