The Effect of Cross-Linking Agents and Collagen Concentrations on Properties of Collagen Scaffolds

Background: Collagen-based scaffolds are appealing products for various applications in pharmaceutics and tissue engineering and military applications like wound healing. Objectives: This study was conducted to extract acid soluble collagen protein from calf skin tissue and cross-linked it using cross-linking agents. The collagen scaffolds with different 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) / N-hydroxysuccinimide (NHS) molar ratios as cross-linking agents were investigated. Methods: The type I extracted collagen was used as a raw material for making collagen based scaffolds. Different EDC/NHS molar ratios as cross-linking agents were used. Matrix morphology and mechanical strength of the scaffolds were determined to evaluate the physicochemical properties of the collagen matrices with different cross-linker molar ratios. Furthermore collagen and cross-linked collagen were characterized using standard methods like SDS- page, FT-IR and SEM analysis. Results: The results confirmed that the extracted collagen is pure and free of any non-collagen protein contamination. Furthermore, the results showed that average pore size of the scaffolds from EDC/NHS cross-linker with molar ratio of 1:1 (I) was less than the scaffolds that were made using EDC/NHS cross-linker with molar ratio of 2:1 (II). Moreover, collagen samples that were cross-linked using 1:1 EDC/NHS molar ratios showed increased mechanical strength comparing to 2:1 EDC/NHS molar ratio. Conclusions: The applied protocol is a convenient method for extraction of collagen and obtaining pure calf skin collage type I. Furthermore the best molar ratio of EDC/NHS cross-linking agents to cross-link collagen is 1:1 for obtaining stronger collagen structure.